Implantable Cardioverter Defibrillator (ICD) Insertion

Pacemakers & ICDs

Implantable Cardioverter Defibrillator (ICD) Insertion | Johns Hopkins Medicine


A pacemaker is a small device that sends electrical impulses to the heart muscle to maintain a regular heart rate.

In general, pacemakers are not very effective for preventing A-Fib and are not specifically used to treat A-Fib. But they can be of benefit to some patients.

Newer dual chamber pacemakers can possibly terminate A-Fib episodes with pacing and supress Premature Atrial Contractions (PACs) from triggering A-Fib by overdrive pacing.

Implanting a pacemaker seems to be most helpful if you have a slow heart rate or pauses (5+ seconds) as a result of taking A-Fib medications. But there is a danger for patients with this approach.

A slow or even very slow heart rate usually doesn’t cause any harm. As for heart rates, “normal” is indeed a wide swath. Some people, particularly athletes, can have a very slow heart rate and be perfectly healthy.

The same holds for asymptomatic pauses.

In the words of Dr. John Mandrola:

“Do not implant pacemakers in patients with non-symptomatic bradycardia (slow heart rate).1

Non-symptomatic slow heart rate or pauses don’t justify exposing patients to the risks of implanting a pacemaker. Another consideration is that implanting pacemaker leads in the veins of the upper chest often prevents or hinders future procedures that require vascular access a Pulmonary Vein Ablation/Isolation (PVI/A).

A pacemaker usually isn’t implanted unless your heart rate is too slow2 or you have Sinus Node and/or Atrioventricular (AV) Node problems. But be advised that pacemakers tend to have bad effects over the long term, “…a long-term morbidity (is) associated with a pacemaker.”3 Leadless pacemakers seem to have less complications than traditional ones.

For more information on Pacemakers, you may want to visit the pacemaker chat site:  (Thanks to Mara for alerting us to this site.)

[I admit to not knowing much about pacemakers. Happily one of the’s contributors installs pacemakers and offers the following observations

“I to tell patients who receive pacemakers that, after a couple of months, they can have a VERY active, normal lifestyle. All of the current pacers have a “rate responsive” mode, meaning they are designed specifically for activity. The more active you are, the faster the pacer goes. Three triathlon runners, and two NFL players have pacers. Most people forget they have a pacemaker.

A recent trend is to implant the ventricular lead on the septum vs. the right ventricular apex, which gives better cardiac output and a more ‘normal’ heartbeat. You might want to ask your doctor about this possibility. Even if your doctor does not prefer this technique, he/she will be impressed that you did your homework.

In addition, you always want a dual chamber pacer which will give better cardiac output. It will also attempt to synchronize between the atria and ventricles, unless the patient is in Chronic A-Fib.

If the A-Fib is intermittent, the pacer will temporarily switch modes to VVIR (ventricular only pacing) during the A-Fib, and then back to normal DDDR (dual chamber) pacing when the A-Fib terminates.

This is all done by the device memory/logic program.

So, during A-Fib, the DDDR pacer will switch to VVIR and pace only the ventricle during the A-Fib.”

Implantable Cardioverter Defibrillator (ICD)

Implantable Cardioverter Defibrillator (ICD)

An implantable cardiac defibrillator (ICD) is a device that is put within the body and is designed to recognize certain types of abnormal heart rhythms (arrhythmias) and correct them by delivering precisely calibrated and timed electrical shocks, when needed, to restore a normal heartbeat.

Having a defibrillator implanted in your heart is, from the point of view of most A-Fib patients, not a probable option.  A defibrillator shock is painful, being “kicked in the chest.” Most people would rather have A-Fib than risk being shocked throughout the day and night. Also, it does not address the underlying problem or condition of your heart that causes your A-Fib.

