Wegener's granulomatosis most commonly involves the sinuses, lungs and kidneys with necrotizing granulomatous vasculitis. In 12 percent of a large series of patients with Wegener's granulomatosis there was cardiac involvement, largely manifested by pericarditis and coronary arteritis. We present three patients with this disease who developed unusual cardiac complications. Patient 1 had renal failure requiring hemodialysis, pericardial tamponade requiring pericardiocentesis, and later developed constrictive pericarditis requiring pericardiectomy. Patient 2 developed pericarditis and high grade atrioventricular block, and patient 3 developed pericarditis and atrial tachycardia resistant to pharmacologic and transesophageal atrial pacing methods. All three patients greatly improved with cyclophosphamide therapy. The rhythm disturbances seen in patients 2 and 3 were attributed to coronary arteritis. The renal failure in patient 1 was due to Wegener's granulomatosis, but whether the constrictive pericarditis was due to uremic pericarditis or the pericarditis of Wegener's granulomatosis is uncertain. As patients with Wegener's granulomatosis live longer with cyclophosphamide therapy and because inpatient arrhythmia monitoring and recording has become more widespread, these uncommon manifestations of Wegener's granulomatosis may be seen more often.