K. Kulan et al., SIGNIFICANCE OF QT DISPERSION ON VENTRICULAR ARRHYTHMIAS IN MITRAL-VALVE PROLAPSE, International journal of cardiology, 54(3), 1996, pp. 251-257
The present study was designed to detect the arrhythmogenic effect of
mitral valve prolapse, and the relationship between QT, QT dispersion
and ventricular arrhythmias in subjects with mitral valve prolapse. Si
xty-four mitral valve prolapse subjects (24 men and 40 women, mean age
27 +/- 6), and 80 healthy control subjects (32 men and 48 women, mean
age 28 +/- 7) were studied. The frequency of ventricular arrhythmias
by means of 24-h ambulatory electrocardiographic (EGG) monitoring was
investigated. Grade greater than or equal to 3 ventricular arrhythmias
according to modified Lown and Wolf classification were accepted as c
omplex arrhythmias. The QT intervals were measured from the beginning
of depolarization of the QRS complex to the end of the T wave. Using t
he Bazett formula, QT interval was corrected (QTc) for heart rate. QT
dispersion was calculated as the difference between the maximum and mi
nimum QT intervals on any of 12 leads. Premature ventricular complexes
seemed to develop in 56 of 64 (87.5%) subjects with mitral valve prol
apse. Thirty-eight of the mitral valve prolapse subjects had complex p
remature ventricular complexes during 24-h ECG and the prevalence of p
remature ventricular complexes was found to be higher than the control
subjects (P < 0.001). We found QT and QTc intervals of 388 +/- 27 and
406 +/- 33 ms in mitral valve prolapse subjects, these values in cont
rol subjects were 382 +/- 18 and 402 +/- 11 ms respectively (P > 0.05)
. QT dispersion and QTc dispersion intervals were 71 +/- 17 and 78 +/-
19 ms in mitral valve prolapse subjects and these values were 43 +/-
16 and 52 +/- 22 ms in control subjects, respectively (P < 0.001). No
correlation was found between complex premature ventricular complexes
and QT, but there was a correlation between complex premature ventricu
lar complexes and QT dispersion in the mitral valve prolapse subjects.
It was concluded that QT dispersion might be a useful marker of cardi
ovascular morbidity and mortality due to complex ventricular arrhythmi
as.