Rajeev Kumar Pathak

and 11 more

Introduction: The prognosis of mixed cardiomyopathy (CMP) in patients with implanted cardioverter-defibrillators (ICDs) has not been investigated. We aim to study the demographic, clinical, device therapies and survival characteristics of mixed CMP in a cohort of patients implanted with a defibrillator. Methods: The term mixed CMP was used to categorise patients with impaired left ventricular ejection fraction attributed to documented non-ischemic triggers with concomitant moderate coronary artery disease. This is a single center observational cohort of 526 patients with a mean follow-up 8.7±3.5 years. Results: There were 42.5% patients with ischemic cardiomyopathy (ICM), 26.9% with non-ischemic cardiomyopathy (NICM) and 30.6% with mixed CMP. Mixed CMP, compared to NICM, was associated with higher mean age (69.1±9.6 years), atrial fibrillation (55.3%) and greater incidence of comorbidities. The proportion of patients with mixed CMP receiving device shocks was 23.6% compared to 18.4% in NICM and 27% in ICM. The VT cycle length recorded in mixed CMP (281.6 ± 43.1ms) was comparable with ICM (282.5 ± 44ms; p=0.9) and lesser than NICM (297.7 ± 48.7ms; p=0.1). All-cause mortality in mixed CMP (21.1%) was similar to ICM (20.1%; p=0.8) and higher than NICM (15.6%; p=0.2). Kaplan-Meier curves revealed hazards of 1.57 (95% CI: 0.91, 2.68) for mixed CMP compared to NICM. Conclusion: In a cohort of patients with ICD, the group with mixed CMP represent a phenotype predominantly comprised of elderly with higher incidence of comorbidities. Mixed CMP resembles ICM in terms of number of device shocks and VT cycle length. Long-term prognosis of patients with mixed CMP is worse than NICM and similar to ICM.
Background: The subcutaneous implantable-cardioverter defibrillator (S-ICD) is an appealing alternative to transvenous ICD systems. However, data on indications for S-ICD explantations are sparse. Objectives: To assess incidence and indications for S-ICD explantation at a large tertiary referral center. Methods: We conducted a retrospective study of all S-ICD explantations performed from 2014 to 2020. Data on demographics, comorbidities, implantation characteristics, and indications for explantation, were collected. Results: A total of 64 patients underwent S-ICD explantation during the study period. During that time, there were 410 S-ICD implantations at our institution of which 53 (12.9%) were explanted with a mean duration from implant to explant of 19.7±20.1 months. The mean age of the patients at explantation was 44.8±15.3 years, and 42% (n=27) were female. The indication for S-ICD implantation was primary prevention in 58% and secondary prevention in 42% of the patients. The most common reason for explantation was infection (32.8%) followed by abnormal sensing (25%) and need for pacing (18.8%). Those who underwent S-ICD explantation for pacing indications were significantly older (55.7±13.6 vs 42.3± 14.6 years, p = 0.005) with a wider QRS duration (111±19 ms vs 98±19 ms, p = 0.03) at device implantation compared to patients who underwent explantation for other indications. Conclusion: Incidence of S-ICD explantation in a large tertiary practice was 12.9%. While infection was the indication for a third of the explantations, a significant number were due to sensing abnormalities and need for pacing. These data may have implications for patient selection for S-ICD implantation.