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Lifetime Course of Hypertrophic Cardiomyopathy Over 5 Decades
Quick Takes
- Investigators reviewed outcomes of 202 patients with hypertrophic cardiomyopathy (HCM) who were followed at least annually for up to 5 decades.
- The annual mortality rate due to HCM was relatively low at 1.3% per patient-year.
- The annual rate of sudden cardiac death (SCD) was 0.3% per patient-year, but mean age at SCD was 50 years vs. 69 years for those who died from other HCM-related causes.
Study Questions:
What is the clinical course of hypertrophic cardiomyopathy (HCM) over several decades?
Methods:
This study followed a cohort of 202 patients with HCM who were each initially evaluated at a center in Florence, Italy between 1970 and 1992. Patients were subsequently followed at least annually through 2020. Study endpoints included HCM-related mortality and non–HCM-related mortality. HCM-related mortality was defined as sudden cardiac death (SCD), death related to heart failure (HF), or fatal embolic stroke in the context of atrial fibrillation (AF). Investigators also calculated the proportion of HCM-related deaths that might have been preventable with contemporary management strategies. These included: 1) patients not on oral anticoagulation who experienced fatal embolic stroke in the context of AF, 2) SCD in patients lacking an implantable cardioverter-defibrillator (ICD) and who had ≥1 risk factor for SCD, 3) patients eligible for septal myomectomy who were treated conservatively and had New York Heart Association class III-IV HF and left ventricular outflow gradient >50 mm Hg, and 4) patients who were candidates for heart transplant but died of HF prior to age 65 years.
Results:
Patient follow-up averaged 27 years (range 3-50 years), starting at a mean age of 41 years. At baseline, >90% of patients were either asymptomatic or had mild symptoms, and 10% had AF. During the follow-up period, 52% of patients died (105 of 202) and 48% survived (97 of 202), including 25% >70 years of age. During follow-up, the mortality rate in the first decade (0.8%/patient-year) was lower than in the second (1.3%/patient-year) or third (2.7%/patient-year) decades. Cause of death was HCM-related in 69 patients; of these, 42 deaths were due to HF, 16 due to SCD, and 11 were due to embolic stroke associated with AF. Mean age at SCD was 50 years, whereas mean age with any HCM-related death was 64 years. The overall HCM-related mortality rate was 1.3%/patient-year, including 0.3%/patient-year due to SCD. Overall, 17% of patients received an ICD, 6.9% underwent septal myomectomy, and 2.0% received a cardiac transplant. Almost all of the HCM-related deaths in the time period prior to the widespread availability of effective treatment strategies were potentially preventable with contemporary therapies.
Conclusions:
The annual rate of mortality in patients with HCM is relatively low. The majority of HCM-related deaths are due to HF. Patients with SCD were younger than those with death secondary to HF. More than 40% of patients in the cohort could have potentially benefitted from therapies not commonly available 20 years ago.
Perspective:
Current knowledge regarding the clinical course of HCM has been derived from studies with a follow-up period of <10 years. This longitudinal study lasted 5 decades and the average patient follow-up duration was 27 years, ranging from 3 to 50 years. The authors state that, to their knowledge, this study is the longest of all observational HCM cohort studies.
Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Cardiac Surgery, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Aortic Surgery, Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Acute Heart Failure, Heart Transplant, Interventions and Structural Heart Disease, Interventions and Vascular Medicine
Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Cardiomyopathy, Hypertrophic, Death, Sudden, Cardiac, Defibrillators, Implantable, Embolic Stroke, Geriatrics, Heart Failure, Heart Transplantation, Risk Factors, Secondary Prevention, Uterine Myomectomy
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