QT dispersion (QTD) reflects heterogeneity of myocardial repolarization and has been proposed to be a predictor of adverse outcomes in a variety of cardiac disease states. The objective of this study was to characterize QTD in right-sided pressure overload.
We identified 30 consecutive patients referred for routine transthoracic echocardiography found to have pulmonary hypertension (PH), defined as systolic pulmonary artery pressure>30mmHg and 30 age and gender matched controls without PH. QTD was calculated from 12 lead electrocardiogram as the difference between maximum and minimum QT intervals in at least 11 of 12 leads. Right and left ventricular dimensions, wall thickness, and function were assessed by echocardiography.
QTD was significantly higher in patients with PH as compared to controls (70+/−12ms vs 45+/−12ms, p=.03). QTD was unrelated to RV size, wall thickness, and function. There was a direct correlation between increasing QTD and LV mass (r=.37, p=.04). On multivariate analysis, LV mass remained the only independent correlate of QTD (r2=.15, p=.04).CONCLUSIONS: QTD is related to LV mass but not to RV dimensions and function or to the degree of PH.
The prognostic significance of QTD in PH merits further study.
J.M. Lazar, None.