Supraventricular Premature Contractions Research Articles

Validation of an artificial intelligence system for holter ECG analysis

Abstract Introduction Holter ECG is a commonly used tool to identify heart rhythm disorders. As physician-based analysis of such Holter ECG is time consuming, various approaches using computerized interpretation have been developed. However, accuracy of these tools remains inferior to physician-based analysis. Thus, this study assesses the diagnostic performance of an artificial intelligence (AI)-powered Holter ECG service in comparison to results from reference databases as well as with physician-based evaluation. Methods 231 ECG recordings, covering 2,261 hours of ECG with annotations for 10,024,315 heartbeats from the following reference databases were used: MIT-BIH Arrhythmia (MITDB), American Heart Association ECG (AHDB), MIT-BIH Atrial Fibrillation (AFDB), Long Term Atrial Fibrillation (LTAFDB). Those recordings were originally collected from a mixed population of inpatients and outpatients between 1975 and 2008. Analysis of these recordings regarding the detection of QRS complexes, QRS classification and detection of Atrial Fibrillation (AF) was performed using a novel service for AI-based ECG analysis. Results were compared to the diagnosis stated within the database. QRS complex detection accuracy was performed on recordings from MITDB and AHADB by checking if time positions are within 150 ms to reference annotations. The QRS classification in three classes (normal, supraventricular, ventricular) was then compared for each detected heartbeat. Mismatches were adjudicated manually by three experts. Episodes of Atrial Fibrillation were detected in recordings from MITDB, AFDB and LTAFDB and compared to the reference episodes from the databases. The accuracy was evaluated based on the overlap with the reference annotations in the time-domain. Results Sensitivity and Precision of heartbeat detection compared to the reference databases exceeded 99% Figure 1 displays the results of heartbeat classification. Normal heartbeats were classified with a sensitivity of 99.6%, precision of 99.9% and specificity of 99.6%. For ventricular heartbeats, a sensitivity of 99.58 %, precision of 99.88 and specificity of 99.99% were achieved. Premature supraventricular contractions were recognized with a sensitivity of 99.58 %, precision of 100% and specificity of 100%. When comparing the 248,187 QRS complex classifications of MITDB and AHADB to the AI-powered analysis, 128 discrepancies were revealed. 43 were due to a discrepancy of convention as these beats were in sections that were also marked as AF episodes by the databases and the AI-powered analysis marks all beats in AF episodes as normal. Of the 85 remaining discrepancies, more than 87% were adjudicated in favor of the AI-powered analysis by the experts. Figure 2 shows the comparison of AF detection results showing Sensitivity and Precision above 99%. Conclusion AI-powered Holter ECG analysis compared to reference ECG stripes exceed 99% of sensitivity, specificity and precision.QRS complex detectionAF/ AFib detection

Arrhythmias and electrocardiographic characteristics in cancer patients treated with immune checkpoint inhibitors

Objective: To evaluate the incidence of arrhythmias and electrocardiographic (ECG) characteristics in cancer patients treated with immune checkpoint inhibitors (ICIs). Methods: This was a cohort study conducted in the Fourth Hospital of Hebei Medical University. Cancer patients initiating ICIs treatments from November 2020 to September 2022 were included in this study. Baseline 12-leads ECG before ICIs initiation and post-treatment ECG were analyzed. An abnormal ECG was defined as the presence of any of the following changes: sinus arrhythmias, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia, ventricular tachycardia, premature contractions, conduction disorder, and ST-T changes. Results: A total of 87 patients were enrolled, aged 63 (57, 68) years, with 66 (75.9%) males. And 44.8% (39/87) of patients presented with at least one confirmed cardiovascular disease or cardiovascular risk factor at baseline. The incidence of abnormal ECG increased from 31.0% (27/87) at baseline to 65.5% (57/87) after receiving (5.0±2.7) cycles of ICIs treatment (P<0.001). The incidence of sinus arrhythmias was significantly increased after ICIs treatment (23.0% (20/87) vs. 9.2% (8/87), P=0.023), of which only the incidence of sinus tachycardia was significantly increased (11.5% (10/87) vs. 2.3% (2/87), P=0.039). There was also a significantly increased incidence of ST-T changes after ICIs treatment (31.0% (27/87) vs. 17.2% (15/87), P=0.012), which mainly attributed to the T wave changes (29.9% (26/87) vs. 13.8% (12/87), P=0.001). The incidence of premature contractions was also significantly increased after ICIs treatment (9.2% (8/87) vs. 0, P=0.008). Additionally, compared with baseline, the P wave axis was significantly increased after ICIs treatment ((56.94±21.01)° vs. (52.00±22.69)°, P=0.043). After ICIs treatment, the heart rate was significantly increased ((79.07±15.37) beats/min vs. (75.64±13.37) beats/min, P=0.029). Sokolow-Lyon index ((2.21±0.81)mV vs. (2.33±0.75)mV, P=0.138), QTc interval ((431.44±36.04)ms vs. (428.00±30.05)ms, P=0.415) all showed signs of change after treatment, but did not reach the traditional significant level. Conclusions: The incidence of abnormal ECG is significantly increased after ICIs treatment, especially for sinus tachycardia, premature contractions and T wave changes; the P wave axis and heart rate is also significantly increased after treatment. It is important to perform regular ECG monitoring in patients receiving ICIs treatment.

