Prognostic implications of papillary muscle delayed hyperenhancement in dilated cardiomyopathy patients

Abstract

Abstract Background Similar to left ventricle (LV) myocardial delayed hyperenhancement (HE), papillary muscle delayed hyperenhancement (papHE) at cardiac magnetic resonance (CMR) may indicate fibrotic or infiltrative processes. The prevalence in patients with non-ischemic dilated cardiomyopathy (DCM) and its impact on outcome are unknown. Objectives We aimed to determine the prevalence of papHE in an outpatient DCM cohort with longitudinal follow-up. Methods From the Maastricht Cardiomyopathy Registry, we included 528 consecutive patients who underwent Late Gadolinium Enhancement (LGE) Cardiac Magnetic Resonance imaging (CMR), and both papHE and papillary tip delayed hyperenhancement (tipHE) were assessed. The primary outcomes were all-cause mortality, sudden cardiac death, life-threatening arrhythmia, and hospitalization for heart failure (HFH). Unadjusted Kaplan Meier curves were constructed and compared using log-rank tests. PapHE was related to outcomes, using univariable and multivariable Cox regression analysis, correcting for clinical covariables (age, sex, and LV ejection fraction). In a second model, we corrected for myocardial HE, on top of the covariables included in the first model. Mitral valve regurgitation was assessed during follow-up echocardiography in 409 patients (77%). Results Three hundred and twenty five patients (62%) had tipHE and 131 patients (25%) had papHE. The median follow-up duration was 5.6 (IQR 3.5-9.0) years. PapHE was associated with all-cause mortality (HR=1.76, 95% CI 1.04-2.97), sudden cardiac death (HR=2.23, 95% CI 1.10-4.54) and HFH (HR=2.42, 95% CI 1.16-5.06), but not with life-threatening arrhythmias, after correction for clinical covariables. The presence of isolated tipHE was not associated with adverse outcomes. The correlation of myocardial HE was stronger than that of papHE, specifically with sudden cardiac death (HR=2.40, 95% CI 1.10-5.23 for myocardial HE) and life-threatening arrhythmias (HR=2.97, 95% CI 1.04-8.46 for myocardial HE). Additional correction for myocardial HE rendered the correlation between papHE and the studied outcomes insignificant. Finally, papHE did not correlate to mitral regurgitation. Conclusions PapHE is present in 25% of DCM patients. The presence of papHE correlated with sudden cardiac death and HFH, still myocardial HE remains a stronger predictor. Our results support the incorporation of myocardial HE in implantable cardioverter-defibrillator guideline recommendations. Future studies should investigate if the addition of PapHE helps to improve such guidelines further.