Elsevier

Heart Rhythm

Volume 20, Issue 6, June 2023, Pages 886-890
Heart Rhythm

Clinical
Heart Failure
Imaging modality for left ventricular ejection fraction estimation and effect of implantable cardioverter-defibrillator on mortality in patients with heart failure

https://doi.org/10.1016/j.hrthm.2023.03.010Get rights and content

Background

Implantable cardioverter-defibrillators (ICDs) improve outcomes in patients with heart failure (HF) with left ventricular ejection fraction (LVEF) ≤35%. Less is known about whether outcomes varied between the 2 noninvasive imaging modalities used to estimate LVEF—2-dimensional echocardiography (2DE) and multigated acquisition radionuclide ventriculography (MUGA)—which use different principles (geometric vs count-based, respectively).

Objective

The purpose of this study was to examine whether the effect of ICD on mortality in patients with HF and LVEF ≤35% varied on the basis of LVEF measured by 2DE or MUGA.

Methods

Of the 2521 patients with HF with LVEF ≤35% in the Sudden Cardiac Death in Heart Failure Trial, 1676 (66%) were randomized to either placebo or ICD, of whom 1386 (83%) had LVEF measured by 2DE (n = 971) or MUGA (n = 415). Hazard ratios (HRs) and 97.5% confidence intervals (CIs) for mortality associated with ICD were estimated overall, checking for interaction, and within the 2 imaging subgroups.

Results

Of the 1386 patients in the present analysis, all-cause mortality occurred in 23.1% (160 of 692) and 29.7% (206 of 694) of patients randomized to ICD or placebo, respectively (HR 0.77; 97.5% CI 0.61–0.97), which is consistent with that in 1676 patients in the original report. HRs (97.5% CIs) for all-cause mortality in the 2DE and MUGA subgroups were 0.79 (0.60–1.04) and 0.72 (0.46–1.11), respectively (P = .693 for interaction). Similar associations were observed for cardiac and arrhythmic mortalities.

Conclusion

We found no evidence that in patients with HF and LVEF ≤35%, the effect of ICD on mortality varied by the noninvasive imaging method used to measure LVEF.

Introduction

Sudden cardiac death is the most common mode of death for patients with heart failure with reduced ejection fraction (HFrEF).1,2 National guidelines recommend an implantable cardioverter-defibrillator (ICD) in patients with HFrEF with left ventricular ejection fraction (LVEF) ≤35% but do not recommend any specific imaging modality to determine LVEF.3,4 Two-dimensional echocardiography (2DE) and radionuclide ventriculography, also known as multigated acquisition radionuclide ventriculography (MUGA), are 2 commonly used noninvasive imaging approaches that use different mechanisms to estimate LVEF. Less is known about whether the effect of ICD on mortality varies between the 2 noninvasive imaging modalities used to estimate LVEF, the examination of which was the objective of the present study.

Section snippets

Source of data and study patients

The present analysis is based on a public use copy of data of the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) sponsored by the National Heart, Lung, and Blood Institute, the details of the rationale, design, and results of which have been previously reported.5 SCD-HeFT was a prospective, randomized, placebo-controlled trial comparing the effect of amiodarone or ICD on all-cause mortality in patients with chronic HFrEF (LVEF ≤35%) receiving conventional heart failure therapy. The

Baseline characteristics

The baseline characteristics of patients receiving ICD or placebo are summarized in Table 1. Of the 971 patients whose LVEF was estimated using 2DE, 486 were randomized to placebo and 485 were randomized to ICD. These patients had a mean age of 59 and 60 years, respectively, and both groups had a mean LVEF of 24% (Table 1). In contrast, of the 415 patients whose LVEF was estimated using MUGA, 208 were randomized to placebo and 207 were randomized to ICD. These patients had a mean age of 60 and

Discussion

The findings from our post hoc analyses of the SCD-HeFT data demonstrate that the effect of ICD in the subgroup of patients whose LVEF was estimated using the noninvasive imaging modalities of 2DE or MUGA is similar to that observed in the original trial. Furthermore, we demonstrate that there is no evidence of heterogeneity of the associations of ICD with all-cause and cause-specific cardiac mortalities between patients in the 2 noninvasive imaging modality groups. To our knowledge, this is

Conclusion

The findings of the present post hoc analysis of the SCD-HeFT data demonstrate that there is no evidence of heterogeneity in the effect of ICD on mortality in patients with HFrEF regardless of whether 2DE or MUGA was used to measure LVEF to determine the eligibility for the device.

References (13)

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Funding Sources: Dr Ahmed was in part supported by grants from the Department of Veterans Affairs (I01HX002422).

Disclosures: Dr Fonarow reports consulting with Abbott, Amgen, AstraZeneca, Bayer, Cytokinetics, Edwards, Janssen, Medtronic, Merck, and Novartis. None of the other authors report any conflicts of interest related to this manuscript. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Department of Veterans Affairs.

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Equal contribution.

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