Electrophysiologic characteristics of the transplanted heart

The electrophysiologic characteristics of the denervated human heart were assessed in 20 cardiac transplants recipient from the Cardiology Department, at the Hospital of San Pablo, Barcelona, Spain. We studied the donor and the recipient sinus node function at rest and exercise test. Holter recording of 24 hours was performed in a few cases. At rest, in 14 patients the intrinsic heart rate of the donor atrium was slower when we used the technique of Jose. When we analyzed all the results we did not find statistical differences in the heart rate of either: the donor or the recipient atria (r = 0.58, p less than 0.01). However we observed a marked increase in heart rate of the donor with exercise test and normal activity (Holter), probably reflecting an increase in circulating catecholamines (exercise test: base-line 116 +/- 16 vs maximum exercise 140 +/- 10, p less than 0.001; Holter: minimal rate 64 +/- 9.66 vs maximal rate 112 +/- 23, p less than 0.001). We also describe the cardiac arrhythmias including two sudden deaths associated with ventricular tachyarrhythmias and in five patients sinus node disfunction in relation with episodes of acute rejection. We concluded that is important to perform a standard 12 lead electrocardiogram, exercise testing, Holter recording and electrophysiologic study as part of the ongoing routine evaluation of surviving cardiac transplant patients.