Quantitative Description of Ventricular Output Curves in Conscious Dogs

Ventricular output curves obtained from normal dogs, chronic cardiac-denervated dogs, and dogs with beta-adrenergic blockade were analyzed in terms of a compartmental mathematical model. The model states that the change in ventricular output per change in mean atrial pressure is proportional to the estimated cardiac output reserve. The solution of the differential equation is an exponential build-up curve which agrees in all cases within the statistical fluctuation of the experimental curves. Using this approach, one can analyze each ventricular output curve in terms of its initial slope, estimated reserve and a proportionality constant. Factors affecting the estimated reserve and proportionality constant would thus affect the slope of the ventricular output curve. By using this model, a quantitation of ventricular function from ventricular output curves can be better approached.