Follow-up and characteristics of recipients of cardiac resynchronization therapy with and without a defibrillator

Background: Cardiac resynchronization therapy defibrillator (CRT-D) and pacemaker (CRT-P) are treatment options for patients with advanced heart failure and electrical dyssynchrony. Current guidelines provide only factors favoring, not specific recommendations as to implant CRT-D or CRT-P. This analysis aimed to compare and contrast populations of CRT-D and CRT-P recipients.

Methods: Retrospective data were collected from medical records, including 231 patients treated with either CRT-D or CRT-P between 2015 and 2019. Following data were analyzed demographics, co-morbidities, pharmacotherapy, laboratory tests, and data related to the procedure of implantation. The primary endpoint of the study was all-cause mortality.

Results: A total of 231 patients were included (mean age [standard deviation, SD], 64.1 [12.3] years, 76% male), of these, 13.6% (n = 32) with CRT-P and 86.4% (n = 199) with CRT-D. Mean New York Heart Association (NYHA) class did not differ between the groups: 2.23 (0.9) in CRT-P and 2.35 (0.6) in CRT-D group (P = 0.42). Mean left ventricular ejection fraction was lower in patients eligible for CRT-D: 27.1% vs. 38% (P < 0.001). Patients were followed for a median (interquartile range [IQR]) of 29 (13-44) months and survival in the CRT-P group was 84%, in CRT-D - 82% (P = 0.74). Patients in the CRT-P group were older, and more often after atrioventricular node ablation. The CRT-P group had tendency towards higher Charlton Comorbidity Index, reaching a mean of 4.66 (1.5) points vs. 3.96 (1.5) points in CRT-D (P = 0.06).

Conclusions: Populations with CRT-P and CRT-D differ in terms of comorbidities; however, they have similar survival. Further studies are required to identify a group of patients, who derive a benefit from adding a defibrillator.