what is a wandering pacemaker rhythm

Ectopic Supraventricular Arrhythmias

Various rhythms result from supraventricular foci (usually in the atria). Diagnosis is by electrocardiography. Many are asymptomatic and require no treatment.

(See also Overview of Arrhythmias .)

Ectopic supraventricular rhythms include

Atrial premature beats

Atrial tachycardia, multifocal atrial tachycardia, nonparoxysmal junctional tachycardia, wandering atrial pacemaker.

Atrial premature beats (APB), or premature atrial contractions (PAC), are common episodic impulses. They may occur in normal hearts with or without precipitating factors (eg, coffee, tea, alcohol, pseudoephedrine ) or may be a sign of a cardiopulmonary disorder. They are common in patients with chronic obstructive pulmonary disease (COPD). They occasionally cause palpitations.

Diagnosis is by electrocardiography (ECG—see figure Atrial premature beat ).

Atrial premature beat (APB)

Image courtesy of L. Brent Mitchell, MD.

APBs may be normally, aberrantly, or not conducted and are usually followed by a noncompensatory pause. Aberrantly conducted APBs (usually with right bundle branch block morphology) must be distinguished from premature beats of ventricular origin.

Atrial escape beats are ectopic atrial beats that emerge after long sinus pauses or sinus arrest. They may be single or multiple; escape beats from a single focus may produce a continuous rhythm (called ectopic atrial rhythm). Heart rate is typically slower, P wave morphology is typically different, and PR interval is slightly shorter than in sinus rhythm.

Atrial tachycardia is a regular rhythm caused by the consistent, rapid atrial activation from a single atrial focus. Heart rate is usually 150 to 200 beats/minute; however, with a very rapid atrial rate, nodal dysfunction, and/or digitalis toxicity, atrioventricular (AV) block may be present, and ventricular rate may be slower. Mechanisms include enhanced atrial automaticity and intra-atrial reentry.

Atrial tachycardia is the least common form (5%) of paroxysmal supraventricular tachycardia and usually occurs in patients with a structural heart disorder. Other causes include atrial irritation (eg, pericarditis

Symptoms are those of other tachycardias (eg, light-headedness, dizziness, palpitations, and rarely syncope).

Diagnosis is by electrocardiography (ECG); P waves, which differ in morphology from normal sinus P waves, precede QRS complexes but may be hidden within the preceding T wave (see figure True atrial tachycardia ).

True atrial tachycardia

Vagal maneuvers may be used to slow the heart rate, allowing visualization of P waves when they are hidden, but these maneuvers do not usually terminate the arrhythmia (demonstrating that the AV node is not an obligate part of the arrhythmia circuit).

Treatment involves managing causes and slowing ventricular response rate using a beta-blocker or calcium channel blocker. An episode may be terminated by direct current cardioversion . Pharmacologic approaches to termination and prevention of atrial tachycardia include antiarrhythmic drugs in class Ia, Ic, or III. If these noninvasive measures are ineffective, alternatives include overdrive pacing and ablation .

Multifocal atrial tachycardia (chaotic atrial tachycardia) is an irregularly irregular rhythm caused by the random discharge of multiple ectopic atrial foci. By definition, heart rate is > 100 beats/minute. On ECG, P-wave morphology differs from beat to beat, and there are ≥ 3 distinct P-wave morphologies. The presence of P waves distinguishes multifocal atrial tachycardia from atrial fibrillation . Except for the rate, features are the same as those of wandering atrial pacemaker. Symptoms, when they occur, are those of rapid tachycardia. Multifocal atrial tachycardia can be due to an underlying pulmonary disorder such as chronic obstructive pulmonary disease coronary artery disease , and electrolyte abnormalities such as hypokalemia . Treatment is directed at the underlying disorder.

Nonparoxysmal junctional tachycardia is caused by abnormal automaticity in the AV node or adjacent tissue, which typically follows open heart surgery, acute inferior myocardial infarction, myocarditis, or digitalis toxicity. Heart rate is 60 to 120 beats/minute; thus, symptoms are usually absent. ECG shows regular, normal-appearing QRS complexes without identifiable P waves or with retrograde P waves (inverted in the inferior leads) that occur shortly before ( < 0.1 second) or after the QRS complex. The rhythm is distinguished from paroxysmal supraventricular tachycardia by the lower heart rate and gradual onset and offset. Treatment is directed at causes.

Wandering atrial pacemaker (multifocal atrial rhythm) is an irregularly irregular rhythm caused by the random discharge of multiple ectopic atrial foci. By definition, heart rate is ≤ 100 beats/minute. Except for the rate, features are the same as those of multifocal atrial tachycardia. Treatment is directed at causes.

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Wandering Atrial Pacemaker

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ESSENTIALS OF DIAGNOSIS

Progressive cyclic variation in P-wave morphology

Heart rate 60–100 bpm

Variation of P-wave morphology, P-P interval, and P-R interval

GENERAL CONSIDERATIONS

This rhythm is benign

This rhythm and multifocal atrial tachycardia are similar except for heart rate

The other possible explanation is that there is significant respiratory sinus arrhythmia, with uncovering of latent foci of pacemaker activity

Usually, it is associated with underlying lung disease

In the elderly, it may be a manifestation of sick sinus syndrome

In the young and athletic heart, it may represent enhanced vagal tone

SYMPTOMS AND SIGNS

Usually causes no symptoms and is incidentally discovered

Occasional patient may feel skipped beats

PHYSICAL EXAM FINDINGS

Variable S 1

DIFFERENTIAL DIAGNOSIS

Multifocal atrial tachycardia (heart rate > 100 bpm)

Frequent premature atrial complexes and atrial bigeminy

LABORATORY TESTS

None specific

ELECTROCARDIOGRAPHY

ECG to document rhythm

CARDIOLOGY REFERRAL

Not required

MEDICATIONS

No specific treatment

Monitor and treat the underlying cause, such as sick sinus syndrome or lung disease

DIET AND ACTIVITY

No restrictions

General healthy lifestyle

Once a year if sinus node abnormality is suspected; otherwise when symptoms arise

COMPLICATIONS

May progress to sick sinus syndrome

This condition by itself is benign

PRACTICE GUIDELINES

Indications for pacemaker:

– If part of sick sinus syndrome

– If associated with documented symptomatic bradycardia

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Wandering Atrial Pacemaker ECG Interpretation #312

Description.

• Rhythms are often named according to the origin of the electrical activity in the heart or the structure where the problem is occurring.
• Wandering Atrial Pacemaker is aptly named due to the electrical impulses causing the atrial activity are moving or wandering.
• These changes in the locus of stimulation affect the morphology of the P waves.
• In Wandering Atrial Pacemaker ECG, you must observe at least three different shaped P waves. No other changes in the tracing may be observed. The rhythm may or may not be regular.
• The PR interval is often affected, but does not have to be.
• The bottom line, is you must observe at least three different shaped P waves.

Practice Strip

Analyze this tracing using the five steps of rhythm analysis.

