Premature Contractions Research Articles

Precipitate, preterm labor in acute organophosphate poisoning in pregnancy: A case report

Introduction: Acute organophosphorus poisoning (AOPP) during pregnancy is uncommon. When complicated by preterm labor, it presents therapeutic dilemmas due to the lack of established guidelines. Case Presentation: We describe a case of a 19-year-old primigravida at 33 weeks of gestation with AOPP. During her treatment, she unexpectedly experienced preterm, precipitate labor, resulting in the delivery of a live, healthy baby. Discussion: Late-pregnancy exposure to organophosphates may trigger preterm labor through receptor hyperstimulation from excess acetylcholine, causing premature contractions. Atropine, progesterone, and magnesium sulfate may help manage these effects. Conclusion: This case underscores the importance of vigilance and frequent clinical examinations in patients with AOPP to identify subtle early signs of potential complications.

Holter Monitoring Analysis of Women Infected with the Human Immunodeficiency Virus.

The aim of the study was to assess the clinical features of women infected with the human immunodeficiency virus (HIV) using Holter monitoring. Thirty-five female patients infected with HIV using a Holter monitor at the Ditan Hospital were retrospectively analyzed. In terms of basic rhythms, there were 30 cases of sinus rhythm, 27 cases of ventricular premature beat, 26 cases of supraventricular premature beat, 12 cases of mild reduction of HRV, 9 cases of normal heart rate variability (HRV), 8 cases of supraventricular tachycardia, 5 cases of abnormal ST-segment changes and 2 cases of sinus bradycardia 2 cases of paroxysmal atrial fibrillation 2 cases of junctional escape rhythm. There was only one case in each of the following ECG changes: persistent atrial fibrillation, sinus tachycardia, couplet supraventricular premature beats, accelerated idioventricular rhythm, sinoatrial block, second-degree Mobitz type I atrioventricular block, second-degree Mobitz type II atrioventricular block, complete right bundle branch block, T-wave abnormality, and significant reduction of HRV. The Holter monitor can show more changes in the electrocardiogram (ECG) of HIV-- positive patients, particularly significant ECG abnormalities, such as paroxysmal atrial fibrillation, and can direct early clinical treatment to serious adverse results.

Clinical and genetic analysis of a case of Triadin knockout syndrome due to variant of TRDN gene and a literature review

To explore the genetic etiology and clinical phenotype of a child with Triadin knockout syndrome (TKOS), and to review the relevant literature of TKOS patients due to variants of TRDN gene. A child who was admitted to the Children's Hospital of Xi'an Jiaotong University on March 19, 2023 due to sudden cardiac arrest 3 days earlier was selected as the study subject. Peripheral blood samples (2 to 3 mL) were collected from the child and her parents for the extraction of genomic DNA and whole exome sequencing (WES). Pathogenic variants were searched from databases such as the Genome Aggregation Database (gnomAD) and Online Mendelian Inheritance in Man (OMIM), and were assessed based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). Sanger sequencing was carried out for family validation of the pathogenic variants. Using keywords such as "arrhythmias" "TRDN" and "Triadin" both in Chinese and English, relevant literature on TKOS patients due to variants of the TRDN gene was retrieved from the CNKI, Wanfang Data Knowledge Service Platform, and PubMed databases, and the time of literature retrieval was set from January 1, 2012 to December 1, 2023. This study has been approved by the Ethics Committee of the Affiliated Children's Hospital of Xi'an Jiaotong University (No. 20230097), and informed consent was obtained from the parents of the child. The child had experienced syncope and cardiac arrest after exercise. Electrocardiographic examination revealed QTc interval prolongation, T-wave inversion in precordial leads V1-V3, polymorphic ventricular premature beat (VPB), and ventricular tachycardia (VT) along with increased heart rate. WES and Sanger sequencing revealed that the child has harbored a homozygous c.463del(p.E155Kfs*20) variant of the TRDN gene, for which both of the parents were heterozygous. Based on the guidelines from the ACMG, the variant was classified as pathogenic (PVS1+PM2+PM3). The child was ultimately diagnosed with TKOS. In total 12 publications on TOKS cases caused by TRDN gene variants were retrieved, which involved 30 patients and 28 carriers of single heterozygous variant of the TRDN gene. Among the 30 TKOS patients, 20 had carried homozygous variants of the TRDN gene, and 10 had carried compound heterozygous variants, and all had exhibited significant clinical phenotype of arrhythmia, with most cases had experienced malignant arrhythmia induced by exercise and/or excitement during infancy or early childhood, leading to recurrent syncope and cardiac arrest. Of note, none of the 28 carriers of single heterozygous variant had abnormal clinical phenotype. The homozygous c.463del(p.E155Kfs20) variant of the TRDN gene probably underlay the pathogenesis of cardiac arrest in this child. Above discovery has enriched the mutational spectrum of the TRDN gene.

