Transesophageal Electrophysiological Study Research Articles

MULTIFOCAL ATRIAL TACHYCARDIA AND HYPERTROPHIC CARDIOMYOPATHY IN THREE PATIENTS WITH COSTELLO SYNDROME

Abstract Introduction Costello syndrome is a rare disease, caused by mutation of the HRAS gene, associated with intellectual disability, growth retardation, facial dimorphisms. Cardiac abnormalities, mainly cardiac hypertrophy and multifocal atrial tachycardia, are present in 1/3 of patients. Clinical Cases From 2019 to 2023, 3 newborns with Costello syndrome came under our observation. M.M. showed respiratory distress, hypotonia and dysmorphic notes; genetic analysis highlighted the pathogenic variant c.64C>A (p.Gln22Lys). On the echocardiogram, septal hypertrophic cardiomyopathy was found with left outflow obstruction and mitral insufficiency. Therapy with propranolol was undertaken. Holter ECG never revealed arrhythmias. At the last check–up, SIV hypertrophy, continent mitral valve, free left ventricular outflow. The second patient, O.L., arrived at 10 days of age following a run of supraventricular tachycardia. He had bilateral clubfoot and facial dimorphisms. The echocardiogram was normal. On Holter ECG atrial tachycardia interrupted by rare sinus beats. Therapy with flecainide was undertaken, without benefit. Subsequently, was undertaken amiodarone, then associated with digitalis. She was discharged with satisfactory control of the average ventricular rate, but later due to the appearance of chaotic atrial arrhythmia, propranolol was added; on the Holter ECG in triple therapy, periods of sinus rhythm alternating with short episodes of atrial tachycardia were observed. Genetic analysis revealed the pathogenic variant c.34G>A, p.(Gly12Ser) of the HRAS gene. The third patient, F.A., presented atrial tachycardia. Flecainide therapy had transient benefit. Subsequently propranolol was added, without benefit. Therapy with amiodarone was initiated. Transesophageal electrophysiological study demonstrated multifocal atrial tachycardia, unresponsive to overdrive pacing. Partial control of the average ventricular rate was achieved in triple therapy. On the echocardiogram, mild concentric hypertrophy and dysplastic pulmonary valve. Genetic testing detected the c.35G>C, p(Gly12Ala) variant of the HRAS gene. Conclusions Costello syndrome requires cardiac monitoring for the possible presence of multifocal atrial tachycardia and hypertrophic cardiomyopathy. Arrhythmia, which can also occur independently of hypertrophy, can be self–limited in the first months of life with aggressive pharmacological treatment but can persist or worsen in ¼ of patients.

P184 TRANSESOPHAGEAL ELECTROPHYSIOLOGICAL STUDY FOR FOLLOW UP OF NEONATAL PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA

Abstract Introduction Paroxysmal supraventricular tachycardia (TPS) is the most common form of arrhythmia in neonatal age. The transesophageal electrophysiological study allows us to demonstrate the possible persistence of arrhythmia after the first year of age. Aim of the study: To evaluate the reliability of transesophageal electrophysiological study in the follow–up of these patients. Materials and methods: We retrospectively observed 8 patients who came to our observation in neonatal age for TPS. All patients underwent echocardiogram and Holter and were discharged to effective drug therapy for rhythm control (with one or two drugs). Afterwards, they carried out follow–up with Holter in drug therapy every 3 months. Within one year of age, antiarrhythmic therapy was discontinued and a transesophageal electrophysiological study was performed, including atrial stimulation at increasing frequencies and programmed atrial stimulation with single, double and triple extrastimulus. In case of TPS inducibility, therapy was resumed and the study was repeated after one year in wash out. Results We observed 8 patients who came for TPS in neonatal age. 7 of these had a structurally normal heart; one patient had aortic coarctation corrected with aortoplasty. After one year of therapy, 4 patients (50%), half of whom were in dual therapy (flecainide associated with beta–blocker and/or amiodarone) were non– inducible; these patients, who were permanently discontinued, no longer presented arrhythmic episodes in the follow–up. The remaining 4 resumed therapy (double in half of the cases) for another year and then repeated the study in wash out: one patient continued to present arrhythmias (patient with correct aortic coarctation); the other 3 were non–inducible. In the subsequent follow–up, 3 of these patients only one showed a recurrence of arrhythmia. Conclusions The transesophageal electrophysiological study is a simple, minimally invasive and reliable method to identify subjects at risk of TPS recurrence. The persistence of arrhythmia in our study is independent of the pharmacological treatment carried out in mono or dual therapy. We also observed that in case of positivity after one year of therapy, the study can be repeated later allowing therapy to be interrupted at a later time.

