PREVALENCE AND PROGNOSTIC-SIGNIFICANCE OF ATRIAL ARRHYTHMIAS AFTER ORTHOTOPIC CARDIAC TRANSPLANTATION

Objectives. We studied the duration and prognostic significance of atr ial arrhythmias in the denervated transplanted heart, specifically the occurrence of atrial fibrillation in the absence of vagal modulation. Background. Substantial animal data indicate that vagally induced dis persion of atrial refractoriness plays a central role in the induction and maintenance of atrial fibrillation. Methods. We studied the occur rence of atrial arrhythmias in the denervated hearts of 88 consecutive orthotopic transplantations in 85 patients by means of continuous tel emetry and all available electrocardiographic tracings. Results. Fifty percent of recipients (43 of 88) developed at least one atrial arrhyt hmia. Atrial fibrillation occurred 23 times (21 recipients), atrial fl utter 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 putter 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 increase d risk of subsequent death (10 of 21 recipients with vs. 15 of 67 with out atrial fibrillation, risk ratio 3.15 +/- 0.18, p = 0.005 by Cox pr oportional hazards model). All 5 recipients who developed ''late'' atr ial 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 fai lure (two recipients), infection (three recipients) and multiorgan fai lure (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 echocardiology was 2.7 +/- 3.3 days; that to biopsy was 4.8 +/- 6.3 days. Atrial flutter was not associated with s ubsequent death. Only 7 (15.9%) of 44 recipients demonstrated moderate or severe allograft rejection at the time of the arrhythmia. Conclusi ons. Atrial arrhythmias occur frequently in the denervated transplante d heart, often in the absence of significant rejection. Late atrial fi brillation may be associated with an increased all cause mortality.