Independent study finds IV vernakalant helps ECV in patients with cardioversion resistant AF

The study, entitled "Vernakalant-facilitated electrical cardioversion: comparison of intravenous vernakalant and amiodarone for drug-enhanced electrical cardioversion of atrial fibrillation after failed electrical cardioversion" authored by Andreas Müssigbrodt et al., is published in the Advanced Access section of journal Europace website ( June 8, 2015 ).

Cardiome Pharma Corp. did not fund the study, design its protocols or have any role in study implementation or analysis.

The non-randomized study examined if either of two pharmacologic converting agents, vernakalant or amiodarone, facilitated subsequent ECV in 63 patients with IRAF (n = 44; 70%) or FECV (n = 19; 30%) after consecutive ECV.

Patients were assigned to receive either a single dose of vernakalant (n = 33; 52%) or amiodarone (n = 30; 48%) prior to another attempt with ECV at the discretion of the treating physician.

Ten minutes after completion of the drug infusion, transthoracic ECV was attempted again with a shock that had the same energy as the previous shock. In the event of another episode of IRAF, no more attempts of ECV were repeated.

The study found that 66.7% of the patients in the vernakalant group (22 of 33 patients) were successfully electrically cardioverted after drug infusion compared to 46.7% (14 of 30 patients) of patients treated with amiodarone (P=0.109).

Treatment with vernakalant was also listed as a predictor of successful, drug-facilitated ECV based upon the results of a multivariate analysis (OR 0.057, 95% CI 0.006-0.540, P=0.013). In addition, a subgroup analysis found that patients who had undergone previous AF ablation and who were provided vernakalant had a conversion rate of 66.7% (6 of 9 patients) compared to 11.1% (1 of 9 patients) in the same population who were provided amiodarone (P=0.016).

The authors concluded that vernakalant "may therefore be considered as a useful agent for facilitated ECV in cardioversion resistant AF." The study did not report any major adverse events.

"We are very excited to see the results from this small non-randomized study in a resistant patient population but larger, controlled clinical studies will be necessary to confirm its findings," said Dr. Steen Juul-Möller, Cardiome’s Medical Director.

"These results underline the vernakalant -induced stabilizing effect on the atrial wavelets in Atrial Fibrillation, facilitating cardioversion even in patients with AF relapse after lung vein isolation ablation."

In addition, Dr. Juul-Möller commented that "Taken together with the independent data published earlier this year suggesting that challenging post-surgical patients also received a benefit from vernakalant, this new data within resistant patients suggests that physicians who are using vernakalant in their clinical practice show continued high interest to explore its use by expanding scientific evidence."

Between November 2011 and May 2014 , 63 patients (66.7% males) who had initially failed to attain SR with transthoracic ECV, or who failed to remain in SR after briefly converting, were infused with either vernakalant or amiodarone prior to another attempt to electrically cardiovert the patient. The primary end-point was acute successful ECV into sinus rhythm after drug facilitated ECV.

Sixty-seven percent (66.7%) of patients provided vernakalant successfully converted with pharmacologically facilitated ECV compared to 46.7% of amiodarone treated patients. IRAF recurrence was observed in 24.2% of the vernakalant treated patients compared to 36.7% of patients treated with amiodarone (P=0.283).

FECV occurred in 9.1% of vernakalant-treated patients compared with 16.7% of amiodarone-treated patients (P = 0.271). Additional results and analyses are available within the study. There were no major adverse events.

Three patients (9.1%) in the vernakalant group described transient tingling paraesthesia in their upper body versus 0% in the amiodarone group. QT prolongation over 500ms or QRS widening >50% was not observed in either group. There were no incidences of atrial flutter.