In Reply We thank Nishimura et al for their insightful comments on our analysis assessing the efficacy of implantable cardioverter defibrillator (ICD) therapy in patients with and without improved ejection fraction.1 We agree that there has been significant progress in medical and device therapy since the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) was conducted. β-Blocker therapy is now an established part of heart failure treatment, and aldosterone receptor blockers, which were not used routinely for heart failure at the time, have since been shown to reduce all-cause mortality and sudden cardiac death. Further, cardiac resynchronization therapy, which has also been introduced since SCD-HeFT, may alter the efficacy of defibrillators in patients with reduced ejection fraction and left bundle branch block, which made up 22% of the SCD-HeFT cohort.2 Although the mechanism of effect of these therapies has not been fully elucidated, a common outcome of the medical and cardiac resynchronization therapies is improvement in left ventricular ejection fraction, which we have learned does not provide immunity from sudden cardiac death. We agree with Nishimura et al that prospective studies using current medical therapies are necessary to answer the question at hand. Until then, we hope that the lessons we learned from this post hoc analysis of SCD-HeFT will be useful to clinicians.
Adabag S, Patton KK, Buxton AE. Benefits of Contemporary Implantable Cardioverter Defibrillators in Patients With Improved Ejection Fraction: When is the Most Clinically Relevant Time to Evaluate?—Reply. JAMA Cardiol. 2017;2(12):1397–1398. doi:10.1001/jamacardio.2017.3458
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