HRS: Vernakalant trumps amiodarone in sinus rhythm conversion

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Denver—The intravenous pharmacologic agent vernakalant (Cardiome) fared better than amiodarone to make the conversion of recent onset AF to sinus rhythm in patients suffering from atrial fibrillation (AF), according to a late-breaking clinical trial presented at the Heart Rhythm Society (HRS) scientific sessions last Friday.

Lead author A. John Camm, MD, of the St. George’s Hospital Medical School in London, presented the results of the multi-center, double-blind randomized clinical trial that evaluated the effectiveness of either vernakalant and amiodarone to reach sinus rhythm 90 minutes after infusion.

The clinical trial enrolled 254 patients diagnosed with symptomatic AF of three to 48 hours who were eligible for cardioversion. Two-thirds of the enrolled patients were male, the majority were white and the average age was 62.

Additionally, three-fourths of patients had hypertension, 30-40 percent had structural heart disease and all were adequately anticoagulated and hemodynamically stable.

Patients were randomized at a 1:1 ratio into two groups: 128 patients who were treated with vernakalant and 126 who received amiodarone during the duration of the trial.

According to Camm, 30 percent of the patients in each study arm reported that the episode of AF was their first event, while one-third of patients in both groups reported this incidence of AF as being their third or more event.

“The primary endpoint of this study was to determine the proportion of patients with a conversion of sinus rhythm within 90 minutes of the start of infusion,” said Camm.

During the study, researchers also measured three secondary endpoints for each of the study arms: time to conversion to sinus rhythm within 90 minutes, the number of patients without AF at 90 minutes and a change in the quality of life.

Camm reported that 52 percent of patients in the vernakalant arm reached the primary endpoint of achieving sinus rhythm within the 90-minute timeline compared with only 5.2 percent of the patients who met this endpoint in the amiodarone arm.

“This difference was statistically significant,” said Camm.

Additionally, Camm said that the “definition of the conversion to sinus rhythm was the production of sinus rhythm which exceeded one minute.”

In regard to secondary endpoints where researchers measured the conversion from AF to sinus rhythm, “The conversions were faster with vernakalant than with amiodarone,” said Camm.

Ten minutes after administering the drug, 24.1 percent of patients in the vernakalant arm had converted to sinus rhythm compared to only 0.09 percent of patients in the amiodarone arm.

At 90 minutes, 53.4 percent of patients in the vernakalant arm were free of AF symptoms, while only 32.8 percent in the amiodarone arm achieved freedom from AF at this time period.

According to Camm, there was one incident of non-fatal cardiac arrest in the amiodarone group and one patient who presented with sustained ventricular tachycardia in the vernakalant group.

“In conclusion, vernakalant was more effective in the rapid conversion of AF to sinus rhythm than was amiodarone,” said Camm. “Vernakalant was associated with a higher rate of symptom relief than treatment with amiodarone and vernakalant was associated with more significant improvement with patient’s perception of well being.”

Camm concluded, “In this study, vernakalant was safe and well tolerated and there were no cases of ventricular fibrillation or drug related deaths.”