Pressure-controlled intermittent coronary sinus occlusion has been reported to reduce infarct size in dogs with coronary artery occlusion, possibly because of increased ischemic zone perfusion and washout of toxic metabolites. The influence of this intervention on regional myocardial function was investigated in open and closed chest dogs. In six open chest dogs with severe stenosis of the left anterior descending coronary artery and subsequent total occlusion, a 10 minute application of intermittent coronary sinus occlusion increased ischemic myocardial segment shortening from 5.5 +/- 1.2 to 8.2 +/- 2.6% (NS) and from -0.1 +/- 2.1 to 2.3 +/- 1.2% (NS), respectively. In eight closed chest anesthetized dogs, intermittent coronary sinus occlusion was applied for 2.5 hours between 30 minutes and 3 hours of intravascular balloon occlusion of the proximal left anterior descending coronary artery. Standardized two-dimensional echocardiographic measurements of left ventricular function were performed to derive systolic sectional and segmental fractional area changes in five short-axis cross sections of the left ventricle. Fractional area change in all the severely ischemic segments (less than 5% systolic wall thickening) was -4.0 +/- 4.7% at 30 minutes after occlusion, and increased with subsequent 60 and 150 minutes of treatment to 13.1 +/- 3.3 and 7.0 +/- 3.3%, respectively (p less than 0.05). At the most extensively involved low papillary muscle level of the ventricle, regional ischemic fractional area change was increased by intermittent coronary sinus occlusion between 30 and 180 minutes of coronary occlusion from -0.4 +/- 0.1 to 14.4 +/- 4% (p less than 0.05), whereas a further deterioration was noted in untreated dogs with coronary occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)