Ventricular arrhythmia outcomes in hypertrophic cardiomyopathy from a high level myectomy centre

Abstract

Abstract Background The presence of ≥15% late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (MRI) is used as a prognostic indicator for sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). [1] According to the European Society of Cardiology clinical practice guidelines (2014), septal myectomy is only indicated for symptomatic relief from left ventricular outflow tract obstruction (LVOTO) that is refractory to medical therapy, provided LVOTO gradient ≥ 50 mmHg. [2] At present, there is scarce data correlating the burden of ventricular arrhythmia and sudden cardiac death with LGE percentage or showing benefit of myectomy in reducing the burden of the same. Purpose We aimed to compare the burden of ventricular arrhythmia burden in patients with HCM who underwent septal myectomy compared with those who did not. Methods Adult patients with HCM followed in the advanced heart failure outpatient clinic at Allegheny General Hospital were included in this study. All included patients had cardiac MRI with LGE quantification and data related to cardiac events through devices placed for various indications (such as evaluation of reported palpitations, established supraventricular tachycardia, implantable cardioverter-defibrillator for primary or secondary prevention). Patients were divided into 2 groups: those undergoing myectomy (post myectomy group) and those that did not undergo myectomy (non-myectomy group). Chi square test was used to calculate incidence of premature ventricular contractions (PVCs), non-sustained ventricular tachycardia (NSVT) and sustained ventricular tachycardia (SVT) in the non-myectomy and post myectomy group. Results 76 patients with HCM (interventricular septal thickness ≥1.5 cm and LGE positive) longitudinally followed in the Allegheny General Hospital advanced heart failure outpatient clinic from 2016 to 2022 were included. 37 patients underwent septal myectomy. Baseline characteristics of post myectomy and non-myectomy group were matched and are listed in table 1. Left ventricular mass index was expectedly higher in patients undergoing myectomy. LGE was quantified on cardiac MRI prior to myectomy (mean 16.4% in myectomy group, 14.6% in non-myectomy group). Burden of ventricular arrhythmia (PVCs, NSVT and SVT) was found to be significantly lower in the post myectomy group (n=13, 44.83%) compared to the non-myectomy group (n=36, 92.31%). None of the patients included were noted to have ventricular fibrillation or sudden cardiac death. Conclusion Septal myectomy may reduce the incidence of ventricular arrhythmia and thus impact outcomes related to sudden cardiac death. This is likely a consequence of removal of arrhythmogenic scar tissue. Larger studies are required to further evaluate the burden and correlation of ventricular arrhythmia with scar tissue volume measured on cardiac MRI.