[Changes of cardiac electrophysiological parameters after destruction of epicardial nervous plexi innervating sinoatrial node].

Electrophysiological methods were used in experiments on 15 dogs for the study of topography of right atrial epicardial nerves, their connections with sinoatrial node, and possibilities of selective surgical denervation of sinoatrial node. Epicardial nerves were electro-coagulated or cryo-destructed in ventral, lateral and dorsal atrial zones near base of vena cava inferior. The following parameters were registered: heart rate, time of restoration of sinus node function, conduction through atrioventricular node, refractoriness of atria and atrioventricular node. Comparison of cardiac parameters before and after destruction of epicardial nerves showed that in lateral and ventral zones sympathetic nerves reach sinus node through lateral and ventral zones while parasympathetic -- along dorsal zone. Selective surgical destruction allows to modify sinus node function in a desired way.

Heart tissue viability monitoring in vivo by using combined fluorescence, thermography and electrical activity measurements.

A prototype system for in vivo monitoring of the heart tissue viability by using combined measurements of fluorescence, thermography and electrical activity has been elaborated for cardiac surgery. The fluorescence imaging of nicotinamide adenine dinucleotide NAD(P)H in the blue light range (lambda=467 nm) by using UV light (lambda=347 nm) excitation was used to detect metabolic disturbances. The method of the principal component analysis was used for the processing of the fluorescence image sequences. Far infrared (lambda=7.5-13 microm) imaging was used to evaluate temperature dynamics of the tissue surface during circulation disturbances. Evaluation of the epicardial electrogram shape by using continuous wavelet transform was used to detect and evaluate ischemia-caused disturbances of the electrical activity of the tissue. The combination of temperature, fluorescence and electrical activity estimates obtained from synchronically registered parameters during the experiments on model systems and experimental animals yielded qualitatively new results for the evaluation of cardiac tissue viability and enabled to achieve a versatile evaluation of the heart tissue viability.

Diagnosis and surgical treatment of ectopic atrial tachycardia.

Eighty-two patients with ectopic atrial tachycardia (EAT) were subjected to radical closed heart surgery (without cardiopulmonary bypass). The age of the patients ranged from 1 to 51 years. Permanent EAT was present in 19 patients, incessant EAT in 14, and paroxysmal EAT in 49 patients. Preoperative electrophysiological study included computed analysis of the P wave vector. Ectopic foci were established in the right atrium in 34 patients, in the left atrium in 11, in the interatrial septum in 32, and extracardially in 5 patients. For ablation or isolation of the foci, the cryogenic technique was used in 74 patients, cryo- and laser techniques in 4, and the laser technique alone in 1 patient. In 3 patients resection of the atrial auricles including the ectopic focus was undertaken. In 4 patients complete AV block was induced and a cardiac pacemaker implanted. After primary surgery, favourable results were obtained in 71 patients. In 11 patients recurrences were observed; 8 of these patients underwent successful repeat surgery. In 3 patients medical treatment was effective. Finally, the follow-up results have been promising-79 patients (96.4%) (including 4 patients in whom a complete AV block was created) have become arrhythmia-free. When EAT is resistant to medical treatment, closed heart ablation of the ectopic focus has proved to be safe (no mortality or morbidity) and effective. It can therefore be recommended not only for the termination of EAT but also for the prevention of dilated cardiomyopathy.

Cryosurgery in tachycardia treatment.

Cryosurgical techniques have become established and acceptable therapy in the treatment of resistant arrhythmias. In this report, both experimental and clinical data are presented describing the results of various cryosurgical techniques used at the Cardiac Rhythm Disturbance Center in Lithuania, USSR.