Older age, history of arrhythmia, high body mass index (BMI), moderate or severe mitral regurgitation (MR), reduced left atrial (LA) contractile percent and increased LA volume could predict major atrial fibrillation (AFib) endpoints in patients with hypertrophic cardiomyopathy (HCM), according to a study published June 30 in JACC: Clinical Electrophysiology.

Christopher M. Kramer, MD, FACC, et al., used data from the Hypertrophic Cardiomyopathy Registry to evaluate major AFib endpoints in patients with HCM. Participants were recruited from 44 sites across six countries and received an annual telephone follow-up during which researchers collected data on hospitalizations, medical procedures and other clinical events. Data were also collected from cardiac MRI and blood was drawn for biomarker and genetic analysis.

For this analysis of 2,631 patients with paroxysmal AFib (registry participants with persistent or permanent AFib at baseline were excluded), the major clinical AFib endpoints were the need for electrical cardioversion, catheter ablation, hospitalization for more than 24 hours, and the clinical decision to accept permanent AFib.

Results showed that over the median follow-up of 33.5 ± 12.4 months, the researchers identified 127 major AFib endpoint events in 96 patients. Of these events, 85 patients had one event, six had two events, two had three, one had six, one had eight and one patient had 10 events. There were 24 all-cause deaths.

In what the authors state is the first study in HCM to examine predictors of major AFib endpoints, vs. all-incident AFib, the strongest predictors were age, LA volume index, LA contractile percentage, increased BMI, moderate or severe MR and history of arrhythmia. Age-dependent factors were LA volume index, LA contractile percentage and BMI. For younger patients, obesity was the strongest risk factor, while in those who were middle-aged and older, they were moderate or severe MR, increased LA volume index and reduced LA contractile percent.

"The principal findings were that age is an important predictor of major [AFib] endpoints in HCM and that the other predictors, which includes obesity, moderate or severe MR, history of arrhythmia, and CMR-derived increased LAV index and decreased contractile function, were age-dependent," write the authors. They add that prospective testing of a risk score based on these parameters may be warranted.

Clinical Topics: Arrhythmias and Clinical EP, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Valvular Heart Disease, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Magnetic Resonance Imaging, Mitral Regurgitation

Keywords: Middle Aged, Aged, Atrial Fibrillation, Body Mass Index, Electric Countershock, Mitral Valve Insufficiency, Heart Atria, Cardiomyopathy, Hypertrophic, Magnetic Resonance Imaging, Atrial Appendage, Catheter Ablation, Registries, Hospitalization, Obesity, Telephone, Electrophysiology

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