Cardiac rhythm disturbances among children with idiopathic congenital central hypoventilation syndrome

The objective of this study was to determine whether subjects with congenit al central hypoventilation syndrome (CCHS) had an increased frequency of ca rdiac arrhythmias and decreased heart rate variability when compared to sub jects without a known deficit in control of breathing, and that these abnor malities would be exaggerated by anesthesia. Continuous ambulatory Holter r ecordings were obtained in patients with CCHS and compared to two otherwise healthy control groups without a deficit in control of breathing: one with an intact airway (n = 11) and a second group with a tracheostomy (n = 6). Holter recordings were obtained before, during (under general anesthesia), and after bronchoscopy. Fourteen children with CCHS (age: 9.3 +/- 4.4 years mean +/- S.D.) were studied, and 7 underwent bronchoscopy. Seventeen contr ol children were studied (age 6.6 +/- 3.6 years): 11 without a tracheostomy , and 6 with a tracheostomy who also underwent bronchoscopy. Maximum heart rate during baseline recording was significantly lower in the CCHS subjects as compared to controls (P = 0.0001). At baseline the differ ence in the number of arrhythmias/24 hr/subject in all CCHS vs. all control subjects was significant (P = 0.0002); for the subjects who had bronchosco py, CCHS vs. control, the difference was also significant (P = 0.03). In ad dition, there was a significant decrease in the number of events/24 hr/subj ect among the CCHS subjects between baseline and post-bronchoscopy (P = 0.0 288). The predominant arrhythmias were sinus bradycardia and transient asys tole. The longest asystole in a CCHS subject was 6.50 sec, and in a control subject, 1.42 sec (at baseline the means of the longest asystole were 2.69 +/- 1.4 vs. 1.24 +/- 0.13; P = 0.003 in the CCHS vs. control groups). Othe r indices of heart rate variability were significantly reduced in the CCHS subjects (P < 0.05). These results substantiate our hypothesis that subjects with CCHS have more arrhythmias than controls, an increased frequency of bradyarrhythmias, and decreased cyclical sinus arrhythmia. Pediatr Pulmonol, 2000; 29:351-358, ( C) 2000 Wiley-Liss, Inc.