Computation of derived diagnostic quantities during intermittent coronary sinus occlusion in dogs

The haemodynamic responses to pressure controlled intermittent coronary sinus occlusion (PICSO) were recorded intraoperatively in dogs. After analogue-digital conversion the data for coronary sinus pressure were submitted to numerical analysis for detection of systolic and diastolic envelopes and their subsequent fitting by a non-linear model. From the model variables derived quantities, such as plateau and rise times, were constructed so as to resemble the most important features of coronary sinus pressure rise during each occlusion-release cycle. The derived quantities were then monitored during all consecutive cycles throughout the entire experiment. In each dog the measurements were taken during normal coronary artery perfusion, left anterior descending coronary artery infarction, and reperfusion. The analysis comprise time course, stability, and physiological correlates of the derived quantities, on some of which a closed loop regulation may be based. Predicted plateaus (systolic and diastolic) and mean integrals (systolic and diastolic) were found to be stable quantities which, on subaveraging of about five successive estimates, yielded a 10% accuracy on the mean. By contrast, the rise times required subaveraging of about 15 cycles to achieve the same relative stability. It is concluded that, on subaveraging, derived quantities lend themselves for closed loop regulation input. Thus this quantitative assessment of numerical coronary sinus pressure analysis, as obtained from animal data, may lay the basis for future human application.