Excerpt for Pacemaker Syndrome, A Simple Guide To The Condition, Diagnosis, Treatment And Related Conditions by , available in its entirety at Smashwords

Pacemaker Syndrome,





The Condition,




Related Conditions


Dr Kenneth Kee

M.B.,B.S. (Singapore)

Ph.D (Healthcare Administration)

Copyright Kenneth Kee 2018 Smashwords Edition

Published by Kenneth Kee at


This book is dedicated

To my wife Dorothy

And my children

Carolyn, Grace

And Kelvin

This book describes Pacemaker Syndrome, Diagnosis and Treatment and Related Diseases which is seen in some of my patients in my Family Clinic.

(What The patient Need to Treat Pacemaker Syndrome)

This eBook is licensed for your personal enjoyment only. This eBook may not be re-sold or given away to other people. If you would like to share this book with another person, please purchase an additional copy for each reader.

If you’re reading this book and did not purchase it, or it was not purchased for your use only, then please return to and purchase your own copy.

Thank you for respecting the hard work of this author.


I have been writing medical articles for my blog (A Simple Guide to Medical Disorder) for the benefit of my patients since 2007.

My purpose in writing these simple guides was for the health education of my patients.

Health Education was also my dissertation for my Ph.D (Healthcare Administration).

I then wrote an autobiolographical account of his journey as a medical student to family doctor on his other blog

This autobiolographical account “A Family Doctor’s Tale” was combined with my early “A Simple Guide to Medical Disorders” into a new Wordpress Blog “A Family Doctor’s Tale” on

From which many free articles from the blog was taken and put together into 800 eBooks.

Some people have complained that the simple guides are too simple.

For their information they are made simple in order to educate the patients.

The later books go into more details of medical disorders.

The first chapter is always from my earlier blogs which unfortunately tends to have typos and spelling mistakes.

Since 2013, I have tried to improve my spelling and writing.

As I tried to bring the patient the latest information about a disorder or illness by reading the latest journals both online and offline, I find that I am learning more and improving on my own medical knowledge in diagnosis and treatment for my patients.

Just by writing all these simple guides I find that I have learned a lot from your reviews (good or bad), criticism and advice.

I am sorry for the repetitions in these simple guides as the second chapters onwards have new information as compared to my first chapter taken from my blog.

I also find repetition definitely help me and maybe some readers to remember the facts in the books more easily.

I apologize if these repetitions are irritating to some readers.

Chapter 1

Pacemaker Syndrome

What is Pacemaker Syndrome?

Pacemaker syndrome is a group of symptoms related to the loss of AV synchrony (i.e. the atria contract at the same time as paced ventricular contractions) in patients with a pacemaker.

The result is reduced cardiac output to which the total peripheral blood resistance will rise.

Not all patients show a rise in blood pressure and some will have a fall in their blood pressure.

A Pacemaker is an artificial device (implanted in the body under the skin) connected to the heart electrically to regulate the heart rate and rhythm.

There are patients with VVI pacemakers, mainly with sinoatrial (SA) rather than atrioventricular (AV) disease, who show reverse ventriculo-atrial (VA) conduction during ventricular pacing which can produce fatigue, dizziness and hypotension.

Pacemaker syndrome is linked with atrial cannon waves produced by simultaneous atrial and ventricular contractions.

Replacement with a dual chamber pacemaker (two leads placed in the right atrium and right ventricle) is needed.

Pacemaker syndrome is defined as:

1. Loss of AV synchrony.

2. Retrograde VA conduction.

3. Absence of rate response to physiological need.

The frequency of pacemaker syndrome has been evaluated to differ from 7% (symptoms serious enough to require pacemaker revision) to over 80% (mild to moderately severe symptoms)

Asymptomatic pacemaker syndrome is possibly frequent and the real incidence of pacemaker syndrome much higher

Pacemaker syndrome is a disease that indicates the medical after effects of suboptimal atrioventricular (AV) synchrony or AV dyssynchrony, regardless of the pacing mode, after pacemaker implantation.

It is an iatrogenic disease (adverse effect resulting from medical treatment) that is under diagnosed.

Generally, the symptoms of the syndrome are a combination of:

1. Reduced cardiac output,

2. Loss of atrial contribution to ventricular filling,

3. Loss of total peripheral resistance response, and

4. Non-physiologic pressure waves.

Persons with a low heart rate before pacemaker implantation are at higher risk of forming pacemaker syndrome.

Normally the first chamber of the heart (atrium) contracts while the second chamber (ventricle) is relaxed, permitting the ventricle to fill before it contracts and pumps blood out of the heart

When the timing between the 2 chambers is not synchronized, less blood is pumped on each beat.