Prevention of Atrial Fibrillation using Vaughan Williams Class IC Drugs for Multiple Premature AtrialContractions: A Clinical Observational Study

Background: Atrial fibrillation (A-Fib) poses a significant clinical challenge, particularly in the elderly and those with hypertension. If A-Fib represents one stage in the spectrum of electrical degeneration caused by aging-induced remodeling of the left atrial wall, catheter ablation is not an essential treatment. The efficacy of Vaughan Williams Class IC drug in preventing the progression of multiple premature atrial contractions (mPAC) toward paroxysmal atrial fibrillation (PAF) and A-Fib in the earlier stage of histological change was investigated. Method and results: Group A (4 patients with mPAC) and Group B (9 patients with PAF) were treated with Class IC drugs. Treatment outcomes were compared between these two Groups and Group C (8 patients with chronic A-Fib). Follow-up assessments were performed to evaluate the maintenance of sinus rhythm. All mPAC patients maintained sinus rhythm during the follow-up period. In the PAF group, 8 out of 9 patients maintained their sinus rhythm. Conclusion: Early treatment with Class IC drugs shows promise in preventing the progression of A-Fib and maintaining sinus rhythm in patients with mPAC and PAF. These findings highlight the potential role of pharmacological therapy in delaying the onset of A-Fib, thereby improving clinical outcomes and reducing the need for invasive procedures such as ablation.

The Prognosis of Idiopathic Premature Ventricular Beats in Children with Structurally Normal Hearts.

The objective of this study is to evaluate the prognosis of idiopathic premature ventricular beats (PVBs) in children. We retrospectively evaluated 73 children (<18 years old) with idiopathic PVBs and structurally normal hearts. All patients were evaluated by 24-hour Holter electrocardiography (ECG) and echocardiography at the first admission and followed with a mean of 27 ± 7.6 months after diagnosis. Baseline Holter ECG and echocardiographic findings were compared to the last visit. The mean age of the patients was 11.1 ± 4.8 years, and half were symptomatic at initial examination. Baseline Holter showed complex beats in 35 cases, non-sustained ventricular tachycardia in 7 cases, and frequent PVBs in 19 cases. Complete recovery (CR) of PVBs was observed in 37 cases (50.7%) at a median of 15 (minimum: 5, maximum: 33) months after diagnosis. There were no significant differences in CR rates between patient groups with left bundle branch block (LBBB) vs. right bundle branch block (RBBB) morphology of PVBs, simple vs. complex PVBs, and daytime vs. nighttime dominance of PVBs (P > .05 for all parameters). The CR rate of PVBs was different among patients with infrequent, moderate, and frequent PVBs (62.8%, 36.4%, and 31.6%, respectively). Premature ventricular beats disappeared more often during follow-up in patients with infrequent PVBs (P = .045). However, the absolute decrease and disappearance rates of PVBs were similar across all groups (72.1%, 81.8%, and 89.5%, respectively; P = .319). The resolution rates of PVBs were not statistically different between the patient group who received pharmacological treatment and the group who followed up without treatment (P = .070). No myocardial dysfunction was observed in any patient during follow-up. No cases experienced major cardiac events. Idiopathic PVBs usually regress in childhood regardless of frequency and complexity or receiving antiarrhythmic medication. The risk of ventricular dysfunction is low during childhood; however, they require careful evaluation and follow-up.

Heart Rate and Rhythm Changes in Dogs Treated in a Hyperbaric Oxygen Chamber

In veterinary medicine, hyperbaric oxygen chamber treatment (HBOT) is gaining popularity. Therefore, an increasing number of patients referred for this therapy are being recorded, mainly due to ischemic events, wound healing support, and a high risk of reperfusion damage. During the HBOT procedure, several changes occur in the body’s micro- and macroenvironments. This study involved 34 dogs of various ages and health statuses. The atmospheric conditions in the test hyperbaric chamber included a pressure of 1.5 atmosphere absolute (ATA) at 100% oxygenation. The individuals were divided into three groups: (1) individuals with degenerative mitral valve disease (DMVD), (2) individuals with diseases other than cardiac issues, and (3) healthy individuals who qualified for the HBOT procedure. The period of measurement using the Holter apparatus was divided into four stages: 30 min before the subject’s placement in the hyperbaric chamber; a 4-min compression period (setting chamber conditions); a 90 min HBOT period; and a 1 min decompression period of the hyperbaric chamber. During the HBOT, there was a statistically significant decrease in heart rate in groups 2 and 3 compared to group 1. The heart rate in group 1 remained unchanged through every period of the study. In addition, some of the dogs developed respiratory arrhythmia; in two dogs, premature ventricle beats occurred. The changes observed during the ventricular period indicate that the HBOT procedure causes a significant change in heart rate in dogs without cardiac diseases.

