Contribution of cardiac resynchronization therapy in hypertrophic cardiomyopathy with systolic dysfunction: A case-control study

Abstract

Cardiac resynchronization therapy (CRT), known as an effective treatment for heart failure in dilated cardiomyopathy (DCM), remains uncertain in hypertrophic cardiomyopathy (HCM), with conflicting results reported from previous studies. We aimed to study the efficiency of CRT in patients with HCM, heart failure and left ventricle systolic dysfunction. From implantable cardioverter defibrillator (ICD) data-base of a single university center, patients with HCM, who received CRT, were identified and matched with resynchronized DCM in a 2:1 ratio on age at implantation (± 5 years), gender and left ventricular ejection fraction (LVEF) at implantation (± 5%). Clinical, electro-cardiographic and echocardiographic parameters were gathered at 1–6 months, 6–12 months and last follow-up after implantation. Between 2007 and 2018, we included 18 HCM patients (women 7(39%); at ICD implantation, age 59 ± 9 years, LVEF 38 ± 6%, NYHA class 2.8 ± 0.4) matched with 36 controls. At one year after implantation, the relative median change from baseline showed better improvement in HCM patients regarding: 1/NYHA class (−50% vs. − 20%, P < 0.001), 2/LVEF (+ 30% vs. + 6%, P < 0.01), 3/left ventricular end-systolic (LVES) volume (− 39% vs. − 21%, P < 0.01), 4/cardiac output (+ 18% vs. + 5%, P < 0.001) and 5/BNP (− 51% vs. − 24%, P = 0.02). HCM patients retained the benefit of CRT at last follow-up (41 ± 24 months) for NYHA (− 33% vs. − 12%, P < 0.01), LVEF (− 36% vs. − 11%, P < 0.01), LVES volume (− 42% vs. − 20%, P = 0.01) and cardiac output (+1 8% vs. − 2%, P < 0.001). The rate of bi-ventricular pacing (98% vs. 99%, P = 0.81) and the QRS duration (130ms vs. 130ms, P = 0.57) at one year after CRT were comparable in the both groups. Among HCM patients, 2 (11%) of them died and 2 (11%) had a heart transplant. CRT improved heart failure symptoms and carried out reverse remodeling of the left ventricle in HCM with better outcomes than in DCM in long-term follow-up.