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This article deals with the 23-years assessment of natural history of 57 patients with paroxysmal supraventricular tachycardia debuted in childhood. Variants of clinical course of disease are described: cardiac, syncopal, abdominal, asymptomatic. In absence of treatment majority of paroxysmal tachycardias were characterized by wavy change of their clinical manifestations with periods of pronouncedly increased and decreased activity lasting from 3 to 5 years. Time interval between attacks was important for prognosis. Severity of disease was determined by relationship of three factors: frequency, duration of attacks and ability of a tachycardia to cause disturbances of central hemodynamics. Tachycardia with asynchronous AB conduction and heart rate above 250/min in one year old and above 220/min in older children was associated with increased risk of development of acute heart failure during an attack. Risk of heart failure was not related directly to frequency of attacks but arose when duration of tachycardia with critical heart rate exceeded 8 hours.

Forty patients with paroxysmal tachycardias were studied. After intravenous bolus administration of ATP, 10-20 mg sinus rhythm restored in 24 patients with nodal reciprocal tachycardia or Wolff-Parkinson-White syndrome. In patients with ventricular tachycardia, antidromal paroxysmal tachycardia in the presence of the Wolff-Parkinson-White syndrome and atrial flutter, bolus administration of ATP made the diagnosis more precise. Adverse reactions were seen in 75% of patients. There was a case of cardiac asystole, 50 sec long, with symptoms of clinical death. The sick sinus syndrome and atrioventricular block are regarded as a contraindication for bolus administration of ATP due to binodal dysfunction induced by the agent.

The paper deals with the problems in the diagnosis and treatment of patients with the most malignant rhythm disturbances, i. e. ventricular arrhythmias. A great emphasis is laid on the so-called "primary" arrhythmias appearing without a manifest cardiac abnormality. The arrhythmias proceed unfavorably and are followed by profound morphofunctional myocardial changes occurring chiefly in the upper portions of the ventricular septum, more frequently on the right. Cryodestruction of arrhythmogenic areas is an effective method for surgical correction of arrhythmias having an unfavorable course.

Out of 99 examinees, 78 patients had mitral valve prolapse of various degree. The control group included 21 individuals without the prolapse who had the same clinical signs. All the patients underwent Holter monitoring and bicycle ergometry; diagnostic transesophageal atrial pacing was performed in 26 examinees. Rhythm and conduction disturbances were shown to occur as frequently in patients with mitral valve prolapse as in the controls. For diagnosing extrasystolic arrhythmias, it was recommended to apply Holter monitoring to detect paroxysmal supraventricular tachyarrhythmias and to employ transesophageal cardiac pacing to find accessory pathways.

A feasibility to provoke reciprocal atrioventricular tachycardias was examined in 23 patients with atrioventricular nodal tachycardia and 17 with orthodromal tachycardia in the presence of the Wolff-Parkinson-White syndrome with endocardiac and transesophageal diagnostic pacing. Atrioventricular nodal tachycardia could be induced in all 23 (100%) patients both by endocardiac and transesophageal pacing. Orthodromal tachycardia was provoked only in 9 (53%) of 17 patients by transesophageal pacing. It was generally noted that tachycardia induction required more "aggressive" regimens of transesophageal pacing than endocardiac one. Endocardiac diagnostic pacing is now a more informative technique, but transesophageal pacing requires further development.

The authors describe the technique and the results of the operation of the dextra-located Kent's bundle in patients with the Wolff - Parkinson - White syndrome. In all 10 patients the interruption of the pathological conductivity was successful (1 patient was operated on again). In the left-sided localization in 8 out of 11 patients the stimulation syndrome was removed permanently, in 2 temporarily and in 1 the operation was unsuccessful. In 1 patient radio-frequency cardiostimulator has been grafted to stop the attacks.

Thirty patients with frequent attacks of supraventricular tachycardia were investigated, and a reciprocal paroxysmal atrioventricular tachycardia due to additional atrioventricular junctions was diagnosed in 16 of those. Heart rhythm disorders were rooted in the apparent Wolff-Parkinson-White syndrome in 8 patients, and in its latent variety in another 8. A comparative assessment of diagnostic potentials of esophageal and intracardiac electrophysiologic investigation demonstrated the latter to be an effective method for provoking reciprocal atrioventricular tachycardias and allow a reliable assessment of basic antegrade refractory periods and intervals of the heart's conductive system, including the effective refractory period of Kent's bundle, in patients with additional atrioventricular junctions. In esophageal electrophysiologic studies, electrographic V-A interval exceeding 90 ms during an attack of tachycardia is a major sign of reciprocal atrioventricular tachycardia due to additional atrioventricular junctions.

