value of signal-averaged electrocardiogram and QT dispersion as predictors of arrhythmic vulnerability in patients with left ventricular hypertrophy

Left ventricular hypertrophy [LVH] predicts increased risk for ventricular arrhythmias [VAs] which probably accounts for the elevated risk of sudden cardiac death. To investigate the value of signal-averaged electrocardiogram [SAECG] and QT dispersion as noninvasive markers for ventricular arrhythmias in patients with LVH. We subjected 60 patients with LVH;30 hypertensive [group 1], 15 with hypertrophic cardiomyopathy [HCM] [group II] and 15 with valvular aortic stenosis [group III] to a complete echo-Doppler examination, 12-lead electrocardiogram and SAECG for estimation of left ventricular mass index [LVMI], detection of QT dispersion and late diastolic potentials [LDPs]. Ventricular arrhythmias were detected in 32% of patients with LVH. LDPs were detected in 17% of patients with LVH. All patients with LDPs had VAs. All VAs in patients with LDPs were of Lown grade [2] and [3], whereas most of VAs in patients without LDPs were of Lown grade [1]. Patients with LVH had significantly high QT dispersion, QTc dispersion and LVMI when compared to control subjects [P=0.04, 0.03 and 0.01, respectively]. Patients with HCM had significantly high QT dispersion, QTc dispersion and LVMI when compared to group I [P=0.02, 0.03 and 0.02, respectively] and group II [P=0.02, 0.02 and 0.04, respectively]. Significant correlation was found between LVMI and LDPs as well as QT and QTc dispersion [P=0.042 for LDPs, 0.036 for QT dispersion and 0.028 for QTc dispersion]. Of the many ECG and echocardiographic variables subjected to univariate and multivariate analysis, only three were identified as significant independent predictors of VAs: QT, QTc dispersion, LVMI and LDPs [P=0.006 and 0.04 for QT dispersion; 0.008 and 0.043 for QTc dispersion, 0.008 and 0.033 for LVMI and 0.0001 and 0.0001 for LDPs]. QT dispersion, QTc dispersion, LVMI and LDPs may be a useful adjuncts to the noninvasive assessment of patients with LVH, particularly in the prediction of sudden death

Left ventricular structure and function in normotensive young adults with a family history of systemic hypertension

This study included 20 normotensive adolescents with hypertensive parents [SHT] who carry a high risk of becoming hypertensive later in life. These subjects were compared with a group of 20 normotensive adolescents with normotensive parents [SNT] and a group of 20 adolescents with borderline hypertension [BH]. Control groups were matched for age and sex. Echocardiography was utilized with all its different modalities [M-mode, 2-D and Doppler] to assess the morphological and functional status of the heart in the different groups studied. Diastolic impairment of LV function and echocardiographic increase in LVM and LVMI in normotensive young adults with family history of hypertension is directly related to the risk of developing subsequent hypertension. So, these noninvasive simple parameters might be used to identify predictors of arterial hypertension

Doppler assessment of right ventricular function in patients with essential hypertension

Forty patients [16 males and 24 females] with essential hypertension [EH] with age ranged between 35-55 years as well as 15 normal subjects with matched age and sex were subjected to Doppler evaluation of right ventricular [RV] diastolic function. Patients were subdivided into 2 groups according to the echocardiographic criteria of left ventricular hypertrophy [LVH]. This study revealed, impaired RV diastolic function in patients with EH. The right ventricular anterior wall thickness [RVAWT] increased significantly in hypertensive patients. This study revealed significant increase in mean pulmonary artery pressure in group I when compared to control group [p <0.001]. There was a good positive correlation between RVAWT and IVST, PLVWT and LVM index in group I and group II. In conclusion, structural and functional changes induced by EH are not limited to the LV but also involve RV and pulmonary circulation

Study of left ventricular mass in patients above 60 years with isolated systolic hypertension

The study comprised 40 patients with ISH, 21 males and 19 females, their age ranged between 60-80 years [mean 65 +/- 7.25] and 20 healthy subjects of matched age and sex as a control group. This study revealed highly significant increase in left ventricular mass [LVM] and left ventricular mass Index [LVMI] in the whole test group versus control group while a non significant differences were observed in these parameters when comparing male versus female subgroups; subgroup with body mass index [BMI] >30 versus subgroup with BMI <30, and subgroup with hypertension HTN >5 years versus subgroup with HTN <5 years. A nonsignificant increase in LVM and LVMI in subgroup with mild ISH versus control, while a significant increase in these parameters was observed in subgroups with moderate and severe IS versus control and between the 3 subgroups of mild, moderate and severe ISH