[The application of 2-dimensional echocardiography to the control of the location of the electrode catheter during endocardial cardiography]. / Anwendung der zweidimensionalen Echokardiographie zur Kontrolle der Lage des Elektrodenkatheters während der endokardialen Kardiographie.

Modern methods for treatment of ventricular tachycardia require the exact knowledge of the position of the electrode catheter during intracardiac electrophysiological investigations. X-ray positioning in several projections facilitates the localisation of tachycardia with an accuracy of 4-8 cm2. From eight cadaver hearts schematic diagrams of the right ventricle for two dimensional echocardiography were derived. Endocardiac ventriculocartography under sonographic control was applied in 27 patients 45 times. With this method we were able to detect the electrode catheter in 42 of 45 (93%) patients effectively. Sonographic control facilitates not only the localisation of tachycardia without radiation burden but also its correlation with anatomic ventricular structure which is not possible by roentgenology. 3 negative results were due to negative echoes. In 3 of 5 cases the fulguration of the ventricular tachycardia focus under echo control was possible. Sonographic check up therefore is predilection method for endocardiac ventricular cardiography and can be recommended.

[Electrophysiologic effects of serotonin on atrioventricular conduction in dogs]. / Elektrofiziologicheskoe deistvie serotonina na atrioventrikuliarnuiu provodimost' u sobak.

In 12 anaesthetized dogs acute effects of serotonin on the atrioventricular conduction system were studied by obtaining intracardiac electrograms. The significant increase in the heart rate and decrease in aortic pressure elicited by an intravenous infusion of 50 mg/kg.min serotonin for 30 minutes were comparable to those observed in previous investigations. Our data indicate a serotonin induced acceleration of the sinus node pacemaker and atrioventricular conduction by direct and indirect mechanisms.

Computer-assisted two-dimensional echocardiography in preoperative evaluation of left ventricular function in patients with aortic valve disease.

Seventy-six healthy adults and 228 patients with aortic valve disease were studied by means of two-dimensional echocardiography (2D-EchoCG). Functional properties of the left ventricle in patients with aortic valve disease were studied by means of computer analysis of echocardiograms and patients requiring cardiac surgery were identified. It was found that an increased left ventricular (LV) end-systolic volume (110 ml and more), assessed by 2D-EchoCG, is an unfavourable prognostic sign, and elevated risk factor of cardiac surgery. It invariably proved to be related to LV dysfunction after the surgery. A decreased diastolic LV mass/volume ratio (1.255 and less), found in 16% of patients with pressure overload, means nonadequate development of hypertrophy and an elevated risk of cardiac surgery.

[Direct recording of the electrical activity of the sinoatrial node]. / Priamaia registratsiia élektricheskoi aktivnosti sinoatrial'nogo uzla.

The electrical activity of the sinoatrial node was recorded simultaneously from the epicardial and endocardial surfaces of the sinoatrial node in 73 dogs. The electrical activity of sinoatrial node had the form of a slow deflection and a rapid preatrial deflection, the duration of the former being 81 +/- 28 msec and reflecting slow propagation of excitation within the sinus node. Duration of the rapid preatrial deflection was 17 +/- 11 msec. It reflects the rapid propagation of the sinus impulse (probably, the rapid spread of the excitation in corona of the sinus node and invasion in crista terminals). The form and duration of the slow and rapid deflections changed under the influence of drugs.