Mechanical dysfunction in the border zone of an ovine model of left ventricular aneurysm

doi:10.1016/0003-4975(95)00521-L

The Annals of Thoracic Surgery

Volume 60, Issue 4, October 1995, Pages 986-998

https://doi.org/10.1016/0003-4975(95)00521-L Get rights and content

Background.

The pathophysiology of regional mechanical dysfunction in the border zone (BZ) region of left ventricular aneurysm was studied in an ovine model using magnetic resonance imaging tissue-tagging and regional deformation analysis.

Methods.

Transmural infarcts were created in adult Dorsett sheep (n = 8) by ligation of the distal homonymous coronary artery and were allowed to mature into left ventricular aneurysms for 8 to 12 weeks. Animals were imaged subsequently using double oblique magnetic resonance imaging with radiofrequency tissue tagging. Short axis slices were selected for analysis that included predominantly the septal component of the aneurysm as well as adjacent BZ regions in the anterior and posterior ventricular walls. Dark grid patterns of magnetic presaturations were placed on the myocardium and tracked as they deformed during the diastolic, isovolumic systolic, and systolic ejection phases of the cardiac cycle. Regional ventricular wall strains were calculated in BZ regions and regions remote from the aneurysm and compared with strains measured in corresponding regions from normal control sheep (n = 6).

Results.

Diastolic midwall circumferential strains (fiber extensions) were relatively preserved, but abnormal circumferential lengthening strains were observed in the BZ regions during isovolumic systole. Peak circumferential strains ranged from 0.04 to 0.07 in the BZ regions but averaged −0.05 in the normal hearts (p = 0.002 for the anterior BZ and p = 0.001 for the posterior BZ). Midwall end-systolic fiber strains were depressed in the anterior BZ (−0.03 to −0.09 for the BZ versus −0.11 for the normal heart, p < 0.0001) but not in the posterior BZ (p = 0.19).

Conclusions.

Our data support the theory that the stretching of BZ fibers during isovolumic systole contributed to a reduction in fiber shortening during systolic ejection and thus reduced the overall contribution of these fibers to forward ventricular output.

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: Presented at the Thirty-first Annual Meeting of The Society of Thoracic Surgeons, Palm Springs, CA, Jan. 30–Feb. 1, 1995.

View full text

Mechanical dysfunction in the border zone of an ovine model of left ventricular aneurysm

Background.

Methods.

Results.

Conclusions.

J Thorac Cardiovasc Surg

Ann Thorac Surg

Am J Cardiol

Am Heart J

J Thorac Cardiovasc Surg

Ann Thorac Surg

The functional border zone in conscious dogs

Circulation

Quantitative analysis of regional systolic function with left ventricular aneurysm

Circulation

Regional three-dimensional geometry and function of left ventricles with fibrous aneurysms: a cine-computed tomgraphy study

Circulation

Left ventricular shape changes induced by aneurysmectomy with endoventricular circular patch plasty reconstruction

Eur Heart J

Human heart tagging with MR imaging: A method for noninvasive assessment of myocardial motion

Radiology

Three-dimensional motion and deformation of the heart wall: estimation with spatial modulation of magnetization—a model-based approach

Radiology

Circumferential myocardial shortening in the normal human left ventricle: assessment by magnetic resonance imaging using spatial modulation of magnetization

Circulation

Three-dimensional left ventricular deformation in hypertrophic cardiomyopathy

Circulation

Evaluation of left ventricular segmental wall motion in hypertrophic cardiomyopathy with myocardial tagging

Circulation