14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-137

Changes in ventricular repolarization following balloon valvuloplasty and angioplasty for aortic stenosis and coartaction of aorta: evidence for mechano-electrical feedback in humans

Berardo Sarubbi*°, Giuseppe Pacileo*, Valentino Ducceschi*°, Maria Giovanna Russo*, Carlo Pisacane*, Raimondo Calvanese*, Giuseppe Santoro*, Maurizio Cotrufo°, Raffaele Calabro*°.
*Division of Paediatric Cardiology, Second University of Naples, Monaldi Hospital, °Second University of Naples, Italy, Research Doctorate in “Cardiological and Cardiosurgical Sciences”

Introduction

Ventricular arrhythmias and sudden arrhythmic death are a common feature in patients with dilated cardiomyopathies, left ventricular hypertrophy and regional wall motion abnormalities. The leading cause of ventricular tachyarrhythmias in these patients is supposed to be the mechanical dysfunction itself through the “mechanoelectrical feedback”, defined as the development of electrophysiological changes during or after changes in mechanical loading^1-2.

Basic research and animal experiments have shown that diastolic stretch, following a sudden increase in ventricular volume and pressure, decreases monophasic action potential (MAP) duration³ and amplitude⁴ and the ventricular effective refractory periods³ for as long as stretch is applied and can generate spontaneous depolarisations⁵, whose velocity of generation has been supposed to trigger the volume pulse-related ectopic ventricular excitations⁶. Electrical instability, following mechanical stretch, has been experimentally observed both in terms of development of afterdepolarization and in terms of increased dispersion of refractoriness and repolarization.

The aim of the present study was to assess the presence of mechano-electrical feedback in humans, evaluating ventricular repolarization time indexes following acute changes in left ventricular pressure.