The paper presents a generalized experience in the surgical treatment of patients with frequent attacks of paroxysmal tachycardia associated with additional cardiac conduction pathways, that are not affected by the drug treatment. The results are described of 27 operations of destruction of anomalous cardiac conduction pathways. The use of a special ultrasound destructor permits the surgeon to perform the operation on the functioning heart, thus providing maximal radical surgery with minimal cardiac trauma and best effects.

Detection rates and features of the clinical course of paroxysmal reciprocal sinoatrial tachycardia were examined in 34 patients. The features of the tachycardia should include its short-term and less marked clinical manifestations. In tachycardia, mean heart rate was 118 +/- 13 per minute. Long-term ECG monitoring was found to be the most adequate tool for the diagnosis of paroxysmal sinoatrial tachycardia. The potentials of transesophageal electrostimulation of the heart in the diagnosis and assessment of the clinical significance of that tachycardia were demonstrated to be limited due to instability of induced paroxysms.

The author discusses the results of examination conducted by means of continuous ECG recording for many hours, intracardiac electrography, and programmed electric stimulation of the heart in patients with ischemic heart disease and arrhythmias. It was established that ventricular extrasystoles, including the so-called precursors of ventricular fibrillation, are recorded in most patients suffering from chronic ischemic heart disease and acute myocardial infarction, in 66 and 95% of those examined, respectively. The article gives the electrophysiological criteria of the diagnosis of sino-atrial, atrial, nodal atrio-ventricular, supraventricular in additional paths of stimulation conduction, and ventricular paroxysmal tachycardia.

Having briefly touched upon the problem of terminology and classification of arrhythmias the authors consider the diagnosis and clinical evaluation of some disorders, including the extrasystole (the significance of the extrasystolic interval), ectopic arrhythmias from the region of the atrio-ventricular junction (with simultaneous consistent or transent disruption of the intraventricular conduction), isolated atrial tachycardia, some variants of auricular fibrillation, flutter paroxysms, paroxysms of ventricular tachycardia, with continued auricular fibrillation in particular, and also the earlier described electrocardiographic phenomenon tentatively interpreted as sinistroatrial fibrillation with dextraatrial tachycardia, as well as major types of disrupted condution. The authors give a brief exposure of their views as to the principles of the treatment. Emphasis is placed on the importance of a comprehensive clinical approach to the diagnostic matters and to the evaluation of arrhythmias, as well as to the fundamental need to define more precisely the pathogenesis of the disturbed rhythm in a concrete patient so as to adopt an effective treatment.

An intracardiac electrophysiologic study of 73 patients, including those without ventricular arrhythmias, those with chronic ventricular ectopic activity of varying levels, and those with paroxysmal or nonparoxysmal ventricular tachycardia, has identified specific electrophysiologic phenomena that may be used as criteria for the diagnosis of paroxysmal ventricular tachycardias and assessment of the effect of anti-arrhythmic drugs at electrophysiologic testing.

Under observation were kept 80 patients with signs pointing to the sick sinus syndrome. Most of them suffered from ischemic heart disease, from atherosclerotic cardiosclerosis and acute myocardial infarction. Persistent sinus bradycardia with active and passive heterotopic arrhythmias were recorded in 42 patients. Sino-auricular block of the II and III degrees or asystolia of the atria with ectopic arrhythmias were observed in 37 cases. A number of patients displayed fibrillary bradyarrhythmia, extrasystole with post-extrasystolic depression of the rhythm and other disturbances. The so-called tachycardia-bradycardia syndrome characterized by the presence of tachycardiac arrhythmias occurring against the background of a marked bradycardia was registered in 25 persons. Fifteen patients demonstrated attackes of the Morgagni-Adams-Stokes syndrome, usually associated with lengthy periods of cardiac asystole. The treatment of ectopic arrhythmias in patients with the sick sinus syndrome presents considerable difficulties, but in many of them these disorders could be successfully eliminated by a careful and rigidly controlled application of antiarrhythmic agents (isoptin, ajmalin, pulsnorma, rhythmodan, beta-adrenergical blocking agents). For some patients exhibiting a tendency toward asystole electric stimulation of the heart is indicated.