Three faces of one paroxysmal supraventricular tachycardia

Fragments of a transesophageal electrophysiological study of a 35-year-old patient with induction of paroxysmal atrioventricular nodal re-entry tachycardia occurring with three different electrocardiographic patterns are presented.

P34 ASYMPTOMATIC VENTRICULAR PRE–EXCITATION WITH DISAPPEARANCE DURING EXERTION: ALWAYS AN INDEX OF BENIGNITY?

Abstract Introduction The disappearance of pre–excitation at high heart rates points to a low arrhythmic risk: why resort to electrophysiological studies anyway? Clinical Case L.S., a 12–year–old patient, performed an ECG for sports examination with evidence of ventricular pre–excitation from an asymptomatic left lateral accessory route (Fig. A). A 24 h ECG–Holter during training showed the disappearance of the pre–excitation at high frequencies (Fig. B) which is considered a low risk index. The patient underwent a transesophageal electrophysiological study (SETE) during which an effective refractory antegrade period of 228 ms of the pathway was objectified through atrial extrastimuli (*) (Fig. C: drive of atrial stimuli (*) followed by extrastimulus with conduction on an accessory route (E)). In addition, a 1: 1 conduction was observed on the atrial pathway up to at least 270 bpm (222 ms). The antegrade refractory period of the resting path was <250 ms and therefore identified a high–risk condition to be treated with ablation. Discussion The disappearance of pre–excitation at high heart rates is usually considered indicative of an accessory pathway with a long refractory period and therefore at low risk, however it must be sudden. According to European guidelines, the execution of invasive studies in asymptomatic patients who are employed in high–risk jobs or competitive sports has a class I B indication, but in the remaining asymptomatic cases the indication is IIa B. The Holter ECG alone or the stress test, with a careless evaluation of the disappearance of the pre–excitation (sudden vs progressive with minimal residual pre–excitation) would have erroneously led to labeling this accessory pathway at low risk. In the left lateral accessory pathways, with the increase of the HR, there can be a disappearance or pseudo–disappearance of the pre–excitation for anatomical reasons (being further away from the SA node) and for an increase in the AV conduction speed, not therefore for a long refractory period of the pathway. SETE is closer to the atrial side of the left accessory pathway and allows to correctly classify the risk. Conclusion SETE is a low–cost and minimally invasive method that should be considered as an integral part of the study of patients with asymptomatic ventricular pre–excitation even if non–invasive stratification indicates low risk.

Transesophageal Electrophysiological Study in Management of Pediatric tachyarrhythmias

Transesophageal Electrophysiological Study in Management of Pediatric tachyarrhythmias

Impact of transesophageal electrophysiological study on midterm management of pediatric tachyarrhythmias.