Tachyarrhythmia during gestation: peculiarities of manifestations and clinic

Abstract Background Arrhythmias can occur during gestation. The data of peculiarities of development and manifestations of arrhythmias in pregnant women are limited. Purpose To determine the peculiarities of diagnostic and clinic in pregnant women with arrhythmias. Methods In this single-center, prospectively study we consequently included 87 cases of arrhythmias in pregnant (mean age 26.7±3.5 years, mean gestation age 24.6 ±3.3 weeks). The main types of arrhythmias and peculiarities of clinical manifestations were studed. Results In 56% of cases, arrhythmia firstly occurred during current gestation. The most common symptoms of arrhythmia in pregnant women firstly occured in the second trimester at 16 (13;21) weeks of gestation. The most common symptoms of arrhythmia were palpitations (58.6%), general weakness (52.9%), dyspnoe (34%) and dizziness (29.8%). The most common types of arrhythmias were paroxysmal supraventricular tachycardia (54%) and premature contractions (39%). Ventricular tachycardia was diagnosed less frequently – in 7%. Dynamic observation was chosen in 17% in benign course of arrhythmia. Antiarrhythmic drugs were prescribed in 32% in women with severe symptoms and haemodynamic instability. In cases of drug refractory and severe arrhythmias electrophysiological examination and radiofrequency ablation without fluoroscopy were performed in 51%. Despite different arrhythmia management the further course of gestation was benign without major complication: cases of increased incidence of uterine contractile activity and placental abruption were rare (n=2). ). Neonatal outcomes characterized by normal range of fetal birth weight and 5 minute Apgar score. There was no incidence of maternal and fetal mortality and arrhythmia recurrence after ablation in follow-up. Conclusion Arrhythmias may occur for the first time in women during pregnancy. Manifestation and recurrence of arrhythmias are observed mainly in the second trimester at 16 weeks of gestation. The most frequent variants of cardiac arrhythmias are paroxysmal supraventricular tachycardia (54%) and premature contractions (39%), which have a favorable course and prognosis.

Arrhythmias in patients with acute ST-elevation myocardial infarction induced by various risk factors during the first day after myocardial reperfusion by primary percutaneous coronary intervention

