Myocardial temperature variation: effect on regional function and coronary flow in dogs.

Incremental changes in the temperature (28-42.5 degrees C) of the anterior left ventricular wall in a canine, working, beating right heart bypass preparation (constant preload, afterload, and heart rate) were produced to measure the effect of regional temperature on myocardial function and blood flow. Circumferential-axis segment lengths were measured with sonomicrometry in both the temperature-varied, left-anterior descending coronary artery (LAD)-supplied myocardium and the normothermic (38 degrees C) circumflex-supplied myocardium.

Effects of propranolol and exercise on cardiac dynamics and organ blood flow distribution in dogs.

The additive effects of propranolol and exercise on peripheral blood flow distribution were studied in conscious dogs. During treadmill exercise (8-10 km/h and 0% grade for 15 min.) cardiac performance increased significantly in parallel with myocardial and muscular blood flow (greater than 100%).

Detection and quantification of small right-to-left shunts by the phase-plane method.

In six anesthetized dogs 70 indicator-dilution curves and phase-plane plots were recorded. Indocyanine green was injected into the superior vena cava and sampled through a dichromatic cuvette densitometer from the femoral artery. Dye-dilution curves were recorded from dogs with normal cardiovascular systems and repeated after right-to-left shunts of different magnitude were surgically produced.

Blood cardioplegia delivery. Deleterious effects of potassium versus lidocaine.

Delivery of cardioplegic (CP) solutions to all regions of the myocardium is critical for optimal myocardial protection during cardiac surgery. However, there are little data regarding the effects of CP agents upon coronary vascular resistance (CVR) and CP delivery. Accordingly, we evaluated blood CP (Hct 30) delivery and CVR during 75 minutes of multi-dose hypothermic blood CP arrest in an in vivo isolated dog heart preparation.

Myocardial protection by lidocaine during cardioplegia.

This study was undertaken to examine the effects of lidocaine (L) (400 mg/liter) in a normokalemic crystalloid (S) (K +: 5 meq/liter, Na+: 120 meq/liter) and in a hyperkalemic crystalloid cardioplegic solution (K) (K+: 25 meq/liter, Na+: 120 meq/liter) during 90 min of hypothermic (28 degrees C) aortic occlusion followed by 45 min of reperfusion (R). Four groups of dogs were studied: group 1 (S), n = 6; group 2 (S + L), n = 6; group 3 (K), n = 6; group 4 (K + L), n = 6. Left ventricular (LV) function was defined as percentage changes in center of mass between pre- and postarrest function curves.