A case of sick sinus syndrome that developed torsades de pointes, pacing failure and sensing failure during administration of bepridil.

A 65-year-old Japanese woman was admitted to hospital because of palpitations and faintness. She was diagnosed as having sick sinus syndrome and a permanent pacemaker was therefore implanted. Administration of bepridil (200 mg daily) was started for prevention of atrial flutter and fibrillation after PM implantation. On the twenty-fifth day of Bpd therapy, she developed recurrent syncope, ECG showed QT prolongation. torsades de pointes, and sensing failure. Electrical defibrillation (DF) was performed for ventricular fibrillation or ventricular tachycardia. It was presumed that Bpd had caused not only proarrhythmia but also a transient decrease in the amplitude of ventricular activation at the site of the pacing lead, as the sensing level was gradually restored after the drug was ceased and her plasma concentrations of Bpd decreased. It is also believed that DF had caused a sustained increase in pacing threshold because she developed pacing failure after DF and her pacing threshold had not returned to its prior level although the blood levels of Bpd had been below the minimum detectable level. Although it is well known that torsades de pointes occasionally develops in association with Bpd therapy, it is less evident that pacing and sensing failure may develop in association with Bpd therapy. This case report suggests that we should be aware of this possible outcome when employing Bpd and pacemaker implantation as combination therapy.