Introduction. Acute coronary syndrome, in particular acute ST-elevation myocardial infarction (STEMI), is often accompanied by complex hemodynamically significant arrhythmias and conduction disorders. Such patients have a worse prognosis compared to patients with sinus rhythm. Arrhythmias in patients with STEMI are facilitated by the presence of comorbidities such as arterial hypertension, diabetes mellitus, obesity, and post-COVID-19 syndrome. The aim of the study. To elucidate the nature of arrhythmias in patients with acute STEMI induced by various risk factors during the first day after myocardial reperfusion by primary percutaneous coronary intervention. Materials and methods. The study involved 50 patients aged 45 to 83 years (average age – 63,4 ± 9,6 years; men – 70,97 %, women – 29,03 %), who were treated during 2021-2023 at the cardiology and reperfusion therapy department of Cardio-vascular center of ʺSaint Panteleimon Hospital in Lvivʺ and the infarction department of ʺLviv Regional Clinical Cardiological Centerʺ. The patients under investigation were subjected to daily electrocardiogram (ECG) monitoring for 24 hours after stenting of the infarct-related coronary artery, using a 7-channel ECG recorder Solvaig 06000.7 with computer processing of the recording using the DiaCard2 software. The obtained material was further subjected to software packages Microsoft Excel 2022, Statistica 10. Results. It was established that among supraventricular rhythm disturbances the most common were premature contractions, the average number of which per patient was significantly higher in the presence of obesity. Similarly high it was in post COVID-19 patients, as well as in those with hypertension. In post-coronavirus infection and in hypertension cases, extrasystoles were often in the form of pairs, triplets, bigemia, and trigemia; paroxysms of supraventricular tachycardia were also recorded in these patients. Among the ventricular arrhythmias also the most frequent were premature cardiac contractions, significantly more oftenly recorded in patients with hypertension and those experienced COVID-19; only in these patients were documented extrasystoles in the form of pairs, triplets, bigeminy, trigeminy, runs of ʺR to Tʺ, which are currently considered as harbingers of life-threatening ventricular arrhythmias. In the presence of hypertension and post-COVID-19, episodes of unstable ventricular tachycardia were also observed. Conclusions. In patients with STEMI, both supraventricular and ventricular premature contractions and episodes of supraventricular and unstable ventricular tachycardia are quite common during the first day after primary percutaneous coronary intervention with infarct-related coronary artery stenting, which is evidence of myocardial electrical instability. The nature of rhythm disturbances in the presence of hypertension and post-COVID-19 is prognostically unfavorable and indicates a higher risk of lifethreatening arrhythmias in these patients. Myocardial revascularization should be supplemented with optimal medical treatment in order to prevent the adverse cardiovascular events in post-STEMI patients. Further research should be directed toward elucidation of predictive value of detected arrhythmias with respect to the occurrence of unfavorable cardiovascular events in the early and long-term post-infarction period.

Ambulatory electrocardiographic monitoring in patients with Fabry disease: study design and cohort characterization

Aim. To develop study design and analyze the characteristics of a cohort of patients with cardiac manifestations of Fabry disease (FD) in order to study the possibilities of electrocardiography (ECG) telemonitoring for screening for cardiac arrhythmias (CA), requiring a change in therapeutic tactics.Material and methods. This prospective cohort study included 11 patients (8 men and 3 women) with documented FD, with cardiac complaints and ECG signs of heart involvement. For ECG telemonitoring, non-invasive digital event recorders ECG Dongle (Nordavind-Dubna, Russia) were used. Primary endpoint was registration of CA requiring a change in therapeutic tactics (implantation of a pacemaker/defibrillator-cardioverter/prescribing anticoagulants). Secondary endpoint was dynamics of monitored parameters for operational correction of the therapeutic regimen.Results. The cohort of patients is predominantly male (73/27%; mean age, 41±13,7 years). At the time of inclusion, 8 (73%) patients received enzyme replacement therapy for 4-73 months. Most patients are active Internet users, are aware of telemedicine possibilities and are interested in remote monitoring. The main complaints were related to cardiac function interruptions, palpitations, and chest discomfort. Left ventricular hypertrophy was diagnosed on ECG in 7 (64%) patients. Echocardiography revealed symmetrical left ventricular hypertrophy in 5 patients, asymmetric interventricular septal hypertrophy in 2 patients. Other echocardiographic abnormalities included valvular heart disease (mitral and tricuspid valve prolapse with mitral and tricuspid regurgitation, presence of supplemental chords) and aortic root dilatation. Initially, the ECG was dominated by sinus rhythm (n=10); 1 patient had documented ventricular tachycardia, 4 patients had single and coupled ventricular premature contractions; supraventricular tachycardia and premature contractions in 2 patients. Four patients had a PR interval shortening without signs of accessory pathways, 1 patient — Wolff-Parkinson-White syndrome, 1 patient — prolonged QTc interval.Conclusion. For effective management of FD, additional multicenter studies are required to develop algorithms for making tactical decisions in the process of cardiac monitoring, taking into account the characteristics of the cardiovascular manifestations of this disease. The article proposes a technology for telemedicine cardiac monitoring using ECG event recorders for outpatient CA screening.