The significance of electrophysiological investigation of the heart for the diagnosis and treatment of cardiac rhythm disorders is shown. The results of the study of electrophysiological mechanisms and of diagnostic criteria of the more frequent reciprocal tachycardias are analysed: sino-atrial, atrial, atrioventricular nodal, tachycardias in Wolff--Parkinson--White syndrome. Ventricular tachycardia, and also disorder of the rhythm caused by automatic activity of the ectopic focus. Possibilities of the method in the study of the function of the conductive system of the heart and the assessment of the antiarrhythmic drugs are stressed. The problem of the differentiated treatment of cardiac rhythm disorders is discussed. The role of the electrophysiological investigation in the choice of individual medicinal therapy and in the pre-operation study of patients with cardiac arrhythmias is stressed.

Thirty-one patients with paroxysms of supraventricular tachycardia (SVT) were examined using trans-esophagus electrical stimulation of the left atrium. SVT paroxysms were provoked in 23 patients. An analysis of the esophagus electrogram recorded revealed SVT paroxysms in the presence of the latent Wolff-Parkinson-White (WPW) syndrome in 12 patients, orthodromic SVT in the presence of the WPW syndrome in seven, and paroxysmal reciprocal atrioventricular node tachycardia in four patients. Paroxysms were also induced in three out of 8 patients with atrial fibrillation. Two patients displayed a fall in the ST segment.

A study using two methods of noninvasive registration of ventricular late potentials (VLP), computer averaging and beat-to-beat spatial averaging, was conducted in 27 patients with ventricular tachycardia and 11 healthy volunteers. Both techniques are described in detail. The duration of QRS complex on high resolution ECG was found to be significantly longer in patients with VLP as compared to those of patients without VLP and having ventricular tachycardia as well as healthy adults. The data obtained by both methods do not differ significantly. The beat-to-beat method was not informative in about 20% of cases because of the ineffective filtering procedure and the presence of myographic noise on the amplified CS. The duration of VLP was 44 +/- 20 ms in patients with documented ventricular tachycardia. The sensitivity of the assessment of arrhythmogenic ventricular activity was 70% with the computer method, and 59% with the beat-to-beat spatial averaging technique. The specificity and predictive value of both registration methods were 100%.

The article discusses the possibilities of differential diagnosis of supraventricular arrhythmians by means of carotid zone stimulation, atrial VCG and ECG recorded from right-bronchial leads. Atrial VCG can reveal the character of the ectopic P-wave and thus helps in the diagnosis of arrhythmias with conspicuous atrial activity. ECG recorded from bronchial leade makes it possible to obtain a large atrial wave and determine elements of decisive importances in the diagnosis of many rhythm disorders: junctional and combined contractions, various types of ectopic P-waves, the character of antero- and retrograde conduction. The tactics of treatment with cardiac glycosides is determined by precise diagnosis of the arrhythmia and its connection with digitalis toxicosis.

Observation of 13 patients with the septal location of additional conducting pathways is given, 2 of them had James' fibres, 1 had a combination of James' and Mahaim bundles, in the remainder the Kent's bundle was in the anterior position. Removal of conduction through Kent's and His' bundles is described in detail. The syndrome of pre-excitation was successfully removed in 10 out of 12 patients, 1 had relapses later and 2 died. A detailed analysis of all 35 operated on patients with the pre-excitation syndrome is given. Good results were obtained in 88.57%.

For differentiation of tachycardias the authors offer a method of recording the curves of differentially increased spike potentials (DISP) of atriae from the surface of the chest wall, based on the recording of the electrical activity of the atriae in the shape of a high amplitude atrial spike complex. The DISP curves have been recorded in 36 patients with tachycardias, in whom by usual ECG it was difficult to determine the tachycardia type, in some cases it was impossible, for instance in confluence of the P wave with the QRS complex or the T wave. The typical and constant form of the atrial spike complex on the DISP curve in the sinus rhythm permits determining the sequence of the stimulations of atriae and the type of disorders of the cardiac rhythm. The recording of the DISP of atriae as to complexity does not differ from the recording of the usual ECG.