• Rhythm: Irregular
• P wave: Changing Shapes (3 or more)
• PR interval: Variable
• Interpretation: Wandering Atrial Pacemaker

Authors and Reviewers

• ECG heart rhythm modules: Thomas O'Brien.
• ECG monitor simulation developer: Steve Collmann
• 12 Lead Course: Dr. Michael Mazzini, MD .
• Spanish language ECG: Breena R. Taira, MD, MPH
• Medical review: Dr. Jonathan Keroes, MD
• Medical review: Dr. Pedro Azevedo, MD, Cardiology
• Last Update: 11/8/2021
• Electrocardiography for Healthcare Professionals, 6th Edition Kathryn Booth and Thomas O'Brien ISBN10: 1265013470, ISBN13: 9781265013479 McGraw Hill, 2023
• Rapid Interpretation of EKG's, Sixth Edition Dale Dublin Cover Publishing Company
• EKG Reference Guide EKG.Academy
• 12 Lead EKG for Nurses: Simple Steps to Interpret Rhythms, Arrhythmias, Blocks, Hypertrophy, Infarcts, & Cardiac Drugs Aaron Reed Create Space Independent Publishing
• Heart Sounds and Murmurs: A Practical Guide with Audio CD-ROM 3rd Edition Elsevier-Health Sciences Division Barbara A. Erickson, PhD, RN, CCRN
• The Virtual Cardiac Patient: A Multimedia Guide to Heart Sounds, Murmurs, EKG Jonathan Keroes, David Lieberman Publisher: Lippincott Williams & Wilkin) ISBN-10: 0781784425; ISBN-13: 978-0781784429
• Project Semilla, UCLA Emergency Medicine, EKG Training Breena R. Taira, MD, MPH
• ECG Reference Guide PracticalClinicalSkills.com

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The Wandering Atrial Pacemaker

Complete heart block with no av dissociation, ventricular pacing minimisation algorithms, exotic ventricular ectopy part one, rarely reported case of non-conducted focal atrial tachycardia.

Today, it is unusual to see an electrocardiograph (ECG) with the diagnosis of Wandering Atrial Pacemaker , but when we do, it is often incorrect. The last one I saw was a marked sinus arrhythmia with unifocal atrial ectopics and it is important to differentiate these two diagnoses as the treatment and prognosis are very different.

Wandering atrial pacemaker, as the name implies, is an irregular ECG rhythm which wanders from sinus to at least two other different atrial ectopic foci resulting in P waves with three different morphologies.

Here is an example:

The rate is slow and there are two atrial ectopic foci: crista terminalis (looks like the sinus P wave), low atrial (inverted P waves), and not surprisingly, atrial fusion beats with maybe more than one P wave morphology. Clearly, the atrium is very irritable, and therefore the rhythm is a precursor to atrial fibrillation. The term chaotic atrial mechanism is also used. Most examples of this rhythm are difficult to diagnose because the rhythm is faster than 100 bpm and hence is called multifocal atrial tachycardia .

It is easy to see how this rhythm can be confused with atrial fibrillation with an uncontrolled ventricular response. Indeed, an ECG performed soon after this Holter monitor recording showed atrial fibrillation, confirming the transient appearance and thus rarity of this rhythm.

In the past this ECG was seen with severe cor pulmonale, cyanosis and right heart disease. The uncontrolled atrial fibrillation in such a sick patient was often a terminal event.

Dr Harry Mond

About Assoc Prof Harry Mond

In 49+ years as a practicing cardiologist, Dr Harry Mond has published 260+ published manuscripts & books. A co-founder of CardioScan, he remains Medical Director and oversees 500K+ heart studies each year.

Download his full profile here.

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Wandering Pacemaker

When several pacemakers are competing, p-waves with different origins and thus configurations occur. The rhythm is slightly different from beat to beat.

note If the heart rate increases to above 100bpm, it is called Multifocal Atrial Tachycardia . Possible causes are hypoxia, COPD and medication such as digoxin.

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• v.13(9); 2021 Sep

Electrical Injury and Wandering Atrial Pacemaker

Ranjan k singh.

1 Internal Medicine, Anti-Retroviral Therapy Centre, District Hospital, Khagaria, IND

The supply of household electricity remains a low-voltage (110-220 V) energy source, and its effects on the human body depend on several factors, including the type of contact and duration of contact, among other things. In a significant number of cases, direct contact with household electricity causes reversible cardiac arrhythmia-ventricular fibrillation, ventricular premature beats, atrial tachycardia, and atrial fibrillation.

Wandering atrial pacemaker (WAP) is a benign atrial arrhythmia observed in elderly patients suffering from obstructive pulmonary diseases that result from an ischemic heart. This report discusses WAP as observed in a patient who suffered an electrical injury.

Introduction

The effects of electrical injury vary from skin burn to internal organ damage directed especially at the cardiovascular and nervous systems. The extent of electrical injury depends on the type of electricity source, i.e., direct current (DC) or alternating current (AC), the duration of contact with the source of electricity, the state of the body whether wet or dry, the presence of calluses over the palm, the route of electrical flow, and the level of voltage [ 1 ]. The severity of an electric shock depends on the current flow (I) measured in ampere (A). It is linked to the resistance of the conductor (R, unit: ohm ‘W’) and the potential difference between the two ends of a conductor (Volt; unit V), and is derived by applying the formula based on Ohm’s law: i.e., I = V/R. The severity of an electrical burn, by contrast, depends on the energy (Watt) and is derived from Joule’s formula W=I2 x R x T (duration of exposure with the source of current).

Household electrical supply is a low-voltage (220 V) AC at 60 Hz frequency. The physiological effects of contact with a low-frequency AC (60 Hz) current vary at different amperes. For example, 1mA (1/1000 A) is barely perceptible as numbness, whereas 20 mA can cause respiratory muscle paralysis, while 100 mA reaches a threshold for ventricular fibrillation [ 1 , 2 ]. The resulting cardiac arrhythmia may take the form of ventricular fibrillation, ventricular tachycardia, ventricular premature beats, atrial premature beats, atrial arrhythmia, and/or heart block [ 2 ].

Case presentation

A 40-year-old male patient was brought into the emergency ward after suffering an accidental electrical injury that involved an entry wound in the middle of his left hand and an exit wound in the back of his chest. He was holding the hanging rod for a ceiling fan when the connection was plugged in, resulting in electric shock. He lost consciousness and fell to the ground with the rod clenched in his hand for a minute and a half. The electricity source was disconnected and cardiopulmonary resuscitation was administered to the patient by his neighbors. The patient regained consciousness and complained of aching all over the body along with general weakness. 

He had a black hole in the middle of his left palm (Figure ​ (Figure1A) 1A ) and a linear burn on the back of his chest (Figure ​ (Figure1B 1B ).

His pulse was irregularly irregular at 78/minute, and his blood pressure was 110/78 mm Hg. His total leucocyte count was 8600/cmm with neutrophils at 64%, and his hemoglobin was 13 gm/dL. Urinalysis did not show myoglobin. Serum sodium and potassium were 134 mEq/L and 4.2 mEq/L, respectively. Electrocardiography (ECG) showed occasional ventricular premature beat with wandering atrial pacemaker (Figures ​ (Figures2A 2A - ​ -2B). 2B ). Of note, the patient did not have any kind of cardiac ailment previously. The patient was hydrated with intravenous fluids and his wounds were treated with antiseptic dressings and antibiotics. He remained under observation for 48 hours and the ECG showed sinus rhythm (Figure ​ (Figure2C 2C ).

