Premature Ventricular Contractions Research Articles

Revealing the unrevealed: echocardiography for non-ischemic scar tissue detection.

The detection of myocardial scar tissue profoundly influences athletes care and prognostic categorization. Athletes appear to be at risk of developing fatal arrhythmias when harboring a quiescent cardiac disorder. Early identification of disease in asymptomatic individuals through preparticipation screening is means to prevent these events. We presented a male marathon runner master athlete who came at our Department of Sports Medicine for a preparticipation screening. Baseline 12-lead standard electrocardiogram was normal. A maximal cycle ergometer exercise test revealed exercise-induced premature ventricular contractions (PVCs) with uncommon morphology. Echocardiography revealed an hyperechogenic zone at mid-basal posterior segments of the left ventricle. Twenty-four-hours ECG Holter monitoring, with training session, showed some isolated polymorphic PVCs even during training session. Cardiac magnetic resonance (CMR) confirmed the presence of a non-ischemic left ventricular scar (subepicardial) into the mid-basal segment of the posterior wall. Echocardiography is a first-line, economic, and accessible diagnostic test for athletes and it can be useful, when abnormalities are detected, to indicate further investigations, such as CMR. Although non-ischemic left ventricular scarring is difficult to detect on echocardiography, this event is sometimes possible and require further investigation when observed.

Визначення предикторів стійких порушень серцевого ритму у військовослужбовців із тяжким перебігом міокардиту

The aim – to study heart rhythm and conduction disturbances in different localization and distribution of myocardial lesions in combatants with severe myocarditis based on the results of a 6-month follow-up.Materials and methods. 46 male military personnel with a severe course of acute myocarditis (AM) with a reduced ejection fraction (EF) of the left ventricle (LV) (≤ 40 %) with an average age of (35,1±2,4) years were examined. Examinations were carried out in the 1st month after the onset of symptoms of myocarditis and after 6 months of observation. The diagnosis of myocarditis and the severe course of the disease were established on the basis of the Recommendations for the diagnosis and treatment of myocarditis of the All-Ukrainian Association of Cardiologists of Ukraine. All patients underwent for 24-hour ECG monitoring with analysis of the frequency and spectrum of rhythm and conduction disturbances and cardiac magnetic resonance (CMR) imaging with contrast analysis of the topography of the lesion and counting the number of LV segments affected by inflammatory changes and LV segments with the presence of late gadolinium enhancement (LGE).Results and discussion. When comparing the results of heart MRI with the data of daily ECG monitoring, a clear association of the presence of frequent ventricular extrasystoles (VE) and paroxysms of non-sustained ventricular tachycardia (NSVT) with the localization of LGE in the interventricular septum (IS) was established – among patients with LGE lesions at the onset of AM more than in a third (37.0 %) had frequent VE, and NSVT paroxysms, which increase the risk of developing life-threatening ventricular arrhythmias, were detected in 25,9 % of cases. After 6 months of observation in the presence of LGE in the IS, the frequency of detection of frequent VE and NSVT paroxysms was also significantly higher compared to other localization of the lesion and amounted to 20,0 and 13,3 %, respectively. With the help of correlation analysis, an associative relationship was revealed between the presence of LGE in the IS and the presence of frequent VE and NSVT paroxysms in the debut of myocarditis – r=0.73 (р<0.01) and r=0.66 (р<0,01) respectively, and also after 6 months of observation – r=0.65 (р<0.01) and r=0.59 (р<0.05), respectively. According to the results of the multivariate regression analysis, predictors of frequent VE persistence after 6 months were: LVEF ≤30 %; LV end-diastolic volume index ≥105 ml/m2; presence of inflammatory changes in ≥5.0 LV segments; presence of LGE in ≥4.0 LV segments and its presence in the IS, determined in the 1st month from the onset of the disease. The predictors NSVT paroxysms persistence after 6 months were the same factors with the exception of LV EF, and, according to the value of the β coefficient (β=1.302; p<0.001), the most significant contribution was the presence of LGE in the IS.Conclusions. In combatants with severe myocarditis, the presence of late gadolinium enhancement in the interventricular septum is an additional risk factor for the persistence of frequent ventricular extrasystoles and paroxysms of non-sustained ventricular tachycardia during 6 months, while the presence of late gadolinium enhancement in the posterior and lateral walls of the left ventricle has no reliable relationship with the presence of rhythm and conduction disorders. On the basis of multivariate regression analysis, predictors of frequent ventricular extrasystoles and paroxysms of non-sustained ventricular tachycardia persistence were established in combatants with myocarditis.

