Regional Myocardial Function during Acute Coronary Artery Occlusion and Its Modification by Pharmacologic Agents in the Dog
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TLDR
The results indicate the power of this approach, which provides continuous quantification of regional wall function in myocardial ischemia and during therapeutic interventions, and suggests a protective effect of this drug.Abstract:
Myocardial regional function during acute coronary artery occlusion was studied using ultrasonic dimension gauges in open-chest dogs. Three pairs of 2-mm ultrasonic crystals were implanted 1 cm apart near the endocardium in an ischemic segment, a control segment, and a segment at the margin of the ischemic zone. In the ischemic segment, coronary artery occlusion resulted in prompt dyskinesis which progressed to holosystolic expansion; length at enddiastole (diastolic length) increased by 11%, segment stroke work decreased by 91%, and the diastolic pressure-length relationship was displaced and steepened. In the marginal segment, active shortening and stroke work decreased by 37% and diastolic length increased by 4%. In the control segment, an initial increase in active shortening was observed, followed by compensatory operation of the Frank-Starling mechanism. Nitroglycerin administered during coronary artery occlusion decreased diastolic length and increased shortening in all three segments. An early beneficial effect of isoproterenol on all segments was later replaced by deterioration in marginal and ischemic segments. After propranolol administration, the decrease in shortening of the marginal segment was reduced to half of that observed during a control coronary artery occlusion, suggesting a protective effect of this drug. These results indicate the power of this approach, which provides continuous quantification of regional wall function in myocardial ischemia and during therapeutic interventions.read more
Citations
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Regional myocardial functional and electrophysiological alterations after brief coronary artery occlusion in conscious dogs.
TL;DR: Observations indicate that brief interruptions of coronary flow result either in a prolonged period of local ischemia or that alterations of mechanical induced by ischemIA far outlast the repayment of the oxygen debt.
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Linearity of the Frank-Starling relationship in the intact heart: the concept of preload recruitable stroke work.
Donald D. Glower,J. A. Spratt,N D Snow,J. S. Kabas,J. W. Davis,C. O. Olsen,G. S. Tyson,David C. Sabiston,J S Rankin +8 more
TL;DR: The Frank-Starling relationship generally has been examined with filling pressure as the index of preload, resulting in a curvilinear function that plateaus at higher filling pressures, which is proposed as a potential measure of intrinsic myocardial performance independent of loading, geometry, and heart rate.
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Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC).
Rosa Sicari,Petros Nihoyannopoulos,Arturo Evangelista,Jarosław D. Kasprzak,Patrizio Lancellotti,Don Poldermans,Jen-Uwe Voigt,José Luis Zamorano +7 more
TL;DR: In spite of its dependence upon operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.
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The three-dimensional dynamic geometry of the left ventricle in the conscious dog.
TL;DR: The dynamic geometry of the left ventricle was assessed with the use of chronically implanted pulse-transit ultrasonic dimension transducers and found that the dynamic contraction pattern was dependent on the physiological state of the dog.
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Structure and Mechanics of Healing Myocardial Infarcts
TL;DR: It is hypothesized that normal passive material properties dominate the mechanics during acute ischemia, edema during the subsequent necrotic phase, large collagen fiber structure during the fibroticphase, and cross-linking of collagen during the long-term remodeling phase.
References
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TL;DR: Dogs treated with propranolol showed significantly less necrosis than did untreated controls, but the mechanism of the drug's action remains unknown.
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TL;DR: A new technic for continuously recording the dimensions of internal organs in intact unanesthetized animals has been developed as a modification of sonar technics and has continued to function reliably for more than 3 months after installation in the animal.