[New data on etiology of heart conduction disturbances]. / Novoe ob étiologii narushenii vnutriserdechnoi provodimosti.

AIM: To make a clinicogenealogical analysis of different types of heart conduction disturbances in families of Krasnoyarsk city. MATERIALS AND METHODS: 104 probands with ECG-verified idiopathic forms of atrioventricular and intraventricular blocks of different severity and 331 their close relatives (kinship degree I and II) were examined using standard clinical investigations, ECG, echocardioscopy, electrophysical investigations in some cases and coronarography. RESULTS: All the observed 104 families were divided into 3 groups according to the type of heart conduction in proband. Group 1 consisted of 24 probands with atrioventricular block and 80 their relatives. The sick relatives had for the most part atrioventricular blocks (31.2%). 26 probands of group 2 had complete right bundle branch blocks. Of their 81 relatives, the sick ones had primarily conduction disturbances in right bundle branch (incomplete block--44.7%, a complete block--5.2%). Group 3 consisted of 54 probands with left bundle branch block and 170 relatives. The left bundle branch block was present in 27.4% of the relatives. CONCLUSION: A definite family aggregation of heart conduction disturbances was found. This proves genetic determination of this pathology.

[Combined use of left atrial transesophageal pacing and cordarone in atrial flutter]. / Sochetannoe primenenie chrezpishchevodnoi stimuliatsii levogo predserdiia i kordarona pri lechenii trepetaniia preserdii.

AIM: To investigate the effectiveness of superfrequent transesophageal left atrial stimulation (TLAS) and its combination with cordarone in management of atrial flutter (AF). MATERIALS AND METHODS: 650 patients with paroxysmal AF underwent TLAS. The paroxysm duration varied from 1 hour to 1 month. In 312 patients TLAS was performed prior to treatment with antiarrhythmic drugs (group 1), in 338 patients--after intravenous administration of cordarone (group 2). RESULTS: Superfrequent TLAS has restored sinus rhythm (SR) in 85(27.2%) and 169(50%) patients of groups 1 and 2, respectively (p < 0.001). TLAS promoted conversion of AF in atrial fibrillation (AFi) in 185(59.3%) and 159(47.1%) patients of groups 1 and 2, respectively (p < 0.01). Moreover, SR recovered 24-48 hours after TLAS in 87(27.9%) and 64(18.9%) patients of groups 1 and 2 respectively (p < 0.01). Sinus rhythm recovered in a total of 172(55.1%) and 233(69.0%) patients, AF was converted to AFi in a total of 88(31.4%) and 95(28.1%) patients (p > 0.05) of groups 1 and 2, respectively. TLAS was uneffective in 42(13.5%) and 10(2.9%) patients of groups 1 and 2, respectively. CONCLUSION: Superfrequent TLAS is a highly effective and non-invasive modality in the treatment of paroxysmal AF. It promotes recovery of SR. In some patients TLAS induces AFi which is more controllable by medication as regards the heart rate. Cordarone contributes to the response to TLAS in patients with paroxysmal AF.

[Use of transesophageal left atrial cardiac pacing for assessment of cordarone effectiveness in patients with atrioventricular tachycardia]. / Primenenie chrezpishchevodnoi stimuliatsii levogo predserdiia dlia otsenki éffektivnosti lecheniia kordaronom patsientov s atrioventrikuliarnymi takhikardiiami.

