Functional characterization of left ventricular segmental responses during the initial 24 h and 1 wk after experimental canine myocardial infarction.

Roan, P G; Scales, F; Saffer, Shelley I.; Buja, L. Maximilian; Willerson, James T.

doi:10.1172/jci109546

Cited by 58 publications

(23 citation statements)

References 68 publications

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“…Theoretical and experimental validation of this technique has been published elsewhere (20,29). The beginning and end of systole were determined from the onset of the rapid upstroke of the LV pressure tracing and the peak negative dP/dt, respectively (30). Percent systolic thickening fraction was calculated as the ratio of net systolic thickening to end-diastolic wall thickness, multiplied by 100 (20).…”

Section: Assessment Ofregional Myocardialfunctionmentioning

confidence: 99%

“…Percent systolic thickening fraction was calculated as the ratio of net systolic thickening to end-diastolic wall thickness, multiplied by 100 (20). Net systolic thickening was defined as the maximal systolic increase in wall thickness from the end-diastolic value (30). When paradoxical wall thinning persisted for 50% or more of systole, the maximal extent of wall thinning was subtracted from wall thickening to give net systolic thickening (7, 10-12, 14, 21, 30).…”

Section: Assessment Ofregional Myocardialfunctionmentioning

confidence: 99%

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Demonstration of free radical generation in "stunned" myocardium of intact dogs with the use of the spin trap alpha-phenyl N-tert-butyl nitrone.

Bolli¹,

Patel²,

Jeroudi³

et al. 1988

J. Clin. Invest.

667

220

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Recent studies suggest that oxygen free radicals may mediate postischemic myocardial dysfunction ("stunning"), but all the evidence for this hypothesis is indirect. Thus, we used electron paramagnetic resonance (EPR) spectroscopy and the spin trap, a-phenyl N-tert-butyl nitrone (PBN), to directly investigate whether free radicals are produced after a 15-min coronary artery occlusion and subsequent reperfusion in 30 open-chest dogs. After intracoronary infusion of PBN, EPR signals characteristic of oxygen-and carbon-centered radical adducts were detected in the venous blood draining from the ischemic/reperfused vascular bed. The myocardial release of PBN adducts began during coronary occlusion but increased dramatically in the first few minutes after reperfusion. After this initial burst, the production of radicals abated but did not cease, persisting up to 3 h after reflow. The EPR spectra (as6 = 2.67-2.79 G, aN = 14.75-15.00 G) were consistent with the trapping by PBN of secondary oxygen-and carbon-centered radicals, such as alkoxy and alkyl radicals, which could be formed by reactions of primary oxygen radicals with membrane lipids. There was a linear, direct relationship between the magnitude of PBN adduct production and the degree of ischemic flow reduction. Recovery of contractile function (measured as systolic wall thickening) after reperfusion was greater (P < 0.05) in dogs given PBN than in controls.This study demonstrates that reversible regional myocardial ischemia in the intact animal is associated with prolonged free radical generation, and that the intensity of such generation is related to the severity of ischemia. The results provide direct evidence to support the hypothesis that reactive oxygen metabolites contribute to the persistent contractile dysfunction (myocardial stunning) observed after brief ischemia in vivo.

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Section: Assessment Ofregional Myocardialfunctionmentioning

confidence: 99%

Section: Assessment Ofregional Myocardialfunctionmentioning

confidence: 99%

Demonstration of free radical generation in "stunned" myocardium of intact dogs with the use of the spin trap alpha-phenyl N-tert-butyl nitrone.

Bolli¹,

Patel²,

Jeroudi³

et al. 1988

J. Clin. Invest.

667

220

View full text Add to dashboard Cite

show abstract

“…More recently, the use of chronically implanted ultrasonic crystals has permitted the precise measurement of regional dimen-sions of the left ventricle in unanesthetized animals. [2][3][4] These studies examined the effect of restricted regional blood flow upon regional myocardial function after coronary occlusion in the conscious dog. Rivas et al5 studied the relationship between this reduced blood flow and the extent of the subsequent infarct in the canine myocardium.…”

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confidence: 99%

Correlation of regional myocardial blood flow and function with myocardial infarct size during acute myocardial ischemia in the conscious pig.

Savage¹,

Guth²,

White³

et al. 1981

Circulation

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SUMMARY Regional myocardial function and blood flow were determined for 48 hours after permanent occlusion of the left circumflex coronary artery in conscious swine. Systolic wall thickening and end-diastolic wall thickness (EDWTh) were correlated with regional myocardial flow (RMBF) at 15 minutes, 24 and 48 hours after occlusion. Both regional function and blood flow were compared with the extent of myocardial necrosis (determined histologically) after 48 hours in functionally distinct zones. Group 1 (control zones) was characterized by increased systolic wall thickening, EDWTh, RMBF and had no necrosis.

