Introduction
Heart
failure (HF), as a final common stage of many cardiovascular diseases,
is a major public health problem affecting approximately 40 million
people globally.[1] A spontaneous progressive
clinical syndrome with dyspnea, water and sodium retention, pump failure
underlying causes, pathophysiological complexities, and concomitant
comorbidities, which made both diagnosis and treatment particularly
challenging.[2]Ischemic
cardiomyopathy (ICM) and idiopathic dilated cardiomyopathy (DCM) share
common structural alterations with a high mortality from sudden cardiac
death (SCD) and pump failure.[3] According to New
York Heart Association (NYHA) classification, the all-cause mortality of
patients with NYHA class II is 5% to 15%, of which 50% -60% is
sudden death. The all-cause mortality rate of NYHA class III increases
to 30% to 50%, and class IV usually exceeds 50%.[4]
During the past decades, great progresses have been made in decreasing
the occurrence of SCD. In particular, ICD implantation has become a
priority for primary prevention ICDs in patients with
indication.[5] However, individual DCM trials have
failed to gain the conclusion of a mortality benefit with prophylactic
ICD implantation.[6] European guidelines have
recommended that ICD therapy to prevent SCD in patients with symptomatic
HF (NYHA class II–III) and LVEF
≤35% after ≥3 months of optimal
medical therapy who are expected to survive for at least 1 year with
good functional status.[7, 8] Nevertheless, in
most studies HF patients with DCM represent a minor subgroup of the
overall study population.[9] Whether there is a
difference in prognosis between primary prophylactic ICD therapy in
patients with ICM and DCM remains unclear. To address this issue, we
conducted a retrospective study, which enrolled 82 patients with DCM or
ICM and with guideline indications for primary prophylactic ICD or CRT-D
treatment. We aimed to identify subgroups with greater or lesser
advantage from ICD therapy.