AIM: To assess by means of transesophageal left atrial pacing the effectiveness of cordarone treatment for arrhythmias caused by re-entry mechanism. MATERIALS AND METHODS: Effectiveness of cordarone treatment was estimated in 25 patients with atrioventricular nodal tachycardia (AVNT) and in 33 patients with WPW syndrome and reciprocal atrioventricular tachycardia (RAVT) with frequent paroxysms of tachycardia 1-5 times per week. Transesophageal left atrial pacing (TELAP) was performed before antiarrhythmic treatment and on cordarone treatment day 14-18. Cordarone was given for two months in common regimen (the first 10 days--600 mg/day, the next 10 days--400 mg/day and then 200 mg/day). RESULTS: The first TELAP induced paroxysmal AVNT or RAVT in all the patients. According to the results of the second TELAP, all the patients were divided into three groups. Group 1 included 28 patients in whom the second TELAP was unable to induce tachycardia. All these patients had increased effective refractory period (ERP) of AV node and/or of accessory pathway (AP) values and a decreased Wenkebach point (WP) < 150/min during the second TELAP in comparison with the first TELAP. All these patients had no spontaneous paroxysms of T during the 3-month follow-up. Group 2 included 18 patients in whom the second TELAP induced AVT lasting < 30 seconds. 16 of these patients had tachycardia with less heart rate during the second TELAP in comparison with the first TELAP, 153 + (-) 8 bpm vs 188 + (-) 10 bpm, p < 0.001, respectively. Also, in these 16 patients we found an increase of values of ERP of AV node and/or AP > 360 ms and a decrease of WP < 150 bmp. 14 of these 16 patients had no spontaneous paroxysms of AVT and 2 patients had short episodes of AVT during the 3-month follow-up with effects of vagal manoeuvers. From 2 other patients of group 2 one had short episodes of spontaneous T and one had long episodes of tachycardia with effect of verapamil i.v. Group 3 included 12 patients in whom the second TELAP induced the same AVT as the first TELAP. Values of ERP of AV node and/or AP and WP during the first and second TELAP were not different. All of these patients had long spontaneous paroxysms of AVT during cordarone treatment day 14-18. The treatment was discontinued in all patients of group 3. CONCLUSION: Cordarone is effective in prevention of AVT. Negative results in provocation of AVT during TELAP after 14-18 days of cordarone treatment is a very specific predictor of cordarone treatment effectiveness. Provocation by TELAP of short episodes of AVT with reduced heart rate and higher values of ERP of AV node and AP and lowering of WP < 150 bpm may not predict ineffectiveness of cordarone in patients with AVT. Moreover, the majority of these patients had no spontaneous episodes of AVT. Provocation by TELAP during cordarone treatment of the same AVT episodes as before cordarone treatment is a very specific predictor of cordarone effectiveness.

[The etiological aspects of the sick sinus syndrome]. / Nekotorye étiologicheskie aspekty sindroma slabosti sinusovogo uzla.

A clinico-genetic study of sick sinus syndrome in Krasnoyarsk population established its prevalence as 0.296%. The disease affected females more frequently than males. The highest morbidity was registered at the age 60-69. Genetic evaluation demonstrated high hereditary predisposition to the syndrome as it developed in 60 out of 309 (19.4%) relatives of the patients, the inheritance being autosomal dominant and in part sex-limited. Females predominated among the disease-affected relatives and among those whose relatives had the syndrome. The syndrome is also age-related. The authors discuss the role of ischemic heart disease in the origin of sick sinus syndrome.

[Functional state of the sinoatrial node in patients with intraventricular block]. / Funktsiona'lnoe sostoianie sinusovogo uzla u bo'lnykh s vnutrizheludochkovymi blokadami.

The function of sinus node (SN) was studied in 101 subjects with intraventricular blocks (IVB) and 30 controls. The patients with IVB showed a significant increase in the corrected time of SN function recovery and that of sinoatrial conduction both before and after medicamentous++ autonomic block, as compared to the controls. In general, signs of SN dysfunction were detected in 47 (46.5%) subjects with IVB. In 18.8% of the examinees, SN dysfunction was due to abnormal autonomic exposures, 27.7% had abnormalities in SN proper or perinodal tissue. ++Tachy-bradycardia was found in 53.5% patients with the sick sinus syndrome and IVB, 25% had concurrent atrioventricular conduction disturbances. A concomitant SN lesion was common in patients with IVB. One should take into account a type of this syndrome and the status of atrioventricular conduction when the optimal conditions of continuous electrical cardiostimulation are applied to patients with IVB and clinical signs of the sick sinus syndrome.

