Alternation in refractoriness and in conduction delay in the ischemic myocardium associated with the alternation in the ST-T complex during acute coronary occlusion in anesthetized dogs

1986 ◽  
Vol 19 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Hisakuni Hashimoto ◽  
Masaharu Asano ◽  
Mitsuyoshi Nakashima
Keyword(s):  
Coronary Occlusion ◽  
Ischemic Myocardium ◽  
Conduction Delay ◽  
T Complex ◽  
Acute Coronary Occlusion ◽  
Anesthetized Dogs

scholarly journals Accumulation of radioiodinated 15-(p-iodophenyl)-6-tellurapentadecanoic acid in ischemic myocardium during acute coronary occlusion and reperfusion

1984 ◽  
Vol 4 (1) ◽  
pp. 80-87 ◽  
Author(s):  
Jesus A. Bianco ◽  
Linda A. Pape ◽  
Joseph S. Alpert ◽  
Miaorong Zheng ◽  
Donald Hnatowich ◽  
...  
Keyword(s):  
Coronary Occlusion ◽  
Ischemic Myocardium ◽  
Acute Coronary Occlusion

Differential cardiac sympathetic activity during acute myocardial ischemia

1990 ◽  
Vol 258 (5) ◽  
pp. H1534-H1541 ◽  
Author(s):  
B. H. Neely ◽  
G. R. Hageman
Keyword(s):  
Sympathetic Activity ◽  
Coronary Occlusion ◽  
Left Ventricular ◽  
Ischemic Myocardium ◽  
Neural Responses ◽  
Ischemic Region ◽  
Innervation Patterns ◽  
Anesthetized Dogs ◽  
Increased Activity ◽  
Cardiac Nerves

Efferent sympathetic activities were simultaneously recorded from two thoracic cardiac nerves in 33 chloralose-anesthetized dogs. Efferent innervation patterns were determined by electrical stimulation prior to recording in each animal. One of the nerves selected for recording was shown to innervate the proposed ischemic region, whereas the other nerve was selected because it was shown to innervate nonischemic regions. Left ventricular ischemia was produced by occlusion of a branch of either the left anterior descending (LAD) or left circumflex (LCX) coronary arteries. Heart rate was paced. Cardiac postganglionic sympathetic efferent activities were recorded during a 30-min coronary occlusion in 22 animals. Thirty minutes after LAD occlusion (n = 10), postganglionic sympathetic activity to ischemic myocardium was decreased (84 +/- 5% of control; P less than 0.05) while activity to nonischemic myocardium was unchanged. Thirty minutes after LCX occlusion (n = 12), postganglionic sympathetic activity to ischemic myocardium was also decreased (87 +/- 3% of control; P less than 0.01); however, sympathetic activity to nonischemic myocardium was increased (159 +/- 10% of control; P less than 0.001). Thus, in the anesthetized canine, regional left ventricular ischemia elicits differential sympathetic neural responses that are dependent on the location of the ischemic myocardium as well as the efferent destinations of the nerves. Changes in cardiac postganglionic sympathetic efferent activities are characterized by decreased activity to ischemic regions, with either no change or increased activity to nonischemic regions.

Failure of pyruvate to salvage myocardium after prolonged ischemia

1986 ◽  
Vol 250 (1) ◽  
pp. H114-H120 ◽  
Author(s):  
D. D. Gutterman ◽  
W. M. Chilian ◽  
C. L. Eastham ◽  
T. Inou ◽  
C. W. White ◽  
...  
Keyword(s):  
Infarct Size ◽  
Clinical Utility ◽  
Coronary Occlusion ◽  
Control Groups ◽  
Risk Area ◽  
Intracoronary Infusion ◽  
Acute Coronary Occlusion ◽  
Anesthetized Dogs ◽  
Potential Clinical Utility ◽  
And Control

Thrombolytic therapy for acute coronary occlusion may be more effective if combined with substrate-enhanced reperfusion. In this study, we examined the utility of pyruvic acid, an important metabolic substrate, in salvaging ischemic myocardium. Twenty-six anesthetized dogs underwent 3 h of circumflex coronary occlusion followed by 90 min of reperfusion with administration of intracoronary pyruvate or vehicle. To test the sensitivity of the model in detecting differences in infarct size, eight additional dogs underwent coronary occlusion of shorter duration (45 min), an intervention that is known to reduce infarct size. Collateral perfusion to the ischemic zone during coronary occlusion was similar in experimental and control groups. Whereas a shorter duration of occlusion (45 min) decreased the infarct-to-risk area ratio by 54% compared with a longer duration of occlusion (90 min), neither early (15 min prior to occlusion) nor late (3 h after occlusion) onset of intracoronary infusion of pyruvate shifted the infarct-risk relationship (control: y = 74x - 8.7, r = 0.99; early infusion: y = 0.76x - 9.5, r = 0.85; late infusion: y = 0.58x - 5.5, r = 0.79). The failure of intracoronary administration of pyruvate to limit infarct size raises questions as to its potential clinical utility in the setting of acute myocardial ischemia.

Vagal inhibitory effects on peripheral circulation in acute coronary occlusion

1979 ◽  
Vol 57 (6) ◽  
pp. 547-555 ◽  
Author(s):  
Conrad Pelletier
Keyword(s):  
Coronary Occlusion ◽  
Peripheral Circulation ◽  
Aortic Pressure ◽  
Vagal Afferents ◽  
Adrenergic Blockade ◽  
Inhibitory Effects ◽  
Acute Coronary Occlusion ◽  
Anesthetized Dogs ◽  
Vascular Beds ◽  
Constrictor Response

The reflex adjustments of the peripheral circulation in response to acute coronary occlusion were studied in anesthetized dogs with isolated vascular beds perfused at constant flow. Coronary occlusion caused significant increases in perfusion pressure which averaged 27 ± 4 mmHg in the hindlimb, 19 ± 8 mmHg in skeletal muscle, and 13 ± 5 mmHg in the mesenteric artery. These responses were less than half those caused by a similar decrease in aortic pressure obtained with hemorrhage. Coronary occlusion caused no significant changes in renal and paw-circulations, while marked vasoconstriction resulted from hemorrhage. When aortic pressure was maintained constant throughout the duration of coronary occlusion, there was a significant vasodilatation in all beds studied. After vagotomy, coronary occlusion caused a constrictor response similar in magnitude to that caused by hemorrhage in each vascular bed and the dilator responses to occlusion at constant aortic pressure were abolished. Both constrictor and dilator changes were prevented by alpha-adrenergic blockade. Mechanical distension of the left ventricle in four dogs with carotid sinus nerves cut caused a significant reflex dilatation in the hindlimb. Thus, coronary occlusion initiates an inhibitory reflex mediated by vagal afferents which opposes peripheral vasoconstriction most effectively in the renal and paw circulations.

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