Clinical Validation of a Capacitive Electrocardiogram Cushion Utilized for Arrhythmias Monitoring

Textile capacitively-coupled (CC) electrodes have the potential of being integrated into home textiles to realize long-term cardiac surveillance, since they are more comfortable and convenient than conventional contact electrodes. Previous study mainly focused on the measurement performance of CC-based electrocardiogram (ECG) devices, but the diagnostic value of these novel devices, such as capability of supporting preliminary arrhythmia diagnosis, has not been investigated comprehensively. In this study, we proposed a CC-based ECG cushion and assessed measurement performance and diagnostic value by a clinical test on 4 healthy people and 7 arrhythmia patients. In addition to precise measurement of critical ECG structures (true positive rate of R waves: 0.994±0.006, mean absolute error of RR intervals: 1.690±1.331 ms), the proposed cushion can provide valuable information, comparable with the Holter, for cardiologists to distinguish the normal beats, ventricular beats and premature supraventricular contractions during long-term monitoring. In conclusion, the proposed cushion is verified to provide enough signal details for preliminary diagnosis of arrhythmia, as a promising system for disease screen and danger alarm of arrhythmia in certain scenario of long-term cardiac surveillance at home.

Subclinical Arrhythmias and Conduction Disturbances in Children with Myopericarditis: A 24-hour Holter Monitorization Study.

Myopericarditis is reported as a benign clinical entity in children and adolescents. However, there is no study investigating specifically the arrhythmias in these children. In the present study, we aimed to investigate the frequency of arrhythmias and conduction disturbances from surface electrocardiography and 24-hour Holter monitor, in children with myopericarditis. The medical records of the children with the diagnosis of myopericarditis between 2016 and 2021 were retrospectively reviewed. Clinical features, surface electrocardiography, and 24-hour Holter recordings were evaluated in terms of rhythm and conduction abnormalities. Mean troponin level was 7980.52 ± 14880.27 ng/L at admission. At discharge, the mean troponin level was 8.27 ± 10.73 ng/L and it was above the upper limit of normal in 19/27 (70.4%) patients. Surface electrocardiography was normal in terms of arrhythmias and conduction disturbances in all patients. Twentyfour-hour Holter monitarization was found to be normal in 23 patients. In 4 patients, there were clinically insignificant arrhythmias; nonsustained accelerated idioventricular rhythm=1, ventricular couplet with low rate=1, infrequent supraventricular premature contractions=1, and infrequent ventricular premature contractions+Wenckebach type atrioventricular block=1. Our findings support that myopericarditis is a benign clinical problem in children also in terms of arrhythmia.

Arrhythmias in pregnant women without structural heart disease: characteristics and outcomes

Abstract Funding Acknowledgements Type of funding sources: None. Background Heart rhythm disorders are relatively common in pregnant women. There are few data of arrhythmia characteristics and perinatal outcomes in patients without any structural heart disease. Purpose To describe the clinical peculiarities, pregnancy course and characterize outcomes. Methods A total of 99 pregnant without structural heart disease with arrhythmia was included, aged: 29.05±5.37years with a mean gestation age 22.7±7.29 weeks. Clinical characteristics, obstetric and neonatal outcomes were determined. Results The most common reported arrhythmias were supraventricular tachycardia (n=46; 46.5%) and premature contractions (n=36; 36.3%). Advanced heart block (n=9; 9.1%) and ventricular tachycardia (n=8; 8.1%) were rare during pregnant with structurally normal heart. The 56% of arrhythmia cases among the examined patients first occurred during current pregnancy. Studying the peculiarities of arrhythmia manifestations, it was determined that in the I trimester of pregnancy the disease symptoms appeared in 11% of the examined women, in the II trimester – in 59%, in the III trimester – in 31%. In the clinic, the most common symptoms of arrhythmia were palpitations (62.6%), general weakness (59.6%), dyspnea (38,4%) and dizziness (29.9%). Pregnancy course was benign in the majority of cases. Termination of pregnancy was in three cases (3%) – in one case due to extracardial cause, in two cases due to life threatening course of ventricular tachycardia. Premature birth was in 2 cases (2.02%). In 75% of pregnancy was vaginal delivery, in 25% - cesarean section. Preeclampsia was in 2 cases (2.02%). There were 99 live births without maternal and fetal mortality. Conclusions In pregnant women with no structural heart disease supraventricular tachycardia and premature beats are most common. Majority of patients have good course of pregnancy and outcomes.

