Left Ventricular Untwist Rate Research Articles

Response to Letter Regarding Article, “Left Ventricular Untwisting Rate by Speckle Tracking Echocardiography”

We appreciate the interest of Dwivedi et al in our study.1 They raise 3 points with respect to our results. The first deals with their belief that the untwisting rate (UR) should be abnormal in patients with diastolic heart failure (DHF), the second deals with cardiac function in these patients at rest and with exercise, and the third has to do with the underlying mechanisms. Dwivedi et al base their impression that DHF patients should have a reduced UR on reduced Ea, on other studies showing abnormal UR, and on a report in patients with hypertrophic cardiomyopathy that Dwivedi and colleagues believe showed that peak UR is an …

Left Ventricular Untwisting Rate by Speckle Tracking Echocardiography

Recent studies validated the measurement of left ventricular (LV) untwisting rate (UR) by speckle tracking echocardiography. A few reports suggest that it may provide additional noninvasive insight into LV diastolic function. Simultaneous echocardiographic imaging and LV pressure measurements (7F Millar catheters) were performed in 8 adult dogs. Loading conditions were altered by caval occlusion, whereas lusitropic state was changed by dobutamine and esmolol infusion. Inferior vena cava occlusion at all experimental stages (baseline, dobutamine, esmolol) led to a significant decrease (P < or = 0.01) in LV end-systolic volume (ESV) and a significant increase in UR (P = 0.03). The best relation was observed between LV UR and ESV (r = -0.8, P < 0.001). The clinical study was conducted in 67 patients (age 57+/-17 years, 19 women) undergoing simultaneous right heart catheterization and echocardiographic imaging, with 20 healthy subjects as a control group. There were 34 patients with ejection fraction (EF) <50% (25+/-9%), and 33 patients with normal EF and diastolic dysfunction (64+/-7%). Patients with LV systolic dysfunction had a significantly lower UR (-55 omicron/s) in comparison with the control group (-89 omicron/s) and patients with normal EF (-104 omicron/s, P < 0.05), and the determinants of LV UR were twist, ESV, and tau (r2 = 0.83, P < 0.001). In patients with diastolic dysfunction and normal EF, twist and ESV were the independent predictors (r2 = 0.71, P < 0.001). LV UR is reduced in patients with depressed EF, but not in those with diastolic dysfunction and normal EF, and is primarily determined by twist and ESV.