A New Remote Monitoring System: Evaluation of the Efficiency and Accuracy of the Smart Emergency Medical System-Health Internet of Things Device

Background: The remote medical monitoring system can facilitate monitoring patients with cardiac arrhythmia, and consequently, reduce mortality and complications in individuals requiring emergency interventions. Hence, it is necessary to evaluate new telemedicine devices and compare them with standard devices. Therefore, this study aimed to evaluate and compare the new remote monitoring system, Smart Emergency Medical System-Health Internet of Things (SEMS-HIOT) developed by the Health Technology Development Centre of Babol University of Medical Sciences on patients with different cardiac arrhythmias and compare it with the standard device. Materials and Methods: In this case-control study, 60 patients were divided into the six most common arrhythmia groups (n=10 per each group and equal gender) as atrial fibrillation, ventricular tachycardia, paroxysmal supraventricular tachycardia, premature ventricular contractions, atrial tachycardia, and premature atrial contractions. Also, 20 healthy individuals (including 10 men and 10 women) without any arrhythmia (normal rhythm) were considered as the control group. Three similar SEMS-HIOT devices were used as test devices and a standard cardiac monitoring device as the control device. The clinical parameters, including heart rate, pulse rate, oxygen saturation, body temperature, and cardiac electrical activity via electrocardiogram (ECG) lead-II were recorded. Results: Findings showed that the performance of the SEMS-HIOT test device was similar and in the same range for all indices in each group and there were no significant differences compared to the performance of the control device (P>0.05). Also, the ECG records measured with SEMS-HIOT and standard device indicate no significant differences (P>0.05). Conclusion: Our study showed that the cardiac indices as well as ECG findings, which were measured with SEMS-HIOT and common standard devices confirmed the accuracy and reliability of the new telematics device for monitoring patients with cardiac diseases.

Accelerated idioventricular rhythm after left bundle branch pacing lead implantation

Premature ventricular contractions with right bundle branch block morphology induced during left bundle branch (LBB) pacing (LBBP) lead implantation serve as a marker indicating that the lead is close to or has reached the LBB region. However, no reports to date have described accelerated idioventricular rhythm (AIVR) induced by LBBP lead deployment.We herein describe a patient who underwent LBBP for complete atrioventricular block. The patient's intrinsic escape rhythm was overtaken by AIVR induced immediately after LBBP lead deployment.AIVR is another marker indicating that the lead has reached the LBB region.

Comparison of Cardiac Magnetic Resonance and Advanced Echocardiography in Evaluation of Patients with High Burden of Premature Ventricular Contractions and Normal Standard Echocardiography

Comparison of Cardiac Magnetic Resonance and Advanced Echocardiography in Evaluation of Patients with High Burden of Premature Ventricular Contractions and Normal Standard Echocardiography

ECG classification via integration of adaptive beat segmentation and relative heart rate with deep learning networks

We propose a state-of-the-art deep learning approach for accurate electrocardiogram (ECG) signal analysis, addressing both waveform delineation and beat type classification tasks. For beat type classification, we integrated two novel schemes into the deep learning model, significantly enhancing its performance. The first scheme is an adaptive beat segmentation method that determines the optimal duration for each heartbeat based on RR-intervals, mitigating segmenting errors from conventional fixed-period segmentation. The second scheme incorporates relative heart rate information of the target beat compared to neighboring beats, improving the model’s ability to accurately detect premature atrial contractions (PACs) that are easily confused with normal beats due to similar morphology. Extensive evaluations on the PhysioNet QT Database, MIT-BIH Arrhythmia Database, and real-world wearable device data demonstrated the proposed approach’s superior capabilities over existing methods in both tasks. The proposed approach achieved sensitivities of 99.81% for normal beats, 99.08% for premature ventricular contractions, and 97.83% for PACs in beat type classification. For waveform delineation, we achieved F1-scores of 0.9842 for non-waveform, 0.9798 for P-waves, 0.9749 for QRS complexes, and 0.9848 for T-waves. It significantly outperforms existing methods in PAC detection while maintaining high performance across both tasks. The integration of aforementioned two schemes into the deep learning model improved the accuracy of normal sinus rhythms and arrhythmia detection.

