AF confers elevated mortality risk in hypertrophic cardiomyopathy
Incident atrial fibrillation in a cohort of patients with hypertrophic cardiomyopathy, or HCM, was associated with elevated risk for cardiac death, according to research published in EClinicalMedicine.
“Compared with general population, AF is signicantly more common in HCM patients. ... Furthermore, AF in HCM has been regarded as a progressive arrhythmia responsible for a major impact on clinical course,” Min-Tsum Liao, MD, from the division of cardiology in the department of internal medicine at National Taiwan University Hospital Hsinchu Branch, and colleagues wrote. “Sudden cardiac arrest and AF may share similar risk factors in HCM population. However, the relationship between the risk for sudden cardiac arrest and AF has not been well studied.”
In a large-scale, longitudinal cohort study, researchers analyzed 10,910 patients with HCM (mean age, 62 years) from the Registry for Catastrophic Illness to determine the association between AF and risk for sudden cardiac arrest. The primary outcome was sudden cardiac arrest and the secondary outcome was nonsudden cardiac death, defined as death from HF, stroke or cardiac causes not related to HCM. Patients were stratified by whether they developed AF after being diagnosed with HCM.
During a follow-up of median 8.5 years, 3.4% of patients experienced sudden cardiac arrest and 7.3% of patients died of nonsudden cardiac causes. In patients with AF, the annual incidence rate of sudden cardiac arrest was 1.2%, a 3.6-fold higher risk than in patients without AF (12.45 per 1,000 person-years vs. 3.57 per 1,000 person-years), and the annual incidence rate of nonsudden cardiac death was 3.1%, a 2.1-fold higher risk than in patients without AF (31.29 per 1,000 person-years vs. 6.63 per 1,000 person-years).
In a multivariable Cox regression analysis, AF was significantly associated with increased risk for sudden cardiac arrest (HR = 3.633; 96% CI, 2.756-4.791) and nonsudden cardiac death (HR = 2.086; 95% CI, 1.799-2.418).
Researchers further noted AF development was independently associated with older age, female sex and history of HF hospitalization.
“AF is an important component of clinical course in many patients with HCM. Incident AF independently increases the risk of sudden cardiac arrest and nonsudden cardiac death, especially stroke-related death,” Liao and colleagues wrote. “Our findings underscore the importance of AF detection in HCM patients, followed by prophylaxis of oral anticoagulants and the evaluation of sudden cardiac arrest risk in those with diagnosed AF.”
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