Low voltage currents cause severe electrical burns to the skin as a result of high energy output from the current flow. Dry skin with callouses over palm (resistance of 500 W) and a long contact of palm with the source of electricity attribute to severe burn in this patient (Joule formula). Thereby, the electrical energy output is dissipated and there is less internal injury [ 3 , 4 ].

Low voltage currents travel through the body along low-resistance pathway nerves and blood vessels to cause severe cardiac injury. Also, the distance between the entry and exit wounds can determine the severity of the cardiac injury. The heart remains in the central location of the electrical current’s pathway between the left palm and back of the chest. Current spikes occur in the palm and fingers of an individual holding a metal rod that is suddenly connected to an electric source [ 5 ]. The electric shock causes depolarisation of cardiac muscles and increases membrane pores of the cells resulting in arrhythmias; sinus tachycardia, ventricular premature beats, ventricular tachycardia, and atrial fibrillation are common [ 6 , 7 ]. Wandering atrial pacemaker (WAP) is a benign atrial arrhythmia that has been observed in this case study. WAP and multifocal atrial tachycardia (MAT) differ only with the heart rate - WAP has a heart rate less than 100 bpm whereas MAT has a heart rate greater than 100 bpm. In the WAP rhythm, the pacemaker wanders with the impulses originating from the sinoatrial node to the atrium, and to the atrioventricular junction with a changing focus. Hence, the P waves on an ECG are presented in different configurations. WAP is differentiated from sinus arrhythmia by the fact that heart rate variability occurs from beat-to-beat, and is not phasic. Also, in sinus arrhythmia, the P-wave morphology and the P-R interval are constant [ 7 ]. Most of the arrhythmias occur soon after electric shock and are short-lived. However, delayed arrhythmias occurring 12 hours after electric shock have been reported, too [ 8 ].

Conclusions

Household electric supply is low voltage AC of 60 Hz. It is the electric current that determines the pathophysiological effects in the body but the voltage does determine the outcome of electric shock. Even a low-voltage shock can cause ventricular fibrillation if resistance is low and current flow reaches a threshold of 100 mA. The severity of burn lesion is determined by the resistance of skin and duration of exposure with the source of current. Most cardiac arrhythmias are short-lived and do not require treatment.

The content published in Cureus is the result of clinical experience and/or research by independent individuals or organizations. Cureus is not responsible for the scientific accuracy or reliability of data or conclusions published herein. All content published within Cureus is intended only for educational, research and reference purposes. Additionally, articles published within Cureus should not be deemed a suitable substitute for the advice of a qualified health care professional. Do not disregard or avoid professional medical advice due to content published within Cureus.

The authors have declared that no competing interests exist.

Human Ethics

Consent was obtained or waived by all participants in this study. NA issued approval NA. This is a case report.

Thursday, March 4, 2021

Blog #200 — wandering pacemaker (vs mat).

There is no clinical information is available for the ECG and 2-lead rhythm strip shown below in  Figure-1 .

• HOW would you interpret this tracing?
• What treatment is likely to be needed? 

====================================

Editorial  Comment:

It is always challenging to interpret tracings without the benefit of clinical information. That said — this situation is common in clinical practice. My experience in this area derives from the 30 years during which I was charged with interpreting  all  ECGs ordered by 35 medical providers at a primary care clinic — as well periodic stints during which I interpreted hospital tracings without the benefit of any history. 

• The challenge lies with having to decide  which  tracings in the  “pile of ECGs to be interpreted”  were those for which I needed to pull the medical chart ( or call the provider ) because of ECG findings of immediate potential concern.
• Obvious time constraints made it impossible to pull the chart for each ECG that I was given to read ( I’d never get anything else done if I did so ).
• I therefore became well versed in the skill of limiting the charts that I would pull to those patients whose ECGs showed findings I thought were important  and  potentially indicative of an acute situation that may have been overlooked.

=====================================

MY Thoughts  on the ECG in Figure-1:

As always — systematic interpretation of  any  ECG should begin with assessing the cardiac rhythm. In general —  lead II  and  lead V1  are the 2  best  leads on a 12-lead tracing for assessing atrial activity — and we have the advantage in  Figure-1  of a  simultaneously-recorded  2-lead rhythm strip of both of these leads.  By the  Ps ,  Qs and  3R Approach:

• The rhythm in  Figure-1  is  clearly   irregular .
• The  QRS  complex is  narrow ( ie,  not  more than half a large box in duration = ≤0.10 second ) . 
• The rate  varies  from  50 /minute — to just under  100 /minute.
• More than 1 P wave morphology is present . That said — P waves  do  appear to be related to neighboring QRS complexes, because the PR interval for the P wave shapes that we see remains constant  ( See   Figure-2 ) .

MY Thoughts  on Figure-2:

There are 2 different P wave shapes in  Figure-2 .

• The tracing begins with  3  sinus  beats ( ie,  RED arrows highlight 3 similar-looking upright-in-lead-II P waves — all with the same PR interval ) .
• P wave shape then changes  for beats #4, 5 and 6  ( ie,  BLUE arrows highlighting an almost isoelectric, if not negative P wave with fixed PR interval ) .
• The atrial focus then shifts back , with return to sinus P waves for beats #7, 8, 9 and 10 (ie,  return of RED arrows highlighting similar-looking, upright P waves in lead II — albeit with variability in the R-R interval ).
• The rhythm in  Figure-2  concludes with a  slowing-down  of the ventricular rate, as  the 2nd atrial focus returns , in which the P wave is almost isoelectric (ie,  BLUE arrows for beats #11 and 12 ).

BOTTOM LINE  regarding  Figure-1:  The rhythm in  Figure-2  is most consistent with a  Wandering  Atrial  Pacemaker . This is because the change from one atrial site to the next occurs gradually over a period of several beats.

• PEARL:  The reason it is uncommon ( if not rare ) in clinical practice to see a wandering atrial pacemaker — is that most providers do not pay  long enough  attention to  beat-to-beat  change in P wave morphology needed to identify  gradual  shift between  at least  3 different atrial sites.

SUMMARY:  Review of the  KEY  features of wandering atrial pacemaker is the theme below for our  ECG  Media  Pearl #17 ( a 3:30 minute audio recording ).

• Written review of wandering pacemaker appears below in  Figure-3 .
• Review of  MAT  is covered in our  ECG Blog #199 .

Today’s   E CG  M edia   P EARL  # 17 ( 3:30 minutes   Audio )  —   What is a  Wandering  Atrial Pacemaker ( as opposed to MAT )?

