Radial Strain Gradient Across the Normal Myocardial Wall in Open-chest Pigs Measured with Doppler Strain Rate Imaging

Matre, Knut; Fanneløp, Tord; Dahle, Geir; Heimdal, Andreas; Grong, Ketil

doi:10.1016/j.echo.2005.01.031

Cited by 36 publications

(31 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…25 The short axis images of the anterior wall, only, were analyzed with 4 elliptically shaped ROI's with size 2 Â 6 mm and SL 2 mm as well as 2 elliptically shaped ROI's with size 4 Â 6 mm and SL 4 mm. Using a ROI of 6 mm across the beam enables averaging over several ultrasound beams in the lateral direction.…”

Section: Discussionmentioning

confidence: 99%

“…After premedication with ketamine/atropine, anesthesia was induced and maintained with loading doses and continuous infusions of fentanyl, midazolam, pancuronium and pentobarbital as previously described in detail. 25,26 The animals undervent tracheotomy and intubation; ventilation was continued with a mixture of N 2 O (56e57%) and oxygen. Fluid substitution was given as 15 mL kg h À1 of Ringer's Acetate with 20 mmol L À1 KCl added.…”

Section: Experimental Preparationmentioning

confidence: 99%

“…24 We have evaluated a method for experimental radial strain measurement in up to 4 myocardial layers in pigs using epicardial echocardiography, demonstrating a transmural gradient with higher levels of systolic strain in inner compared to outer wall layers. 25 A significant coronary stenosis manifests itself by subendocardial ischemia, strongly correlating to reduced wall thickening. 1 Our hypothesis was that alterations in transmural blood flow gradients during coronary stenosis would alter the radial strain gradient as measured with multilayer SI.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Multilayer radial systolic strain can identify subendocardial ischemia: An experimental tissue Doppler imaging study of the porcine left ventricular wall

Matre

Moen

Fanneløp

et al. 2007

European Journal of Echocardiography

View full text Add to dashboard Cite

Aims: This study investigates whether subendocardial ischemia can be detected by measuring multilayer radial systolic strain from epicardial tissue Doppler imaging. Methods:In 10 anesthetized open-chest pigs an extracorporeal shunt from the proximal brachiocephalic to the left anterior descending coronary artery was constricted in steps. Color microsphere injections and short axis Tissue Velocity Imaging (TVI) recordings were performed with open shunt, with a non-significant stenosis, and with 2 steps of shunt flow reduction.Results: With open shunt and no transmural flow gradient, there was a gradient of peak ejection strain with high values subendocardially for both 4 and 2 layer measurements. For 2 layer measurement strain was 56.0 AE 10.5% subendocardially and 22.0 AE 5.2% subepicardially. A non-significant stenosis, not altering transmural flow distribution, reduced strain to 40.3 AE 5.4% in the endocardial half-layer. With reduced shunt flow resulting in subendocardial ischemia, peak ejection strain decreased further, primarily in inner wall layers, and postsystolic strain became evident. At severe stenosis (52.4 AE 1.8% shunt flow reduction) strain was reduced to 3.8 AE 3.6% in the subendocardium and 0.0 AE 2.6% in the subepicardium. Conclusion: Evaluation of myocardial function with multilayer radial systolic strain has a potential for detecting subendocardial ischemia.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Experimental Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multilayer radial systolic strain can identify subendocardial ischemia: An experimental tissue Doppler imaging study of the porcine left ventricular wall

Matre

Moen

Fanneløp

et al. 2007

European Journal of Echocardiography

View full text Add to dashboard Cite

show abstract

“…Because the frame rate was 96 -102 frames/s, the step size for integration was 9.8 -10.4 ms. Next, strain is obtained by evaluating the change of distance between pairs of two points defined on all pixels on the image by utilizing the displacement values. The distance of all two-pixel pairs at the initial time frame is equivalent to "L 0" on the above equation and set at 3 mm in this study (17). The initial time frame is set at end diastole to evaluate contraction; in other words "deformation" of the myocardium occurring in systole.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of transmural distribution of viable muscle by myocardial strain profile and dobutamine stress echocardiography

