Abstract 12498: Incidence Of Non-Sustained Ventricular Tachycardia and Arrhythmic Disease Progression During Follow-Up in Hypertrophic Cardiomyopathy Patients

Abstract

Introduction: One of the most well-established risk markers for sudden cardiac death is non-sustained ventricular tachycardia (NSVT; 3 ventricular beats with a rate of ≥120 bpm, lasting for <30 seconds). Forty-eight-hours Holter monitoring is recommended to identify NSVT in patients with hypertrophic cardiomyopathy (HCM) . Purpose: The study aims to estimate the 48 hour-incidence of NSVT in HCM patients and to analyze arrhythmic disease progression during follow up. Methods: The study retrospectively evaluated HCM patients enrolled in the Registry for Hereditary Cardiovascular Diseases from 2011 to 2020. A total of 145 patients met the inclusions criteria to be a proband with HCM or a relative with left ventricular hypertrophy ≥13mm. A cross sectional analysis was done in 131 patients with at least one available Holter monitoring. A follow-up Holter monitoring was available in 97 patients. Results: Of 145 patients, the mean age was 54±15 years and 98 (68%) were male. The proportion of patients free of NSVT were 66% after 48 hours of Holter monitoring (n=131) (Kaplan-Meier estimates). Fifteen percent of NSVTs occurred from 36 to 48 hours into the Holter monitoring. The mean follow-up time between first and latest Holter (n=97) was 4.3 (±2.5) years and the median Holter monitoring time was both 48 (IQR, 48-48) hours at the first and 48 (IQR, 47-48) hours at the latest Holter. The proportion of patients free of NSVT in the first 48 hour Holter monitoring was 69% compared to 63% in the latest 48 hour Holter monitoring (p=0.17). Wilcoxon signed rank test showed no difference in number of ventricular cycles or the calculated frequency analyzing the first episode of NSVT in each Holter. Cox regressions analysis showed no significant difference in event rates between first and latest Holter (HR 0.84, 95% CI 0.26-2.70, p=0.77) and no association between age and NSVT (HR 1.03, 95% CI 0.83-1.28, p=0.80). Conclusions: NSVT occurred with an incidence rate of 34% per 48-hours Holter monitoring. An important part of NSVTs was identified in the last 12 hours of monitoring. The was no significant progression in the incidence rate of NSVT nor the characteristics of NSVT during follow up. Age had no effect on the incidence of NSVT.