[Which variables predict the appearance of right bundle-branch block and its course after heart transplantation?]

The purpose of this study was to analyze a series of variables in donors as well as of the preoperative and early and late postoperative of patients developing a right branch block of the bundle of His (RBBBH) in the first week after heart transplantation (HT), and to evaluate factors predicting the disappearance or progression of this conduction disorder.

58 consecutive patients having undergone an orthotopic HT were studied. 15 of them showed a RBBBH after the HT (age: 43 +/- 13, 12 male, 3 female) and 43 did not (age: 54 +/- 17, 40 male and 3 female). ECGs and echocardiographic studies were performed after 1 week, 1, 3 and 6 months and 1 year. The following factors were analyzed: age and sex of the donor baseline cardiopathy, donor's weight related to recipient's weight, time of ischaemia and cardiopulmonary by-pass, number of rejections per patient/year, previous pulmonary vascular resistance. These parameters were compared among the patients who showed RBBBH and those who did not, and between those whose blocks disappeared in the follow-up and those whose blocks persisted.

We found differences is the sex of donors, age of recipients, baseline etiology and time of cardiopulmonary by-pass (with block: 43 +/- 13 years old, dilated cardiomyopathy 73%, 106 +/- 25 minutes, whereas without block: 54 +/- 17 years old, dilated cardiomyopathy 42%, 92 +/- 18). The different parameters between the patients whose block underwent a regression or a progression were sex, lung resistances and right ventricle diameter (progression of the block: men 100%, 3.43% +/- 1.05 UW, progressively growing ventricular diameters. No progression or regression of the block: men 67%, 1.63 +/- 0.74 UW, ventricular diameters with progressive decrease).

Younger recipients, with a diagnosis of dilated cardiomyopathy, to whom a woman's heart is implanted and who show a longer extracorporal circulation time are those who show a higher incidence of RBBBH: Male patients with high pulmonary resistances undergo a progressive increase in the diameter of the right ventricle and a progressive increase in the RBBBH degree.