A prospective analysis of the efficacy and safety of ethacizine during premature atrial contractions and premature ventricular contractions

Abstract Background Ethacizine, a class Ic antiarrhythmic agent, is prescribed for managing severe or refractory supraventricular and ventricular arrhythmias, including premature atrial (PACs) and ventricular contractions (PVCs). Despite its use, there is a lack of substantial research exploring the therapeutic effects of ethacizine at present. Purpose The study evaluated the efficacy and safety of ethacizine in addressing PACs and PVCs, in cases where other antiarrhythmic medications proved ineffective. Methods We performed a prospective analysis of ethacizine treatment (50 mg. b.i.d.) for early (30-45 days) and late periods (150-210 days), in male (n=58; 59.2%) and female (n=40; 40.8%) patients aged ≥ 18 years (18-72 y.o; mean age 45 years), with 46 cases of PACs and 52 cases of PVCs, who had previously been treated with another antiarrhythmic medication (bisoprolol, metoprolol, sotalol, verapamil, amiodarone, or propafenone) and had not achieved the target rate of extrasystoles (≤1000/24h). Results The findings reveal a substantial decrease in the mean parameters of PACs during both, the early period (initial 6877 ± 2432, following 761 ± 341); (88,9%); t([45]) = [13,336], p = [&amp;lt; .001) and the late period (initial 6877 ± 2432, following 574 ± 294); (91,7%); t([45]) = [15,124], p = [&amp;lt; .001). The quantitative reduction in PACs reached a maximum of 93.8% in the early period (19406 PACs □ 1211 PACs) and 94.3% in the late period (19406 PACs □ 1105 PACs). The mean parameters of PVCs in the early period experienced a significant reduction (initial 3205 ± 1145, following 550 ± 194); (82,8%); t([51]) = [8,284], p = [&amp;lt; .001). Similarly, the mean PVC values in the late period exhibited a noteworthy decrease (initial 3205 ± 1145, following 490 ± 181); (84,8%); t([51]) = [8,553], p = [&amp;lt; .001). For PVCs, the maximum effect observed in the early period was 94.8% (18929 PVCs □ 989 PVCs), and in the late period, it reached 95% (18929 PVCs □ 950 PVCs). The target rate in the late period (≤1000/24h.) for PACs reached 89%, and for PVCs - 86% (Figure 1). Adverse effects were noted in a mere four subjects (4%). These events manifested as 2nd-degree AV block (Mobitz 1), sustained ventricular tachycardia, asymptomatic nonsustained polytopic ventricular tachycardia, and asymptomatic transient ST-segment elevation observed through 24-hour ECG holter monitoring. Conclusion A prospective study on ethacizine treatment (50 mg. b.i.d.) confirmed its effectiveness and safety in reducing PACs and PVCs. It demonstrated a sustained reduction in extrasystole occurrences for an extended period, achieving the target rate with minimal side effects. Ethacizine merits consideration for addressing extrasystolic arrhythmia, particularly in cases where other antiarrhythmic medications prove ineffective.Results of the study

Significance of J wave with inverted ST-T polarity induced by ill-timed atrial premature beats and its association with Torsade de Pointes in patients with acute acquired long QT syndrome

Abstract Background When ventricular cardiomyocytes become depolarized during their relative refractory period (RRP), the amplitude of the action potential (AP) becomes lower than that of preceding AP, since some sodium channels are in their refractory state. If the membrane voltage does not reach a level high enough to activate voltage-dependent calcium channels, the AP duration becomes markedly shortened due to loss of AP dome. In patients with long QT syndrome (LQTS), intrinsic differences in AP duration and/or AP restitution kinetics exist between ventricular endocardium and epicardium. Thus, we hypothesized that atrial premature beats (APBs) can capture the RRP and amplify a transmural voltage gradient that manifests as a J wave with inverted ST-T polarity (APB-induced J wave). Purpose To investigate the prevalence of APB-induced J wave and examine the contribution to the development of Torsade de Pointes (TdP) in patients with acute acquired LQTS. Methods A total of 34 consecutive patients with acute acquired LQTS (14 men; median age, 69 years; median QTc, 645.5 ms) and documented TdP were enrolled. APBs were observed before the onset of TdP in 18 (52.9%) patients. The 34 patients were divided into 2 groups based on the presence or absence of APB-induced J wave with inverted ST-T polarity: APB-J wave group (n=8) and non-APB-J wave group (n=26). Results APB-J wave group constituted 23.5% (8/34) of the studied patients. There were no significant differences in clinical characteristics (sex, age and QTc) between the 2 groups. Macroscopic T-wave alternans was more frequently observed before TdP onset in APB-J wave group than non-APB-J wave group (75% vs 15.4%, p=0.003). The ill-timed APBs with J wave directly initiated TdP in all patients in APB-J wave group. APB-J wave group experienced TdP even after initiating conventional therapy more frequently than non-APB-J wave group (3.5 vs 1 event, p=0.04). Conclusions APB-induced J wave is observed in approximately one-fourth of acute acquired LQTS patients with TdP and is associated with an increased risk of TdP. Our observations suggest that APBs can amplify the transmural dispersion of repolarization manifested as a J wave.Figure1Figure2

A multilabel deep learning model for the detection of conduction and rhythm disorders from PDF outputs of a widely available portable ECG Device

