Abstract P556: Temporal and Global Trends of the Incidence of Sudden Cardiac Death in Hypertrophic Cardiomyopathy: A Meta-Analysis

Introduction: Since hypertrophic cardiomyopathy(HCM) initial description, sudden cardiac death (SCD) has been the most feared complication of HCM.

Hypothesis: Temporal, geographical, and age-related trends of SCD rates in HCM have drastically decreased over time.

Methods: Databases were systematically searched to Nov 2021 for studies reporting on SCD event rates in HCM. Patients with SCD equivalents (appropriate ICD shocks and non-fatal SCD) were excluded. Random-e!ects model was utilized to pool study estimates calculating the overall incidence rates(IR) for each time-era, geographical region, and age-group. We analyzed 2 eras (before vs. after 2000, following implementation of ICD in HCM). Following 2000, 5-year intervals were used to reflect the temporal change in SCD.

Results: 98 studies(N=70,510patients and 431,407patient-years) met inclusion criteria. Overall rate of HCM SCD was 0.43%/year (95% CI: 0.37-0.50%; I2=75%; SCD events:1,938; person-years of follow-up: 408,715), with young patients(<18 years) demonstrating a>2-fold-risk for SCD vs. adults(18- 60years) (IR:1.09%; 95% CI: 0.69-1.73% vs. IR: 0.43%; 95% CI: 0.37-0.50%)(P-value for subgroup di!erences:<0.01). Contemporary SCD rates from 2015-present were 0.32%/year; significantly lower compared to 2000 or earlier (IR: 0.32%; 95% CI:0.20-0.52%, vs. IR: 0.73%; 95% CI:0.53-1.02%,respectively). Reported HCM-SCD rates were lowest in North America (IR: 0.28%;95% CI:0.18-0.43%) and highest in Asia(IR: 0.67%; 95% CI:0.54-0.84%).

Conclusions: Contemporary HCM-related SCD are low (0.32%/year) representing a 2-fold decrease compared to prior treatment eras, with young HCM patients at the highest risk. SCD risk stratification maturation and primary prevention ICD application are likely responsible for the notable decline in SCD trends. Moreover, worldwide geographical disparities in SCD was evident, underscoring the need to increase access to SCD prevention for all HCM patients.

Temporal and Global Trends of the Incidence of Sudden Cardiac Death in Hypertrophic Cardiomyopathy

BACKGROUND

Since the initial clinical description of hypertrophic cardiomyopathy (HCM) over 60 years ago, sudden cardiac death (SCD) has been the most visible and feared complication of HCM.

OBJECTIVES

This study sought to characterize the temporal, geographic, and age-related trends of reported SCD rates in adult HCM patients.

METHODS

Electronic databases were systematically searched up to November 2021 for studies reporting on SCD event rates in HCM patients. Patients with SCD equivalents (appropriate implantable cardioverter-defibrillator [ICD] shocks and nonfatal cardiac arrests) were not included. A random-effects model was used to pool study estimates calculating the overall incidence rates (IR) for each time-era, geographic region, and age group. We analyzed 2 periods (before vs after 2000, following clinical implementation of ICD in HCM). Following 2000, 5-year intervals were used to demonstrate the temporal change in SCD rates.

RESULTS

A total of 98 studies (N = 70,510 patients and 431,407 patient-years) met our inclusion criteria. The overall rate of HCM SCD was 0.43%/y (95% CI: 0.37-0.50%/y; I² = 75%; SCD events: 1,938; person-years of follow-up: 408,715), with young patients (<18 years of age) demonstrating a >2-fold-risk for sudden death vs adult patients 18-60 years of age (IR: 1.09%; 95% CI: 0.69%-1.73% vs IR: 0.43%; 95% CI: 0.37%-0.50%) (P value for subgroup differences <0.01). Contemporary SCD rates from 2015 to present were 0.32%/y and significantly lower compared with 2000 or earlier (IR: 0.32%; 95% CI: 0.20%-0.52% vs IR: 0.73%; 95% CI: 0.53%-1.02%, respectively). Reported SCD rates for HCM were lowest in North America (IR: 0.28%; 95% CI: 0.18%-0.43%,) and highest in Asia (IR: 0.67%; 95% CI: 0.54%-0.84%).

CONCLUSIONS

Contemporary HCM-related SCD rates are low (0.32%/y) representing a 2-fold decrease compared with prior treatment eras. Young HCM patients are at the highest risk. The maturation of SCD risk stratification strategies and the application of primary prevention ICD to HCM are likely responsible for the notable decline over time in SCD events. In addition, worldwide geographic disparities in SCD rates were evident, underscoring the need to increase access to SCD prevention treatment for all HCM patients.