Cardiac magnetic resonance for ventricular arrhythmias: a systematic review and meta-analysis

BackgroundCardiac magnetic resonance (CMR) allows comprehensive myocardial tissue characterisation, revealing areas of myocardial inflammation or fibrosis that may predispose to ventricular arrhythmias (VAs). With this study, we aimed to estimate...

Impact of Premature Ventricular Complex Burden on Ischemic Stroke in Patients with Non-Valvular Atrial Fibrillation.

Background/Objectives: Limited data are available regarding the prognostic impact of premature ventricular complex (PVC) burden in patients with atrial fibrillation (AF). We sought to compare clinical outcomes in patients with AF according to PVC burden via 24 h Holter monitoring. Methods: From January 2010 to December 2020, 4834 oral anticoagulant (OAC)-naïve non-valvular AF (NVAF) patients who underwent 24 h Holter monitoring were included for analysis. Results: Among the 4834 OAC-naïve NVAF patients, 2835 patients (58.6%) exhibited at least one PVC within a 24 h monitoring period, and 120 patients (2.5%) displayed a daily PVC burden exceeding 10%. In the follow-up echocardiography, patients with a daily PVC burden of ≥10% exhibited lower left ventricular ejection fraction, larger left atrial volume, and higher right ventricular systolic pressure and E/e' than those with a daily PVC burden of <10%. The risk of ischemic stroke (adjusted HR 2.332, p = 0.015) and heart failure admission (adjusted HR 2.147, p = 0.010) were significantly higher in the patients with a daily PVC burden of ≥10% than in those with a daily PVC burden of <10%. However, the incidence of cardiac death was not significantly different between the two groups. A daily PVC burden of ≥10% was independently associated with the risk of ischemic stroke in the OAC-naïve NVAF patients, irrespective of the CHA2DS2-VASc score, AF type, and left atrial size. Conclusions: The current results suggest that evaluating and monitoring the burden of PVCs in patients with NVAF is an important aspect of predicting stroke and heart failure admission.

AirECG: Contactless Electrocardiogram for Cardiac Disease Monitoring via mmWave Sensing and Cross-domain Diffusion Model

The electrocardiogram (ECG) has always served as a crucial biomedical examination for cardiac diseases monitoring and diagnosing. Typical ECG measurement requires attaching electrodes to the body, which is inconvenient for long-term monitoring. Recent wireless sensing maps wireless signals reflected from human chest into electrical activities of heart so as to reconstruct ECG contactlessly. While making great progress, we find existing works are effective only for healthy populations with normal ECG, but fall short when confronted with the most desired usage scenario: reconstructing ECG accurately for people with cardiac diseases such as atrial fibrillation, premature ventricular beat. To bridge the gap, we propose AirECG, which moves forward to reconstruct ECG for both healthy people and even cardiac patients with morbid ECG, i.e., irregular rhythm and anomalous ECG waveform, via contactless millimeter-wave sensing. To realize AirECG, we first custom-design a cross-domain diffusion model that can perform multiple iteration denoising inference, in contrast with the single-step generative models widely used in previous works. In this way, AirECG is able to identify and eliminate the distortion due to the unstable and irregular cardiac activities, so as to synthesize ECG even during abnormal beats. Furthermore, we enhance the determinacy of AirECG, i.e., to generate high-fidelity ECG, by designing a calibration guidance mechanism to combat the inherent randomness issue of the probabilistic diffusion model. Empirical evaluation demonstrates AirECG's ability of ECG synthesis with Pearson correlation coefficient (PCC) of 0.955 for normal beats. Especially for abnormal beats, the PCC still exhibits a strong correlation of 0.860, with 15.0%~21.1% improvement compared with state-of-the-art approaches.