Fewer than 10% of patients get shocked when a shock isn’t needed, according to Edward K. Kasper, MD of The Johns Hopkins Hospital..5 In another study 18% of patients with A-Fib received inappropriate first shocks.6 

More than 30% of people who have ICDs develop emotional problems such as anxiety and depression—in part due to worry and uncertainty over whether the device will deliver an unnecessary shock and the fear of being shocked.7

What’s it  living with an ICD and A-Fib? Roby T. shared:

“The worst part was the ICD firing,” he recalls. “It hit me a baseball bat and knocked me over.” His wife, Mary, was afraid to leave him alone. And the anxiety levels took their toll, even during sleep. “He became really anxious expecting a firing at any time,” she says. “You could see the fear in his eyes,” she reluctantly remembers. “He had to start taking antidepressants.”8

Our pacemaker expert writes:

Last updated: Thursday, February 27, 2020

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Implantable Cardioverter Defibrillator (ICD)

Implantable Cardioverter Defibrillator (ICD) Insertion | Johns Hopkins Medicine

News | EP Lab | May 12, 2020 FDA Approves Medtronic Cobalt and Crome ICD Portfolio May 12, 2020 — Medtronic has received FDA approval for its Cobalt and Crome implantable cardioverter-defibrillators (…

May 8, 2020 — Final results from the UNTOUCHED study of the Emblem Subcutaneous Implantable Defibrillator (S-ICD)…

The Boston Scientific Emblem MRI-safe S-ICD system does not require a transvenous lead, leading to fewer complications with this type of ICD.

May 8, 2020 — A new clinical trial is the first to compare the safety and efficacy of subcutaneous implantable…

Valentina Kutyifa, M.D., Ph.D., University of Rochester Medical Center, Rochester, N.Y., is doing research in the BIO-LIBRA Study to determine it ICD or CRT-D devices work better in men or women with heart failure often present with non-ischemic cardiomyopathy.

Feature | Cardiac Resynchronization Therapy Devices (CRT) | March 09, 2020 | Valentina Kutyifa M.D., Ph.D. Cardiovascular disease is the leading cause of death for women in North America, and women with heart failure often…

Earlier this year, Medtronic began a worldwide pivotal study evaluating its investigational Extravascular Implantable Cardioverter Defibrillator (EV ICD) system to treat dangerously fast heart rhythms.

The EV ICD system is designed to deliver lifesaving defibrillation and pacing therapy via a device the same size as traditional, transvenous ICDs, but with a lead (thin wire) placed outside the heart and veins.

Feature | EP Lab | November 11, 2019 | Hrishikesh Kadam The Future of Cardiac Rhythm Management Device Technology Cardiac rhythm management (CRM) devices in use today are evolving to raise the bar beyond monitoring and managing…

One of the cardiology technologies in the list of top advances in 2019 is Medtronic’s Tyrx Absorbable Antibacterial Envelope using to enclose cardiac implantable electronic devices (CIEDs). It reduced the risk of major infection by 40 percent, and pocket infection by 61 percent, data presented at ACC 2019.

Cleveland Clinic Unveils Top 10 Medical Innovations for 2020 November 6, 2019 — Cleveland Clinic announced the Top 10 Medical Innovations for 2020 at a multimedia presentation last… Early ICD Use Prolongs Survival After Coronary Stenting September 18, 2019 — Early use of an implantable cardioverter-defibrillator (ICD) after primary coronary intervention… News | Leads Implantable Devices | August 05, 2019 August 5, 2019 — Abbott is recalling the Ellipse Implantable Cardioverter Defibrillators (ICDs) because electrical… News | EP Lab | July 31, 2019 Cardiac Device Complications Vary Widely Among Hospitals July 31, 2019 — The chances of patients experiencing complications after having a cardiac device implanted vary… News | Sudden Cardiac Arrest | July 02, 2019 Wearable Defibrillator Offers a Bridge Therapy For patients at risk for sudden cardiac arrest (SCA) who are being evaluated for a permanent implantable cardioverter…

A physician explaining an implantable cardioverter defibrillator (ICD) to a patient. Image courtesy of Biotronik.

Feature | Implantable Cardioverter Defibrillator (ICD) | May 24, 2019 | Dave Fornell, Editor This is a brief overview of updates on implantable cardioverter defibrillators (ICD), including new technology…

Figure 1: The PADIT infection risk score ranging from 0 to 14 points classified patients into three risk groups, low (0-4), intermediate (5-6) and high (≥7). The risk groups had rates of hospitalization for infection of 0.51%, 1.42% and 3.41%, respectively 

News | EP Lab | May 15, 2019 Implantable EP Device Infection Risk Score Unveiled at HRS 2019 May 15, 2019 — A new infection risk scoring system has been developed data from the large PADIT Trial.[1] The… News | EP Lab | May 15, 2019 Studies Find Race and Gender Disparities in Implantable Heart Devices May 15, 2019 – Three new studies show that patients who are medically indicated for implantable heart devices,…

A new study shows travelers with common cardiac devices can pass through airport body scanners without restrictions or precautions.

