INTRACARDIAC HEMODYNAMICS IN PATIENTS WIT H THE SICK SINUS SYNDROME IN CARDIAC PACING

A EKS-500 pacemaker was implanted in 36 patients with the sick sinus s yndrome. Out of them, 18 patients had coronary heart disease, 6, hyper tensive disease and myocardial hypertrophy, and 12, idiopathic arrythm ias. After surgery, equilibrium, radionuclide ventriculography was per formed in the patients at rest in the presence of spontaneous rhythm a nd pacing, as well as during exercise. In patients with idiopathic arr hythmias, cardiac output and index remained within normal ranges durin g sinus bradycardia, which was attained by increased stroke volume, wh ereas in patients with myocardial disease, the normal values of these parameters were recorded only at a rate 60 imp/min. During exercise, t he patients with idiopathic arrhythmias showed a noticeable rise in ca rdiac output not only due to higher heart rate, but due to increased s troke volume, and those with myocardial disease displayed the increase only due to higher heart rate.