A DDENDUM   ( 3/4/2021 ) :

I received the following note from  David Richley  regarding today’s tracing: “I think I would use different terminology to describe this because to me the atrial pacemaker doesn’t so much ‘wander’ as ‘jump’. I would describe this as sinus arrhythmia with junctional escape rhythm at 60-65/minute every time the sinus node discharge rate slows to below that rate. I interpret the escape beats as junctional rather than atrial, because athough the P waves, ( which are initially negative in II, aVF and V4-V6 — and positive in aVR ) precede the QRS — the PR segment is very short, suggesting an AV nodal origin. However, we describe this phenomenon — I do agree that it’s likely to be completely benign.

MY Thoughts:  Dave’s comment is one of the reasons why:  i )  The diagnosis of wandering pacemaker requires clear demonstration of shift in the atrial pacemaker in  at least  3 different sites. We  only  see 2 different sites here;  and ,  ii )  The diagnosis of wandering atrial pacemaker is  not  common. 

• It’s impossible to rule out Dave’s theory from the single tracing we have.
• That said — the BLUE arrow P wave site may or may not be of AV nodal origin ( you can see a similar, near-isoelectric P wave with short PR interval from a low atrial site ).
• I also considered the possibility of the BLUE arrow P waves representing junctional escape — but decided against it because the difference in R-R interval from what we see between beats #9-10  vs  what we see between beats #10-11 is  more  than what I’d expect based on the cadence of rate variation I see from beats #7-10.
• Bottom Line:  We both agree there is a shift in the pacemaker site in a rhythm that is likely to be benign. And, we both agree that additional monitoring would be needed for a definitive response.  THANK YOU Dave!

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• Wandering atrial pacemaker
• 2 Clinical Features
• 3.1 Palpitations
• 4.2 Diagnosis
• 5 Management
• 6 Disposition
• 8 External Links
• 9 References
• Three or more ectopic foci within the atrial myocardium serve as the pacemaker
• Rate is less than 100bpm (in contrast to MAT )
• Is irregularly irregular therefore sometimes confused with atrial fibrillation and sinus arrhythmia
• Intrinsic cardiac or pulmonary disease
• Metabolic derangements
• Drug toxicity (including Digoxin )

Clinical Features

• Often seen in the extremes of age and in athletes
• Rarely causes symptoms

Differential Diagnosis

Palpitations.

• Narrow-complex tachycardias
• Wide-complex tachycardias
• Second Degree AV Block Type I (Wenckeback)
• Second Degree AV Block Type II
• Third Degree AV Block
• Premature atrial contraction
• Premature junctional contraction
• Premature ventricular contraction
• Sick sinus syndrome
• Acute coronary syndrome
• Cardiomyopathy
• Congenital heart disease
• Congestive heart failure (CHF)
• Mitral valve prolapse
• Pacemaker complication
• Pericarditis
• Myocarditis
• Valvular disease
• Panic attack
• Somatic Symptom Disorder
• Drugs of abuse (e.g. cocaine )
• Medications (e.g. digoxin , theophylline )
• Thyroid storm
• Pulmonary embolism
• Dehydration
• Pheochromocytoma

• ECG should show three distinct P wave morphologies with a ventricular rate <100bpm
• Rarely requires treatment

Disposition

• Outpatient management
• Multifocal atrial tachycardia
• Dysrhythmia

External Links

• Richard Cunningham
• fardis tavangary
• Ross Donaldson
• Privacy policy
• Disclaimers

Introduction to Atrial Rhythms

This page provides an introduction to atrial rhythms and links to our EKG interpretation courses and drills.

Atrial rhythms originate in the atria rather than in the SA node. The P wave will be positive, but its shape can be different from a normal sinus rhythm because the electrical impulse follows a different path to the AV (atrioventricular) node. These EKG differences are covered on our atrial rhythms training module as well as in practice strips which are available via a link in the right column. Atrial rhythms are classified as:

• Atrial Fibrillation (afib)
• Atrial Flutter

Multifocal Atrial Tachycardia

Premature atrial complex, supraventricular tachycardia.

• Wandering Atrial Pacemaker

Wolff-Parkinson-White Syndrome

Atrial rhythm categories.

• Atrial Fibrillation

Irritable sites in the atria fire very rapidly, between 400-600 bpm. This very rapid pacemaking causes the atria to quiver. The ventricles beat at a slower rate due to the AV node's blocking some of the atrial impulses.

There are two types of atrial flutter. Type I (also called classical or typical) has a rate of 250-350 bpm. Type II (also called non-typical) are faster, ranging from 350-450 bpm. EKG tracings will show tightly spaced waves or saw-tooth waveforms (F-waves).

When multifocal atrial tachycardia occurs, multiple (non-SA) sites are firing impulses. The P waves will vary in shape and at least three different shapes can be observed. The PR Interval varies. Ventricular rhythm is irregular.

This occurs when an ectopic site within the atria fires an impulse before the next impulse from the SA node. If the ectopic site is near the SA node, the P wave will likely have a shape similar to a sinus rhythm. But this P wave will occur earlier than expected.

This term covers three types of tachycardia that originate in the atria, AV junction or SA node.

Wandering atrial pacemaker is an irregular rhythm. In is similar to multifocal atrial tachycardia but the heart rate is under 100 bpm. P waves are present but will vary in shape.

This occurs when the impulse travels between the atria and ventricles via an abnormal path, called the bundle of Kent. The impulse, not being delayed by the AV node, can cause the ventricles to contract prematurely. EKG characteristics include a shorter PR Interval, longer QRS complex and a delta wave.

Training Resources

Atrial rhythm training.

After a brief review of cardiac rhythm analysis, this module explains morphologic features and qualifying criteria of atrial rhythms.

Atrial Rhythms

EKG Rhythm Tests

Hundreds heart rhythms in this practice test. Test can be tailored for specific learning needs.

EKG Monitor Challenge

A quiz using a simulated patient monitor. Evaluate a scrolling waveform rather than a paper tracing.

Lesson #1: Rhythm Analysis Method 312

The five steps of rhythm analysis will be followed when analyzing any rhythm strip.

• Analyze each step in the following order.

Rhythm Regularity

• P wave morphology
• P R interval or PRi
• QRS complex duration and morphology
• Carefully measure from the tip of one R wave to the next, from the beginning to the end of the tracing.
• A rhythm is considered “regular or constant” when the distance apart is either the same or varies by 1 ½ small boxes or less from one R wave to the next R wave.

Heart Rate Regular (Constant) Rhythms

• The heart rate determination technique used will be the 1500 technique.
• Starting at the beginning of the tracing through the end, measure from one R wave to the next R wave (ventricular assessment), then P wave to P wave (atrial assessment), then count the number of small boxes between each and divide that number into 1500. This technique will give you the most accurate heart rate when analyzing regular heart rhythms. You may include ½ of a small box i.e. 1500/37.5 = 40 bpm (don’t forget to round up or down if a portion of a beat is included in the answer).

Step 2 (Cont)

Heart rate - irregular rhythms.

• If the rhythm varies by two small boxes or more, the rhythm is considered “irregular”.
• The heart rate determination technique used for irregular rhythms will be the “six-second technique”.
• Simply count the number of cardiac complexes in six seconds and multiply by ten.

