STUDY OF PHASIC STRUCTURE OF CARDIAC CYCL E BY RADIONUCLIDE VENTRICULOGRAPHY IN PATIENTS WITH PERMANENT CARDIAC-PACEMAKERS

Velocity and temporal parameters of left ventricular work obtained by radionuclide ventriculography were studied in 22 patients with ischemi c heart disease and 18 subjects without coronary artery diseases early after implantation of a single chamber pacemaker (EKS-500). Indicatio ns for pacemaker implantation were different types of bradiarrhythmias . Radionuclide ventriculography with Tc-99m-labelled albumin was perfo rmed during spontaneous rhythm and during pacing with rates 55-85 imp. /min. Analysis of a representative cardiac cycle during pacing showed that changes of both systolic and diastolic parts of activity/time cur ve in two groups were different. Patients with ischemic heart disease had more pronounced prolongation of preejection time (phase of isometr ic contraction) and minimal limit of standard maximal ejection velocit y. These findings confirmed a decrease in compensatory hyperfunction o f the heart.