Enhanced β-adrenergic response in mice with dominant-negative expression of the PKD2L1 channel.

Polycystic kidney disease (PKD) is the most common genetic cause of kidney failure in humans. Among the various PKD-related molecules, PKD2L1 forms cation channels, but its physiological importance is obscure. In the present study, we established a transgenic mouse line by overexpressing the dominant-negative form of the mouse PKD2L1 gene (i.e., lacking the pore-forming domain). The resulting PKD2L1del-Tg mice exhibited supraventricular premature contraction, as well as enhanced sensitivity to β-adrenergic stimulation and unstable R-R intervals in electrocardiography. During spontaneous atrial contraction, PKD2L1del-Tg atria showed enhanced sensitivity to isoproterenol, norepinephrine, and epinephrine. Action potential recording revealed a shortened action potential duration in PKD2L1del-Tg atria in response to isoproterenol. These findings indicated increased adrenergic sensitivity in PKD2L1del-Tg mice, suggesting that PKD2L1 is involved in sympathetic regulation.

Frequent supraventricular premature contractions are an independent predictor for detection of atrial fibrillation in patients with embolic stroke undetermined source

Frequent supraventricular premature contractions are an independent predictor for detection of atrial fibrillation in patients with embolic stroke undetermined source

The Effects of Different Hormones on Supraventricular and Ventricular Premature Contractions in Healthy Premenopausal Women.

Background and Objectives: The effects of gender differences on cardiac parameters have been well-established. In this study, we aimed to evaluate the possible associations of plasma levels of different sex hormones with premature atrial or ventricular contractions in premenopausal women. Materials and Methods: We conducted a prospective study which included women in late reproductive age who presented with palpitations during an eight-month period. A 12-lead electrocardiography, a transthoracic echocardiogram, blood samples, and 24-hour rhythm Holter were conducted on the third day of the menstrual cycle. Results Overall, 93 healthy premenopausal women with a median age of 42 years were enrolled. QTc interval was within normal limits in all patients. The 24 h range of premature atrial contractions (PACs) and premature ventricular contractions (PVCs) was 0–6450 and was 0–21,230, respectively. The median number of PVCs was 540 and the median number of PACs was 212, respectively. In total, 51 patients (54.8%) had a frequency of PVCs > 500/24 h and 37 patients (39.8%) had a frequency of PACs > 500/24 h, respectively. No statistically significant association was shown between any hormone and the frequency of PACs. Regarding PVCs, patients with a PVCs frequency > 500/24 h had higher estradiol levels compared to patients with PVCs less than 500/24 h (median 60 pg/mL versus 42 pg/mL, p = 0.02, OR: 1.01). No association was found between PVCs and other hormones. Conclusions: In premenopausal healthy women, higher estradiol levels are independently associated with increased PVCs. This suggests that estradiol in late reproductive stages may exert proarrhythmic effects.

Expert consensus document on automated diagnosis of the electrocardiogram: The task force on automated diagnosis of the electrocardiogram in Japan. Part 1: Nomenclature for diagnosis and abnormal findings.

As these terms should accurately represent the abnormal findings and conditions as much as possible, we propose to unify these terms into terminologies that are not confusing and easy to understand for everyone.

Diagnostics of the heart condition in ukrainian riding horses with a portable ecg monitor

