June 21, 2013

Rhythm response tied to gene variant

A genetic variant that increases risk for atrial fibrillation also impacts the response to a common therapy for the heart rhythm disorder.

Illustration of heart

Atrial fibrillation (AF) – the most common disorder of heart rhythm – impairs quality of life. Patients with symptomatic AF may require electrical treatment (direct current cardioversion, DCCV) to restore a normal heart rhythm, but AF recurs within the first month for about half of patients who undergo DCCV.

Dawood Darbar, M.D., associate professor of Medicine, and colleagues explored whether genetic variants associated with AF also impact the timing of AF recurrence after DCCV therapy. They evaluated 208 patients who underwent successful DCCV, and found that a certain genetic variant on chromosome 4q25 predicts AF recurrence. They report in the June issue of Heart Rhythm that homozygous carriers (two copies) of the 4q25 variant experience earlier AF recurrence (median time 7 days) compared to heterozygous carriers (one copy, 54 days) and wild-type patients (64 days).

The findings reveal that homozygous carriers of the 4q25 risk variant may be poor candidates for DCCV because of early AF recurrence and suggest the need for alternative strategies for managing AF in these patients.

This research was supported by grants from the National Institutes of Health (HL085690, HL065962), including a Clinical and Translational Science Award (TR000445), and by an American Heart Association National Established Investigator Award.