QT dispersion in patients with mitral valve prolapse is related to the echocardiographic degree of the prolapse and mitral leaflet thickness

Background Ventricular arrhythmias are common in patients with mitral valve prolapse (MVP). Previous studies have provided evidence that a higher degr ee of systolic mitral valve displacement and the presence of a thickened an terior mitral leaflet are related to an increased incidence of complex vent ricular arrhythmias and risk of sudden death in these patients. The aim of our study was to investigate whether QT dispersion in patients with MVP is associated with the echocardiographic degree of the prolapse and mitral lea flet thickness. Methods QT and JT intervals and dispersions were measured in 89 patients wi th primary mitral valve prolapse (26 men and 63 women with mean age 39 +/- 14 years). All patients underwent a full echocardiographic examination and a scoring system was used to determine the degree of MVP. Anterior mitral l eaflet thickness was also measured. Twenty-four hour Holter monitoring was used to assess ventricular arrhythmogenesis. Results According to their echocardiographic score, patients were divided i nto three groups (Group A, B and C) reflecting the different degrees of the prolapse. QT dispersion in patients with the highest degree of MVP, i.e. G roup C was significantly greater (65 +/- 13 ms) than that of the other two groups (Group A: 38 +/- 14 ms, P < 0.005 and Group B: 45 +/- 12 ms, P < 0.0 05). Similar differences between groups were also found for JT dispersion. Multiple regression analysis revealed that among the demographic and clinic al variables that were tested, only the echocardiographic degree of the pro lapse and anterior mitral leaflet thickness were independently associated w ith QT dispersion. Holler monitoring showed that the incidence of complex v entricular arrhythmias was also higher in patients with more severe MVP. Conclusions Our results indicate that QT and JT dispersions are related to the echocardiographic degree of MVP and mitral leaflet thickness. The echoc ardiographic assessment of the severity of the prolapse may help to identif y a subgroup of patients at increased risk of life-threatening arrhythmias. (C) 2001 The European Society of Cardiology.