Abstract. Electrocardiographic reference values of clinically healthy horses are needed for assessment of the reduced performance or cardiac pathology animals. The purpose of this study was to establish the rate of occurrence of arrhythmias in clinically healthy horses of the Ukrainian riding breed at rest, during exercises and recovery period. Experimental group of animals included 36 horses of 3 – 17-years old, 16 mares (adult female horses), 11 geldings (castrated males) and 9 stallions (adult males). The electrodes were placed with modified base-apex system on the surface of animals’s body. ECG recording was performed at rest (15 minutes), during exercises and recovery period, for 30–40 and 15 minutes, respectively. Prevalence and rate of occurrence of arrhythmias was analyzed with obtained recordings. A significant number of the second degree atrioventricular blocks were detected in 13.9 % cases (n=5) during the recovery period. 33.3 % (n=12), 8.3 % (n=3) and 19.4 % (n=7) of cases of supraventricular premature contractions were detected during exercises, at rest and during recovery period, respectively. The incidence of supraventricular premature contractions was < 3/animal and < 5/animal during exercises and recovery period, respectively; with exception for one animal which 9 and 7 premature contractions were detected, respectively. Ventricular premature contractions were identified in 2.7 % (n=1) and 5.6 % (n=2) cases, at rest and exercises, respectively. Supraventricular tachycardia with 6–9 consecutive premature contractions during trot was detected in 1 horse (2.7 %). The results of this study have confirmed the presence of arrhythmias in clinically healthy horses. The type of arrhythmias significantly depends on the period (rest, exercises and recovery) of the animal’s activity, particularly. Key words: arrhythmias, heart condition diagnostics, portable ECG-monitor, ECG records, horses

Real world data on non-complex catheter ablations performed on zero fluoroscopy in a secondary centre in the south of Belgium

Objective We have designed a study, whose aim was to confirm the feasibility and safety of the zero fluoroscopy approach in the treatment of supraventricular tachycardias (SVT) and premature ventricular contractions (PVCs) originating in the right ventricle in a secondary centre located in the south of Belgium. Methods We included in our retrospective analysis patients with a clinical history and/or electrocardiographic documentation of SVT or frequent symptomatic monomorphic PVCs referred to our centre from November 2019 to March 2020 for catheter ablation. Results A total of 49 patients were considered eligible for potential enrolment in the study, 3 were excluded because of presence of a manifest left sided atrio-ventricular accessory pathway, 5 because of left ventricular PVCs and 4 because of left atrial tachycardia. 4 patients were instead excluded because of need of utilisation of fluoroscopy during the procedure. A total of 33 patients were therefore included in the analysis. Right atrial flutters and typical AVNRT were the most common arrhythmia treated, corresponding together to the 81% of the total. Right femoral access was obtained in 86% of cases with left femoral access used in the remaining when right femoral access was not successful after the third attempt. Coronary sinus cannulation was efficacious within 10 min in 76% of cases. There were four minor complications overall. Conclusion The main finding of our study is that non-complex ablations can be performed on zero-fluoroscopy safely and with a good clinical outcome also in a secondary centre.

Hereditary Long Q-T Without Congenital Deafness (Romano-Ward) Syndrome

We report a case o fhereditary long Q-T syndrome without congenital deafness (Romano-Ward syndrome). In four members of a family, a father and his daughters, the Q-T intervals on the EKG were found to be prolonged. There were no other accompanying familial anomalies such as deafness or a tendency to extracellular hypokalemia The youngest daughter which had the longest. Q-T interval had several Adams-Stokes attacks, and died in the last attack at the age of 23 months. Her two older siblings died at the age of 15 and 10 months with the same typical clinical histories. The eldest daughter, a 12-year old girl, has no clinical symptoms at all, while the fourth child, 5-yeltr old girl has several occasions of near fainting attacks. The EKG of the father showed several runs of supraventricular premature contractions that ceased spontaneously, besides evidence of the prolongation of Q-T interval. The beta-adrenergic blocking drug (propranalol) given in a relatively small maintenance dose, proved to be effective in preventing attacks of the father and the fourth child, despite the unchanged prolongation of the Q-T interval.

Features of circadian regulation and cardiac rhythm disorders in patients with arterial hypertension and frequent recurrences of atrial fibrillation

