13th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 1998

January 24-31, 1998
Marilleva, Trento, Italy

RT-47

Increased QT dispersion and other repolarization abnormalities as a possible cause of electrical instability in isolated aortic stenosis. Increased QT dispersion in isolated aortic stenosis

Valentino Ducceschi, Berardo Sarubbi, Antonello D'Andrea, Biagio Liccardo, Nicola Briglia, Antonio Carozza, Joseph Marmo, Lucio Santangelo, Aldo Iacono, Maurizio Cotrufo.
Seconda Universita degli Studi di Napoli, Facolta di Medicina e Chirurgia, Istituto Medico-Chirurgico di Cardiologia, Naples, Italy

Abstract

Background. Aim of our study was to analyze the ventricular repolarization phase in patients with isolated aortic stenosis (AS).

Methods. We selected a population of 39 pts with isolated AS; as controls we considered a group of 31 age-matched healthy subjects. Disease severity was assessed by echocardiography, calculating the maximum and mean pressure gradients (max and mean PG) and the functional valve orifice area. Various electrocardiographic intervals (QT, QTc, JT, JTc) and indexes (QT and QTc dispersion) were adopted for a detailed non-invasive evaluation of the ventricular repolarization.

Results. In pts with AS, M-QT (391 ± 45 msec vs 362 ± 25 msec, p = 0.002), M-QTc (431 ± 29 msec vs 412 ± 19 msec, p = 0.003), M-JT (290 ± 41 msec vs 265 ± 26 msec, p = 0.003), M-JTc (331 ± 29 msec vs 302 ± 19 msec, p < 0 .001), QTD (67 ± 34 msec vs 40 ± 15 msec, p < 0.001), QTcD (77 ± 36 msec vs 52 ± 23 msec, p < 0.001) all resulted significantly greater than in controls. QTD and QTcD both resulted linearly related either to max PG (r = 0.388, p = 0.018 and r = 0.357, p = 0.03) or to mean PG (r = 0.513, p = 0.004 and r = 0.438, p = 0.015), while M-JT and M-JTc turned out to be directly related only to mean PG (r = 0.436, p = 0.016 and r = 0.483, p = 0.007).

Conclusions. Our findings suggest a prolonged duration of ventricular recovery and a greater dispersion of ventricular repolarization in patients with AS and might account for the electrical instability proper to this valve dysfunction. Besides, the existence of a linear direct relation between the severity of AS and the degree of inhomogeneity of left ventricular recovery strongly suggest the hypothesis that in AS arrhythmogenic substrates development parallels the worsening of the valve defect.

Key Words

QT interval
QT dispersion, aortic stenosis, ventricular repolarization, ventricular recovery, OA