Transesophageal electrophysiological study (TEEPS) is a minimally invasive procedure that helps in evaluating the risk of recurrence of supraventricular tachycardia based on the inducibility of the tachycardia. The purpose of this study was to evaluate the diagnostic capability, negative predictive value of noninducibility of tachycardia and safety of TEEPS among the Indian pediatric population. It is a retrospective single-center observational study of all patients who underwent TEEPS from January 01, 2014, to December 31, 2020. Twenty-two TEEPS procedures were done in eighteen children with three children undergoing more than one procedure. The median duration of follow-up was 42.97 months (8.52-82.12 months). Out of the 22 procedures, four were conducted for acute tachycardia termination, two for tachycardia suppression assessment, and sixteen to assess tachycardia inducibility off medications. Tachycardia was noninducible in nine children and inducible in six children. Two children had clinical recurrence of tachycardia on follow-up. Out of these two children, one had noninducibility of tachycardia on TEEPS. The negative predictive value of TEEPS was 88.89% in this study. None of the children had any postprocedure complication. TEEPS is a safe procedure. It is used to assess the efficacy of medication in the suppression of arrhythmia. The noninducibility of tachycardia has a high negative predictive value and is a good indicator of nonrecurrence of clinical tachycardia on midterm follow-up.

РЕДКИЕ ФОРМЫ НАДЖЕЛУДОЧКОВОЙ ТАХИКАР

The article presents data on the structure, frequency of occurrence of some rare forms of supraventricular tachycardia in childhood, highlighting the clinical and electrophysiological variant of rhythm disturbance to determine the nature of further treatment and follow-up. Of the 1124 children who applied for tachycardia, 194 children were selected, who underwent an in-depth study of the properties of the conduction system of the heart by performing a transesophageal electrophysiological study. The structure of supraventricular tachycardia was established with the following: atrioventricular reciprocal tachycardia, atrioventricular nodal reciprocal tachycardia, focal atrial tachycardia and atrial fibrillation/flutter. The relatively rare detection of concomitant pathology in children with SVT (11.8%) emphasizes the need for a detailed collection of cardiac history, clinical and laboratory examination at the previous stages of medical care.

Atrial standstill in the newborn: a case report

Introduction. Persistent atrial standstill is a rare syndrome characterized by absence of mechanical and electrical atrial activity. The article presents a unique case of atrial standstill in the newborn patient with tachyarrhythmia.Brief description. The first manifestation of atrial standstill in the patient was heart failure (HF) manifestations and wide-complex tachycardia according to electrocardiography, which was identified as ventricular tachycardia. At the local outpatient clinic, the child was prescribed with antiarrhythmic therapy (AAT), which decreased heart rate. Three months later, a transesophageal electrophysiological study was carried out in our center in order to determine the arrhythmia origin. A multiform idioventricular rhythm with a heart rate of 46-119 beats per min was diagnosed, atrial pacing spike (A waves) was not recorded. Given bradyarrhythmia, hemodynamic abnormalities on echocardiography (significant atrial enlargement, decreased contractility), the patient, in order to prevent the risk of sudden cardiac death, underwent implantation of single chamber pacemaker in VVIR mode and bipolar ventricular lead. Anticoagulant therapy was prescribed. After 6-month follow-up, relief of HF symptoms and an increase in left ventricular contractile function was noted.Discussion. Timely diagnosis and implantation of pacemakers allowed avoiding AAT and minimizing the HF symptoms. Continuous ventricular pacing and anticoagulant therapy are important in HF prevention.

Incessant Automatic Atrial Tachycardia in a Neonate Successfully Treated with Nadolol and Closely Spaced Doses of Flecainide: A Case Report

Supraventricular tachyarrhythmia (SVT) is the most common type of arrhythmia in childhood. Management can be challenging with an associated risk of mortality. A female neonate was diagnosed with episodes of SVT, controlled antenatally with digoxin. Flecainide was commenced prophylactically at birth. Despite treatment, the infant developed a narrow complex tachycardia at 5 days of age. The electrocardiogram features were suggestive of either re-entry tachycardia or of automatic atrial tachycardia (AAT). Following several unsuccessful treatments, a wide complex tachycardia developed. A transesophageal electrophysiological study led to a diagnosis of AAT. Stable sinus rhythm was finally achieved through increasing daily administrations of flecainide up to six times a day, in association with nadolol. The shortening of intervals to this extent has never been reported before and supports the evidence of a personal, age-specific variability in pharmacokinetics of flecainide. Larger studies are needed to better define the appropriate dose and timing of administration.