The procedures involved in different techniques of cardiac electrostimulation for the diagnosis of the pre-excitement syndrome were examined in 154 patients. In a group of 150 patients with provoked (140) or spontaneous (10) tachycardia developing in response to endocardial electrocartography, the paroxysmal supraventricular tachycardia was noted in 95.5%, atrial flutter in 11.4%, atrial flutter-fibrillation in 5.7%, atrial fibrillation in 29.8%, A-V tachycardia in 3.7%. The methods of diagnostic cardiac electrostimulation are of great importance in determining the type, localization, electrophysiologic properties and mechanisms of heart rhythm disorders and in selecting a rational therapeutic method.

Eighty-five patients with a variety of paroxysmal cardiac arrhythmias were studied. Total informative value of Holter ECG monitoring was 84.7%. Additional data on previously undetected rhythm and conductivity disorders were obtained in some cases. The duration of tachyarrhythmias varied widely, fasting 7 to 10 minutes in most cases, and about half the cases were undetected by standard ECG. The comparison of patients' subjective assessments and complaints with ECG monitoring data showed that some patients were either unaware of serious arrhythmias or could only sense individual paroxysms. In all cases, Holter monitoring data were correlated with the results of invasive electrophysiologic studies. Paroxysms could not be induced in 4 patients, while Holter monitoring diagnosed tachyarrhythmias in those cases.

Fifteen patients with paroxysmal ventricular tachycardia (PVT) were subjected to prolonged intracardiac electrophysiologic investigation (EPI) combined with tests of a variety of antiarrhythmic agents. One to 4 (2 +/- 0.3) agents were found to be capable of preventing ventricular tachycardia in response to endocardial stimulation in 93.3% of cases. Subsequent antiarrhythmic treatment by a drug thus selected prevented ventricular tachycardia paroxysms in all patients: there were no recurrent paroxysms in 10 (71.4%) patients, while tachycardiac attacks grew much less frequent, as compared to the pretreatment situation, and could be easily controlled by an additional dose of the drug in 4 (28.6%). Prolonged intracardiac EPI is a highly efficient method of individual assessment of drugs' antiarrhythmic effect that allows a timely and correct choice of treatment capable of reliable prevention of paroxysms.

The indications for the catheterization of the heart and the recording of cavity electric potentials at the emergency aid centre are being considered. The possibilities have been studied of the electrography of the conductive system of the heart for differentiation of supraventricular paroxysmal tachycardias with blocks of pedicles of the His' bundle and ventricular paroxysmal tachycardias, and of irregular ventricular tachycardia and attacks of auricular fibrillation with pedicle blocks, and for the determination of the level of the atrioventricular blocks.

The concealed Wolff-Parkinson-White (WPW) syndrome, the electrophysiologic and morphologic basis of cardiac arrhythmias, was shown to be a cause of the attacks of supraventricular tachycardia. The latter is rooted in the concealed WPW syndrome in about 30% of patients showing no electrocardiographic signs of pre-excitation. Electrophysiologic criteria of the diagnosis of supraventricular tachycardias due to the concealed WPW syndrome are listed. Concealed Kent's bundle was most commonly found on the left side. As regards antiarrhythmic therapy, disopyramide is one of the most effective drugs for patients with supraventricular tachycardias due to the concealed WPW syndrome.

The study involved 24 patients with supraventricular paroxysmal reciprocal tachycardia (SPRT) showing no ECG evidence of ventricular pre-excitation between the attacks. SPRT attacks could be provoked by frequent esophageal left-atrial stimulation in all patients, particularly with impulse frequencies in the 160 to 200 imp/min range, associated with first-degree atrioventricular block featuring Wenckebach's phenomenon. In most cases, induced SPRT was similar to a spontaneous attack. During an induced attack, the duration of Q--P interval was less than 70 ms in 15 (62.5%) suggesting that the scope of reciprocal excitation was limited to the atrioventricular node, and more than 70 ms in 9 (37.5%), indicating the involvement of complementary ventriculo-atrial pathways.