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“…A Konigsberg pressure transducer was inserted in the left ventricular apex and polyethylene catheters were inserted into the left atrium and descending aorta for monitoring pressure was well as for injecting microspheres and collecting reference blood samples. A proximal segment of the left anterior descending coronary artery (LAD) was gently dissected away from the epicardium and an inflatable balloon occluder, described previously4' 18 was placed around the artery. Epicardial crystals attached to small (1 cm') dacron patches were sutured to the epicardial surface, and smaller endocardial crystals were inserted into the subendocardium obliquely so as not to disturb the intervening myocardium between the crystal pairs.…”

mentioning

confidence: 99%

“…7F polyethylene catheter positioned in the LAD proximal to the occlusion site and observing the anterograde run-off in the epicardial vessels of the distal LAD bed. Next, to determine the size of the occluded bed (or "anatomical risk region"), we mounted the heart on a perfusion apparatus similar to that described previously.4' 21 The aorta was cannulated and perfused with a warm solution of 0.5% (vol/vol) monastral blue dye (DuPont) in normal saline, and the LAD was cannulated and perfused simultaneously with a warm 1 % solution of phosphate-buffered triphenyltetrazolium chloride, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] both at a perfusion pressure of 100 to 120 mm Hg. Thus this method identified the area at risk as well as the extent of infarction therein.…”

mentioning

confidence: 99%

Effects of propranolol and diltiazem alone and in combination on the recovery of left ventricular segmental function after temporary coronary occlusion and long-term reperfusion in conscious dogs.

et al. 1985

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We evaluated the ability of propranolol and dilitazem alone and in combination to enhance the recovery of left ventricular (LV) segmental function during 1 month of reperfusion after two temporary occlusions of the left anterior descending coronary artery (LAD) in conscious dogs instrumented with ultrasonic crystals for the measurement of regional net systolic wall thickening (NET). LV segments were classified according to their contractile function after 1 hr of LAD occlusion: class 1, greater than 67% of preocclusion (control) NET; class 2, 0% to 66.9%; class 3, less than 0% (paradoxical systolic wall thinning). Propranolol (1 mg/kg iv) or diltiazem (20 ,ug/kg/min) was given 65 min after LAD occlusion in dogs that had 2 (group 1) or 4 hr (group II) of LAD occlusion. Diltiazem plus propranolol (same doses) were given to another group of dogs that underwent 4 hr (but not 2) of LAD occlusion. Untreated control dogs received 25 ml of saline and underwent 2 or 4 hr of LAD occlusion. The NET of class 2 and 3 segments in group l control dogs increased significantly during 1 month of reperfusion, from 32 + 5% and -43 ± 6% to 66 + 9% and 26 + 9%, respectively (p < .05). Neither diltiazem nor propranolol enhanced the long-term recovery of these segments in group I dogs. However, diltiazem prevented further deterioration of contractile dysfunction observed in control dogs immediately after reperfusion in both segment classes. The NET of class 2 segments in group I1 control dogs after 4 weeks of reperfusion remained at levels observed during LAD occlusion: 30 + 4% to 37 + 12%. Class 3 NET increased from -33 + 5% to 12 ± 12% with 1 month of reperfusion, but these segments were essentially akinetic. Propranolol or diltiazem alone did not produce significant overall increases in NET, but diltiazem again prevented further declines in NET of class 2 and 3 segments during early reperfusion. However, the combination of diltiazem and propranolol significantly enhanced overall recovery of class 2 NET in group 1I dogs (44 ± 3% to 88 + 7%) and prevented the worsening of NET associated with early reperfusion. Compared with untreated dogs, propranolol plus diltiazem also significantly decreased the extent of histologic necrosis in class 2 and 3 segments as well as the macrohistochemically determined infarct size in group I1 dogs. Propranolol alone caused significant declines in heart rate and LV dP/dtmax; diltiazem alone lowered aortic pressure significantly; aortic pressure and LV dP/dt were lowered by combined propranolol and diltiazem. Thus we conclude that (I) diltiazem alone prevents further deterioration of LV segmental function early after reperfusion following 2 to 4 hr of occlusion, but neither diltiazem nor propranolol alone enhances segmental functional recovery, and (2) the combination of propranolol and diltiazem results in significantly improved recovery of systolic segmental function and a significant reduction in the extent of necrosis in moderately dysfunctional segments after 4 hr of temporary LAD occlusion ...

show abstract

Functional characterization of left ventricular segmental responses during the initial 24 h and 1 wk after experimental canine myocardial infarction.

Cited by 58 publications

References 68 publications

Demonstration of free radical generation in "stunned" myocardium of intact dogs with the use of the spin trap alpha-phenyl N-tert-butyl nitrone.

Demonstration of free radical generation in "stunned" myocardium of intact dogs with the use of the spin trap alpha-phenyl N-tert-butyl nitrone.

Correlation of regional myocardial blood flow and function with myocardial infarct size during acute myocardial ischemia in the conscious pig.

Effects of propranolol and diltiazem alone and in combination on the recovery of left ventricular segmental function after temporary coronary occlusion and long-term reperfusion in conscious dogs.

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