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Background: Current guidelines recommend vernakalant for pharmacologic cardioversion of recent-onset atrial fibrillation. However, this drug is not established as chronic therapy., Methods and Results: In total, 15 rabbit hearts were Langendorff-perfused. A burst pacing protocol-induced atrial fibrillation in 7 of 15 hearts at baseline (10 episodes). Subsequently, a combination of acetylcholine and isoproterenol (ACH/ISO) has been administered to increase occurrence of atrial fibrillation resulting in a reduction of atrial action potential duration (-25 ms, P < 0.05) as well as atrial effective refractory period (aERP; -36 ms, P < 0.05). Then, atrial fibrillation occurred in all 15 hearts (124 episodes). Additional treatment with vernakalant (10 μmol/l) induced a significant reduction of atrial fibrillation (6 of 15 hearts, 63 episodes). Infusion of vernakalant did not significantly alter atrial action potential duration (+8 ms) but increased aERP (+16 ms, P < 0.05 as compared with ACH/ISO).Results were compared to 12 further rabbit hearts treated with ranolazine. Late sodium current inhibition by ranolazine also induced a significant increase of aERP. Here, atrial fibrillation was inducible after ranolazine infusion in 6 of 12 hearts (46 episodes). Of note, 10 of 12 hearts presented atrial fibrillation during sole treatment with ACH/ISO (174 episodes)., Conclusion: Vernakalant and ranolazine demonstrated a comparable antiarrhythmic efficacy. Therefore, vernakalant treatment may represent a potential therapeutic option to reduce atrial fibrillation recurrence.

Background and Purpose: Supraventricular premature beats (SPBs) may help to assess the risk of atrial fibrillation (AF) in patients with cryptogenic stroke and therefore guide therapy., Methods: An internal loop recorder was implanted in consecutive patients with acute cryptogenic stroke. The occurrence and quantity of SPBs and short supraventricular runs (SVRs) in 24-hour ECG in patients with and without future AF were analyzed. We evaluated the relative risk of the upper quartile of SPB and SVR patients against the remainder and used binary logistic regression to evaluate a possible independent influence of SPBs and SVRs on AF occurrence., Results: Twelve of 70 included patients (mean age, 59±13 years) experienced development of AF during a mean monitoring duration of 536±212 days. Patients with AF had a median of 22.8 SPBs/h versus 1.2 SPBs/h (P<0.0001) in patients without AF and a median of 0.7 SVRs/h (AF) versus 0 SVR/h (non-AF). Patients in the upper quartile of SPBs (>14.1/h) and SVRs (>0.2/h) demonstrated a relative risk of 4.0 (95% confidence interval, 1.1-14.6; P=0.04) and 6.9 (95% confidence interval, 1.8-26.7; P=0.005) for future AF, respectively. In binary logistic regression, SPBs (P=0.02) and SVRs (P=0.05) remained significant independent predictors for occurrence of AF., Conclusions: Numerous SPBs and SVRs demonstrated a high risk for future AF in patients with cryptogenic stroke.

Background and Purpose: A significant number of patients with cryptogenic stroke suffer from intermittent atrial fibrillation (iAF) which was not detected during the standard diagnostic procedures. We investigated whether implantation of an insertable cardiac monitor (ICM) is feasible in patients with cryptogenic stroke, and compared the iAF detection rate of the ICM with 7-day Holter monitoring., Methods: Sixty patients (median age 63; interquartile range, 48.5-72 years) with acute cryptogenic stroke were included. ICM was implanted 13 days (interquartile range; 10-65 days) after the qualifying event. Seven-day Holter was performed after the ICM was implanted., Results: The iAF was detected by the ICM in 10 patients (17%; 95% CI, 7% to 26%). Only 1 patient (1.7%; 95% CI, 0% to 5%) had iAF during 7-day Holter monitoring as well (P=0.0077). Episodes of iAF lasting 2 minutes or more were detected 64 (range, 1-556) days after implantation. There were no recurrent strokes during the observation period. The implantation procedure was well tolerated with no adverse events; the daily data transmission protocol was easy to handle by the patients., Conclusions: ICM implantation for the detection of iAF during outpatient follow-up is feasible in patients with cryptogenic stroke. ICMs offer a much higher diagnostic yield than 7-day Holter monitoring.