Conversion of POAF by an Atrial Repolarization Delaying Agent (ARDA)

Background: Postoperative, new-onset atrial fibrillation (POAF) occurs up to 30–50% after cardiac surgery and is associated with a significant increase in morbidity, mortality and longer in-hospital stay. Prompt POAF conversion is desirable to prevent atrial remodelling.

Vernakalant (VK) is a highly atrial-selective ARDA. To study the real life situation, we performed a register study for intravenous VK administration.

Patients and Methods: A total of 129 consecutive patients (age: 72 years [44–92 years]; 90 males). Diagnoses: CAD 61; AV 34; MV 14; CAD + AV 16; CAD + MV 3; AV + MV. Parameters included in the analysis: age, sex, diagnosis prior to surgery, surgical procedure, on pump/off pump surgery, duration of surgery, ECC, and aortic cross-clamping; use of catecholamines; LVEF, time between surgery and onset of POAF; time between onset and first dose of VK.

Regimen of VK administration on the IMC and during continuous rhythm and intraarterial blood pressure monitoring: 1hr after new-onset POAF the first dose: 3 mg/kg i.v. over 10min of VK was given, in case of non-conversion a second dose: 2 mg/kg i.v. over 10min.

Statistical tests were (a) the chi-square test for independence in case of categorical covariates and (b) testing the regression coefficient in a single-covariate logistic regression in case of interval-scaled covariates.

Results: In 57 patients (44%), conversion was achieved after the first dose of VK. For additional 41 patients (32%), conversion was achieved after the second dose. The overall success rate was 76%.

The 3 categories of surgery were: CABG (47%) surgery, valve replacements (37%), and CABG plus valve replacements (16%). The mean time between surgery and onset of AF averaged 92 ± 77 hours, (median 70 hours, interquartile range 54–97 hours).

The type of surgery was identified as the main factor influencing the conversion rate.

The following variables lowered conversion rate: no preoperative -blocker, troponin level >500 µg/l, blood pressure >140 mm Hg Mean time to conversion was 13.7 min (±14.1 min), median 10min (interquartile range 8–13 min). At the first follow-up (8. post day), 92% of the converted patients showed sinus rhythm, non-responders: 80% (p < 0.01). Mean time to conversion was 13.7 min ±14.1 min (median: 10 min; interquartile range: 8–13 min).

Conclusion: VK was highly effective in cardiac post-surgery patients and proved to be very safe. Stay in IMC and hospital was shortened. Thus, VK can be seen as a promising avenue to treat POAF.