Cardiac response to water activities in children with Long QT syndrome type 1

by Anna Lundstr öm, Urban Wiklund, Annika Winbo, Håkan Eliasson, Marcus Karlsson, Annika Rydberg BackgroundSwimming is a genotype-specific trigger in long QT syndrome type 1 (LQT1). ObjectiveTo examine the autonomic response to water activities in children and adolescents with LQT1. MethodsIn this cross-sectional study, LQT1 patients were age and sex matched to one healthy control subject. Electrocardiograms (ECGs) were recorded during face immersion (FI), swimming, diving, and whole-body submersion (WBS). Heart rate (HR) and heart rate variability (HRV) was measured. The high frequency (HF) component of HRV was interpreted to reflect parasympathetic activity, while the low frequency (LF) component was interpreted as reflecting the combined influence of sympathetic and parasympathetic activity on autonomic nervous modulation of the heart. ResultsFifteen LQT1 patients (aged 7 –19 years, all on beta-blocker therapy) and fifteen age and sex matched non-medicated controls were included. No significant ventricular arrhythmias were observed in the LQT1 population during the water activities. Out of these 15 matched pairs, 12 pairs managed to complete FI and WBS for more tha n 10 seconds and were subsequently included in HR and HRV analyses. In response to FI, the LQT1 group experienced a drop in HR of 48 bpm, compared to 67 bpm in the control group (p = 0.006). In response to WBS, HR decreased by 48 bpm in the LQT1 group and 70 bpm in the control group (p = 0.007). A s ignifica...
Source: PLoS One - Category: Biomedical Science Authors: Source Type: research