Maruo

Nakatani²,

Jin³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

bution of viable myocardium in the ischemic myocardium has not been quantified and fully elucidated. To address this issue, we evaluated transmural myocardial strain profile (TMSP) in dogs with myocardial infarction using a newly developed tissue strain imaging. TMSP was obtained from the posterior wall at the epicardial left ventricular short-axis view in 13 anesthetized open-chest dogs. After control measurements, the left circumflex coronary artery was occluded for 90 min to induce subendocardial infarction (SMI). Subsequently, latex microbeads (90 m) were injected in the same artery to create transmural infarction (TMI). In each stage, measurements were done before and after dobutamine challenge (10 g ⅐ kg Ϫ1 ⅐ min Ϫ1 for 10 min) to estimate transmural myocardial viability. Strain in the subendocardium in the control stage increased by dobutamine (from 53.6 Ϯ 17.1 to 73.3 Ϯ 21.8%, P Ͻ 0.001), whereas that in SMI and TMI stages was almost zero at baseline and did not increase significantly by dobutamine [from 0.8 Ϯ 8.8 to 1.3 Ϯ 7.0%, P ϭ not significant (NS) for SMI, from Ϫ3.9 Ϯ 5.6 to Ϫ1.9 Ϯ 6.0%, P ϭ NS for TMI]. Strain in the subepicardium increased by dobutamine in the control stage (from 23.9 Ϯ 6.1 to 26.3 Ϯ 6.4%, P Ͻ 0.05) and in the SMI stage (from 12.4 Ϯ 7.3 to 27.1 Ϯ 8.8%, P Ͻ 0.005), whereas that in the TMI stage did not change (from Ϫ1.0 Ϯ 7.8 to Ϫ0.7 Ϯ 8.3%, P ϭ NS). In SMI, the subendocardial contraction was lost, but the subepicardium showed a significant increase in contraction with dobutamine. However, in TMI, even the subepicardial increase was not seen. Assessment of transmural strain profile using tissue strain imaging was a new and useful method to estimate transmural distribution of the viable myocardium in myocardial infarction. myocardial infarction; strain; viability; echocardiography IT IS WELL KNOWN that myocardial contraction has transmural heterogeneity. Several experimental studies confirmed that the subendocardium contributes greater to overall myocardial thickening than the subepicardium (6, 25). On the other hand, when a reduction of coronary blood flow occurs, a severe reduction of perfusion and kinesis occurs in the subendocardium, but only a trivial reduction can be detected in the subepicardium (5, 31). After a long period of ischemia, myocardial necrosis progresses from the endocardium to the epicardium (8, 13).Myocardial strain reflects regional myocardial function. With the recent advancement of tissue Doppler echocardiography, myocardial strain can be obtained noninvasively (3, 33) and has been reported to be useful to quantify regional myocardial systolic function in ischemic heart disease (9, 11, 24, 29, 36). The recently developed myocardial strain imaging system provides us myocardial strain in each wall layer and shows its distribution in a form of transmural myocardial strain profile (TMSP; see Ref. 1). Thus combination of TMSP and dobutamine stress echocardiography (DSE), which has been used for the assessment of myocardial viability (18), is expected to demonstr...

show abstract

“…Volumes were indexed (normalised) for body surface area (BSA) calculated as BSA = k BW 2/3 /100 where BW is body weight in kg and k for pigs is 9 m 2 kg À2/3 [13]. Tissue velocity images were transferred to a work station, converted to strain rate images (SRI) and analysed for strain with commercially available software (EchoPacPC, GE Vingmed Ultrasound, Horten, Norway) as described earlier [14]. Radial peak ejection and postsystolic strain was calculated in the subendo and subepicardial halves of the anterior left ventricular wall with aortic valve opening and closure defined from pulsed wave Doppler recordings.…”

Section: Data Acquisitionmentioning

confidence: 99%

Esmolol before 80min of cardiac arrest with oxygenated cold blood cardioplegia alleviates systolic dysfunction. An experimental study in pigs☆

Fanneløp

Dahle

Matre

et al. 2008

European Journal of Cardio-Thoracic Surgery

View full text Add to dashboard Cite

Objective: Myocardial dysfunction after reperfusion can be a clinical problem in the early postoperative phase after on-pump cardiac surgery. The aim was, in an experimental setting, to investigate if administration of the b-adrenergic receptor blocker esmolol prior to cross-clamping for 80 min with cold oxygenated blood cardioplegia would improve myocardial protection and early postoperative function. Methods: Twenty-four anaesthetised pigs were randomly allocated into one of two equally sized groups and put on mild hypothermic cardiopulmonary bypass. Esmolol 1 mg kg À1 or saline was administered into the arterial line 4 min prior to aortic cross-clamp. Cardiac arrest during 80 min of cross-clamp was obtained with repeated antegrade cold oxygenated blood cardioplegia; the pigs were weaned from bypass following a standardised protocol. Left ventricular global and regional myocardial function and tissue blood flow were evaluated with conductance catheter, echocardiography and coloured microspheres at baseline and at 1, 2 and 3 h after declamping. Four animals did not fulfil the protocol and were excluded. Results: No significant differences between groups could be demonstrated for left ventricular global and local function and tissue blood flow at baseline. At 1 h after declamping the slope of preload recruitable stroke work (PRSW slope ) averaged 73.7 AE 12.7 mmHg (SD) in controls and 72.7 AE 11.1 mmHg in esmolol-treated animals. In controls PRSW slope decreased to 62.1 AE 11.0 and 58.4 AE 12.7 mmHg after 2 and 3 h, respectively ( p < 0.005 vs 1 h for both). In the esmolol-treated animals PRSW slope remained unchanged at 72.0 AE 11.4 and 73.7 AE 12.9 mmHg at 2 and 3 h after declamp and were significantly higher ( p < 0.025 and <0.001) than the corresponding values in the control group. The slope of the end systolic pressure volume relationship did not differ between groups at 1 and 2 h after declamp, but were 1.85 AE 0.86 and 2.51 AE 0.96 mmHg ml À1 in controls and in esmolol-treated animals, respectively, after 3 h ( p < 0.025). Conclusions: Esmolol administered prior to cold oxygenated cardioplegic arrest alleviates left ventricular dysfunction in the early hours after cardiopulmonary bypass. #

show abstract

Radial Strain Gradient Across the Normal Myocardial Wall in Open-chest Pigs Measured with Doppler Strain Rate Imaging

Cited by 36 publications

References 27 publications

Multilayer radial systolic strain can identify subendocardial ischemia: An experimental tissue Doppler imaging study of the porcine left ventricular wall

Multilayer radial systolic strain can identify subendocardial ischemia: An experimental tissue Doppler imaging study of the porcine left ventricular wall

Evaluation of transmural distribution of viable muscle by myocardial strain profile and dobutamine stress echocardiography

Esmolol before 80min of cardiac arrest with oxygenated cold blood cardioplegia alleviates systolic dysfunction. An experimental study in pigs☆

Contact Info

Product

Resources

About