Heart Failure guideline-based medical therapy impact on malignant arrhythmias and survival in patients with an Implanted Cardioverter Defibrillator (ICD) or Cardiac Resynchronization-Defibrillator device (CRTD)

Background: Recent circumstantial evidence suggests adherence to heart failure (HF) guideline-based therapy reduces ventricular arrhythmias (VA) and mortality.

Aim: To evaluate the impact of HF therapy on VA and overall mortality incidence in HF patients with ICD.

Methods: Retrospective analysis of all HF patients implanted with ICD/CRTD. Discharge treatment and dose (% of HF guideline target recommendation) of beta-blockers (BB), Angiotensin antagonists (AA), Mineralocorticoid Antagonsits (MRA), and Anti-Arrhythmic Drugs (AAD) were recorded. Outcomes included all VA episodes and mortality. Statistics included univariate, multivariable and survival analyses.

Results: The study included 186 patients, mean age 66.412 years, 15.1% female. ICD was implanted in 79(42.5%) and a CRTD in 107(57.5%). Median [IQR] follow-up time was 3.8 [2.1;6.7] years. There were 52(28%) patients with sustained VA and 77(41.4%) deaths. Rates of treatment were 83% (BB), 87% (AA), 59% (MRA), and 43.5% (AAD). Notably, doses were low: 25[12.5;50]% for BB and AA, 25[0;50]% for MRA. Age, gender, device (CRTD versus ICD), HF etiology, treatment rates of HF medications or AAD were not associated with VA. However, VA group was treated with significant lower BB dose as compared to no VA group.(23.9±19% versus 35.5±27% target dose; p=0.012). In Cox multivariable model including gender, device type (ICD/CRTD), number of HF medications and BB dose (% target), BB dose was significantly and independently associated with lower rate of VA (HR 0.104, 95% [0.014-0.799]; p=0.030). Multivariable survival analysis for mortality revealed no association between BB or MRA and mortality, while AA treatment was significantly and independently associated with reduced mortality (HR 0.489; 95% CI 0.272-0.877; p=0.016).

Conclusions: In this cohort of real-life HF patients, % use of HF medications was high but doses were low. Higher dose of BB were associated with lower incidence of VA, while treatment with AA (but not BB) was associated with improved survival.