Abstract Background Wearable and portable devices with ECG capabilities can provide broad access to screening for cardiovascular disorders. However, most are approved for the detection of only atrial fibrillation. Most algorithms for detecting rhythm and conduction disorders are trained and tested on 12-lead ECGs or the lead I of clinical ECGs, with an unclear role for extending the diagnostic range of wearable and portable devices. Moreover, no current algorithms enable cardiovascular diagnosis on data available to end users, who largely have access to the PDF outputs of their data. Purpose To validate a novel artificial intelligence (AI) model trained to identify conduction disorders and arrhythmias on synthetic ECG outputs from lead I data of clinical ECGs, to detect the same disorders on cardiologist-annotated PDF outputs from the Alivecor KardiaMobile single-lead ECGs (Kardia ECGs). Methods We extracted lead I data from 3,076,352 clinical ECGs across 5 hospitals of a large U.S.-based hospital system from 2000-2024 and simulated wearable PDF outputs from commercial devices using a novel plotting approach that replicated the variations in plotted formats. Gold-standard cardiologist written diagnosis statements were processed to generate 8 clinical labels spanning conduction and rhythm disorders, and we developed a multilabel model to predict these labels using an EfficientNet-B3 convolutional neural network. We examined the performance of the model on 24,808 Kardia ECGs annotated by cardiologists. Results The model achieved a high performance on clinical ECGs in a held-out subset of the synthetic lead I ECG printouts resembling wearable outputs (AUC &amp;gt; 0.9 for all 8 labels). In the independent 24,808 Kardia ECGs, annotated by experts, the model achieved high performance across all labels. For the rhythm disorders atrial fibrillation or atrial flutter, premature atrial contraction, and premature ventricular contraction, the model had AUROCs of 0.99, 0.91, and 0.95, respectively. For the conduction disorders 1st-degree AV block and 2nd or 3rd-degree AV blocks, the model had AUROCs of 0.94 and 0.99, respectively. Finally, for supraventricular tachycardias, wide QRS, and paced ECGs, the model had AUROCs of 0.998, 0.98, and 0.98, respectively. Conclusions We demonstrate that a deep learning model trained to identify rhythm and conduction disorders based on synthetic ECGs where lead I data from clinical 12 lead ECGs are used to replicate real-world PDF outputs of wearable ECGs, generalizes to real-world wearable and handheld single-lead devices.

Incidence and characteristics of premature ventricular beats in competitive athletes at preparticipation exercise testing

Abstract Introduction The European Society of Cardiology preparticipation screening (PPS) protocol for athletes includes history, physical examination and resting ECG only. However, adding exercise testing (ET) aimed at evaluating ventricular arrhythmias (VAs) inducibility may increase the chances to identify cardiac diseases at-risk of sudden death that would otherwise be missed. Recent studies showed that the risk that premature ventricular beats (PVBs) at ET are associated to an underlying disease depends not just on their number but on characteristics such as morphology and complexity. However, there are no data on the incidence of at-risk PVBs at ET, thus requiring further tests to rule-out a cardiac disease, in apparently healthy athletes. Aim To assess the incidence and characteristics of VAs in a cohort of apparently healthy athletes undergoing annual PPS including ET. Methods We included a consecutive series of 1431 (24±13 year-old, 75% males) competitive athletes who underwent PPS in 2023. According to the Italian law and national guidelines, PPS must include ET with a different protocol according to age: in athletes younger than 35 years (81% of the study group) a rapid constant-load ET target at evaluating VAs inducibility was performed while in athletes older than 35 years a standard incremental ET was carried out. PVBs recorded during ET were assessed in terms of morphology, complexity and response to exercise. Results the incidence of at least 1 PVB was 14.5%, with a statistically significant increase according to age (p&amp;lt;0.001, Figure). If only athletes with frequent (at least 5 isolated PVBs) or complex (at least 1 couplet/triplet/NSVT) VAs are considered, the incidence was 4.3%, still with a significant increase according to age. In particular, among athletes older than 35 years, the incidence of PVBs was 34.1% and of frequent/complex PVBs was 15.2%. As shown in the table and figure, more than half of athletes with PVBs showed at-risk features such as persistence/increase (rather than suppression) of VAs during exercise and an "uncommon" morphology (i.e. different than infundibular or fascicular). Conclusions PVBs during ET for preparticipation screening occurred in a sizeable proportion of athletes, particularly in those older than 35 years, and many showed at-risk features such as complexity, uncommon morphologies or exercise-inducibility. Despite VAs at ET may be the only sign of a disease at risk of sudden death, their high incidence may substantially impact on the need for further investigations after PPS. Hence, more efforts should be put to identify which PVBs characteristics are predictive for an underlying cardiac disease, particularly in master athletes.

Prevalence of cardiomyopathies and myocardial scar in patients with non-complicated premature ventricular beats: a CMR study

