Usefulness of electrocardiographic QT interval to predict left ventricular diastolic dysfunction

Whether a normal electrocardiogram excludes left ventricular (LV) diastolic dysfunction (DD) and whether electrocardiographic parameters are associated with DD is unknown. We therefore sought to investigate the relation between electrocardiographic parameters and DD. We first evaluated 75 consecutive patients referred for echocardiography for clinical suspicion of heart failure (phase 1). Electrocardiography and comprehensive echocardiography were performed on all patients and were analyzed separately in a blinded fashion. Receiver operating characteristic curves and multivariate regression analyses were used to determine which electrocardiographic parameters were most closely associated with DD. Next, we prospectively validated our results in 100 consecutive, unselected patients undergoing echocardiography (phase 2). In phase 1 of our study, the mean age was 59 ± 14 years, 41% were women, 31% had coronary disease, 53% had hypertension, and 25% had diabetes. The mean ejection fraction was 54 ± 15%, and 64% had DD. Of all the electrocardiographic parameters, the QTc interval was most closely associated with DD. QTc was inversely associated with E' velocity (r = -0.54, p <0.0001), and the area under the receiver operating characteristic curve for QTc as a predictor of DD was 0.82. QTc prolongation was independently associated with reduced E' velocity (p = 0.021 after adjustment for age, gender, medications, QRS duration, and ejection fraction). In phase 2 of our study QTc was the electrocardiographic parameter most associated with reduced E' velocity (435 ± 31 vs 419 ± 24 ms; p = 0.004), confirming our phase 1 study findings. In conclusion, QTc prolongation was the electrocardiographic marker most predictive of DD and was independently associated with DD.