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

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

RT-89

Early recurrences of atrial fibrillation: role of left ventricular relaxation impairment

Giuseppina Belotti, Antonella Fedele, Cinzia Gatti, Claudio Poluzzi, Giuseppe Penati, Alessandro Locatelli, Antonino Piti.
Cardiology Department, Ospedale Treviglio-Caravaggio, Treviglio, Italy

Introduction

Atrial fibrillation (AF) causes by itself electrophysiological changes^1-3 resulting in atrial electrical remodeling; this remodeling increases the propensity for AF relapse^3,4 and disappears within one week of sinus rhythm restoration⁵. AF-related changes are mediated by rate-induced intracellular calcium overload⁶ and are attenuated^3,7 and shortened in duration⁴ by verapamil. Furthermore, pretreatment with calcium blocking agents might maintain the sinus rhythm for longer period of time after cardioversion⁸. On the other hand, intracellular calcium plays a crucial role also in ventricular relaxation. Intracellular calcium movements regulate relaxation and the cytosol must be cleared of calcium for complete myocyte relaxation to occur; the increase of intracellular calcium is associated to LV impaired relaxation⁹. Ventricular relaxation occurs at the onset of the diastole, during isovolumic relaxation phase and during early rapid filling of the ventricle; when myocardia relaxation is impaired, isovolumic relaxation phase takes more time and early diastolic filling is reduced in rate and amount¹⁰. Doppler ecocardiography allows the evaluation of all these parameters.

The aim of the study was to evaluate whether left ventricular relaxation impairment, that shares pathophysiological mechanism of calcium overload with atrial electrical remodeling, is associated to AF recurrences.

There will be investigated the relation of early recurrences of AF, after external electrical cardioversion (EC), to LV relaxation parameters, evaluated on transmitral flow velocity profile at Doppler echocardiography.