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