Patients who have the pacemaker syndrome may need to adjust the pacemaker or fit of another lead to better coordinate the timing of atrial and ventricular contraction.

What are the causes of Pacemaker Syndrome?


The precise cause is not known.

Several risk factors are linked with pacemaker syndrome.

Risk factors

In the pre-implantation period, there are two variables that predispose to the syndrome:

1. Low sinus rate,

2. Higher programmed lower rate limit

In the post-implantation period, a higher percentage of ventricular paced beats is the only variable that largely predicts development of pacemaker syndrome.

Patients with intact VA conduction are at higher danger for forming pacemaker syndrome.

Around 90% of patients with preserved AV conduction have intact VA conduction

About 30-40% of patients with complete AV block have preserved VA conduction.

Intact VA conduction may not be obvious at the time of pacemaker implantation or even may develop at any time after implantation.

Patients with noncompliant ventricles and diastolic dysfunction are mostly sensitive to loss of atrial contribution to ventricular filling, that the chance of developing the syndrome is highly increased.

This includes patients with cardiomyopathy (hypertensive, hypertrophic, restrictive) and elderly.

Other factors related to formation of pacemaker syndrome are:

1. Decreased stroke volume,

2. Decreased cardiac output, and

3. Decreased left atrial total emptying fraction linked with ventricrular pacing.


The loss of physiological timing of atrial and ventricular contractions, sometimes called AV dyssynchrony, leads to various mechanisms of symptoms production.

This altered ventricular contraction will reduce cardiac output, and in turn will lead to systemic hypotensive reflex reaction with differing symptoms

Loss of atrial contraction

Wrong pacing in patients with diminished ventricular compliance, which may be caused by diseases such as hypertensive cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy and aging, can lead to loss of atrial contraction and notably reduces cardiac output.

In such cases the atrias are needed to supply 50% of cardiac output which normally supplies only 15% - 25% of cardiac output.

Cannon A waves

Cannon A waves, or cannon atrial waves, are waves observed infrequently in the jugular vein of persons with certain abnormal cardiac rhythms.

When the atria and ventricles contract together, the blood will be pushed against the AV valve, and a very large pressure wave goes up the vein.

Atrial contraction pushed against a closed tricuspid valve can cause:

1. Pulsation in the neck and abdomen,

2. Headache,

3. Cough, and

4. Jaw pain.

Increased atrial pressure

Ventricular pacing is linked with raised right and left atrial pressures, and raised pulmonary venous and pulmonary arterial pressures which result in symptomatic pulmonary and hepatic congestion.

Increased production of natriuretic peptides

Patients with pacemaker syndrome show raised plasma levels of Atrial Natriuretic peptides (ANP).

That is because of rise in left atrial pressure and left ventricular filling pressure, which is because of reduced cardiac output induced by dyssynchrony in atrial and ventricular contraction.

Atrial NP and Brain NP are possible arterial and venous vasodilators that can prevail carotid and aortic baroreceptor reflexes trying to compensate for reduced blood pressure.

Normally patients with cannon A waves have higher plasma levels of ANP than those without cannon waves.

VA conduction

A major cause of AV dyssynchrony is VA conduction.

VA conduction, occasionally called retrograde conduction, results in delayed, non-physiologic timing of atrial contraction in relation to ventricular contraction.

Many disorders other than VA conduction cause AV dyssynchrony.

This will further reduce blood pressure, and secondary rise in ANP and BNP.

What are the symptoms of Pacemaker Syndrome?


Many signs and symptoms of pacemaker syndrome are nonspecific, and many are frequent in the elderly population at baseline.

Symptoms are pulsation and fullness in the neck, dizziness, palpitations, fatigue, light-headedness and syncope.

Symptoms and signs of heart failure may occur

Symptoms can differ considerably and also vary in severity.

Symptoms often documented in patients history, are classified according to their effects:

1. Neurological - Dizziness, near syncope, altered mental status and confusion.

2. Heart failure – Dyspnea, orthopnea, paroxysmal nocturnal dyspnea, and edema

3. Hypotension - Seizure, mental status change, diaphoresis, and signs of orthostatic hypotension and shock.

4. Low cardiac output - Fatigue, lethargy, weakness, breathless on exertion, and lightheadedness

5. Hemodynamic - Pulsation in the neck and abdomen, choking sensation, jaw pain, right upper quadrant (RUQ) pain, chest colds, and headache

6. Heart rate related - Palpitations associated with arrhythmias

Especially, the doctor should look for these signs in the physical examination, as these are frequent findings at the time of admission:

Signs are hypotension, tachycardia, tachypnea, raised JVP and cannon waves.