Atrial Flutter as the First Manifestation of Progressive Cardiac Conduction Disease in a Young Apparently Healthy Patient: А Case Report

Abstract We reported a case of a twenty-one-year-old man with an atrial flutter as the first manifestation of progressive cardiac conduction disease. The patient was admitted to the cardiology department due to complaints of shortness of breath and a decrease in exercise tolerance, which had happened after physical exercises (running). During ambulatory ECG monitoring persistent AFL was observed with atrial rate 262-297 bpm and ventricular rate 26-136 bpm (average 56 bpm). AV conduction was very variable – 4:1-14:1. The results of ambulatory ECG monitoring during the whole period of recording indicated signs of atrioventricular conduction disturbances. After cardioversion sinus rhythm was restored additional rhythm and conduction disorders were revealed. Ambulatory ECG monitoring was performed two weeks after the initial one, and throughout this recording were registered sinus rhythm on the background of first-degree AV block; transient Mobitz I AV block; and type 2 second-degree sinoatrial block. Trans-esophageal electrophysiology study was performed. During pharmacological denervation of the heart, signs of slowing of the atrioventricular conduction and sinus node recovery time persisted. These changes along with right bundle branch block were regarded as a progressive cardiac conduction disease with an apparently hereditary cause.

Prediction of antiarrhythmic therapy effectiveness in children

Aim. To optimize treatment tactics in children with arrhythmias based on the evaluation and prediction of the therapy efficacy. Material and methods. Prospective cohort study was performed from 2007 to 2017 A total of 100 patients aged 0 to 7 years with different types of significant arrhythmias received prophylactic antiarrhythmic therapy. Data of medical history, 12-lead electrocardiography (ECG), Holter ECG monitoring, and echocardiography were studied. To verify electrophysiological variant of tachycardia, some patients underwent transesophageal electrophysiologic study. Results. The study showed that antiarrhythmic drug therapy was most efficacious in patients till one year old without signs of arrhythmogenic cardiomyopathy (ACM). Older age of children, the presence of pronounced ACM manifestations are factors that increase the risk of ineffective AAT. Based on the data obtained, a multifactor model was developed to predict the effectiveness of prolonged antiarrhythmic therapy. Conclusion. The study showed that age and intracardiac hemodynamic status affected the efficacy of antiarrhythmic therapy. Proposed model allowed to avoid unnecessary prolonged pharmacological load and to timely administer other methods of treatment in case when ineffective result of the antiarrhythmic therapy was predicted.

Can noninvasive testing identify benign patterns of suggested pre-excitation on electrocardiogram?

The presence of anterograde conduction through an accessory pathway (AP) has been linked to sudden cardiac death. Unfortunately, pre-excitation associated with classic pathways can be difficult to differentiate from benign APs such as nodofascicular fibers. Identifying characteristics on electrocardiogram (ECG) and exercise that differentiate classic and benign AP connections in suggested pre-excitation patterns. Retrospective review of patients presenting between 1995 and 2017 with ventricular pre-excitation on ECG, determined to have either typical left-lateral AP during electrophysiology study (EPS), or benign, or no AP determined by either transesophageal electrophysiology study (TEP), or EPS. A total of 96 patients were included, 14.2 years (4-24), 45% female, 90% Caucasian. Of these, 60 (63%) had a classic APs identified on EPS and 58 (97%) underwent successful ablation. Conversely, 36 (37%) had benign pathways identified. ECG findings differed between the groups: PR-interval 102 versus 120ms (P<.0001), QRS-duration 110 versus 102ms (P<.0001), QRS-axis 74 versus 59 degrees (P=.0005), and QRS onset to peak R/S in limb leads 64 versus 42ms (P<.0001), and precordial leads 66 versus 46ms (P<.0001). Change in QRS duration during exercise differed between the groups: 25 versus 2ms (P<.0001) and ECG characteristics identified the presence of an AP with 97% sensitivity and 94% negative predictive value. Classic and benign APs exhibit different ECG characteristics, though clinical overlap does not allow for absolute differentiation. These data may help with risk stratification decision making though does not obviate the need for additional invasive testing.