Abstract Introduction Frequent or symptomatic premature ventricular beats (PVBs) in subjects with no personal or family history of cardiac disease or sudden death is a recurrent motive for cardiac magnetic resonance (CMR) prescriptions. This represents a significant burden on healthcare services, given the low availability of CMR technique. If CMR is a recommended imaging modality in patients with history of cardiac arrest due to ventricular arrhythmia, sustained ventricular arrhythmias or when first-line tests are abnormal, its diagnostic value in this specific setting has not been evaluated. Purpose To determine the prevalence of significant CMR abnormalities (myocardial fibrosis, arrhythmogenic cardiomyopathies) in patients with no personal nor family history of cardiac disease and non-complicated PVBs. Methods Between September 2010 and July 2021, 416 healthy adults with no personal nor family cardiac disease history underwent CMR at our institution to explore non complicated PVBs, and were retrospectively included (Figure 1). Right and left ventricular (RV/LV) function and dimensions were systematically evaluated on CMR, as the presence of myocardial late gadolinium enhancement (LGE). Criteria for cardiomyopathies (hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), ARVD), the presence and location of myocardial fibrosis were looked after. Results A total of 605 patients were referred for CMR to explore frequent PVBs, representing 14% of all tests performed during this period. Among them, 12 patients (3%) presented significant myocardial abnormalities possibly related to PVBs: 2 patients had sequelae of myocardial infarction and 3 of myocarditis, 1 patient had criteria of HCM and 1 of ARVD, finally 5 presented non-specific myocardial fibrosis (septal mid-wall LGE). In addition, after a mean follow-up of 5 years, there was no death in patients with abnormal CMR, and only 2 patients underwent transcatheter ablation for focal non complicated but symptomatic PVBs. There was no hospitalization for heart failure. Conclusion In patients with non-complicated PVBs and no history of cardiac disease, the rate of cardiomyopathy pattern or myocardial scar on CMR is very low (3%). In this specific population, events were very rare: frequent isolated PVBs, even when associated with myocardial abnormalities, were a benign condition in our study. Given the high volume of patients referred for this indication in daily practice (14% of total CMRs in our center), the limited availability and high costs of CMR, and the difficulties of CMR sequences acquisition in the context of frequent PVBs (possibly leading to misdiagnosis), these data suggest that we should refine the selection of patients undergoing CMR for PVBs exploration.

Characteristics associated with prevalent atrial fibrillation and risk profile for future atrial fibrillation among those in sinus rhythm in an elderly population in the ELSA Brasil Study

Abstract Background Atrial fibrillation (AF) is an arrhythmia that can lead to limiting symptoms and increases the risk of stroke and heart failure (HF). Purpose To evaluate the association of clinical, electrocardiographic, and echocardiographic parameters with prevalent AF or flutter (AFF), and the risk profile for future AFF according to Charge-AF and EHR scores in an elderly population. Methods The ELSA-Brasil is a prospective cohort study designed to investigate cardiovascular disease and diabetes in 15,105 men and women, civil servants from universities or research institutions in six cities of Brazil. We included all participants in ELSA-Brasil aged 60 and over whose diagnosis of AFF could be assessed and had echocardiography performed at the study's baseline. From the initial sample with participants ≥ 60 years (n = 3,263), 400 participants were excluded due to missing data about AFF, and 775 who did not have echocardiographic studies. Results There were 88 (4.2%) participants with AFF at baseline among the 2,088 (65 ± 4.1 years; 53% women) included in this analysis. Those with AFF were older (66.8 ± 4.4 vs 65 ± 4.0 y-o) and had a higher prevalence of HF (16% vs 3.1%), previous myocardial infarction (14.8% vs 3.8%), left bundle branch block (LBBB: 4.6% vs 0,9%), prolonged QT interval (7.9% vs 2.0%), supraventricular extrasystoles (4.6% vs 1.2%), and sinus bradycardia (11.3% vs 2.9%). AFF individuals also presented larger left atrial volume index - LA (33.3 mL/m2 versus 27 mL/m2), left ventricular end-diastolic diameter (4,63 ± 0,6 cm versus 4,47 ± 0,4 cm) and lower left ventricular ejection fraction (LVEF: 63.6 ± 9.1% vs 67.4 ± 6.4%) that non-AFF (all p-values &amp;lt;0.05). In multivariable analysis, prevalent HF, LBBB, larger LA, and lower LVEF were independently associated with the presence of AFF. Among those in sinus rhythm at study baseline, both risk models showed that most individuals in our sample were at low risk. In the Charge-AF, 63% of individuals were identified as presenting low risk (&amp;lt;2.5%), and 12% of the sample was categorized as high risk, with a risk of five-year AFF greater than 5%. Similarly, in the EHR, 67% of participants were classified as low risk, and 13% were considered high risk. Conclusion We found that AFF was present in 4.2% of the subset of older participants in a cohort composed of free-living individuals in Brazil. The presence of AFF was associated with HF history, altered cardiac electrical activity, LA dilation, and worse LV systolic function. Among those with sinus rhythm, 12-13% were considered at high risk of developing AFF (&amp;gt; 5% in five years) based on two clinical scores. Clinical surveillance and monitoring of electrocardiography and echocardiography parameters may help the early identification of risk factors for AFF.

Clinical characteristic and zero-fluoroscopy ablation outcomes of tachyarrhythmias in pregnant: a single center study

