title: Electrophysiological changes following balloon valvuloplasty and angioplasty for aortic stenosis and coartaction of aorta: clinical evidence for mechano-electrical feedback in humans.
abstract: BACKGROUND
  Basic research and animal experiments have shown electrophysiological changes during or after changes in mechanical loading. Electrical instability following mechanical stretch has been observed as development of after-depolarisation and dispersion of refractoriness and repolarisation. The aim of the present study was to evaluate the presence of the mechano-electrical feedback in humans, assessing the ventricular repolarisation changes following acute changes in left ventricular pressure.
  
  
  METHODS
  The study group comprised 30 consecutive patients (22 M and 8 F, aged 2 days-24 years) affected by severe congenital aortic stenosis and 30 patients (20 M and 10 F, aged 6 months-16 years) affected by severe coartaction of aorta. Ventricular repolarisation was evaluated before and after percutaneous balloon valvuloplasty and angioplasty in terms of absolute measures (JT, JTc, QT, QTc) and in terms of dispersion across the myocardium: QT and QTc dispersion (QTD, QTcD), JT and JTc dispersion (JTD and JTcD) and T-peak to T-end interval (Tp-Te).
  
  
  RESULTS
  Patients with severe aortic stenosis and patients with aortic coartaction showed a significant decrease in dispersion of ventricular repolarisation time indexes (QTD, QTcD, JTD, JTcD and Tp-Te) following valvuloplasty and angioplasty.
  
  
  CONCLUSIONS
  Changes in hemodynamic loading can also produce electrophysiological effects in humans. Acute reduction in left ventricular pressure overload following balloon valvuloplasty and angioplasty, decreases electrical instability, as expressed by the reduction across the myocardium of the dispersion of ventricular repolarisation.
authors.affiliation: Second University of Naples, Chair of Cardiology, Division of Pediatric Cardiology, Monaldi Hospital, Via Leonardo Bianchi, 80131 Naples, Italy. bsarubb@tin.it
authors.forename: Berardo
authors.initials: B
authors.lastname: Sarubbi
authors.forename: Raimondo
authors.initials: R
authors.lastname: Calvanese
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cappelli Bigazzi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Santoro
authors.forename: Maria
authors.initials: M
authors.lastname: Giovanna Russo
authors.forename: Raffaele
authors.initials: R
authors.lastname: Calabrò
mesh_terms: D000293:Adolescent; D000328:Adult; D000800:Angioplasty, Balloon; D001017:Aortic Coarctation / Q000503:physiopathology* / Q000628:therapy; D001024:Aortic Valve Stenosis / Q000151:congenital / Q000503:physiopathology* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography; D025461:Feedback, Physiological; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male