P wave Morphology (shape)

• Lead II is most commonly referenced in cardiac monitoring
• In this training module, lead two will specifically be referenced unless otherwise specified.
• The P wave in lead II in a normal heart is typically rounded and upright in appearance.
• Changes in shape must be reported. This can be an indicator that the locus of stimulation is changing or the pathway taken is changing.
• P waves may come in a variety of morphologies i.e. rounded and upright, peaked, flattened, notched, biphasic(pictured), inverted and even buried or absent!
• Remember to describe the shape. This can be very important to the physician when diagnosing the patient.

PR interval (PRi)

• Measurement of the PR interval reflects the amount of time from the beginning of atrial depolarization to the beginning of ventricular depolarization.
• Plainly stated, this measurement is from the beginning of the P wave to the beginning of the QRS complex.
• The normal range for PR interval is: 0.12 – 0.20 seconds (3 to 5 small boxes)
• It is important that you measure each PR interval on the rhythm strip.
• Some tracings do not have the same PRi measurement from one cardiac complex to the next. Sometimes there is a prolonging pattern, sometimes not.
• If the PR intervals are variable, report them as variable, but note if a pattern is present or not.

QRS complex

• QRS represents ventricular depolarization.
• It is very important to analyze each QRS complex on the tracing and report the duration measurement and describe the shape (including any changes in shape).
• As discussed in step 3, when referring to P waves, remember changes in the shape of the waveform can indicate the locus of stimulation has changed or a different conduction pathway was followed. It is no different when analyzing the QRS complex. The difference is that in step 3, we were looking at atrial activity. Now we are looking at ventricular activity.
• Measure from the beginning to the end of ventricular depolarization.
• The normal duration of the QRS complex is: 0.06 – 0.10 second

Lesson #2: Interpretation 312

Introduction.

• The previous slides presented the five-steps of rhythm analysis. These five steps must be followed regardless of how simple of complex the tracing is you are reviewing.
• The information gathered in these steps are telling a story.
• The title of that story is the interpretation.

Atrial Dysrhythmias Types

The dysrhythmias in this category occur as a result of problems in the atria. These atrial dysrhythmias primarily affect the P wave. We will be discussing the following complexes and rhythms:

• Premature Atrial Complexes (PAC’s)

Lesson #3: Premature Atrial Complex

Intro to pacs.

• PACs can occur for a number of different reasons i.e., diet, fatigue, stress, disease, ischemia to name a few.
• Premature complexes frequently occur in bradycardic rhythms, but may occur almost any time.
• PACs occur when an early electrical impulse occurs from a location in the atria other than the SA node.

Intro to PACs 2

• This early impulse causes an early cardiac complex which disrupts the underlying rhythm.
• The locus of stimulation being different, results in a change in the morphology of the P wave.
• PACs can occur occasionally or frequently.
• PACs ECG can be observed with or without a pattern
• The P wave with PAC's will always be upright

EKG Analysis

Notice the following: the R to R interval is irregular, the fifth complex is early and the P wave on the early complex is a different shape.

EKG Practice Strip

Analyze this tracing using the five steps of rhythm analysis.

• Rhythm: Irregular
• P wave: Upright & uniform (except early complexes - biphasic)
• PR interval: 0.16 second
• Interpretation: Sinus Bradycardia with PACs

Lesson #4: Wandering Atrial Pacemaker

Description.

• Rhythms are often named according to the origin of the electrical activity in the heart or the structure where the problem is occurring.
• Wandering Atrial Pacemaker is aptly named due to the electrical impulses causing the atrial activity are moving or wandering.
• These changes in the locus of stimulation affect the morphology of the P waves.
• In Wandering Atrial Pacemaker ECG, you must observe at least three different shaped P waves. No other changes in the tracing may be observed. The rhythm may or may not be regular.
• The PR interval is often affected, but does not have to be.
• The bottom line, is you must observe at least three different shaped P waves.

Practice Strip

• P wave: Changing Shapes (3 or more)
• PR interval: Variable
• Interpretation: Wandering Atrial Pacemaker

Lesson #5: Multifocal Atrial Tachycardia

• Multifocal Atrial Tachycardia is just a faster version of Wandering Atrial Pacemaker. The criteria is the same as Wandering Atrial Pacemaker with the only difference being the heart rate exceeds 100 bpm.
• These changes in the locus of stimulation within the atria affect the morphology of the P waves.
• Remember, you must observe at least three different shaped P waves.
• Due to the presence of irregular R to R intervals coupled with the changing P wave morphology, some people have confused this rhythm with Atrial Fibrillation.

Lesson #6: Atrial Flutter

• Atrial Flutter (sometimes called a flutter) occurs when there is an obstruction within the atrial electrical conduction system.
• Due to this impediment a series of rapid depolarizations occur.
• These depolarizations may occur two, three, four or more times per QRS complex.
• The AV node functions like a “gatekeeper” blocking the extra impulses until the ventricular conduction system is able to accept the impulse.
• The impulse that is accepted will cause the QRS complex to occur.
• Each atrial flutter ECG wave represents atrial depolarization. This will be noted next to the P wave step in rhythm analysis. Instead of P waves, this tracing has “F” waves. No P waves mean there is no PR interval measurement.
• When the tracing is interpreted, the ratio of F waves to each QRS complex will be documented along with the rhythm i.e. Atrial Flutter 4:1 (indicates 4 “F” waves to each QRS complex). Not all Atrial Flutter rhythm strips will have a regular rhythm. In that case just document and report your observations.
• Compare your answers with the answers on the next slide.

Practice Strip Answers

• Rhythm: Regular
• Rate: Ventricles - 80, Atria - 320
• P wave: "F" waves
• PR interval: absent
• Interpretation: Atrial Flutter 4:1

Lesson #7: Atrial Fibrillation

• Atrial Fibrillation (afeb) occurs when multiple electrical impulses occur within the atria. This chaotic electrical activity results in a chaotic wave form between the QRS complexes. P waves are absent. They are replaced by lower case "f" waves. No P waves means there is no PR interval measurement.
• This rapid electrical activity overwhelms the AV node causing impulses to enter the ventricular conduction system at irregular points. This results in irregular R to R intervals.
• Not all fibrillatory waves are created equal. The "f" waves can be coarse (majority measure 3 mm or more) or can be fine (majority of waveforms measure less than 3 mm) to almost absent. Regardless always report your observations. Many times when a patient has "new onset" Atrial Fibrillation the patient will report with a heart rate of 160 bpm or more.
• When a patient experiences A-fib, the atria are not contracting as they normally would. They are just quivering. This absence of contraction of the atria can result in a loss of cardiac output anywhere from 15 - 30% due to the absence of "atrial kick". This is why the heart rate is so high. The body is trying to maintain homeostasis.
• It will be impossible to determine the atrial rate. You will only be able to analyze and report the ventricular rate.
• Atrial Fibrillation with a ventricular response in excess of 100 bpm is commonly referred to as Atrial Fibrillation with “rapid ventricular response” or "uncontrolled A-fib".
• Rate: Ventricles - 90, Atria - Unable to determine (UTD)
• P wave: "f" waves
• Interpretation: Atrial Fibrillation

Lesson #8: Quiz Test Questions 312

Authors and reviewers.