Abstract Background Although recommended avoid any intervention during gestation in cases of drug refractory of arrhythmias catheter ablation may be necessary in pregnant women. Purpose To present clinical characteristics and outcomes of zero-fluoroscopy catheter ablation during gestation. Methods This prospective, single center study included 84 cases of tachyarrhythmias during gestation. In 44 cases of drug refractory was performed catheter ablation without fluoroscopy (main group). We evaluated the further course of gestation and obstetric outcomes after ablation in comparison with pregnant with antiarrhythmic therapy of tachyarrhythmias (n=40, control group). Results Both groups were comparable by mean age of pregnant (28.2±4.2 vs. 27.3±3.9 years, p=0.093) and mean duration of gestation (24 ±3.4 vs. 23.8 ±3.2 weeks, p=0.123). New onset arrhythmia prevailed in both groups (64% vs. 55%, p=0,280). Supraventricular tachycardia was the most common arrhythmia during gestation (81,8% vs. 52,5%, p=0,005), which was followed by premature contraction (13,6% vs. 40%, p=0,007). Cases of ventricular tachycardia were rare (4,6% vs. 7,5%, p=0,665). Ablation was performed under the guidance of CARTO (45%) and Ensite Precision systems (55%) without using fluoroscopy in all cases. Acute procedural success of zero-fluoroscopy ablation was in 100% with mean procedural time 71±17 minutes without any complication. Outcomes: further course of gestation characterized by increased incidence of uterine contractile activity and placental abruption only in main group (4,54%, p=0.464 and 2.3%, p=642 respectively). There were no differences in the rate of other complication: uterine blood flow violation (15.9% vs 12.9%, p=0.234) and preeclampsia (4.55% vs 5%, p=0.237). Vaginal type of delivery was in the majority of cases in both groups (82% vs 83%, p=0.242). Neonatal outcomes characterized with normal range of fetal birth weight (median 3207,39±485,61 vs. 3312,3±234,1 grams, p=0.709) and 5 minute Apgar score (median 8,4±1,6 vs. 8,7±1,2, p=0.921). There was no incidence of maternal and fetal mortality. In 12 month, follow-up all there was no arrhythmia recurrence. Conclusions Zero-fluoroscopy ablation of tachyarrhythmias in pregnant is feasible and can be safety performed during gestation in cases of drug refractory with benign outcomes.

Atherosclerotic coronary artery disease prevalence in master athletes exhibiting exercise-induced ventricular arrhythmias: relevance for preparticipation screening

Abstract Background Coronary atherosclerotic disease (CAD) is the leading cause of sudden cardiac death among master athletes (≥35 years). During pre-participation screening (PPS), the primary indication for investigating CAD in these population is ST-segment depression (STD) at exercise test (ET). Additionally, a developing indication involves the identification of high-risk premature ventricular beats (PVBs). Nevertheless, the prevalence of CAD among master athletes displaying PVBs remains uncertain. Objective The aim of this study was to evaluate the prevalence of CAD in master athletes who underwent coronary computed tomography (CCT) due to high-risk PVBs during PPS (emerging indication), and to compare this population to age-, gender- and risk factors-matched group of athletes who underwent CCT due to STD during ET (traditional indication). Methods We retrospectively enrolled master athletes with no baseline ECG abnormalities and no previous history of heart disease who underwent CCT because of a positive ET during PPS, for PVBs or STD. The entity of the disease was assessed using the CAD-RADs scoring system. Results The population resulted to be composed by 130 Caucasian athletes, median age 54 (46.5-60.5 years, 84% male), 74% practiced endurance sports. Eighty-two (63%) of them underwent CCT for STD and 48 (37%) for high-risk PVBs. A CAD-RADs of 0 was detected in 64.3% of athletes, 1-2 in 22.2%, 3 in 6.3%, and 4A-4B in 7.1%. A significant CAD was found in 10.4% of athletes investigated for PVBs at ET, and 14.6% in subjects with STD (p=0.5). Among athletes with moderate-severe CAD, 82.4% had one or more cardiovascular risk factors, while 17.6% had no risk factors (Figure 1). Conclusions The prevalence of CAD in master athletes is equivalent in case of PVBs and STD. The severity of CAD increases with an increasing number of cardiovascular risk factors. Therefore, in these cases the number of risk factors is an important variable to consider in the prescription of CCT.Figure 1

Prospective assessment of risk factors for appropriate ICD intervention in patients with ischemic cardiomyopathy: results of PARCADIA trial

Abstract Background There is still a big unmet need for better risk stratification tools to identify patients at high risk for sudden cardiac death in the era of primary prevention ICD therapy. Scar burden on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging may be a risk marker for the prediction of ventricular arrhythmia in post-myocardial infarction (MI) patients. Purpose The aim of the PARCADIA trial was to assess whether scar characteristics, determined via LGE-CMR, or other baseline risk markers are associated with appropriate ICD therapy. Methods In this prospective, multi-center, clinical trial, we enrolled post-MI patients with an indication for de novo primary prevention ICD. Main exclusion criteria were indication for cardiac resynchronization therapy and NYHA class IV. Prior to the ICD implantation, LGE-CMR was performed to analyze the amount of scar tissue (LGE core mass + grey zone mass) and LV function / volumes. A 24h Holter recording was performed to collect information on potential triggers like premature ventricular beats (PVB) and sympathetic-vagal balance based on heart rate variability (HRV). Follow-ups were performed in-office every 6 months, including remote monitoring. Appropriate ICD therapy was used as primary endpoint and adjudicated by a clinical event committee. Results 199 patients were enrolled at 5 investigational sites in Europe. Patients mean age was 64.3 years, with a mean LVEF of 27.7 %, timing from the index MI was 9.1 years, and 42.7% received a primary PCI on index MI. After a median follow-up duration of 47.7 months, 23.1% of patients received appropriate ICD therapy. In 135 patients (67.8%), quality of LGE-CMR was sufficient for detailed analysis. The mean LGE core mass (20.5 vs. 19,7 g) and grey zone mass (10.5 vs. 11.4 g) was not different in patients with or without appropriate ICD therapy, also not when corrected for LV mass. However, LVEF (28.5 vs. 32.9 %) was lower, while diastolic myocardial mass (141 vs. 125 g), and end-diastolic volume (265.0 vs. 226.7 ml) were significantly higher in patients with appropriate ICD therapy. On 24h Holter the mean PVB burden (3695 vs. 1643 beats), and non-sustained ventricular tachycardia (12 vs. 0.9), were higher in patients with appropriate ICD therapy, while the HRV (96.1 vs. 113.1 SDNN) was lower. In univariate analysis the variables LVEF, timing to index MI, primary PCI on index MI, PVB burden and HRV appeared to be predictors for appropriate ICD intervention, while in multivariate analysis LVEF and PVB burden remained predictive. Conclusion In post-MI patients with appropriate ICD therapy, scar burden was not different from patients without appropriate ICD therapy. Only LVEF and PVB burden were independent predictors of increased arrhythmogenicity. Improved CMR analysis on scar characteristics (conduction channels) to identify potential arrhythmogenic regions might be the topic for future research.

