Clinical outcomes and associated factors in patients with implantable cardioverter-defibrillators and cardiac resynchronization therapy devices: data from a single-center retrospective registry

Abstract

Aim. To identify clinical and instrumental factors associated with clinical outcomes in patients with implanted implantable cardioverterdefibrillators (ICD) / cardiac resynchronization therapy defibrillators (CRTD). Material and methods. A singlecenter retrospective registry included clinical and instrumental data from 315 patients with an implanted ICD (n=208; 66.0%) or CRTD (n=107; 34.0%). Median age at implantation was 59 years (IQR 50-67); 74.6% were male. Coronary artery disease (CAD) was diagnosed in 131 patients (41.6%), dilated cardiomyopathy (DCM) in 112 (35.6%), and other heart diseases in 72 (22.9%). Device implantation was performed for primary prevention of sudden cardiac death (SCD) in 207 (65.7%) patients and for secondary prevention in 108 (34.3%). In patients with CRTD, the effect of therapy was prospectively assessed at 6-12 months. The study endpoints were: endpoint 1 (EP1) - appropriate ICD therapy; endpoint 2 (EP2) - electrical storm (ES); endpoint 3 (EP3) - death from any cause / heart transplantation / left ventricular assist device (LVAD) implantation. Median followup was 40.9 months (IQR 15.5-89.8 months). Results. EP1 - Data on device function were available for 278 of 315 patients; EP1 was reached in 89 (32.0%) of them. Independent factors for reaching EP1 were implantation for secondary prevention of SCD (OR 2.50; p=0.002) and CAD (OR 2.03; p=0.007). The rate of EP1 differed significantly among etiological groups (logrank p=0.003): 42.7% in CAD; 23.8% in DCM; and 26.9% in “Other” (χ²=9.78; p=0.008). In the CRT-D group, the risk of appropriate ICD therapy was lower than in the ICD group: 20.4% vs 38.3%, but did not reach statistical significance (HR 0.50 [0.25-1.01] p=0.054). EP2 was reached in 18 patients (5.7%). Due to the small number of events, no independent predictors of EP2 were identified. EP3 - Clinical status was known for 286 patients (90.8%). EP3 was reached in 24 patients (8.4%). The only independent factor associated with EP3 was NYHA functional class of chronic heart failure (OR 2.95; p=0.005). Etiology did not affect the occurrence of EP3 (logrank p=0.125). In 100 of 107 patients in the CRT-D group, significant left ventricular reverse remodelling was recorded as an increase in left ventricular (LV) ejection fraction (LVEF) from 27% to 40.5%, a decrease in LV enddiastolic volume by 58.5 mL and LV endsystolic volume by 59 mL (p<0.0001). A reduction in LV endsystolic volume of ≥15% during CRT was achieved in 66 (66%) patients. The rate of EP3 did not differ significantly between the ICD and CRTD groups (8.6% vs 8.0%; p=0.260). Conclusion. The severity of CHF (NYHA functional class) is the leading factor associated with death/transplantation/LVAD implantation, whereas CAD and implantation for secondary prevention of SCD were independent factors associated with appropriate ICD therapy.