The aim — to determine the features of circadian regulation and cardiac rhythm disorders according to Holter monitoring of electrocardiogram (HM ECG) in patients with arterial hypertension (AH) and frequent recurrences of atrial fibrillation (AF), depended on the clinical form and vegetative variant of arrhythmia.Materials and methods. There were examined 146 patients aged from 37 to 86 years with AH stage II complicated by frequent recurrences of AF. As a comparison group, 26 patients were examined aged 39 to 74 years with AH II stage without AF, that was ruled out with anamnesis data and HM ECG. The duration of the arrhythmic anamnesis ranged from 1 to 30 and mean duration was 5.7 ± 0.5 years. Paroxysmal form of AF was in 56 (38.4 %) patients and persistent form of AF was in 90 (61.6 %) patients. The anamnesis of AH ranged from 1 to 40 and mean duration was 11.6 ± 0.6 years. All patients underwent HM ECG according to the standard protocol.Results and discussion. In groups with AH and AF in contrast to group without AH, the total number of supraventricular premature contractions (SPC) per day was higher (p < 0.0001). In the groups with AH and AF there was the prevalence of the pair and group of SPC (p < 0.0001). Short asymptomatic episodes of supraventricular paroxysmal tachycardia (SVPT) were defined in 35.7 % of patients with paroxysmal and in 33.3 % of patients with persistent AF. SVPT wasn’t defined in group with AH (p < 0.001). The analysis of painless myocardium ischemia cases demonstrated statistically significant differences in such cases registration in patients with persistent AF comparing with patients without AF (38.9 and 19.2 % respectively; p = 0.05). The dispersion of the interval QT was significantly higher in the groups of patients with AF in comparison with group without AH (p < 0.05). The ratio of the dispersion PQ/QT was lower in groups of AH and AF compared with the group of AH (p < 0.05).The daily heart rate (p < 0.04) and the circadian index (CI) (p = 0.02) are significantly lower and the mean daily number of asymptomatic SVTS episodes is significantly higher (p < 0.04) in patients with vagal variant of AF. In patients with mixed variant of AF the value of CI (p < 0.05), the daily amount of SPC (p < 0.04) and the number of episodes of paired and group SPC (p < 0.04) are significantly higher.Conclusions. In groups of AH and AF in comparison with group owithout AH, the number of SPC, paired and group SPC, SVPT were higher, increasing of the dispersion of QT and dispersion ratio PQ/QT was observed. The study did not reveal any fundamental differences between clinical forms of AF. The heart rate and CI are significantly lower and the number of asymptomatic episodes of the SVTS is significantly higher in patient with vagal variant of AF. The CI value, daily amount of SPC and episodes of paired and group SPC were significantly higher in patients with mixed variant of AF.

Postimplantational atrial fibrillation in patients of older age categories with nonischaemic cardiac event

The purpose and the objectives of the research were the study of the course nature of postimplantational atrial fibrillation (AF) in patients of older age categories and the identification of individual links of its pathogenetic structures. We examined 387 patients aged 65-80 years with an implanted cardiac pacemaker. The object of the study included 46 (12 %) individuals (30 males and 16 females) with nonischemic postimplantational atrial fibrillation, with no signs of stenosing atherosclerosis of coronary arteries among all the patients. Postimplantational AF in the elderly is characterized by the symptoms of dizziness, nonischemic pain in the precardiac area, shortness of breath, fatigue on physical exertion, predominantly supraventricular premature contraction, diffuse changes, myocardium hypertrophy and dilatation of the cavities of the left heart, diastolic dysfunction of the left ventricle, different classes of ventricular arrhythmias, pulmonary hypertension, the presence of degenerative changes of the heart valves. In patients of older age groups with postimplantational AF a complex multifactorial set of pathological disorders is formed which is manifested by the changes in the rheological properties of blood (hyperviscosity, hyperaggegation of formed elements), the state of protein and lipid metabolism and myocardial remodeling, the presence of systemic inflammation and endothelial dysfunction of the vessels.

O072. An uncommon case of sinusal arrest in Cluster Headache.

It is well known how migraine attacks are strictly associated to abnormalities of cardiac rhythm. Aygun et al[1] have studied 30 patients during migraine attacks, observing abnormalities of rhythm (including sinus arrhythmia, atrial premature contraction and ventricular premature contraction), intervals greater than 0.2 seconds, corrected QT intervals greater than 0.44 seconds, T inversion and ST-segment abnormalities. However, the role of autonomic nervous system variations in migraine attack-related electrocardiographic changes remains uncertain. Moreover, in patients with migraine parasympathetic nervous system alterations were observed during normal daily activity in the headache-free period[2]. In July 2015, a 45-year-old man was referred to us for evaluation because of a recurrent migraine associated with bradycardia. He referred recurrent migraine attacks, frequently occurring at night and in the supine position. During the acute phases of the attacks he described bradycardia, and sometimes, thoracic oppression. Furthermore, our patient told us about a clinical history of panic attacks and renal colics with syncope. He is currently taking topiramate and oxygen therapy at high doses (15 lt/min) during attacks. In order to better understand the previous episodes of syncope and the phases of bradycardia occurrence during the pain attacks, we monitored his electrocardiogram for 24h. During the 24h registration, he had three attacks of migraine preceded by warning signs, one of them at night time. Analyzing the ECG, we observed sinusal rhythm, medium CF 74 bpm (28-115 bpm), normal PR interval, rare supraventricular and ventricular premature contractions. In correspondence to the migraine attacks, we observed sinus bradycardia and sinus pauses with RR maximum interval of 5.5 seconds, sometimes with the occurrence of junctional rhythm, without loss of consciousness. Considering the results of this monitoring, we decided to implant a pace-maker. This case demonstrates the importance of autonomic dysregulation in a patient with migraine, showing the need of further studies to better understand the phenomenon. Written informed consent to publication was obtained from the patient(s).

