Benign prognosis of early sinus node dysfunction after orthotopic cardiac transplantation

Previous reports raised concern about the prognosis of patients with sinus node (SN) dysfunction after cardiac transplantation and led to a low threshold for permanent pacemaker (PM) placement at most institutions. The present study addresses the survival in patients with normal and impaired post operative SN function and the effect of permanent pacing with respect to overall and cardiac mortality. There were 120 patients with normal (corrected SN recovery time < 520 ms, group I) and 47 patients with imparied SN function (corrected SN recovery time > 520 ms and/or sinus arrest +/- escape rhythms). Pacing support was deemed unnecessary in 23 of 47 patients with SN dysfunction (group II; asymptomatic SN bradycardia and corrected SN recovery time 3,812 +/- 5,800 ms) while a total of 24 patients had PM placement a mean of 29 +/- 44 days after transplantation (symptomatic bradycardia or absence of sinus rhythm at discharge, group III). Patients were followed for a mean of 46.7 months. Thirty-five deaths occurred during the study period. Sixteen deaths were cardiac but none were causally related to the SN dysfunction (graft failure due to rejection or atheropathy n = 14; myocardial infarction n = 2). Four of these cardiac deaths were sudden and all occurred in the presence of widespread structural abnormalities (rejection/vasculopathy/myocardial infarction). SN dysfunction was not related to overall (P = 0.25) or cardiac mortality (P = 0.33). Regarding either endpoint, patients who had permanent PM placement did no better than their unpaced counterparts in group II (P = 0.53 and P = 0.33, overall and cardiac mortality, respectively). Likewise, survival did not differ between groups I and III for either endpoint (P = 0.77, P = 0.65, respectively). These data suggest that patients with mild SN abnormality, who are in sinus rhythm at the time of discharge, can be followed by observation without specific therapy.