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

Clinical overlap between healthy athletes and athletes with arrhythmogenic right ventricular cardiomyopathy

Abstract Introduction The extensive physiological cardiac remodelling that results from the haemodynamic stress of endurance exercise shares many features with the pathological manifestations of arrhythmogenic right ventricular cardiomyopathy (ARVC), giving rise to a significant diagnostic challenge for clinicians. Contemporary discriminators of disease have been derived from comparisons between healthy athletes and non-athletic ARVC patients. Differentiation between healthy and diseased athletes may be more difficult. Purpose To assess published clinical differentiators of physiological remodelling from ARVC in a cohort of endurance athletes. Methods This project utilises data from the Pro@heart consortium comprising elite endurance athletes that have received comprehensive cardiac phenotyping using cardiac magnetic resonance imaging, echocardiography, resting and ambulatory electrocardiography and cardiopulmonary exercise testing. Measures of cardiac structure and function with potential to differentiate health and disease were assessed in healthy endurance athletes without symptoms or suspicion of ARVC, endurance athletes diagnosed with ARVC (meeting ARVC task force criteria) and athletes with suspected sub-clinical ARVC (complex ventricular arrhythmias and ≥1 task force criteria). One way ANOVA assessed differences in continuous variables, while Chi Square with pair wise Z test and Bonferroni p value correction were used to test for differences in nominal data. Results Athletes with ARVC and athletes with suspected ARVC displayed more clinical indicators of ARVC compared to healthy athletes (table 1). While a greater proportion of athletes with ARVC and suspected ARVC met ≥1 and ≥3 indicators of pathology compared to healthy athletes, it was relatively common for healthy athletes to meet ≥1 criteria (53%) and ≥3 criteria (14%) (table 2). Comparison of mean values showed right ventricular ejection fraction (RVEF) and right ventricular fractional area change (RV FAC) were lower in athletes with or suspected to have ARVC compared to healthy athletes, however no significant differences in burden of ventricular premature beats (VPB) were noted (table 1). A high burden of VPBs, evidence of ventricular arrhythmia, evidence of late gadolinium enhancement (LGE), a low RVEF, and a reduced RV FAC were more prevalent in athletes with ARVC compared to healthy athletes (table 2). However, there was clinically relevant overlap in all measures between healthy and diseased athletes (table 2). Right ventricular to left ventricular volume ratio was a particularly poor discriminator of pathology (table 1 &amp; 2). Conclusion Electrophysiological, structural and functional abnormalities are not uncommon in healthy athletes resulting in significant overlap with athletic ARVC patients. Future research is required to identify better clinical discriminators of disease, and to assess the clinical significance of abnormal measures in ostensibly healthy athletes

The association between exercise-induced ventricular premature contractions and long-term mortality in patients without coronary artery disease