• EKG heart rhythm modules: Thomas O'Brien
• Medical review: Dr. Jonathan Keroes, MD
• Medical review: Dr. Pedro Azevedo, MD, Cardiology
• Last Update: 11/8/2021
• Electrocardiography for Healthcare Professionals, 6th Edition Kathryn Booth and Thomas O'Brien ISBN10: 1265013470, ISBN13: 9781265013479 McGraw Hill, 2023
• Rapid Interpretation of EKG's, Sixth Edition Dale Dublin Cover Publishing Company
• EKG Reference Guide EKG.Academy
• 12 Lead EKG for Nurses: Simple Steps to Interpret Rhythms, Arrhythmias, Blocks, Hypertrophy, Infarcts, & Cardiac Drugs Aaron Reed Create Space Independent Publishing
• The Virtual Cardiac Patient: A Multimedia Guide to Heart Sounds, Murmurs, EKG Jonathan Keroes, David Lieberman Publisher: Lippincott Williams & Wilkin) ISBN-10: 0781784425; ISBN-13: 978-0781784429
• ECG Reference Guide PracticalClinicalSkills.com

This website is only for professional medical education. Contact your doctor for medical care. 2024 © MedEdu LLC. All Rights Reserved. Terms & Conditions | About Us | Privacy | Email Us

Multifocal Atrial Tachycardia (MAT)

• Ed Burns and Robert Buttner
• Jun 4, 2021

Multifocal Atrial Tachycardia (MAT) Overview

• A rapid, irregular atrial rhythm arising from multiple ectopic foci within the atria.
• Most commonly seen in patients with severe COPD  or congestive heart failure.
• It is typically a transitional rhythm between frequent premature atrial complexes (PACs) and atrial flutter / fibrillation.

AKA “Chaotic atrial tachycardia”

Electrocardiographic Features

• Heart rate > 100 bpm (usually 100-150 bpm; may be as high as 250 bpm).
• Irregularly irregular rhythm with varying PP, PR and RR intervals.
• At least 3 distinct P-wave morphologies in the same lead.
• Isoelectric baseline between P-waves (i.e. no flutter waves).
• Absence of a single dominant atrial pacemaker (i.e. not just sinus rhythm with frequent PACs).
• Some P waves may be nonconducted; others may be aberrantly conducted to the ventricles.

There may be additional electrocardiographic features suggestive of COPD.

Clinical Relevance

• Usually occurs in seriously ill elderly patients with respiratory failure (e.g. exacerbation of COPD / CHF).
• Tends to resolve following treatment of the underlying disorder.
• The development of MAT during an acute illness is a poor prognostic sign, associated with a 60% in-hospital mortality and mean survival of just over a year. Death occurs due to the underlying illness; not the arrhythmia itself.

Arises due to a combination of factors that are present in hospitalised patients with acute-on-chronic respiratory failure:

• Right atrial dilatation (from cor pulmonale )
• Increased sympathetic drive
• Hypoxia and hypercarbia
• Beta-agonists
• Theophylline
• Electrolyte abnormalities: Hypokalaemia and hypomagnesaemia  (e.g. secondary to diuretics / beta-agonists)

The net result is increased atrial automaticity.

ECG Examples

Multifocal atrial tachycardia:

• Rapid irregular rhythm > 100 bpm.
• At least 3 distinctive P-wave morphologies (arrows).

MAT with additional features of COPD :

• Rapid, irregular rhythm with multiple P-wave morphologies (best seen in the rhythm strip).
• Right axis deviation, dominant R wave in V1 and deep S wave in V6 suggest right ventricular hypertrophy due to cor pulmonale. 

Related Topics

• The ECG in COPD
• Right atrial enlargement (P pulmonale)
• Right ventricular hypertrophy

Advanced Reading

• Wiesbauer F, Kühn P. ECG Mastery: Yellow Belt online course. Understand ECG basics. Medmastery
• Wiesbauer F, Kühn P. ECG Mastery: Blue Belt online course : Become an ECG expert. Medmastery
• Kühn P, Houghton A. ECG Mastery: Black Belt Workshop . Advanced ECG interpretation. Medmastery
• Rawshani A. Clinical ECG Interpretation ECG Waves
• Smith SW. Dr Smith’s ECG blog .
• Zimmerman FH. ECG Core Curriculum . 2023
• Mattu A, Berberian J, Brady WJ. Emergency ECGs: Case-Based Review and Interpretations , 2022
• Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
• Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine . 1e, 2020
• Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care . 2e, 2019
• Hampton J, Adlam D. The ECG Made Practical 7e, 2019
• Kühn P, Lang C, Wiesbauer F. ECG Mastery: The Simplest Way to Learn the ECG . 2015
• Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
• Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
• Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004

LITFL Further Reading

• ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
• ECG A to Z by diagnosis – ECG interpretation in clinical context
• ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
• 100 ECG Quiz – Self-assessment tool for examination practice
• ECG Reference SITES and BOOKS – the best of the rest

ECG LIBRARY

Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

Robert Buttner

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library . Twitter: @rob_buttner

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Keeping the Rhythm: Insights into Pacemakers and Irregular Heartbeats

May 16, 2024

Arnold Schwarzenegger, the iconic 'Terminator' star and former California governor, recently joked that he's "a bit more of a machine" now that he's got a pacemaker keeping his heartbeat in check. It's a good reminder that even the toughest action heroes sometimes need a little extra support when it comes to their health. Electrophysiologist Jeffrey Fowler, MD , explains conditions where pacemakers may be beneficial and how they can help regulate heart rates.

How do I know if my heartbeat is irregular?

Overlake’s Electrophysiology Lab, or EP Lab, can diagnose and treat irregular heartbeats, also called arrhythmias. If an arrhythmia is confirmed, an electrophysiologist (heart rhythm specialist) will determine whether a medical or surgical method is needed. That may include medication, a procedure such as catheter ablation or a heart rhythm device, like a pacemaker.

Symptoms of serious arrhythmias include:

• Recurrent palpitations (a feeling of skipped heartbeats or fluttering).
• Pounding in your chest.
• Dizziness or feeling light-headed.
• Shortness of breath.
• Chest discomfort.
• Weakness or fatigue.

Why might I need a pacemaker?

An electrophysiologist may advise a pacemaker when your heart beats too slowly and this can't be fixed with other treatments. A pacemaker is a small device implanted in the chest to help you maintain a normal heart rate. Problems with the heart rhythm may mean your heart is not pumping enough blood to the body. If your heart rate is too slow, the blood is pumped too slowly. When the pacemaker detects that your heart rate is too slow, it sends a small electrical pulse to start or regulate your heartbeat.

You can feel confident that you will receive some of the nation’s best arrhythmia care at Overlake. We have an excellent track record of patient results, including fewer treatment complications, shorter hospital stays and lower hospital readmission rates than most other hospitals. Learn more >

Jeffrey Fowler, MD

Jeffrey Fowler, MD , is an award-winning cardiologist and electrophysiologist at  Overlake Clinics Cardiology .

