Kimiko Tatsumi

Abnormal Cardiac Autonomic Nervous Activity After Right Ventricular Outflow Tract Reconstruction

BackgroundThere are few studies of cardiac autonomic nervous activity (CANA) in patients with congenital heart disease. Methods and ResultsWe evaluated CANA in 54 patients after closure of an atrial/ventricular septal defect (group A), 54 patients after successful right ventricular outflow tract reconstruction (RVOTR) (group B1), 35 RVOTR patients with residual stenosis (group B2), and 47 controls. Cardiac parasympathetic nervous activity (PSNA) was estimated by heart rate (HR) change after cholinergic blockade, HR variability, and arterial baroreflex sensitivity (BRS). Cardiac sympathetic nervous activity was estimated by the heart-to-mediastinum 123I-metaiodobenzylguanidine activity ratio (H/M) and HR increase after isoproterenol infusion (&bgr;). HR response (&Dgr;HR) and peak oxygen uptake (&OV0312;o2) were measured by exercise test. There was no difference in &bgr; among study groups. Group A exhibited mildly impaired PSNA, which recovered 1 year after surgery, and no change in H/M. Impaired PSNA and low H/M were found in groups B1 and B2 compared with controls (P <0.001), although the PSNA tended to recover 1 year after re-RVOTR. In group B1, PSNA and &bgr; were related to &Dgr;HR, and BRS correlated inversely with the number of surgical procedures and age at RVOTR and positively correlated with the follow-up period, whereas &Dgr;HR correlated with peak &OV0312;o2 (P <0.01 to 0.001). ConclusionsAfter RVOTR, postsynaptic &bgr;-sensitivity is maintained and is important in &Dgr;HR during exercise, as is PSNA, although ventricular sympathetic denervation is common. Impaired PSNA immediately after RVOTR improves with improved &Dgr;HR and results in future amelioration of aerobic capacity, whereas ventricular sympathetic reinnervation is uncertain.