Beschreibung:
<jats:p><jats:bold>Abstract: </jats:bold><jats:bold> Aims: </jats:bold> To detect impairment in short‐term heart rate variability (HRV) in children after heart and heart–lung transplantation (TX) as reported in adults. To assess vagal and sympathetic influence on the donor heart rate using frequency domain analysis of HRV.</jats:p><jats:p><jats:bold>Methods and Results: </jats:bold> Measurement of short‐term HRV was performed in 17 patients (age 16.9±3.6, 6.1±3.7 yr after TX) and 12 healthy controls (age 14.8±3.0 yr). Testing consisted of a resting phase of 15 minutes followed by a tilt phase of 45 min. All HRV parameters were significantly impaired in transplanted patients: RR interval (RRI) 717.2±122.5 m/s (controls 827±139.7, p<0.05), standard deviation of RR interval (RRI‐SD) 20.1±15.5 (89.9±38.4, p<0.001), RRI at tilt 607.9±79.7 (654.0±104.7, NS), RRI‐SD at tilt 21.1±20.0 (60.4±31.4, p<0.001). Low‐frequency (LF)/High‐frequency (HF) ratio of HRV showed prominent sympathetic influence in TX‐patients (3.38±5.60 vs. 1.18±0.86, NS) increasing during tilting (5.91±8.36 vs. 4.74±5.27, NS). In subgroup analysis, 4 yr after TX an increasing sympathetic control of heart rate was observed.</jats:p><jats:p><jats:bold>Conclusion: </jats:bold> Short‐term HRV is severely impaired in children after TX. If changes are observed, they are time‐related and show increasing sympathetic influence starting from 4 yr after TX.</jats:p>