[Use of transesophageal stimulation of the left atrium in the diagnosis of ischemia and cicatricial myocardial changes in patients with complete block of the left fascicle of the bundle of His]. / Primenenie chrespishchevodnoi stimuliatsii levogo predserdiia dlia diagnostiki ishemii i rubtsovykh izmenenii miokarda u bo'lnykh s polnoi blokadoi levoi nozhki puchka Gisa.

Transesophageal stimulation of the left atrium was performed in 52 patients who had signs of complete left bundle branch block as evidenced by ECG, 48 patients having sustained block, 4, intermittent one. In 42 (80.8%) patients, the block was temporarily arrested during and/or after discontinuation of the electric stimulation, in 28 of them, the block was stopped during the stimulation without any drugs, in 1, only after obsidan, and in 13, following obsidan and atropine. When the block was being arrested, 13 patients showed ECG ischemic changes, 7 exhibited myocardial scarring alterations, 8 had nonspecific T wave alterations, 8 displayed signs of left ventricular hypertrophy with impaired repolarization. No ECG changes were found in 7 patients. The use of transesophageal electrical stimulation of the left atrium to temporarily abolish complete left bundle branch block may contribute to elucidation of the etiology of the block and choice of the most adequate therapy.

[Clinico-electrocardiographic variants of combined lesions of the sinoatrial and atrioventricular nodes]. / Kliniko-elektrokardiograficheskie varianty pri sochetannom porazhenii sinusovogo i atrioventrikuliarnogo uzlov.

A study of 71 patients with atrioventricular blocks and 57 patients with the sick-sinus syndrome (SSS) revealed electrophysiologic evidence of sinus dysfunction in 38 (53.5%) patients with atrioventricular blocks. Sinus dysfunction was due to pathologic vegetative effects in 15 (21.1%) patients with AV blocks, and a pathology of the sinus node itself in 23 (32.4%). Impaired atrioventricular conductivity, was registered in 29 (38.7%) patients with the SSS. A disorder of atrioventricular automatism was detected in 38 patients, and was combined with impaired AV conductivity in 19 of those. Five clinico-electrocardiographic variants of binodal heart disease have been identified, and possible therapies are discussed for each of those.

[Significance of autonomic block by drugs for the diagnosis and evaluation of the pathogenesis of the sick sinus syndrome]. / Znachenie medikamentoznoi vegetativnoi blokady dlia diagnostiki i otsenki patogeneza sindroma slabosti sinusovogo uzla.

Altogether 65 patients with the sinoatrial node weakness syndrome (SANWS) and 48 patients with the heart pain syndrome (control group) were examined for a study of the corrected time of sinoatrial node function recovery (CTSNFR) and the time of sinoatrial conduction (TSAC) before and after medicamentous vegetative blockade (MVB). A considerable increase in CTSNFR and TSAC sensitivity after MVB was noted. In most of the SANWS patients CTSNFR after MVB was increased, TSAC was decreased. Elevated CTSNFR in the SANWS patients was determined by the effect of propranolol and atropine and was noted mainly during atrial stimulation with a high frequency (over 160 imp/min).

[Sinus node function of ischemic heart disease patients with chronotropic incompetence]. / Funktsional'noe sostoianie sinusnogo uzla u bol'nykh ishemicheskoi bolezn'iu serdtsa s "khronotropnoi nekompetentnost'iu".

Forty-five (17.6%) of 256 coronary patients showed inadequately small heart rate augmentation in response to rationed exercise ("chronotropic incompetence"). To assess their sinoatrial node function, esophageal atrial stimulation was done in all patients before and after drug-induced vegetative block, and the adjusted sinoatrial node function time and sinoatrial conduction time were determined. Electrophysiological evidence suggests that "chronotropic incompetence" is in most cases determined by abnormal sinoatrial rhythm. Rationed exercise testing can be used as a screening test for latent weak sinoatrial node syndrome in coronary patients.