Physiologic--angiographic correlates of coronary arterial stenoses in resting and intensely vasodilated states.

The treatment of ischemic heart disease is dependent upon defining the physiologic significance of coronary arterial stenoses demonstrated on coronary arteriograms. Accordingly, physiologic--angiographic correlates were studied in 12 anesthetized dogs prepared with an electromagnetic flowmeter and micrometer-controlled occluder on the circumflex coronary artery, a pair of sonic crystals in the myocardium within the distribution of the circumflex artery, and a catheter in the thoracic aorta. Measurement of arterial diameters on coronary arteriograms was made to define the minimum percent stenosis that caused: (1) decrease in resting coronary blood flow (CBFr); decline in the peak level of coronary blood flow (CBF) produced by intense vasodilatation induced by intracoronary infusion of ATP (CBFATP); and (3) segmental left ventricular (LV) dysfunction.

Effects of low osmolality contrast materials on coronary hemodynamics, myocardial function, and coronary sinus osmolality in normal and ischemic states.

The effects of intracoronary administration of contrast materials on regional and global left ventricular (LV) function and coronary sinus osmolality were assessed in six anesthetized dogs with segmental myocardial ischemia produced by critical stenosis of the circumflex coronary artery. Effects caused by Renografin (sodium meglumine diatrizoate), two new low osmolality contrast agents (Hexabrix and Hexabrix with added calcium ions), and metrizamide were evaluated. In a nonischemic state, Renografin produced an early (0-10 seconds) decrease in LV contractility followed by a late (10-20 seconds) rebound augmentation in contractility.

Cardiovascular effects of protamine sulfate.

Rapid administration of protamine sulfate after arteriography or cardiopulmonary bypass has occasionally been associated with marked hypotension. Since it is unclear whether this is due entirely to vasodilatation or to myocardial depression in addition to vasodilatation, the authors assessed the direct myocardial and systemic circulatory effects of this drug in seven anesthetized dogs. Direct effects of protamine sulfate on global and regional myocardial function and peripheral arterial resistance were determined in the presence and absence of segmental myocardial ischemia.

Effects of intracoronary administration of contrast materials on left ventricular function in the presence of severe coronary artery stenosis.

The effects of intracoronary administration of contrast materials on regional and global left ventricular (LV) function were assessed in anesthetized dogs with segmental myocardial ischemia produced by critical stenosis of the circumflex coronary artery. Effects caused by sodium meglumine diatrizoate (R76), sodium meglumine calcium metrizoate (ISO), and metrizamide were evaluated. In the nonischemic state R76 produced an early (0-10 seconds) decrease in LV contractility followed by a late (10-20 seconds) positive inotropic effect.