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Hypertrophic Cardiomyopathy and Sudden Death Initially Identified at Autopsy
Barry J Maron1, Shannon Mackey-Bojack1, Emily Facile2
1HCM Institute, Tufts Medical Center, Boston, Massachusetts.
Insights
Sudden death (SD) in hypertrophic cardiomyopathy (HC) can occur unexpectedly, even with mild heart thickening. This study identifies characteristics of HC patients who die suddenly without prior evaluation, highlighting a challenge for prevention strategies.
Area of Science:
- Cardiology
- Pathology
- Genetics
Background:
- Hypertrophic cardiomyopathy (HC) carries a significant risk of sudden death (SD).
- Implantable cardioverter-defibrillators (ICDs) have reduced SD in evaluated HC patients.
- Characteristics of HC patients experiencing SD without prior clinical evaluation are poorly understood.
Purpose of the Study:
- To define the clinical and morphologic features of young HC patients who experienced sudden, unexpected death (SD) without prior clinical evaluation.
- To identify potential risk factors and circumstances associated with SD in this understudied population.
Main Methods:
- Analysis of 86 heart specimens from the Jesse Edwards Registry of young HC patients who died suddenly and unexpectedly.
- Review of clinical data for patients who lacked prior clinical evaluation for risk stratification.
Main Results:
- Patients were predominantly male (87%) with modest left ventricular (LV) wall thickening (18 ± 4 mm).
- SD events occurred during sedentary activities (66%), including sleep (32%), and physical activity (22%).
- This cohort represents a distinct subgroup of HC with mild-to-moderate hypertrophy experiencing SD.
Conclusions:
- A subset of HC patients with mild-to-moderate LV hypertrophy are at risk for sudden death, often during low-exertion activities or sleep.
- These findings present a clinical challenge for sudden death prevention in the current era of ICDs for hypertrophic cardiomyopathy.
- Further research is needed to identify effective preventive strategies for this vulnerable population.
Abstract:
Hypertrophic cardiomyopathy (HC) is associated with a well-recognized risk for unexpected sudden death (SD). Most such reported patients have been referred to dedicated centers and/or expert cardiologists for risk stratification, with the number of SDs decreasing sharply due to penetration of the implantable cardioverter-defibrillator (ICDs) into HC practice. However, the clinical circumstances, and morphologic features of HC patients who incur SD without the opportunity to be considered for preventive intervention with ICDs are largely undefined. Using the long-standing unique Jesse Edwards Registry (St. Paul, Minnesota), we studied 86 selected heart specimens from young HC patients who died suddenly and unexpectedly without prior clinical evaluation, ages 31 ± 16 years. The patients were predominantly male (87%) with only modest phenotypic expression and maximum LV wall thickening of only 18 ± 4 mm. SD events occurred predominantly with sedentary/mild activities (66%) often in bed or asleep (32%), but also during physical activity (22%) including with organized competitive sports. This largely unappreciated sub-population of patients with HC (and SD) is characterized by mild-to-moderate degree of LV hypertrophy, representing a clinical challenge which is particularly relevant in the current ICD era for HC, with the potential for SD prevention.
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