What does this paper add?
1. Most heart failure (HF) patients implanted with a primary prevention ICD/CRTD device were prescribed with guideline-based HF medications albeit with low doses (with regard to HF guidelines-recommended target dose).
2. Patients who were followed via a specialized HF clinic had better HF treatment.
3. A significant correlation found between increased BB dosage and reduced ventricular arrhythmias occurrence.
4. Treatment by Angiotensin Antagonists was associated with reduced overall mortality.
Introduction
Adherence to Heart failure (HF) guideline recommended medical treatment was shown to reduce HF symptoms, hospitalizations, and all-cause mortality in previous publications (1-10). Although the impact of such treatment on reduced ventricular arrhythmia (VA) and sudden cardiac death (SCD) was suggested (1,8,11,12,13), this was not evaluated as a primary outcome in randomized clinical trials but rather as a secondary outcome (1,8) or in the context of a meta-analysis (11-14). Circumstantial evidence suggests that combination HF therapy reduces SCD rate and might mitigate the added survival benefit of an implantable cardiac defibrillator (ICD) device among HF patients in general and specifically among non-ischemic dilated cardiomyopathy (DCM) patients, in whom the evidence for survival benefit with an ICD is weaker (15,16). A meta-analysis of pivotal HF trials has shown a continuous decline of SCD incidence as the trails became more recent. This observation was attributed to the increased utilization of HF guideline-based medications in the recent trials compared with the older ones (15). Moreover, among DCM patients in the DANISH trial (16) there was no significant mortality difference between patients treated with optimal medical management including cardiac resynchronization therapy (CRT) as appropriate and those treated similarly with additional ICD. Again, suggesting that current guideline-based medical therapy may obviate the need of an ICD in selected patients. This finding was reinforced in a recent meta-analysis of randomized trials evaluating the survival benefit of ICD in DCM patients, revealing loss of the survival benefit in trials where >50% of patients were taking a combination of beta adrenergic receptor antagonist (BB), Angiotensin antagonist (ACEi/ARB), and mineralocorticoid receptor antagonist (MRA) (14). In contrast with the above mentioned HF trials, large registries of HF patients have shown relatively low percent of patients treated with optimal HF medical therapy (17-20).
The aim of the current study was to evaluate the prevalence of HF medical therapy and its impact on VA incidence and overall mortality among contemporary primary prevention ICD/CRTD recipients.
Methods