Long-term prognostic value of cardiac autonomic nervous activity in postoperative patients with congenital heart disease

Abstract

Background: Abnormal cardiac autonomic nervous activity (CANA) is not uncommon in postoperative patients with congenital heart disease (CHD).

Methods and results: We attempted to clarify the prognostic value of the CANA variables in postoperative CHD patients and prospectively evaluated the CANA variables in 292 consecutive biventricular and 91 Fontan repair patients. The CANA variables included the heart rate variability, arterial baroreflex sensitivity (BRS), washout ratio of the myocardial metaiodobenzylguanidine scintigraphy, and plasma norepinephrine level. With a follow-up of 10 ± 2 years, 98 total events that required hospitalization, including 13 deaths and 48 unscheduled cardiac events (UCEs), occurred. In all the CHD patients, all the CANA indices predicted the total events and UCEs. Of those, the NE level (p=0.0004) and BRS (p=0.0373) predicted the mortality. In a multivariate analysis, the BRS was an independent CANA-predictor for the total events (p=0.007). In the biventricular patients, the plasma NE level, heart rate variability, and BRS predicted the total events and UCEs and the BRS was the only independent CANA-predictor for the total events (p=0.0329). In the Fontan patients, the plasma NE level was the only predictor for the UCEs (p=0.0242) and no other CANA variables were independent predictors of the total events or UCEs.

Conclusions: All CANA variables, especially the BRS, were useful predictors for future clinical events in biventricular CHD patients, whereas no CANA variables, except for the plasma NE level, predicted future clinical events in the Fontan patients.