Arrhythmias in patients with hypoplastic left heart syndrome

Background: Mortality between stage I and II palliation for hypoplastic left heart syndrome (HLHS) has been associated with arrhythmias. The stage-related proportion, associations, and clinical impact of arrhythmias in patients with HLHS have not been evaluated. In addition, arrhythmia subtypes have not been described in this patient group. Methods: We performed a retrospective analysis of all patients at Duke University Medical Center who received one or more palliative stages for HLHS from September 2000 to October 2008. Results: Overall, 49 (57%) of 86 patients had 63 arrhythmias. The majority of arrhythmias occurred between stage I and II, with 44 (51%) of 86 patients manifesting a new arrhythmia. Arrhythmias occurring in this interval tended to be associated with a higher mortality compared with arrhythmias occurring after stage II (odds ratio = 3.2 [95% CI 0.84-12.0], P = .09). Overall mortality was similar in patients with and without arrhythmias (P = .99). Supraventricular tachycardia was the most common arrhythmia (16/63; 25%), but persistent bradycardias (sinus node dysfunction or high-grade atrioventricular block) had the worst clinical outcome with 73% mortality (8/11). There was no association between arrhythmia occurrence and degree of tricuspid regurgitation, left ventricular hypertension, genetic syndrome, type of stage I operation, or need for extracorporeal membrane oxygenation. Conclusions: A large proportion of patients with HLHS experience serious arrhythmias requiring therapy, especially between stage I and II. Persistent bradycardia following stage I is associated with a high mortality rate. Considering all arrhythmia patients, overall mortality was not different compared with the arrhythmia-free group.