[Comparison of cardiac output between in DDD and in VVI by pulsed Doppler echocardiographic method (correction with Swan-Ganz catheter method)].

Difference of cardiac output and stroke volume between that in DDD and that in VVI was studied by pulsed Doppler echocardiography at different pacing rates. Moreover, to evaluate the usefulness of the method by pulsed Doppler echocardiography, cardiac output by the Swan-Ganz catheter method was measured and compared. Fourteen patients age 37-83 years (mean 65 years) with sick sinus syndrome and implanted multiprogrammable dual chamber pacemakers were studied. Cardiac output was measured as the product of the echocardiographically determined cross sectional area of the aortic anulus and the Doppler-determined mean velocity of left ventricular outflow over systole. Cardiac output was greater in DDD with atrial kick than in VVI at each pacing rate, and increased with elevation of the rate, but it was smaller at 120 PPM than at 110 PPM in DDD. Stroke volume was greater in DDD than in VVI at each pacing rate, and maximum volume was at 60 PPM in both modes. The data by pulsed Doppler echocardiography and by Swan-Ganz catheter method have high correlation. Besides being related with pulse rate, these results may be related with such things as myocardial contractility, preload and afterload. For example, the tension of autonomic nervous system, the changing of venous return volume, the disease of arteriosclerosis and old myocardial infarction, temperature, blood viscosity and so on. We will continue the study considering these factors.