QT dispersion: a link between cardiac dysynchrony and arrhythmogenesis?

Abstract

Background A relationship between mechanical dysynchrony and arrhythmogenicity is suggested by animal studies. This study investigated whether the aortic pre-ejection delay (AED), which reflects left intraventricular dysynchrony, is related to baseline ECG parameters in potential CRT candidates. Methods 41 patients with heart failure aged 69.6 (1.8) yrs [mean (SEM)], in NYHA class III or IV and with a QRS duration of 167.5 (4.5) ms (range 110.0 to 232.5 ms) underwent 12-ECG and transthoracic echocardiography. QT dispersion (QTd) was expressed as the difference between the maximum and the minimum QT intervals in the 6 standard chest leads. Results In multiple linear regression analyses, QTd emerged as a predictor of AED (p=0.0349), independently of QRS duration (p<0.0001) (F value: 13.3, p<0.0001). QT and QRS durations did not emerge as predictors of AED in a multivariate model (F value: 13.3, p<0.0001 for analysis). View this table: Conclusion QTd is related to AED, independently of QRS and QT durations. Whether the reported antiarrhythmic risk of CRT is related to effects on QTd requires further study.