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.
Material and 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.