Automatic detection of ventricular and supraventricular wide QRS arrhythmias using complex of morphological criteria and algorithms

The aim of study is a detection of ventricular and supraventricular wide QRS arrhythmias using complex of morphological criteria and algorithms by method of automatic analysis. For 100 patients (m/f- 61/39, Me (min; max)- 44.5 (10; 85) years) of researched group the analysis of 14306 single wide ectopic complexes (QRS 120-230 ms) has been done. Wide complexes include 11028 (77%) ventricular complexes and 3278 (23%) supraventricular complexes represented by 145 different forms of QRS. For verification of arrhythmias origin transesophageal ECG recording and endocardial electrophysiological study were done. The control group included 59 patients (m/f- 25/34, Me (min; max)- 49.5 (14,85) years) with 720 wide QRS, including 467 (65%) ventricular and 253 (35%) supraventricular complexes represented by 86 forms of QRS. The criteria DrewB.J., ScheinmanM.M. (1995); WellensH.J. (1978), RWPT II (Pava LF, 2010) and the algorithms of BrugadaP. (1991); Bayesian (2000); VereckeiA.(2008) were used to evaluate sensitivity, specificity and diagnostic accuracy of wide QRS complexes recognition one byone and together, using the method of Wald sequential automatic analysis (KT Result3, CJSC INCART, Russia) and method ofartificial neural networks. The best results for the detection of ventricular arrhythmias algorithms were demonstrated by the Brugada P., Drew B.J., Scheinman M.M. algorithm (sensitivity 86.43%, specificity 66.73%, diagnostic accuracy 82.14% in the study group, sensitivity 81.80%, specificity 73.12%, diagnostic accuracy 78.75% in the control group), and the Bayesian algorithm (sensitivity 87.81%, specificity 73.62%, diagnostic accuracy 84.72% in the study group, sensitivity 83.30%, specificity 77.08%, diagnostic accuracy 81.11% in the control group). A complex analysis of the Wald method recognized ventricular arrhythmias in the research group with sensitivity 83.11%, specificity 83.65%, diagnostic accuracy 83.23% and in the control group with a sensitivity 83.51%, specificity of 84.58% anddiagnostic accuracy 83.89%. Artificial neural networks recognized ventricular arrhythmias with sensitivity 91.43%, specificity 91.30% and diagnostic accuracy 91.39% in the control group and with sensitivity 97.06%, specificity 99.39% and diagnostic accuracy 97.6% in the research group. Automatic analysis allows obtaining simultaneously the results of each algorithms/criteria and in combination. It significantly reduces the doctor's work in assessing of amplitude-time characteristics ofthe complexes. Using artificial neural networks increases the accuracy of of ventricular and supraventricular arrhythmias recognition.

Heart rate variability parameters in children with ventricular preexcitation.

The autonomic nervous system has a regulatory effect on cardiac electrophysiology and arrhythmogenesis. We aimed to assess cardiac autonomic status using heart rate variability (HRV) parameters in children with ventricular preexcitation. The electrocardiography, Holter monitoring, transesophageal electrophysiological study (TEEPS), and invasive electrophysiological study (EPS) results of ventricular preexcitation patients obtained over a 7-year period in our clinic were evaluated. According to the TEEPS results, patients' accessory pathway conduction was classified as adverse (n = 40) or nonadverse (n = 25). The HRV parameters of patients were compared according to tachycardia inducibility that assessed by TEEPS and EPS. Also, HRV parameters were compared in patients with adverse and nonadverse pathway conduction. Further, the HRV parameters of preexcitation patients were compared with those of healthy controls. LF/HF, the best measure of sympathovagal balance, was statistically higher in patients with adverse conduction than in patients without adverse conduction and controls (P=0.001). The LF/HF ratio was higher in ventricular preexcitation patients with inducible tachycardia than those without in EPS (P=0.001). In addition, the LF/HF ratio was higher in symptomatic ventricular preexcitation patients than asymptomatic ones (P=0.001). No difference in HRV parameters was found between preexcitation patients and controls. Autonomic tonus in patients with ventricular preexcitation may affect accessory pathway conduction properties, tachycardia inducibility, and symptomology. The indicator of sympathovagal balance, LF/HF ratio, increased in ventricular preexcitation patients with inducible tachycardia and those that were symptomatic.

