Clinical and electrophysiologic correlates of sinus node dysfunction after orthotopic heart transplantation. Observations in 42 patients.

We assessed incidence and course of postoperative SN dysfunction in 42 cardiac transplant recipients. RHY, HR and CSNRT were compared in distinguishing between persistent (9 of 42 patients) and transient (11 of 42) SN dysfunction. Persistent SN dysfunction was distinguished by a significantly lower HR (day 14: 46.2 +/- 12 vs 67 +/- 19 bpm; day 21: 40.3 +/- 21 vs 70.8 +/- 16 bpm; p less than 0.05, respectively) and by RHY: postoperative AS (3 of 42) was found only in patients whose SN dysfunction persisted while patients with SR but prolonged CSNRT more often had transient impairment (6 of 42 vs 2 of 42); CSNRT, in contrast, is unlikely to be useful in distinguishing between transient and persistent SN dysfunction since exceptionally long CSNRTs (11,340 ms. 12,080 ms) occurred in patients with both types. Ischemic times were significantly longer in patients with transient impairment when compared with the group with normal SN function (155.1 +/- 36 vs 109.2 +/- 36 min, p less than 0.05) but did not differ significantly in patients with persistent SN dysfunction (124.8 +/- 32 min). Thus, (1) SN dysfunction after cardiac transplantation is common but most often transient; (2) RHY and HR are adequate follow-up parameters and best predictors of long-term SN function; (3) SN dysfunction after transplantation has important clinical implications given the unreliability of lower pacemakers to take over in 3 patients; (4) transient SN dysfunction is related to duration of ischemia during hypothermic preservation whereas pathogenesis of persistent SN dysfunction remains to be elucidated.