Effect of nitroglycerin on total and regional coronary blood flow in the normal and ischaemic canine myocardium

Mathes, P.; Rival, J

doi:10.1093/cvr/5.1.54

Cited by 64 publications

(16 citation statements)

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“…Nitroglycerin given i.v. during partial coronary occlusion (3,19,32,33) and also before a short period of complete occlusion (34), caused a redistribution of flow toward the endocardium. Intracoronary injection of nitroglycerin caused a shift in the opposite direction (35).…”

Section: Discussionmentioning

confidence: 98%

“…However, in the latter situation, increased flow may merely be going to myocardial regions fed by normal vessels rather than areas supplied by obstructed vessels. While some investigators have found that vasodilators increase flow to compromised myocardium (2)(3)(4)(5)(6)(7)(8), others have found a decrease or no change (9)(10)(11)(12)(13)(14). Fam and McGregor (11) have pointed out that these discrepancies may be related in part to differences in action among the various coronary dilators.…”

Section: Introductionmentioning

confidence: 99%

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Effect of nitroglycerin and dipyridamole on regional left ventricular blood flow during coronary artery occlusion.

Becker

1976

J. Clin. Invest.

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A B S T R A C T Coronary vasodilators have been vari-ously reported to increase, decrease, or have no effect upon blood flow to ischemic myocardium. Consequently, the effects of two different types of dilators, nitroglycerin (TNG) and dipyridamole, were studied with radioactive microspheres in open-chested dogs after coronary artery ligation. Given as a bolus i.v. injection, 0.4 mg TNG resulted in an increase in blood flow to nonischemic areas of myocardium and a preservation of flow to ischemic regions, despite a fall in blood pressure. 5 min later blood pressure and nonischemic flow were back to base line, and a small selective increase in flow to ischemic myocardium was found (0.15-0.18 ml/min per g, P < 0.05). During an 0.2 mg/min infusion of TNG, and also after 1 mg/kg i.v. dipyridamole, ischemic flow was maintained in the face of a 20-30%o reduction in blood pressure. In this setting, nonischemic flow was unchanged during TNG and doubled after dipyridamole. With the addition of methoxamine in both dilator groups, blood pressure retumed to base line while flow to ischemic areas increased above base-line values (TNG, 0.16-0.20 ml/min per g, P < 0.01; dipyridamole, 0.18-0.31 ml/min per g, P < 0.05). Epicardial ST segment elevations increased during TNG infusion and were unchanged after dipyridamole, but with addition of methoxamine, ST segments became less elevated in both drug groups, concomitant with the observed increase in collateral blood flow. These data indicate thaA both types of coronary vasodilators, when used in conjunction with methoxamine to support blood pressure, reduce collateral resistance, increase collateral flow, and reduce epicardial ST-segment elevations.

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Effect of nitroglycerin and dipyridamole on regional left ventricular blood flow during coronary artery occlusion.

Becker

1976

J. Clin. Invest.

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“…Some studies even failed to find substantial increases in heart rate (14,16). Since both of these effects stimulate myocardial metabolism, and thereby augment coronary blood flow (45)(46)(47) it follows that nitroglycerin administered to anesthetized preparations with an open chest, does not elicit a secondary rise in coronary blood flow and reduction in coronary resistance (8)(9)(10)14).…”

Section: Discussionmentioning

confidence: 99%

Direct and reflex effects of nitroglycerin on coronary and left ventricular dynamics in conscious dogs

Vatner¹,

Higgins²,

Millard³

et al. 1972

J. Clin. Invest.

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A B S T R A C T The effects of intravenous and sub-lingual glyceryl trinitrate (nitroglycerin), 40 Ag/kg, were studied on coronary blood flow and resistance, left ventricular (LV) pressures (P) and diameters (D), rate of change of pressure (dP/dt), (dP/dt)/P, and on the velocity (V) of myocardial fiber shortening in conscious dogs. Nitroglycerin i.v. caused substantial coronary vasodilatation prior to any changes in systemic hemodynamics. Mean coronary flow increased by a maximum of 47 ml/min and coronary sinus P02 rose from 16 to 26 mm Hg while pressure and diameter began to fall, and heart rate began to rise. After the maximal fall in mean arterial pressure (-26 mm Hg), a secondary peak in coronary flow occurred which was associated with increases in heart rate (100 beats/min), (dP/dt)/P (22%), and isolength V (12%). Beta blockade prevented the reflex increases in contractility but only a part of the reflex tachycardia; the remainder was prevented by cholinergic blockade. Maintaining heart rate constant minimized the decreases in LV D and increases in contractility. When the reflex inotropic and chronotropic effects were prevented by a combination of atrial pacing and beta blockade the early coronary vasodilatation was unaltered, but the later coronary vasodilatation was minimized. creases in contractility and heart rate. The decreases in diameter are largely the result of tachycardia. Sublingual nitroglycerin produced directionally similar, but quantitatively lesser effects on coronary flow and resistance, LV D, LV P, and contractility.

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“…Study of antianginal drugs by the fractional uptake of radioactive microspheres and tissue clearance of 80 Rb has demonstrated that nitroglycerin and propranolol both increase distribution of flow to the subendocardium in the acutely ischemic canine left ventricle (17,50). The data indicate that this probably occurs through redistribution of flow toward the endocardium rather than through increase in total blood flow.…”

mentioning

confidence: 96%

“…nitroglycerin these changes could be the result of a decrease in both the afterload and the preload of the ischemic left ventricle (17,50). The effect of propranolol is undoubtedly more complex, since in addition to its effect on heart rate and myocardial contractility it may secondarily increase coronary vascular resistance by blockade of /J-receptor sites (51).…”

mentioning

confidence: 99%

Subendocardial Distribution of Coronary Blood Flow and the Effect of Antianginal Drugs

Moir

1972

Circulation Research

158

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Effect of nitroglycerin on total and regional coronary blood flow in the normal and ischaemic canine myocardium

Cited by 64 publications

References 0 publications

Effect of nitroglycerin and dipyridamole on regional left ventricular blood flow during coronary artery occlusion.

Effect of nitroglycerin and dipyridamole on regional left ventricular blood flow during coronary artery occlusion.

Direct and reflex effects of nitroglycerin on coronary and left ventricular dynamics in conscious dogs

Subendocardial Distribution of Coronary Blood Flow and the Effect of Antianginal Drugs

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