Electrophysiological Parameters of Sinus Node Function in Patients with Paroxysmal Tachyarrhythmias

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Transesophageal and invasive electrophysiologic evaluation in children with Wolff-Parkinson-White pattern.

Risk stratification for Wolff-Parkinson-White (WPW) pattern either by noninvasive or invasive tests is important to determine whether an ablation is necessary or not. The aim was to compare noninvasive tests and invasive studies in a pediatric WPW population. A total of 71 WPW patients (median age 14 years [interquartile range, 11-16 years]; 43 male) underwent Holter monitoring, exercise stress test (EST), and transesophageal electrophysiological study (TEEPS). In the case of a ≤270-ms effective refractory period of accessory pathway or induction of supraventricular tachycardia using TEEPS, patients were classified as high risk and underwent invasive electrophysiological study (EPS). Nine of 23 patients with low risk by Holter and eight of 26 patients with low risk by EST had high risk in TEEPS. Risky TEEPS results were detected in 42 of 71 patients and those patients underwent EPS. High-risk characteristic in EPS was detected in seven of nine patients with low risk by Holter and in seven of eight with low risk by EST. Both tests yielded moderate specificity (52-69%) and negative predictive value (61-69%) according to TEEPS. Holter and EST have low predictive value in WPW risk stratification. However, TEEPS and EPS are extremely valuable in WPW risk stratification. TEEPS may reveal important and useful results for WPW risk determination, especially in small children not having undergone EPS in order to avoid its complications.

Comparative Assessment of the Heart's Functioning by Using the Akabane Test and Classical Methods of Instrumental Examination

Acupuncture physicians have studied the application of reflexotherapy to cardiology. However, no one has investigated the connection of ancient Chinese diagnostic methods with modern tools. A total of 102 patients (54 men and 48 women) with heart pathology, namely, sick-sinus syndrome, Wolff–Parkinson–White syndrome, and atrioventricular blockade, were studied using the usual instrumental methods (transesophageal electrophysiological study of the heart, echocardiography), after which they underwent Akabane thermopuncture testing as in traditional Chinese medicine. The results of cardio examination from one side of the Akabane test with that from the other side were compared by means of a multiple stepwise regression analysis. We revealed the effects on the characteristic pattern of acupuncture channel lesions inherent in a definite heart pathology, i.e., the most vulnerable acupuncture channel (AC), of such factors as disturbances of the contractile, conductive, or automatic heart functions, and changes in the chambers' size or circulation volume. Сhanges in the indices of the left and the right branches of these channels usually reflect the opposing natures of the changes in these indicators, which should be considered in reflexotherapy. The main value of the Akabane test along with the use of mathematical analysis lies in early, quick, and inexpensive detection of the above-mentioned heart disturbances.

Sports Eligibility After Risk Assessment and Treatment in Children with Asymptomatic Ventricular Pre-excitation.

