Hemodynamic effects of Vernakalant in cardio-surgical ICU-patients treated for recent-onset postoperative atrial fibrillation

Abstract

Postoperative atrial fibrillation (POAF) is one of the most frequent complications after cardiothoracic surgery and a predictor for postoperative mortality and prolonged ICU-stay. Current guidelines suggest the multi-channel inhibitor Vernakalant as a treatment option for rhythm control. However, rare cases of severe hypotension and cardiogenic shock following drug administration have been reported. To elucidate the impact of Vernakalant on hemodynamics, we included ten ICU patients developing POAF after elective cardiac surgery, all of them awake and breathing spontaneously, in this prospective trial. Patients received the recommended dosage of Vernakalant and were clinically observed and monitored (heart rate, invasive blood pressure, pulse oximetry, central venous pressure) in 1-minute-intervals for 20 minutes before-and 120 minutes after the first dose of Vernakalant. The median time from the end of surgery until occurrence of POAF amounted up to 52.8 [45.9-77.4] hours, it took 3.5 [1.2-10.1] hours from occurrence of POAF until the first application of Vernakalant. All patients received catecholamine support with epinephrine that was held steady and not dynamic throughout the observational phase. We noted stable hemodynamic conditions, with a trend towards a reduction in heart rate throughout the 120 minutes after drug administration. In 7 patients (70%), conversion to sustained sinus rhythm (SR) occurred within 8.0 minutes [6.0-9.0]. No serious adverse events (SAEs) were noted during the observation period. In this prospective trial in ICU-patients showing POAF after cardiac surgery, intravenous Vernakalant did not induce clinically relevant negative effects on patients' hemodynamics but resulted in conversion to sustained SR after a median of 8.0 minutes in 7 out of ten patients.Postoperative atrial fibrillation (POAF) typically occurs around the second postoperative day and shows an especially high incidence of 40-60% in individuals undergoing cardio-surgical procedures. It represents a strong contributor for major cardiac adverse events in the short and the long run 1 . Recent evidence shows that POAF is linked to one third of postoperative strokes 1 . Moreover, POAF leads to complications such as ventricular arrythmias, congestive heart failure, the need for permanent pacemaker implantation, prolonged mechanical ventilation and ICU-stay, an increased risk for infection 1,2 , and is even associated with increased overall and cardiovascular mortality 3 . Various factors such as local inflammation, sympathetic activation or electrolyte imbalances have been discussed as etiologic factors for POAF development 4,5 . Whereas in severely symptomatic or hemodynamically unstable patients SR restoration by electrical cardioversion is persecuted, early pharmacologic cardioversion 6-8 to prevent complications seems reasonable in the remaining patients, although POAF is often transient and self-limiting 9 . Hence, the relatively atrial selective and rate-dependent multi-channel-inhibitor Vernakalant has been recommend...