ICDs Provide Sustained Protection Against Ventricular Arrhythmias in HCM, Suggests Study

A new study published in the journal of Circulation showed that implantable cardioverter-defibrillators (ICDs) offer considerable long-term advantages for individuals with hypertrophic cardiomyopathy (HCM).

ICDs have been utilized in individuals with hypertrophic cardiomyopathy to avoid unexpected death and have been found to save many lives. Nonetheless, knowledge about the effectiveness of ICD treatment has mainly come from small groups of HCM patients in particular countries or regions. Hence, this research assessed how well ICDs prevent sudden death caused by dangerous ventricular arrhythmias in a vast international multicenter HCM community.

Information from databases of 25 HCM facilities, including 8 in the US, 9 in Europe, 4 in Asia, and 1 each in Australia, Africa, Mexico, and South America, was reviewed to find patients with HCM who had ICDs between 1992 and 2024. These patients were monitored for clinical results for an average of 7 years, with a range of up to 32 years.

A total of 3387 individuals (63% males) diagnosed with hypertrophic cardiomyopathy were given implantable cardioverter-defibrillators at an average age of 47±17 years. Throughout the monitoring period, 550 patients (16%) encountered suitable ICD treatment, with 15% being primary-prevention recipients and 35% secondary-prevention recipients.

For primary-prevention individuals, the average time until the first treatment was 4 years, and 16% received treatment ≥10 years after the device was implanted. Factors that predicted treatment included unexplained fainting, an aneurysm in the left ventricular apex, reduced heart function, and short bursts of ventricular tachycardia.

Out of 3140 primary-prevention patients, 6% passed away, with 0.4% from sudden cardiac arrest. Most deaths related to hypertrophic cardiomyopathy were due to advanced heart failure or stroke. The survival rate without hypertrophic cardiomyopathy-related deaths was 97% at 10 years and 91% at 20 years. Device malfunction was seen in 2.4% of patients with severe ventricular tachyarrhythmias.

In this global study involving over 3300 patients with hypertrophic cardiomyopathy and implantable cardioverter-defibrillators, it was found that device therapy successfully stopped dangerous heart rhythms in one out of every 6 patients. Additionally, patients with ICDs had low mortality rates related to HCM. These new findings illustrate the success of the ICD program, which likely has positively impacted the outcomes for numerous HCM patients around the world.

Reference:

Rowin, E. J., Maron, B. J., Siontis, K. C., Tower-Rader, A. F., Massera, D., Koethe, B., Bilen, O., Phelan, D., Arnold, A., Mohal, J. S., Varnava, A. M., Schiavo, M. A., Ditaranto, R., Biagini, E., Ahamed, H., Hari, A., Johar, S., Lau, B.-N., Corrado, D., … Maron, M. S. (2026). International experience with implantable cardioverter defibrillators for the prevention of sudden death in high-risk patients with hypertrophic cardiomyopathy. Circulation, (CIRCULATIONAHA.125.078597). https://doi.org/10.1161/CIRCULATIONAHA.125.078597