A newer type of cardiac defibrillator has been found to significantly reduce major complications for patients than the traditional ICD – PHRI Senior Scientist Jeff Healey presented today on the ATLAS S-ICD trial at Heart Rhythm 2022 in San Francisco.
Download Healey’s full presentation – PDF.

Although implantable cardioverter defibrillators (ICDs) improve survival of patients with heart conditions, they can cause perioperative complications including perforation of heart muscle or lungs, and blood clotting in veins.

Jeff Healey and Blandine Mondésert

The traditional defibrillator – transvenous ICD (TV-ICD), around for decades – features a lead (a flexible wire coated with insulation) placed in the heart or the heart’s network of blood vessels.

With a different type of ICD –  the subcutaneous ICD (S-ICD), developed in the last decade – the lead is implanted under the skin, just below the patient’s armpit, and runs along the breastbone. The S-ICD does not come into contact with any blood vessels.

The study followed patients for six months after their device was implanted in 544 patients (one-quarter female) at 14 clinical sites in Canada. Half of the patients were randomized to a S-ICD; the other half to a TV-ICD.

Healey, co-PI Blandine Mondésert, of Montreal Heart Institute, and their team found that S-ICD reduced the risk of lead-related complications by 92 percent.

By eliminating all intra-vascular and intra-cardiac components of the ICD, the S-ICD prevents most lead-related perioperative complications, including nearly all complications which can lead to death, the study found.

Younger patients, and cardiogenetic

Younger patients are usually under-represented in ICD trials; ATLAS S-ICD included ICD-eligible patients 18 to 60 years old (average age of 49) who had a cardiogenetic syndrome or were at high risk for lead-related complications.

“Canada has a strong history of ICD clinical trials and registries of patients with inherited heart rhythm disorders,” says Healey.

Follow-up of participants of ATLAS S-ICD is ongoing. “We need to increase the statistical power of the trial to assess the comparative rates of inappropriate shocks and failed appropriate shocks,” says Healey, “as well as the impact of ICD type on tricuspid insufficiency and heart failure.”

S-ICD diagram courtesy of Boston Scientific. ©2022 Boston Scientific Corporation or its affiliates. All rights reserved.


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