Noninvasive Quantification of the Contractile Reserve of Stunned Myocardium by Ultrasonic Strain Rate and Strain

Abstract

Background-We sought to investigate ultrasonic strain rate and strain as new indices to quantify the contractile reserve of stunned myocardium during dobutamine infusion. Methods and Results-Stunning of the left ventricular posterior wall was induced in 9 closed-chest pigs after 30 minutes of severe hypoperfusion followed by 60 minutes of reperfusion of the left circumflex coronary artery territory. A second group of 7 animals had no coronary occlusion and served as normal controls. An incremental dobutamine infusion protocol was used in both groups. Changes in regional radial function were monitored by use of ultrasound-derived maximal systolic radial strain rate (SR) and systolic strain (⑀). In the control group, dobutamine induced an increase in both SR and maximal dP/dt, which correlated linearly (rϭ0.85). Conversely, ⑀ values increased at low doses of dobutamine (2.5 to 5 g · kg Ϫ1 · min

Assessment of the regional myocardial deformation changes and viability in anterior acute myocardial infarction patients by strain and strain rate imaging

“…Regional S and Sr reduced and remained so for more than 60 minutes after the perfusion returned to normal (15). The return of S to its previous level following removal of very prolonged (90-120 minutes) coronary occlusion was shown to be a marker for residual myocardial viability in dogs.…”

Progressive nature of chronic mitral regurgitation and the role of tissue Doppler-derived indexes

“…§P Ͻ 0.05 vs. baseline. shown to correlate with shortening velocity at varying loading conditions in isolated muscle strips (1), whereas in vivo, in a porcine ischemia-reperfusion model, radial SR has been shown to quantify baseline cardiac function and contractile reserve (14), suggesting that these indexes accurately reflect myocardial contractility. In MR, chamber dilatation leads to individual myocyte hypertrophy, elongation, and reduced contractility (13,32); therefore, one plausibly could expect subtle LV systolic dysfunction to precede global dysfunction as suggested in our model, and an accurate method of detection may be useful as in other models of cardiac injury (17).…”

Discrimination of Nonobstructive Hypertrophic Cardiomyopathy From Hypertensive Left Ventricular Hypertrophy on the Basis of Strain Rate Imaging by Tissue Doppler Ultrasonography

“…5 Filling pressures would thus be expected to affect ⑀ sys . 34 This load dependency should be taken into account when deformation parameters are used to identify potential changes in contractility and in lusitropic properties. In the present study, LV end-diastolic internal dimension did not differ significantly between HCM and H-LVH patients, although LVEDP was significantly greater in HCM patients than in H-LVH patients.…”