Method for classifying cardiac arrhythmias using photoplethysmography.

Advances in mobile computing and miniature devices have contributed to the accelerated development of wearable technologies for clinical applications. The new trend of wearable technologies has fostered a growth of interest for sensors that can be easily integrated into wearable devices. In particular, photoplethysmography (PPG) is especially suitable for wearable sensing, as it is low-cost, noninvasive, and does not require wet electrodes like the electrocardiogram. Photoplethysmograph signals contain rich information about the blood pulsating variation which is strongly related to the electrical activities of the heart. Therefore, in this paper we hypothesize that the ambulatory PPG monitoring could be employed for arrhythmia detection and classification. This paper presents a method for classifying ventricular premature contraction (VPC) and ventricular tachycardia (VT) from normal sinus rhythm (NSR) and supraventricular premature contraction (SVPC) recorded in patients going through ablation therapy for arrhythmia. Although occasional VPCs are benign, the increase in the frequency of VPC events may lead to VT, which in turn,could evolve into ventricular fibrillation and sudden cardiac death. Therefore the accurate measurement of VPC frequency and early detection of VT events becomes essential for patients with cardiac disease.

Chuckwagon Field Study on 148 Horses: Racing Consecutive Days Affects Baseline Blood Electrolytes, pH and Lactate But Does Not Increase the Prevalence of Cardiac Arrhythmias

IntroductionChuckwagon racing involves 4 Thoroughbred horses pulling a 600 kg wagon through a figure‐8 pattern and running a 1000 m dash. Horses can race four days in a row and there are concerns regarding the contribution of cumulative racing to electrolyte imbalances, arrhythmias, and sudden death, and its impact on recovery. The objective was to investigate the effects of cumulative racing on plasma electrolytes, lactate and prevalence of cardiac arrhythmias.Methods148 horses (9.0 ± 2.7 years) from 13 teams were monitored for heart rate and ECG activity on racing days 1 and 2. Differences in plasma electrolytes, pH and lactate (pre‐vs. post‐exercise and between days) were analysed (paired t‐test). Associations between electrolytes and the presence of arrhythmias during racing and recovery (Pearson correlation) were examined.Results377 ECGs (82 incomplete due to lost electrode) and 750 plasma samples (374 pre, 376 post) were analysed. 4235 arrhythmic events (21.6% warm‐up, 37.6% racing, 20.4% recovery) were recorded and were not different between days 1 and 2. They mainly comprised supraventricular premature contractions during warm‐up and racing (48% and 81.4% respectively) and ventricular premature contractions during recovery (29.2%). A significant association was found between post‐exercise electrolytes and the presence of arrhythmias during racing (P&lt;0.001, r = 0.17). Consecutive racing significantly increased post‐exercise lactate on day 2 (P&lt;0.001). Pre‐exercise pH and electrolytes were significantly different on day 2.ConclusionsAn association exists between post‐exercise electrolytes and occurrence of arrhythmias during consecutive racing, however it is of little clinical significance. Ventricular arrhythmias are as prevalent in chuckwagon horses as in other disciplines. Overall, repetitive racing is well tolerated.Ethical Animal ResearchThe study was approved by the Veterinary Sciences Animal Care Committee of the University of Calgary (AC120049) and owner informed consent was obtained. Sources of funding: Clinical Research Fund from the University of Calgary's Faculty of Veterinary Medicine. Summer Studentships were funded by NSERC. Competing interests: none.