We studied the duration and prognostic significance of atrial arrhythmias in the denervated
transplanted heart, specifically the occurrence of atrial fibrillation in the absence
of vagal modulation.
Substantial animal data indicate that vagally induced dispersion of atrial refractoriness
plays a central role in the induction and maintenance of atrial fibrillation.
We studied the occurrence of atrial arrhythmias in the denervated hearts of 88 consecutive
orthotopic transplantations in 85 patients by means of continuous telemetry and all
available electrocardiographic tracings.
Fifty percent of recipients (44 of 88) developed at least one atrial arrhythmia. Atrial
fibrillation occurred 23 times (21 recipients), atrial flutter 39 times (26 recipients),
ectopic atrial tachycardia 3 times (3 recipients) and supraventricular tachycardia
18 times (11 recipients). The number of atrial fibrillation and atrial flutter episodes
did not differ (23 vs. 39, p = 0.072), but the mean duration of atrial flutter was
longer than that of atrial fibrillation (37.0 +/- 10 vs. 6.6 +/- 3.6 h, p = 0.014).
Atrial fibrillation was associated with an increased risk of subsequent death (10
of 21 recipients with vs. 15 of 67 without atrial fibrillation, risk ratio 3.15 +/-
0.18, p = 0.005 by Cox proportional hazards model). All 5 recipients who developed
"late" atrial fibrillation (> 2 weeks after transplantation) died versus 5 of 16 who
developed atrial fibrillation within the first 2 weeks (p = 0.007). Causes of death
included rejection (three recipients), allograft failure (two recipients), infection
(three recipients) and multiorgan failure (two recipients). Atrial fibrillation was
not associated with age, gender, ischemic time, reason for transplantation, echocardiographic
variables, invasive hemodynamic variables or biopsy grade. Mean time from atrial arrhythmia
to echocardiography was 2.7 +/- 3.3 days; that to biopsy was 4.8 +/- 6.3 days. Atrial
flutter was not associated with subsequent death. Only 7 (15.9%) of 44 recipients
demonstrated moderate or severe allograft rejection at the time of the arrhythmia.
Atrial arrhythmias occur frequently in the denervated transplanted heart, often in
the absence of significant rejection. Late atrial fibrillation may be associated with
an increased all-cause mortality.