Vasodepressor syncope in a cardiac transplant recipient: a case of vagal re-innervation?

At the time of hemodynamic assessment three years after cardiac transplantation, a patient developed symptoms and signs of a vasodepressor reaction. In addition to sudden deceleration of heart rate, a 26% fall in mean blood pressure and a 36% fall in cardiac output was observed. Subsequent investigations revealed the presence of respiratory sinus arrhythmia, profound heart rate acceleration on standing and an approximately normal heart rate response during the following exercise. Contrary to current thinking, these observations suggest that certain individuals may develop autonomic re-innervation following orthotopic cardiac transplantation.