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How do pacemakers and defibrillators work? A cardiologist explains how they interact with the electrical system of the heart

Y our heart’s job is to keep your pulse steady to pump blood throughout your body. Sometimes your heart rate is slower when you’re relaxing, and sometimes it’s faster when you’re exercising or stressed. If your heart’s ability to keep the beat starts to go awry, cardiac electrophysiologists like me look for outside help from an implantable device.

There are two common implantable devices for the heart: artificial pacemakers and defibrillators . Artificial pacemakers keep blood and oxygen flowing during times of stress. Defibrillators are devices that detect dangerously fast heart rates and deliver shocks like those used during cardiopulmonary resuscitation, also known as CPR, to restart the heart.

Understanding how these devices work requires appreciating how the heart’s electrical system works and the weak links that cause malfunctions.

The heart’s natural pacemaker system

Abnormally slow heart rates result from breakdowns in two principal areas of the heart.

First, the sinoatrial, or SA, node sets your “resting” heart rate, usually somewhere between 60 and 100 beats per minute. This is the base effort needed to circulate enough blood to sustain normal bodily function. Elevated levels of certain hormones circulating in the body, such as adrenaline and serotonin, can increase heart rate above resting levels .

Trained athletes frequently have a lower resting heart rate due to extra physical conditioning. Like any other muscle, the heart becomes stronger with training. Because their heart functions more efficiently, athletes require fewer heart beats overall to circulate blood.

The atrioventricular, or AV, node is the second key area of the heart’s electrical wiring. The atrioventricular node takes information about how fast the heart is beating from the sinoatrial node and relays it to the ventricles, the muscular portions of the heart that allow it to pump blood to the rest of the body.

When the atrioventricular node breaks down, the ventricles don’t receive the electrical signal from the sinoatrial node instructing them to “pump,” or create a heartbeat. This causes heart rate to become dangerously slow.

When heart rate is too slow

If resting heart rate is abnormally low or fails to increase with hormonal changes, pacemakers can help keep blood and oxygen circulating at a healthy rate.

Both the SA node and the AV node naturally slow with age , but sometimes this happens at an accelerated pace and leads to abnormally slow heart rates. Slow heart rates can also be caused by other diseases, including thyroid problems and Lyme disease . In these cases, slow rates are treatable without a pacemaker.

A common pacemaker system has a battery and two wires that can send and receive electrical signals. One wire rests near the sinoatrial node, and the second in one of the heart’s ventricles.

If the wire near the sinoatrial node doesn’t detect any electrical activity over a set time, the pacemaker’s battery will send an impulse to the ventricle to initiate an electrical signal. Within fractions of a second, the wire in the ventricle should detect that electrical activity. If an impulse is detected, this signifies that the AV node conducted the signal correctly to the rest of the heart, and the pacemaker does not activate. If the wire doesn’t receive this signal, the battery delivers an impulse through the wire directly to the ventricle, causing the muscle to contract and initiate a heartbeat.

The heart’s muscle will only contract in response to a pacemaker impulse if the muscle is otherwise healthy. Pacemakers do not keep patients alive if the heart shuts down, such as during a massive infection, blood clot or kidney failure. Pacemakers simply keep the heart rate in a comfortable range if the primary problem in the heart is electrical.

Doctors program a pacemaker’s software so the resting pulse doesn’t drop below a certain rate, commonly 50 to 60 beats per minute. If the resting rate is set at 60 beats per minute, the pacemaker will wait exactly one second before initiating an electrical pulse. The heart’s pulse rate can be higher than this number if the sinoatrial node initiates a heartbeat naturally. If the pacemaker detects activity from the sinoatrial node, it will reset its timer for another full second.

Modern pacemakers also contain sensors to predict whether the heart may benefit from a faster heart rate under certain circumstances. For example, pacemaker batteries contain accelerometers like those used in pedometers to detect if a person is in motion. If these sensors activate, the pacemaker can raise its minimum rate like how the heart would normally respond to exercise. Sensors can also detect if a person begins to breathe more quickly or if the heart begins to contract more powerfully, all signs normally associated with increases in heart rate.

When heart rate is too fast

Like pacemakers, a cardiac defibrillator comes with a battery and wires that record the heart’s rate. But instead of treating slow heart rates, defibrillators are programmed to detect fast heart rates, usually in the range of 200 beats per minute. Heart rates in this range are often caused by ventricular tachycardia or ventricular fibrillation , which are potentially lethal heart rhythms resulting from the lower chamber of the heart beating too quickly or quivering.

Certain people are at elevated risk for these types of rhythm disturbances. Many cases of “sudden death” in athletes and other young people are either suspected or proved to be related to ventricular fibrillation.

Defibrillators deliver internal shocks to the heart when their sensors detect either ventricular tachycardia or ventricular fibrillation. These shocks stop the heart for a fraction of a second to give the sinoatrial node a chance to resume its normal activity. These shocks can be painful , so doctors usually also prescribe medications or other procedures to help prevent needing the shocks in the first place.

A defibrillator is like a seatbelt: It is reassuring to have, but ideally it never needs to be deployed.

Beyond the surgery

Pacemakers and defibrillators do require some maintenance. Certain settings, such as how low the pacemaker will allow the pulse to go, can be adjusted over time . Doctors have computers that can communicate with the devices and alter their programming. Some devices use Bluetooth technology.

The battery cannot be recharged and must be replaced, generally after six to 10 years. Battery life depends on how frequently the heart requires the pacemaker to initiate heartbeats. Pacemaker wires occasionally need to be replaced if they fracture or if the insulation wears down after years of bending with each heartbeat. On rare occasions, pacemaker parts are recalled. Usually these parts do not require replacement but may require special attention . More frequent checkups of the electrical “health” of the devices are usually prescribed for early detection of any problems with battery life or wire failures.

Pacemakers and defibrillators are always changing, in part to keep up with medical and nonmedical technologies.

With cloud-based management systems that make medical information available to doctors in real time, security has become a major focus of modern pacemaker software. Other medical technologies such as MRIs can change how pacemakers and defibrillators work if not handled carefully – MRIs create electromagnetic impulses that cardiac devices can misinterpret as heartbeats . Modern devices are engineered with these factors in mind, but still require careful programming for these special circumstances.

When used correctly, pacemakers and defibrillators improve both quality of life and life expectancy. While teams of engineers design these small machines, they rely on doctors knowing who will benefit from this technology and how to program the software to best serve each specific patient and scenario.

This article is republished from The Conversation , >, a nonprofit, independent news organization bringing you facts and analysis to help you make sense of our complex world.

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5 Things to Know About Pacemakers

What it is, who needs one and how the device helps keep millions of older adults healthy.

Merle Myerson, M.D.,

Donna Lulay, a retired educator, had open-heart surgery in 2007 to replace her aortic valve due to a genetic heart valve defect, and in 2023 needed surgery to replace the valve again. The procedures were a success despite one not so uncommon complication: After the second surgery, her heartbeat was slower than it should be, putting her at risk for serious health complications.

Lulay, now 66, was told she needed a pacemaker to help regulate it.

