Objectives: In the US, the FDA requires in-hospital institution of class III drugs. This study retrospectively assessed whether these criteria, which differ markedly from the Dutch exclusion criteria, could predict sotalol-induced torsade de pointes arrhythmias (TdP).
Method: Oral sotalol effect in a control group (50 patients, 62±12 years, 23 men, 27 women) was compared with five patients developing TdP (75±5years, all women), using known and new (JTU area measured in lead V2) risk parameters. Paroxysmal atrial fibrillation was the most common indication for sotalol treatment.
Results: At baseline the strict US regulations would have identified four of five TdP patients on the basis of individual K+ levels, creatinine clearance and QTc. However, 7 of 49 controls would also have been excluded, although they did not develop documented TdP in the >2 years follow-up. Sotalol slightly increased QTc (361±34 to 387±33ms) in controls, due to heart rate reduction. In the TdP group, sotalol dramatically increased QTc (467±33 to 626±52 ms, +35%, p<0.05) accompanied by deep negative TU waves and an increased JTU area and all could be identified as risk patients.
Conclusion: Patients developing TdP on oral sotalol can be identified using the FDA risk criteria and hospitalisation may therefore be appropriate. A European prospective study is required to investigate the costs, sensitivity and specificity of this strategy.
Keywords: JTU area; electrocardiography; gender; proarrhythmia; repolarisation; torsade de pointes.