QT Interval Parameters: A Screen Test for the Detection of Left Ventricular Hypertrophy

Background: Electrocardiographic parameters for the detection of left ventricular hypertrophy (LVH) as an independent cardiovascular risk factor and signifier end-organ damage in patients with hypertension are known. The aim of this study was to evaluate the relation between QT interval parameters and LVH in patients with hypertension. Methods: This cross-sectional study recruited 100 patients with primary hypertension who underwent cardiac echocardiography for the evaluation of left ventricular mass (LVM). Standard 12-lead electrocardiography was performed for all the patients, and QT interval parameters (QT(max), QT(cmax), QT(d) [dispersion], and QT(d)F [difference between maximum and minimum QT intervals]) were calculated. The data were analyzed using SPSS (version 18). The t-test was applied to assess the relationship between QT parameters and left ventricular mass index (LVMI), and the receiver operating characteristic (ROC) curve was drawn to determine the cutoff point for the mentioned electrocardiographic test. Results: The mean age of the patients was 60.52 +/- 9.74 years. The mean of QT(d), QT(max), and QT(cd) in the patients with LVH was significantly greater than that of the patients without LVH (P<0.05). ROC curve analyses of QT interval parameters showed that the cutoff points for QT(max), QT(d), QT(cmax), and QT(cd) values were 420 (specificity=0.79 and sensitivity=0.40), 50 (specificity=0.58 and sensitivity=0.76), 478 (specificity=0.29 and sensitivity=0.58), and 59 (specificity=0.65 and sensitivity=0.76), respectively. Conclusions: According to our findings, QT(cd) and QT(c) would be better tests for the detection of LVH. We recommend further research with larger sample sizes to obtain more generalizable findings.