Hydroquinidine Prevents Arrhythmias Associated With Short QT Syndrome

NEW YORK (Reuters Health) Jul 26 - Hydroquinidine prevents ventricular tachyarrhythmias and arrhythmic events in patients with the often fatal short QT syndrome, new research shows.

"The incidence of arrhythmic events during the follow-up was 4.9% per year in the patients without pharmacological prophylaxis," the researchers found, "whereas no arrhythmic events occurred in those receiving hydroquinidine."

Hydroquinidine can be an alternative to an implantable cardioverter-defibrillator (ICD) in patients who can't or won't receive one, "but it is still underused," said Dr. Carla Giustetto from University of Turin, San Giovanni Battista Hospital, Turin, Italy and colleagues in the August 2nd Journal of the American College of Cardiology.

The research team analyzed data from the European Short QT Registry on 53 patients. Study subjects had a corrected QT interval of 360 ms plus a history of sudden death, aborted sudden death or syncope of arrhythmic origin, or a QTc of 340 ms or less even without symptoms.

Five of 17 patients for whom genetic test results were available had a relevant mutation.

Twenty-eight patients had electrophysiological studies. Their ventricular effective refractory periods were shortened and varied between 140 and 200 ms (mean, 166 ms), but there was no difference between patients with and without a history of cardiac arrest or syncope. Only three of eight patients with a history of cardiac arrest (and 16 of 28 overall) had inducible ventricular fibrillation.

Twenty-two patients were treated with hydroquinidine, but only 12 received the medication long-term. Hydroquinidine significantly prolonged ventricular effective refractory period in these patients, and none of the seven treated patients who had inducible ventricular fibrillation at baseline had ventricular fibrillation induced after hydroquinidine treatment.

Fourteen of 24 patients treated with an ICD had complications, including inappropriate shocks in eight patients, lead fractures in three patients, and ICD infection, device recall, and severe psychological distress in one patient each.

"In the future," the authors conclude, "it would be important to expand this registry, including also asymptomatic subjects with borderline short QT intervals, to understand better the prognosis and to help guide the management of such patients."

SOURCE: http://bit.ly/q0zaem