Background:
Historically, youthful age has been considered the time period of greatest risk for patients with hypertrophic cardiomyopathy (HCM), largely a consequence of increased risk of sudden cardiac death. However, the last two decades have witnessed emergence of an expanded risk stratification algorithm resulting in more reliable identification of at-risk patients and enhanced utilization of implantable cardioverter-defibrillators (ICD) for sudden death prevention. However, whether these advances have significantly altered mortality rates for young HCM patients is currently unresolved.
Objective:
Define the clinical course and adverse event rate in children and young adults with HCM.
Methods:
We studied the long-term outcomes of 321 consecutive HCM patients presenting at 2 institutions between 10 and 29 years of age, and followed over 7.2 ± 4.8 years.
Results:
Over follow-up, 302 patients (94%) survived to 27 ± 5 years, with the majority (96%) experiencing no or mild symptoms at last evaluation. HCM-related death occurred in 16 patients (5%; 0.7%/year): arrhythmic sudden death (n=12), complications following heart transplant (n=3), and progressive heart failure (n=1). In contrast, aborted HCM-related mortality occurred in 41 other high-risk HCM patients (implantable cardioverter-defibrillator (ICD) interventions for ventricular tachyarrhythmia [n =24], resuscitated out of hospital cardiac arrest [n=7], and heart transplant for advanced unrelenting heart failure [n=10]), 2.0%/year, and at a rate almost 3-fold higher than actual HCM mortality. Survival at 5- and 10-years (considering only HCM deaths) was excellent at 97% and 92%, and not significantly different from survival rates recently reported in HCM patients identified during mid-life (ages 30 to 59 years old; 98% and 94%, p=0.23).
Conclusions:
In a cohort of young HCM patients contemporary treatment strategies have resulted in low mortality (<1%/year), due largely to identification of high-risk patients who benefit from sudden death prevention with the ICD, creating the opportunity for extended longevity.
Paradigm of Sudden Death Prevention in Hypertrophic Cardiomyopathy
