Permanent pacing from the coronary sinus in a patient with an implantable defibrillator.

A woman with an ICD underwent permanent pacemaker implantation for bradycardia-tachycardia syndrome. Despite multiple right atrial positions, oversensing secondary to "double counting" was always noted. A coronary sinus pacing catheter was inserted and left atrial pacing was accomplished with acceptable pacing and sensing characteristics. The patient has since done well without further shocks.