Multivariate associates of QT interval parameters in diabetic patients with arterial hypertension: importance of left ventricular mass and geometric patterns

Abstract

The aim of the study was to assess the determinants of increased QT interval parameters in diabetic patients with arterial hypertension and, in particular, the strength of their relationships to echocardiographically derived left ventricular mass (LVM) and geometric patterns. In a cross-sectional study with 289 hypertensive type 2 diabetic outpatients, maximal QT and QT c (heart ratecorrected) intervals, and QT, QT c , and number-of-leadsadjusted QT interval dispersions were manually measured from standard baseline 12-lead ECGs. Electrocardiographic criteria for left ventricular hypertrophy (LVH) were either Sokolow-Lyon or Cornell sex-specific voltages. LVM and geometric patterns were determined by 2D echocardiography. Statistical analyses involved bivariate tests (Mann-Whitney, v 2 , Spearman's correlation coefficients, ANOVA and receiver-operating-characteristic (ROC) curve analyses) and multivariate tests (multiple linear and logistic regressions). QT dispersion measurements showed significant correlations with echocardiographic LVM (r ¼ 0.26-0.27). ROC curves demonstrated a poor isolated predictive performance of all QT parameters for detection of LVH (areas under curve: 0.58-0.59), comparable to that of electrocardiographic voltage criteria. Only patients with concentric hypertrophy had significantly increased QT dispersion (QT d ) when compared to those with normal geometries (64.24 7 21.09 vs 53.20 7 15.35, Po0.05). In multivariate analyses, both electrocardiographic and echocardiographic LVH were independent predictors of increased QT d , as well as only QT d and gender were determinants of LVM. In conclusion, increased QT interval dispersion is associated with LVM and concentric hypertrophy geometric pattern in diabetic hypertensive patients, although in isolation neither QT d nor any QT parameter presents enough predictive performance to be recommended as screening procedures for detection of LVH.

Usefulness of QT-interval parameters for cardiovascular risk stratification in type 2 diabetic patients with arterial hypertension

“…5,16,17 In brief, all adult type 2 diabetic outpatients that had standard ECGs recorded from July 1994 to June 1996 were enrolled in this prospective study. This protocol complied with the ethical guidelines of the Declaration of Helsinki, was approved by the local ethics committee and all participants gave written informed consent.…”

“…17 Two-dimensionally guided M-mode images were obtained from the short axis parasternal view at the level of the tips of the mitral valve leaflets and the measurements of interventricular septal wall thickness (ISWT), posterior wall thickness (PWT) and left ventricular end diastolic diameter (LVEDD) were made at the peak of the ECG R wave according to the Penn convention. 19 Left ventricular mass (LVM) was calculated by the anatomically validated formula of Devereux and Reichek:…”

“…The baseline procedures and criteria for diagnosing clinical variables have also been detailed previously. 5,16,17 Laboratory evaluation included fasting plasma glucose, serum fructosamine, creatinine, triglycerides, total and HDL-cholesterol, and 24-h proteinuria, by automated methods.…”

Combined QT Interval and Voltage Criteria Improve Left Ventricular Hypertrophy Detection in Resistant Hypertension

“…4 Prolonged QT interval duration or dispersion are associated with the occurrence of life-threatening ventricular arrhythmias and thus are presumed to represent potential predictors of increased cardiovascular risk. 5 In patients with hypertension, QT interval parameters have mainly been associated with left ventricular mass, 6,7 although 2 studies 8,9 suggested that they are no better than simple electrocardiographic voltage criteria for LVH detection. Moreover, it has been reported recently that they probably constitute true cardiovascular mortality markers in hypertensive patients.…”

The effect of pesticide exposure on cardiovascular system: a systematic review

“…Prolonged recovery from electrical excitation increases the likelihood of dispersing refractoriness, when some parts of myocardium might be refractory to subsequent depolarization. 33 In animal experiments, prolongation of the QT interval is a direct myocardial pesticide effect and is independent of cholinergic effects. 34 Other common cardiac manifestations include sinus tachycardia.…”