Possible link between strain ST-T change on the electrocardiogram and subendocardial dysfunction assessed by...

Strain ST-T changes on surface electrocardiogram (ECG) may reflect subendocardial dysfunction. We hypothesized that strain ST-T changes are associated with (i) decrease in longitudinal strain, (ii) decrease in early systolic clockwise twist and early diastolic untwisting, and (iii) augmentation of peak twist due to subendocardial dysfunction.

Three levels of left ventricular (LV) short-axis views and three LV apical views were acquired in 46 hypertensive patients with LV hypertrophy and 23 age-matched control subjects using 2D echocardiography. Patients were divided into two groups according to the presence (n = 18) or absence (n = 28) of strain ST-T change on 12-lead ECG. Using 2D strain software, longitudinal, radial, and circumferential strain were measured. Early systolic clockwise twist, end-systolic twist, and untwisting at early diastole were measured from time-domain LV twist curves. No significant intergroup differences in LV ejection fraction were noted. Longitudinal strain was significantly reduced in hypertensive patients with strain ST-T changes compared with those without these changes or control subjects. Although LV twist at end-systole was similar between patients with and without strain ST-T changes, early systolic clockwise twist and untwisting was significantly reduced in strain ST-T change group compared with the no ST-T change group. Multivariate analysis revealed that not LV mass index but strain ST-T change was an independent predictor of global longitudinal strain.

The reduction in longitudinal strain, early systolic clockwise twist, and untwisting in hypertensive patients with strain ST-T changes suggests possible link between this ECG abnormality and subendocardial dysfunction, which can be assessed by 2D speckle tracking echocardiography.