Effects of landiolol, an ultra-short-acting beta1-selective blocker, on electrical storm refractory to class III antiarrhythmic drugs.

Background: Occasionally it is difficult to inhibit electrical storm (ES) with standard pharmacological treatment. In the present study the effect of landiolol, an ultra-short-acting beta(1)-selective blocker, on ES refractory to class III antiarrhythmic drugs was evaluated. Methods and Results: The study group comprised 42 consecutive patients who developed ES for which intravenous class III antiarrhythmic drugs, such as amiodarone and nifekalant, were ineffective. Landiolol was administered intravenously with an initial dose of 2.5 mu g.kg(-1).min(-1), which was doubled if it was ineffective, up to a maximum dose of 80 mu g.kg(-1).min(-1). Landiolol inhibited ES in 33 patients (79%) at a mean dose of 7.5 +/- 12.2 mu g.kg(-1).min(-1). All patients in whom landiolol was ineffective died of arrhythmia. Of the 33 patients in whom landiolol was effective, 25 survived and were discharged (60% of all patients). Landiolol significantly decreased heart rate (P<0.0001), but did not affect blood pressure. Landiolol was not discontinued for adverse effects in any of the responders. Age, APACHE II score, and pH of arterial blood gas differed significantly between the responders and nonresponders. Conclusions: Landiolol is useful as a life-saving drug for class III antiarrhythmic drug-resistant ES. The main mechanism of ES refractory to class III antiarrhythmic drugs could be abnormal automaticity but not reentry. (Circ J 2010; 74: 856-863)