Autonomic control of the cardiovascular system is changed in children with mitral valve prolapse

  • Dr Krzysztof Czyz, Department of Pediatric Cardiology, Poznan University of Medical Sciences, Poland, Poland
  • Prof Waldemar Bobkowski, Department of Pediatric Cardiology, Poznan University of Medical Sciences, Poland, Poland
  • Dr Przemyslaw Guzik, Department of Cardiology and Intensive Therapy, Poznan University of Medical Sciences, Poland, Poland
  • Dr Tomasz Krauze, Department of Cardiology and Intensive Therapy, Poznan University of Medical Sciences, Poland, Poland
  • Dr Jaroslaw Piskorski, Institute of Physics, University of Zielona Gora, Poland, Poland
  • Prof Aldona Siwinska, Department of Pediatric Cardiology, Poznan University of Medical Sciences, Poland, Poland

    • INTRODUCTION. Mitral valve prolapse (MVP) is one of the most common form of cardiac disease in children and may be accompanied by some autonomic abnormalities. Analysis of heart rate variability (HRV), resting heart rate (HR) or baroreflex sensitivity (BRS) allow studying autonomic modulation of cardiovascular system.
    AIM. The aim of this study was to investigate frequency domain HRV, BRS and resting HR to assess the changes in sympathovagal balance in children with MVP.
    METHODS. 43 children with MVP (29 girls; 5-18 years) and 52 healthy children (28 girls; 7-18 years) were included. 30-minute resting ECG (Porti 5, TMSI, Netherlands) and blood pressure (Portapres 2, FMS, Netherlands) signals were recorded non-invasively in supine. The HRV was evaluated by spectral analysis: total power (TP), power of very low (VLF), low (LF) and high frequency (HF) and LF/HF ratio. The BRS was measured using a cross-correlation method.
    RESULTS. Patients with MVP had significantly reduced TP (5207±704 vs 9083±1036 ms˛; p=0.003), VLF (1841±141 vs 3776±582 ms˛; p=0.009), LF (1420±221 vs 2126±261 ms˛; p=0.022), HF (1772±376 vs 2876±435 ms˛; p=0.035) and reduced mean duration of cardiac cycles (764±20 vs 832±20 ms; p=0.028) as compared with healthy children. There was no significant reduction in prolongation of delay of baroreflex (2.01±0.06 vs 1.87±0.06 s; p=0.069) and no significant differences in BRS and LF/HF ratio between both groups.
    CONCLUSIONS. Children with MVP have a changed autonomic control of the cardiovascular system. Our study demonstrates that children with MVP characterized by sympathetic hyperactivity and/or reduced vagal tone.