Abstract
BackgroundCurrent indications for implantable cardioverter defibrillator (ICD) implantation for sudden cardiac death prevention rely primarily on left ventricular (LV) ejection fraction (LVEF). Currently, two different contouring methods by cardiovascular magnetic resonance (CMR) are used for LVEF calculation. We evaluated the comparative prognostic value of these two methods in the ICD population, and if measures of LV geometry added predictive value.MethodsIn this retrospective, 2-center observational cohort study, patients underwent CMR prior to ICD implantation for primary or secondary prevention from January 2005 to December 2018. Two readers, blinded to all clinical and outcome data assessed CMR studies by: (a) including the LV trabeculae and papillary muscles (TPM) (trabeculated endocardial contours), and (b) excluding LV TPM (rounded endocardial contours) from the total LV mass for calculation of LVEF, LV volumes and mass. LV sphericity and sphere-volume indices were also calculated. The primary outcome was a composite of appropriate ICD shocks or death.ResultsOf the 372 consecutive eligible patients, 129 patients (34.7%) had appropriate ICD shock, and 65 (17.5%) died over a median duration follow-up of 61 months (IQR 38–103). LVEF was higher when including TPM versus excluding TPM (36% vs. 31%, p < 0.001). The rate of appropriate ICD shock or all-cause death was higher among patients with lower LVEF both including and excluding TPM (p for trend = 0.019 and 0.004, respectively). In multivariable models adjusting for age, primary prevention, ischemic heart disease and late gadolinium enhancement, both LVEF (HR per 10% including TPM 0.814 [95%CI 0.688–0.962] p = 0.016, vs. HR per 10% excluding TPM 0.780 [95%CI 0.639–0.951] p = 0.014) and LV mass index (HR per 10 g/m2 including TPM 1.099 [95%CI 1.027–1.175] p = 0.006; HR per 10 g/m2 excluding TPM 1.126 [95%CI 1.032–1.228] p = 0.008) had independent prognostic value. Higher LV end-systolic volumes and LV sphericity were significantly associated with increased mortality but showed no added prognostic value.ConclusionBoth CMR post-processing methods showed similar prognostic value and can be used for LVEF assessment. LVEF and indexed LV mass are independent predictors for appropriate ICD shocks and all-cause mortality in the ICD population.
Highlights
The implantable cardioverter-defibrillator (ICD) has been established as an effective therapy for both primary and secondary prevention of sudden cardiac death (SCD) [1, 2]
All events were reviewed by trained device technicians and by an attending electrophysiologist blinded to cardiovascular magnetic resonance (CMR) measurements
In patients with an ischemic heart disease a stronger effect was observed for lower Left ventricular ejection fraction (LVEF) when including trabeculae and papillary muscles (TPM) (p for interaction = 0.017), and for higher Left ventricular end-diastolic volume index (LVEDVI) including and excluding TPM (p for interaction = 0.012 and 0.013, respectively), and higher Left ventricular end-systolic volume index (LVESVI) when excluding TPM (p for interaction = 0.0012), when compared with patients without ischemic heart disease. In this 2-center study of 372 patients, we found a higher rate of appropriate implantable cardioverter defibrillator (ICD) shocks and mortality in patients with lower LVEF, and that both LVEF and Left ventricular mass index (LVMI) have independent prognostic value after adjusting for clinically relevant variables, regardless of the post-processing method used
Summary
The implantable cardioverter-defibrillator (ICD) has been established as an effective therapy for both primary and secondary prevention of sudden cardiac death (SCD) [1, 2]. When measuring LV function and mass using cardiovascular magnetic resonance (CMR), the trabeculae and papillary muscles (TPM) are usually considered part of the blood pool for better reproducibility. These correspond to myocardial tissue and theoretically should be included in the total LV mass (LVM) calculation [8]. To our knowledge no studies have directly compared these two CMR measuring methods in ICD recipients, and determined which method would be a better predictor of events. Current indications for implantable cardioverter defibrillator (ICD) implantation for sudden cardiac death prevention rely primarily on left ventricular (LV) ejection fraction (LVEF). Two different contouring methods by cardiovascular magnetic resonance (CMR) are used for LVEF calculation. We evaluated the comparative prognostic value of these two methods in the ICD population, and if measures of LV geometry added predictive value
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