Kittipovanonth, Maytinee

Background: Strain and strain rate has been shown to identify subtle contraction abnormalities of left ventricle. Objectives: We hypothesized that S and SR derived from velocity vector imaging (VVI) will allow early identification of global and regional RV systolic function in patients with pulmonary hypertension (PHT) compared to conventional echo parameters. Methods: 96 patients, 35 normal RV Systolic Pressure (RVSP < 30 mmHg) and 61 with PHT, {24 mild-moderate (RVSP > 60 mmHg) and 37 severe (RVSP < 60 mmHg)} underwent echo-Doppler assessment of RV. Apical 4 chamber images at end expiration were used for RV lateral wall (LW) and ventricular septal (VS) segment analysis for systolic tangential velocity (Ta V), S and SR. In addition RV end systolic and diastolic area, RV fractional area change (RV FAC), RV performance index (RIMP) and tricuspid annulus systolic excursion were measured. Results: Peak S, systolic SR and Ta V at the basal, mid and apical segments of the RV LW and VS were depressed in patients with PHT compared with controls, Table 1 , P 0.001. Similarly, significant decrease in RIMP was seen in patients with PHT compared to controls, p <0.001. Significant correlation (p<0.001, r >0.6) was noted between the 2D FAC and S, SR. The time to peak systolic S indexed to end diastolic area (EDA) is significantly prolonged, p<0.01 in all segments in patients with PHT indicating dyssynchrony. Conclusion: S and SR allows assesment of Regional RV systolic function otherwise difficult to assess from conventional echo-Doppler technique. PHTN is associated with not only regional RV systolic dysfunction but also with dyssynchrony. Thus, this new tool can offer new insights in the functioning of right ventricular global and regional function. mean±SD of strain

ObjectiveTo evaluate whether global peak systolic strain (PSS) and peak systolic strain rate (PSSR) derived from velocity vector imaging (VVI) allow early recognition of regional and global right ventricular (RV) dysfunction and the impact of this on left ventricular (LV) function in patients with pulmonary hypertension (PHT).BackgroundRV function is an important determinant of prognosis in patients with heart failure, pulmonary hypertension, heart transplant, and congenital heart diseases. However, evaluation of the right ventricle is often limited by its complex geometry and inadequate visualization of RV free wall. Furthermore, the impact of RV dysfunction on the LV function is not well elucidated.MethodsNinety‐nine participants, 35 control patients with normal RV systolic pressure (RVSP) (<30 mm Hg) and 64 patients with PHT (25 with mild‐to‐moderate increase in RVSP [≥36 and <60 mm Hg] and 39 with severe increase in RVSP [≥60 mm Hg]), underwent comprehensive echo‐Doppler assessment and velocity vector imaging (VVI) for strain rate analysis. RV regional peak systolic and diastolic tangential velocity, strain, and strain rate were obtained from the basal, mid and apical segments of the RV free wall and interventricular septum (IVS) from apical 4‐chamber view at end‐expiration. Similar data were obtained from eighteen LV segments from apical 4‐chamber, 2‐chamber, and long‐axis views.ResultsPeak systolic strain, strain rate, and tangential velocity at all segments in the RV free wall and IVS were decreased compared to controls in patients with PHT (P < 0.001). Significant correlation (r > 0.60; P < 0.001) was noted between RVSP and systolic and diastolic strain and strain rate at basal segment in IVS and global RV function. Peak early diastolic strain rate at all segments was also decreased in PHT patients compared with control patients (P < 0.01). Furthermore, RV systolic and diastolic strain and strain rate were lower in group 2 with mild‐to‐moderate hypertension while the conventional echo parameters were normal. Except for IVS segments, other LV segments had no statistical differences in systolic and diastolic velocity, strain, and strain rate compared to controls. However, they were lower than the published normal range.ConclusionsStrain and strain rate derived from VVI demonstrates early recognition of systolic and diastolic RV dysfunction in patients with PHT compared to controls. PHT is associated with global and regional RV systolic and diastolic dysfunction. Systolic and diastolic strain and strain rate from LV was lower compared to controls but were not statistically significant. This may indicate subclinical LV dysfunction in these patients, suggesting that conventional LV function parameters may not be sensitive to recognize subclinical LV dysfunction.

Background: Although a gradual increase in heart rate (HR) during dobutamine stress testing (DST) is desired, few data exists regarding whether this is similarly achieved in patients of widely varying body mass index (BMI). Whether difference in BMI contributes to variation in the hemodynamic and symptomatic response to dobutamine is also unknown. Methods: From prospectively acquired data of 2776 consecutive patients who underwent DST according to standard weight-based clinical protocol, we classified patients into 4 groups of BMI (kg/m 2 ): <25 (normal), 25 to 29.9 (overweight), 30 to 39.9 (obese), and ≥40 (severely obese) and compared the rate of increase of HR, mean blood pressure, and development of symptoms for the groups. Results: Age was 68 + 12 years, 52% were men, BMI was 29.8 + 6.6 kg/m 2 (range 14.5-81.4), 198 (7%) had BMI ≥40, and target HR was achieved in 2433 (88%). The rate of increase in HR was similar for each group of BMI after adjustment for age, gender, baseline HR, negative chronotropic use, and atropine administration. The percentage of patients in each group who achieved target HR was similar and the percentage of target HR achieved at each stage of dobutamine was essentially equivalent. Blood pressure responses and development of symptoms were similar in the 4 groups of BMI. Independent predictors of failure to achieve target HR included age, diabetes mellitus, treatment with negative chronotropic medications, and baseline HR; BMI was not a predictor (odds ratio [OR] 0.98, P = .086). Conclusion: The current weight-based protocol of dobutamine dosing for DST results in similar increases in HR and blood pressure for patients of widely varying BMI.