Preoperative ventricular late potentials and the risk of adverse events in patients with obstructive hypertrophic cardiomyopathy undergoing septal myectomy.

BACKGROUND Ventricular late potentials (VLPs) detected by signal-averaged electrocardiogram are considered as an indicator of electrical instability in diseased myocardium. Little information exists about the VLPs and their effects on clinical prognosis in patients with obstructive hypertrophic cardiomyopathy (OHCM) undergoing septal myectomy. METHODS Patients with OHCM who underwent septal myectomy from January 2019 to December 2019 were prospectively enrolled. All patients underwent signal-averaged electrocardiogram. Patients were subsequently divided into two groups based on the presence or absence of VLPs. All patients were followed up after surgery to obtain information of survival status and adverse events, including all-cause mortality, congestive heart failure requiring hospitalization, new-onset stroke, and unexplained syncope. RESULTS In total, 128 patients (47.5±12.8 years, 57.8% male) were enrolled. There were 21 (16.4%) individuals in the VLPs-positive group and 107 (83.6%) individuals in the VLPs-negative group. There were no statistically significant differences in non-sustained ventricular tachycardia and late gadolinium enhancement on cardiovascular magnetic resonance images between the two groups. Eight adverse events were reported at the 14.9±4.1 months follow-up. The rates of adverse events in groups of VLPs-positive and VLPs-negative were 23.8% (5/21) and 2.8% (3/107) of cases, respectively. These events included three patients hospitalized for heart failure, two who experienced ischemic strokes, and three with unexplained syncope, respectively. Patients in the VLPs-positive group had a higher risk of adverse events than those in the VLPs-negative group (P<0.001). The presence of positive VLPs (hazard ratio =9.095, 95% confidence intervals: 2.080-39.776, P=0.003) was a strong independent risk factor of adverse events by multivariate Cox regression analysis. Cardiac function Class III or IV, as defined by the New York Heart Association classification, was also an independent risk factor of adverse events (hazard ratio =13.756, 95% confidence intervals: 1.667-113.510, P=0.015). CONCLUSIONS VLPs may increase the risk of adverse events in patients with OHCM after septal myectomy, which may be used as a screening test for further risk stratification.