Possible arrhythmiogenic mechanism produced by ibuprofen

Aim: The aim of the present study was to investigate the electrophysiological effect of ibuprofen on the cardiac action potentials (AP) and electrocardiograms (ECG), and to identify its arrhythmiogenic mechanism. Methods: The intracellular microelectrode recording technique was employed to record the fast- and slow-response AP in guinea pig papillary muscles. The cardiac responses of ibuprofen were monitored by ECG, both in in vivo and in vitro studies. Results: The ECG recording revealed that ibuprofen could induce arrhythmias, both in vitro and in vivo. Fatal ventricular fibrillations are readily produced in in vitro experiments by ibuprofen. Our results show that ibuprofen could dose dependently shorten the duration of AP and the effective refractory period (ERP), and it could also decrease the maximum depolarization velocity of phase 0 (V-max) in both the fast- and slow-response AP. The duration of the QRS complex wave (QRS duration) in ECG was prolonged. Although the heart rate was depressed by ibuprofen, the corrected QT interval duration (QTc) decreased. Conclusion: Ibuprofen could inhibit cardiac Na+ and Ca2+ channels as it slows V-max in both fast- and slow-response AP. Furthermore, ibuprofen shortens the ERP and decreases the excitation propagation within the heart, which might provide a substrate for an arrhythmiogenic re-entry circuit. Taken together, we conclude that ibuprofen, when used improperly, may impose a potential hazard in inducing cardiac arrhythmias in patients with existing heart diseases.