AIMS: The recipient atrial remnant has been used as a control in studies ofchronotropic response following orthotopic cardiac transplantation and as a trigger for the donor heart. It is not known, however, whether its function is normal. We investigated the electrophysiological properties of the recipient atrial remnant. METHODS AND RESULTS: Fifty patients were studied, mean age 49 years (range 20-63) and mean time post-orthotopic cardiac transplantation of 31 months (range 1-107). Recipient atrial rhythm, spontaneous cycle length and sinus node function were determined. Atrial fibrillation/flutter was identified in 10/50 (20%). Of those in sinus rhythm, significant bradycardia was present in 12/40 (30%). The mean spontaneous cycle length was 929+/-188 ms. Three patients demonstrated variable atrial electrocardiogram morphology and a further three patients had marked variations in resting cycle length. The sinus node function was abnormal in 2/34 (6%). CONCLUSIONS: Only 56% recipient atria had normal sinus rhythm, with 21% of these demonstrating features consistent with a wandering atrial pacemaker. The recipient atrial remnant is not normal in the majority of transplant recipients and should be used with caution in studies involving its use as a control or as a trigger for the donor heart.
AIMS: The recipient atrial remnant has been used as a control in studies ofchronotropic response following orthotopic cardiac transplantation and as a trigger for the donor heart. It is not known, however, whether its function is normal. We investigated the electrophysiological properties of the recipient atrial remnant. METHODS AND RESULTS: Fifty patients were studied, mean age 49 years (range 20-63) and mean time post-orthotopic cardiac transplantation of 31 months (range 1-107). Recipient atrial rhythm, spontaneous cycle length and sinus node function were determined. Atrial fibrillation/flutter was identified in 10/50 (20%). Of those in sinus rhythm, significant bradycardia was present in 12/40 (30%). The mean spontaneous cycle length was 929+/-188 ms. Three patients demonstrated variable atrial electrocardiogram morphology and a further three patients had marked variations in resting cycle length. The sinus node function was abnormal in 2/34 (6%). CONCLUSIONS: Only 56% recipient atria had normal sinus rhythm, with 21% of these demonstrating features consistent with a wandering atrial pacemaker. The recipient atrial remnant is not normal in the majority of transplant recipients and should be used with caution in studies involving its use as a control or as a trigger for the donor heart.