Inducible atrial flutter and fibrillation after orthotopic heart transplantation.

Inducible atrial flutter (two patients) and fibrillation (two patients) were observed in a series of 35 heart transplant patients who underwent evaluation of sinus node function including premature atrial stimulation. The sinus node function was entirely normal in both patients with inducible atrial flutter. In contrast it was profoundly abnormal in the patients with inducible atrial fibrillation. Atrial fibrillation was no longer inducible as the sinus node function became borderline normal. These observations suggest extensive electrical atrial abnormality, including the sinus node, in patients with atrial fibrillation, and temporary pacing should be available when considering cardioversion in patients with atrial fibrillation early after heart transplantation. Atrial flutter, in contrast, may be inducible in the absence of any sinus node abnormality and without any evidence of rejection.