Many studies concern the management of young patients with symptomatic Wolff-Parkinson-White (WPW) syndrome, but little information exists on the significance and prognosis of ventricular pre-excitation (VPE) in asymptomatic children. The aim of the study was to evaluate the risk of sudden death in young athletes with asymptomatic VPE by transesophageal electrophysiological study (TEEPS) and their sports eligibility after the risk assessment and/or ablative treatment. Ninety-one asymptomatic children and adolescents underwent TEEPS both at rest and during adrenergic stress (exercise testing or isoproterenol infusion). After electrophysiological testing, patients were assessed in the 36months of follow-up. Thirty-three patients (36.3%) had a benign form of VPE and were allowed to participate in competitions. Ten patients (11%) were at borderline risk; thus, sport eligibility was evaluated individually. Forty-eight patients (52.7%) showed inducible sustained atrioventricular reentrant tachycardia and/or atrial fibrillation (AF), 11 of whom (12.1% of total population) had a potential risk of sudden cardiac death due to AF inducibility during physical stress. Forty-five young athletes underwent transcatheter ablation (TCA). TCA was interrupted in 12 patients (26.7%) because of the high procedural risk linked to septal accessory pathway (AP) location. There were no TCA-related complications, and all patients remained asymptomatic during follow-up. Most of the young athletes with asymptomatic VPE may be allowed to participate in competitive sports after an adequate risk assessment and/or ablative treatment. However, in our opinion, special care should be taken to avoid procedural complications, which are unacceptable in asymptomatic patients.

Hypervagotonic binodal dysfunction in children. Features of the natural course

Aim. To evaluate the clinical and electrophysiological picture of binodal disease in children, as well as studying the clinical course of this disease.&#x0D; Methods. To study the clinical and electrophysiological picture of autonomic binodal disease, 426 patients under 18 years old were examined; the average age was 15.35±2.43 years (3-17.9). Patient’s complaints, medical history were examined, ECG, 24-hour ECG, stress ECG (treadmill or bicycle test), echocardiography, transesophageal electrophysiologic study were performed. In the case of a combination with pathological signs of sinus node dysfunction and atrioventricular node conduction disorders with the normalization of all parameters after the atropine administration, hypervagotonic binodal dysfunction was diagnosed. To assess the clinical course of the disease, a group of 72 children was selected, who were monitored repeatedly. Mean follow-up duration was 33 months.&#x0D; Results. During the study period, sinus node dysfunction and atrioventricular blocks completely resolved in 14 (19.44%), seen as normal clinical picture with no complaints, normal heart rate, no signs of sinoatrial block or atrioventricular block, normalization of Wenckebach point position. Another 35 (48.62%) had only one node dysfunction resolved (either sinoatrial or atrioventricular - Wenckebach point position within the age normal values and/or atrioventricular block resolved). In 23 (31.94%) - deterioration of the sinus node and atrioventricular node dysfunction was observed.&#x0D; Conclusion. There are significant differences in the frequency characteristics of heart rhythm and electrophysiological parameters of sinus node function in children with a favorable clinical course of binodal disease and progressive course of the disease.

Пусковые факторы и поддерживающие механизмы экстрасистолии и наджелудочковой тахиаритмии у небеременных и беременных женщин

The frequency of occurrence, trigger factors, supporting mechanisms of arrhythmia and paroxysmal supra-ventricular tachyarrhythmias in non-pregnant and pregnant women were studied. The study involved 26 non-pregnant women aged 18 to 29 years (25,8+2.2 years) and 30 pregnant women from 20 to 32 years (25,6+2,8) without complaint and without structural heart disease. Holter monitoring of ECG and transesophageal electrophysiological study of the heart were performed in all patients. It is revealed that there are arrythmia and paroxysmal supra-ventricular tachycardia in pregnant women more often than in non-pregnant. Reducing the number of extrasystoles and paroxysmal supra-ventricular tachyarrhythmias occurs 6 months after birth. It is established that in non-pregnant and pregnant women there are four types of curves atrio-ventricular conduction (AVC): continuous, intermittent, continuous with the phenomenon of the &amp;#34;gap&amp;#34;, intermittent with the phenomenon of the &amp;#34;gap&amp;#34;. The continuous curve type of AVC is detected in non-pregnant women, in pregnant women – intermittent, in women six months after childbirth - continuous. It is proved that the electrophysiologi-cal substrate curves atrio-ventricular conduction is retrograde functioning additional channel and longitudinal dissociation of atrio-ventricular connections on the fast and slow ways.