News | EP Lab | May 14, 2019 Airport Security Body Scanners Do Not Interfere With Pacemakers, ICDs May 14, 2019 – Results from new research show that passengers with cardiac implantable electronic devices (CIEDs), such…

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Johns Hopkins Pathology

Implantable Cardioverter Defibrillator (ICD) Insertion | Johns Hopkins Medicine

Prevention of Sudden Cardiac Death

Being diagnosed with a disease that can cause sudden cardiac death is NOT a death sentence. If an individual is predisposed to SCD, then it is actually good to have a diagnosis so that appropriate therapy can be initiated.

Unfortunately, many people do not know they are at increased risk for SCD and thus do not have the treatments in place that can prolong their lives indefinitely. The information below lists some of the common measures used to prevent SCD.

It is by no means complete, and anyone who is at risk for SCD, should see a physician for optimal care of their particular risk factor.

Implantable cardioverter-defibrillator (ICD) +

For people who are at increased risk of succumbing to sudden cardiac arrest, an implantable cardioverter-defibrillator (ICD) device is a godsend. The ICD was invented by Dr. Michel Mirowski in the 1970s at Sinai Hospital of Baltimore, an affiliate of Johns Hopkins.

This is a metal device, half the size of a cell phone, which is placed in the chest. It attaches to the heart through several electrode wires. If the heart has an abnormal rhythm or stops, the ICD shocks the heart to reset the heart to a normal rhythm. The ICD has saved thousands of people's lives. Two problems with ICDs exist.

One is finding the people who would benefit the most from ICDs – as these are both expensive and not without risks. The second problem is inappropriate shocks- when the ICD “fires” without appropriate cause- and fear of such shocks can lead to anxiety in patients, affecting quality of life.

ICD devices are frequently placed in individuals with ARVC/D and in individuals who have had a heart attack.

Automated external defibrillator (AED) +

A second way to prevent sudden cardiac death is the use of an automated external defibrillator (AED). AEDs are often found in public places and places of business such as sports arenas, airports, and grocery stores.

These are extremely useful for individuals who have a sudden cardiac arrest, but who are not treated for the condition. If a person was to have a sudden cardiac arrest, a quick-acting good-samaritan could use one of these devices to rapidly restore a heartbeat.

AEDs are designed to be used by lay people and have been credited with saving thousands of lives.

Radiofrequency Ablation (RFA) +

In some cases of sudden cardiac arrest, complete heart stoppage is preceded by a dangerous arrhythmia, or abnormal beating of the heart.

Sometimes cardiologists can identify an abnormal electrical pathway in the heart and can burn the heart tissue in that area by radiofrequency catheter ablation (RFA).

This prevents the abnormal electrical pathway from causing arrhythmias and reduces the risk of sudden cardiac death. This treatment involves the insertion of a catheter through the venous system into the right ventricle.

Then the pathway causing arrthymias can be identified by electrical mapping. Finally, this abberant electrical pathway is zapped, reducing the risk of future arrhythmias. This has been used to successsfully treat Wolf-Parkinson-White disease and many other types of arrhythmia.

Anti-Arrhythmic Medications +

There are numerous pharmaceutical drugs that have proven benefit against arrhythmias that can lead to sudden cardiac death. In general terms these drugs regulate ion channels or nerve stimulation of the heart.

Specifically, they regulate sodium channels, potassium channels, calcium channels, and block sympathetic stimulation of the heart. Different medications work better on different types of arrhythmias.

The right medication can only be determined by a physcian an individual's unique risk factors.

Lifestyle Modification +

Some lifestyle modifcations can reduce the lihood of having a sudden cardiac death event. Unfortunately, some causes of sudden cardiac death occur with greater frequency among individuals who are very physically active.

Individuals with hypertrophic cardiomyopathy and ARVC/D, in particular, are told to refrain from intense physical activity which can cause an arrhythmic event to occur. Non-exertional exercise such as walking is encouraged.