{'fraction_non_alphanumeric': 0.030317385125532923, 'fraction_numerical': 0.018474656560871626, 'mean_word_length': 5.342342342342342, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Contemporary insights and strategies for risk stratification and prevention of sudden death in hypertrophic cardiomyopathy.

After 50 years of recognition and study, it is evident that hypertrophic cardiomyopathy (HCM) is a particularly heterogeneous and unpredictable disease with respect to its clinical expression and natural history.1–5 Sudden death (SD) continues to be the most devastating complication of HCM, dating from its modern description.6 However, there were virtually no effective strategies for SD prevention until recently when HCM entered the implantable cardioverter-defibrillator (ICD) era,7–9 creating an enhanced focus on risk stratification and reliable identification of high-risk patients.8–14 Consequently, it is timely to summarize what has been learned about HCM-related SD over these 5 decades, including the electrophysiological substrate, epidemiology, risk markers, and ultimately the role of ICDs, which have changed the natural course of this complex disease.

This discussion emphasizes the clarification of areas in which disagreement and divergent views arise, by using available information to achieve a balanced assessment of SD in HCM. However, these observations ultimately represent only a “snapshot” in time for what undoubtedly will prove to be an evolving area of investigation and understanding.

The specter of SD has been intertwined with the diagnosis of HCM, which is now regarded as the most common cause of these events in young people, including competitive athletes2,3,5,10–15 (Figure 1). Although the most visible complication of HCM,2,3,7–9,13 SD occurs in only a small minority of patients and is less common than other adverse disease consequences, including atrial fibrillation and progressive heart failure.3,11,16 



Figure 1. SD and age in HCM. Top, SD is most common before ≈25 years of age, whereas heart failure and stroke generally occur later in life. From Maron et al.11 Used with permission from the American Heart Association, copyright © 2000. Bottom, Single most frequent cause of SD in young competitive athletes in the United States. …