There may be variations in pulses and fluctuating blood pressure

A fall of 20 mm Hg or more during ventricular pacing compared with that during atrial or AV synchronous pacing is indicative.

1. Vital signs may indicate tachycardia, hypotension, tachypnea, or low oxygen saturation.

2. Pulse amplitude may vary, and blood pressure may fluctuate.

3. Look for neck vein distension and cannon waves in the neck veins.

4. Lungs may exhibit crackles.

5. Cardiac examination may reveal regurgitant murmurs and variability of heart sounds.

6. Liver may be pulsatile, and the RUQ may be tender to palpation.

7. Ascites may be present in severe cases.

8. The lower extremities may be edematous.

In the laboratory, pacemaker investigation plays a decisive part in deciding if the pacemaker mode had contributed to symptoms.

How is Pacemaker Syndrome Diagnosed?


No specific set of criteria has been developed for diagnosis of pacemaker syndrome.

1. Blood tests:

a. Electrolytes,

b. Coagulation screen,

c. Digoxin levels if appropriate,

d. Myocardial injury markers - e.g., troponins (may indicate recent myocardial infarction)

2. 12-lead ECG - any sign of myocardial ischemia, arrhythmias or abnormal sensing.

3. CXR: evaluate lead position and look for lead fracture.

A CXR can be done to identify the pacemaker model, because most pacemakers have an X-ray code which is visible on a standard CXR.

4. Echocardiogram: to assess for lead position, pericardial effusion or tamponade or lead fracture.

5. Pacemaker assessment:

a. Review triggering thresholds, lead impedance, and battery function.

b. Some brands may have stored electrocardiograms.

6. Magnet application:

This can produce asynchronous pacing mode and can show loss of capture and battery depletion.

7. Telemetry monitoring:

It is normally useful in the early post-implant period;

It can reveal loss of capture.

8. Trans-telephonic monitoring:

Rarely used and is most helpful in determining battery depletion.

9. Fluoroscopy:

This is used to evaluate lead fracture.

What is the treatment of Pacemaker Syndrome?



Diet alone do not treat pacemaker syndrome but a suitable diet for the patient, besides the other treatment regimes mentioned, can help the patient's symptoms.

Several cases mentioned below:

1. For patients with heart failure, low-salt diet is indicated.

2. For patients with autonomic insufficiency, a high-salt diet may be appropriate.

3. For patients with dehydration, the proper oral fluid re-hydration is required.

No specific drugs are used to treat pacemaker syndrome directly because treatment consists of upgrading or reprogramming the pacemaker.

Medical Care

For some patients who are ventricularly paced, normally the addition of an atrial lead and optimizing the AV synchrony typically resolves symptoms.

In patients with other pacing types, other than ventricular pacing, symptoms normally recover after modifying and reprogramming of pacemaker parameters, such as:

1. Tuning the AV delay,

2. Changing the post-ventricular atrial refractory period, the sensing level, and pacing threshold voltage.

The optimal values of these parameters for each individual differ.

Obtaining the best values is by experimenting with consecutive reprogramming and measurement of relevant parameters, such as:

1. Blood pressure,

2. Cardiac output, and

3. Total peripheral resistance, and

4. Observations of symptomatology.

In rare instances, using hysteresis to help maintain AV synchrony can help relieve symptoms in ventricularly inhibited paced (VVI) patients providing they have intact sinus node function.

Hysteresis (pacing parameter allowing longer escape interval) reduces the quantity of time spent in pacing mode, thus relieving symptoms, mainly when the pacing mode is causing AV dyssynchrony.

If symptoms continue after all these treatment methods, replacing the pacemaker itself is sometimes beneficial and can relieve symptoms.

Medical care involves supportive treatment, in case any of the complications occur, the medical team should be ready.

Surgical Care

Occasionally surgical intervention is required.

After consulting an electro-physiologist, possibly an additional pacemaker lead placement is required, which ultimately alleviate some of the symptoms.

In patients with other pacing types, the symptoms normally recover after the improvement of the pacemaker to a dual-chamber pacing system, or reprogramming the pacemaker parameters such as:

1. AV delay,

2. Post-ventricular atrial refractory period,

3. Sensing level, and

4. Pacing threshold voltage.

Medical therapy has a restricted role but electrolyte anomalies may need to be corrected

The medicines regime should be reviewed and adjusted as needed.

What is the prognosis of Pacemaker Syndrome?


Once the pacemaker use has been improved as above, the symptoms recover completely.

What are the complications of Pacemaker Syndrome?


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