Abstract Background/Introduction The treadmill exercise test is widely used clinical test to determine cardiovascular risk and mortality, regardless of clinical risk factors (1). ST-segment changes detected in the exercise test are shown to predict myocardial ischemia (2) and premature ventricular complexes (PVCs) are frequently observed during exercise stress testing (3). Exercise-related PVC is observed in 14% to 23% of healthy individuals without significant heart disease (4,5). The literature on the role of PVCs observed during treadmill exercise testing in predicting prognosis is controversial. Purpose Therefore, we aimed to evaluate the clinical results of PVCs seen during exercise testing in patients who had been diagnosed with non-obstructive coronary artery disease after coronary angiography. Methods The study population consisted of 1624 consecutive patients who were considered high risk according to the Duke treadmill risk score and had no significant stenosis on coronary angiogram from January 2016 to April 2021. Patients with previous history of coronary revascularization, previous myocardial infraction, heart failure, moderate or severe heart valve disease, congenital heart disease, cardiomyopathy, bundle branch block, and left ventricular hypertrophy were excluded from the study. The primary endpoints of the study were long-term all-cause mortality of patients who had PVCs during the exercise test or during the resting phase. Results The long-term mortality was observed in 53 patients out of 1624 patients in the mean follow-up of 47 months. PVCs was observed in 293 (18.7%) patients without long-term mortality, while PVCs was observed in 24 (45.3%) patients with long-term mortality (p&amp;lt;0.001). The model adjusted for all covariates showed that the presence of PVCs in the recovery phase (p&amp;lt;0.007, HR (95% CI) 2.244 (1.244 – 4.047)) and advanced age (p&amp;lt;0.001, HR (95% CI) 1.194 (1.143 – 1.247)) were associated with long-term all-cause mortality (Figure 1). Considering Kaplan-Meier curve, individuals with PVCs in recovery had significantly higher risk of long-term mortality compared with those with without PVCs (log-rank statistic: 22.47, p&amp;lt;0.001) (Figure 2). Conclusion(s) The study highlights that PVCs monitored in the recovery phase of the treadmill exercise test were associated with long -term mortality in patients without structural heart disease and coronary artery disease.Figure 2Figure 1

"Hot phase" clinical presentation of biventricular arrhythmogenic cardiomyopathy: when the perfect electrical storm spontaneously stops.

An 18-year-old male presented with syncope during a training break. Post-syncope, he developed effort dyspnea, which he associated with the Pfizer-BioNTech COVID-19 vaccine received a week earlier. Electrocardiogram showed T inversion in V1-V3, III, and aVF, while 24-hour Holter monitoring revealed frequent ventricular premature beats. A transthoracic echocardiogram showed severe biventricular dilation and mild left ventricular (LV) dysfunction. Cardiac magnetic resonance (CMR) imaging confirmed these findings, showing moderate right ventricular (RV) systolic dysfunction with akinesia of the inferior and inferolateral walls. T2 hypersignal in the middle segment of the inferior inferior interventricular septum suggested myocardial edema. Extensive transmural late gadolinium enhancement was noted in the RV and LV walls. An implantable loop recorder was implanted. Three months later, the patient was admitted with palpitations, fever, and a positive SARS-CoV-2 test. Sustained ventricular tachycardia (VT) episodes were documented and managed with amiodarone and β-blockers. Follow-up CMR showed a slight improvement in LV ejection fraction and resolution of edema. A single-chamber implantable cardioverter-defibrillator (ICD) was implanted. Genetic testing for arrhythmogenic RV cardiomyopathy (ARVC) was negative, and family screening was normal. Two years later, pre-syncope episodes occurred, and ICD interrogation revealed nonsustained VT. The patient is awaiting VT ablation. This case highlights the diagnostic and therapeutic challenges of ARVC, particularly in differentiating it from myocarditis. The "hot-phase" presentation, vaccine association, and subsequent SARS-CoV-2 infection added complexity. CMR was crucial for diagnosis, and VT management required a combination of medical therapy and invasive procedures.

Ventricular arrhythmias occurring in myocardial infarction patients with acute ST-segment elevation within the first 24 hours after primary percutaneous coronary intervention and their prognostic value

Reperfusion therapy in myocardial infarction patients with acute ST-segment elevation significantly reduced the frequency of ventricular tachycardia and ventricular fibrillation, however, such arrhythmias still occur in 6-8% of patients, posing a threat to their lives.The aim of the study was to determine the nature of ventricular arrhythmias occurring in myocardial infarction patients with acute ST-segment elevation within the first 24 hours after primary percutaneous coronary intervention, and their prognostic value regarding the development of complications during the inpatient treatment phase. The study involved 82 individuals (mean age: 62,4±10,2 years; male: 69,23 (58,6-78,92)%, female: 30,77 (21,08-41,4)%). Within 24 hours after the infarct-related artery stenting, all patients underwent a 24-hour Holter ECG monitoring. The course of the disease was analyzed based on the presence of risk factors such as hypertension, diabetes mellitus, past COVID-19, and obesity. Ventricular rhythm disturbances were represented mainly by premature contractions. They occurred significantly more frequently in patients with arterial hypertension (883,71 (96,0; 986.0); p=0,02; p=0,03; p=0,02, compared to patients with a history of COVID-19, diabetes, and obesity, respectively) and in those with past COVID-19 (711,3 (125,0; 846,5); p=0,01; p=0,04, compared to indi­viduals with diabetes and obesity, respectively). Isolated premature ventricular complexes, pairs, triplets were recorded, and in individuals with arterial hypertension and past COVID-19 “runs” of ventricular extrasystoles and episodes of nonsustained monomorphic and even polymorphic ventricular tachycardia, such as Torsades de Pointes, (under the condition of combined risk factors) were noted; predominantly in these patients during the hospital phase such сom­plications as ventricular fibrillation and asystole,with sudden cardiac arrest developed. The obtained results is an evidence of electrical myocardial instability and indicate that myocardial infarction patients with acute ST-segment elevation, in addition to myocardial revascularization, require optimization of pharmacological treatment. The use of intravenous beta-blockers as part of complex treatment prevented the occurrence of life-threatening ventricular arrhythmias during the inpatient treatment phase.