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“I was so upset,” says Lulay, an avid hiker, skier, walker and all-around active individual who also happens to be my first cousin. “Getting a pacemaker when it was unexpected was a shock.” But now, almost a year later, Lulay is back to exercising and traveling, and says she feels “more confident” not having to worry about her heart functioning properly.

Here are five things to know about pacemakers and how they work.

1. Roughly 3 million Americans are living with a pacemaker.

Lulay is one of nearly 3 million people in the U.S. who has a pacemaker, a small battery-powered device that prevents the heart from beating too slowly. Terminator actor Arnold Schwarzenegger , 76, is another  

Most people with pacemakers — more than 70 percent — are 65 or older, according to Yale Medicine.

2. People with abnormal rhythms may need a pacemaker.

There are several types of cardiac devices that can be implanted, or placed under the skin just below the collarbone with wires leading to the heart. A pacemaker is one of them.

It’s needed when the heart doesn’t beat normally — it may be too slow or the electrical signals that control the heartbeat are disrupted.

The device consists of a generator with a battery that provides the electrical impulse for the heart to beat, sensors (electrodes) and wires (leads) that deliver the electrical impulse to the heart muscle. The pacemaker monitors the heart’s rhythm and if it detects certain abnormalities, it will generate an electric impulse so the heart can beat with a normal rhythm.

For many patients, a pacemaker works only when needed — if the heartbeat gets too slow, it will jump in and correct it. However, some people are considered “pacemaker dependent” and rely on the device to constantly regulate the heartbeat. 

You may need a pacemaker if you have an abnormal heart rhythm that is considered serious and is not expected to go away on its own or with other treatment. You may also need one if a less serious rhythm issue causes symptoms such as lightheadedness or fainting, or prevents you from doing your day-to-day activities.

Common reasons that pacemakers are placed include:

• Sinus node dysfunction: The sinus node is specialized heart tissue in the right atrium that initiates the electrical impulse for your heart to beat.
• High-grade block : when a section of the heart’s conduction system does not transmit the electrical signal, for example at the atrioventricular (AV) node that sits between the upper and lower heart chambers.
• Fainting due to abnormal heart rhythms .
• Damage to the heart’s conduction system after procedures such as open-heart surgery or having an aortic valve replaced using a catheter.

There are several tests that your doctor can perform to determine if a pacemaker is right for you.

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Understanding the heart’s electrical system

The heartbeat is an electric signal that is generated in specialized tissue, called the sinus node, in the heart’s upper right chamber, known as the right atria. This signal causes both the left and right atria to contract.

The signal then travels to another area of specialized tissue in the heart called the atrioventricular (AV) node that lies near the border of the upper and lower chambers, finally reaching the two lower chambers (left and right ventricles) and resulting in contraction of the ventricles.  

Normal heart rates are between 60 and 100 beats per minute. 

3. Getting a pacemaker can be a quick process.

The procedure takes approximately one to two hours to complete, and you will be given medicine to make you comfortable but not put you to sleep. A small incision (about 2 inches) will be made on the chest, just below the collarbone, usually on the left side.  The generator is then inserted under the skin.  

The leads have one end inserted into the generator and the other end guided through a blood vessel to a chamber of the heart. Patients generally stay one night in the hospital after getting a pacemaker placed.

Though uncommon, there are some risks to the procedure. These include perforation (a small hole or tear) of a blood vessel or cardiac chamber, a collapsed lung and infection at the site of implantation.

After the procedure, you’ll be somewhat limited in what you can do — especially when it comes to lifting and moving your arm, even driving. But these restrictions typically last only a few weeks.

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4. Your heartbeat will be regularly monitored.  

You will be set up for home monitoring once you get a pacemaker. The monitoring system may be an app on your smartphone or tablet, or a unit that fits on your bedside table. Information from your pacemaker is encrypted and then sent automatically to your doctor’s office and downloaded into your medical chart. The monitoring also shows how often your body has needed to rely on the pacemaker and any abnormal heart rhythms that have occurred. 

Regular monitoring and in-person doctor’s appointments decrease the likelihood of complications. Infections can happen, even long after implantation. If the infection cannot be cured with antibiotics, you may need to have the pacemaker removed and a new one put in.

Another potential complication is that your tricuspid heart valve — which helps blood flow between the two right chambers — could become leaky. This happens when the leads interfere with the function of the valve. It can be managed with medical treatment as well as changing the placement of the lead.

The battery life of a pacemaker is between five and seven years. Replacing the battery can be done with either an outpatient or inpatient visit. 

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5. Pacemakers don’t mix well with some devices. 

With a pacemaker, Lulay says she worries less about her heart and doesn’t feel like the device inhibits her lifestyle. She’s back to traveling and just returned from a trip to Australia and New Zealand.

However, there are some things to be aware of if you have a pacemaker, particularly other machines and devices that can disrupt its function. Jens Cosedis Nielsen, a professor of medicine at Aarhus University in Denmark and a chairperson for the 2021 European Society of Cardiology Guidelines, says patients should stay away from equipment with magnetic forces (like an MRI machine) and direct exposure to electrical currents (like electrotherapy).

And cellphones? People with pacemakers “can use a cellphone as everybody else,” Cosedis Nielsen says. “There is no problem to use your best ear, even if this is the one closest to the pacemaker.”

Here’s a look at what will — and won’t — interfere with a pacemaker:

Note: If you have a pacemaker, you’ll want to carry your pacemaker ID card with you. This has information on what kind of pacemaker you have and the manufacturer, and can help alert health care providers and others to any special accommodations.

The following can interfere with a pacemaker:

• MRI: An MRI has a powerful magnet and patients with some models of pacemakers should not enter the MRI area in a facility. They make newer pacemakers that are “MRI conditional” and are better designed to withstand an MRI scan, so long as the pacemaker is programmed to MRI settings beforehand and then checked and reprogrammed back to original settings after.
• Medical procedures: Some procedures that may present a problem include radiation therapy and extracorporeal shock-wave lithotripsy, which uses hydraulic shocks to dissolve kidney stones. Transcutaneous electrical nerve stimulation (TENS) for treatment of acute and chronic pain has a lower risk for any pacemaker problems. If a medical procedure will affect your pacemaker, the device can be turned off (unless you are dependent on your pacemaker) and then back on, or checked immediately after the procedure and reprogrammed if needed. 
• Metal detectors and airport screening: Metal detectors won’t damage your pacemaker, especially as you pass through in a matter of seconds, but they may detect the metal in your device. Let the TSA agent know you have a pacemaker (keep your card handy). You may need to undergo a separate security procedure, such as screening with a hand wand.
• Magnets: Strong magnets especially can inhibit pacemakers, so be sure to keep at least six inches away. The same goes for headphones that have magnetic material. Avoid magnetic pillows and mattress pads.
• Electric fences: Avoid or limit exposure to electric fences and electric pet containment systems.

The following are felt to pose little or no risk to a pacemaker:

• Consumer appliances and electronics
• Microwave ovens
• Home computer components
• Yard equipment, such as hedge trimmers
• Security badge scanners

Merle Myerson, M.D., is a cardiologist who specializes in health lifestyle and disease prevention. She is a board-certified lipid specialist and has authored many research articles and textbooks on cardiovascular disease.

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