Cardiovascular disease detection from cardiac arrhythmia ECG signals using artificial intelligence models with hyperparameters tuning methodologies

Cardiovascular disease (CVD) is connected with irregular cardiac electrical activity, which can be seen in ECG alterations. Due to its convenience and non-invasive aspect, the ECG is routinely exploited to identify different arrhythmias and automatic ECG recognition is needed immediately. In this paper, enhancement for the detection of CVDs such as Ventricular Tachycardia (VT), Premature Ventricular Contraction (PVC) and ST Change (ST) arrhythmia using different dimensionality reduction techniques and multiple classifiers are presented. Three-dimensionality reduction methods, such as Local Linear Embedding (LLE), Diffusion Maps (DM), and Laplacian Eigen (LE), are employed. The dimensionally reduced ECG samples are further feature selected with Cuckoo Search (CS) and Harmonic Search Optimization (HSO) algorithms. A publicly available MIT-BIH (Physionet) - VT database, PVC database, ST Change database and NSR database were used in this work. The cardiac vascular disturbances are classified by using seven classifiers such as Gaussian Mixture Model (GMM), Expectation Maximization (EM), Non-linear Regression (NLR), Logistic Regression (LR), Bayesian Linear Discriminant Analysis (BDLC), Detrended Fluctuation Analysis (Detrended FA), and Firefly. For different classes, the average overall accuracy of the classification techniques is 55.65 % when without CS and HSO feature selection, 64.36 % when CS feature selection is used, and 75.39 % when HSO feature selection is used. Also, to improve the performance of classifiers, the hyperparameters of four classifiers (GMM, EM, BDLC and Firefly) are tuned with the Adam and Grid Search Optimization (GSO) approaches. The average accuracy of classification for the CS feature-based classifiers that used GSO and Adam hyperparameter tuning was 79.92 % and 85.78 %, respectively. The average accuracy of classification for the HSO feature-based classifiers that used GSO and Adam hyperparameter tuning was 86.87 % and 93.77 %, respectively. The performance of the classifier is analyzed based on the accuracy parameter for both with and without feature selection methods and with hyperparameter tuning techniques. In the case of ST vs. NSR, a higher accuracy of 98.92 % is achieved for the LLE dimensionality reduction with HSO feature selection for the GMM classifier with Adam's hyperparameter tuning approach. The GMM classifier with the Adam hyperparameter tuning approach with 98.92 % accuracy in detecting ST vs. NSR cardiac disease is outperforming all other classifiers and methodologies.

Zero-fluoroscopy catheter ablation of premature ventricular contractions: comparative outcomes from the right ventricular outflow tract and other ventricular sites.

The three-dimensional electroanatomic mapping (EAM) system allows performing catheter ablation (CA) without fluoroscopy in patients with premature ventricular contractions (PVCs). The right ventricle outflow tract (RVOT) location is favorable for performing zero-fluoroscopy CA. Non-RVOT zero-fluoroscopy CA is a challenging procedure. The study aimed to evaluate the efficacy and safety of zero-fluoroscopy CA using the EAM in patients with PVCs from RVOT and non-RVOT. Completely zero-fluoroscopy CA of PVCs guided by EAM was performed in 107 patients with PVCs. 54 patients underwent zero-fluoroscopy RVOT CA. The remaining 53 patients underwent zero-fluoroscopy non-RVOT CA. Demographic and clinical baseline characteristics, procedure parameters, and follow-up were obtained from medical records. Primary outcomes were the acute and the permanent success rate (12-month follow-up), complications, and procedure time. There were no significant differences between groups regarding baseline characteristics. Acute procedural success was achieved in 52 patients (94,44%) in the RVOT zero-fluoroscopy CA group and in 45 patients (86,54%) in the non-RVOT zero-fluoroscopy CA group (ns). A long-term success rate was achieved in 50 patients (90,74%) in the RVOT zero-fluoroscopy CA group and in 44 patients (84,62%) in the non-RVOT zero-fluoroscopy CA group (ns). The median procedure time was 80.5 minutes in the RVOT group and 90 minutes in the non-RVOT group (ns). There were two complications in the non-RVOT group (ns). There were no differences in procedure time efficacy and safety zero-fluoroscopy ablation between RVOT and non-RVOT locations. Non-fluoroscopy CA of PVCs is a feasible, safe, and efficient procedure.

Clinical utility of ambulatory ECG monitoring and 2D-ventricular strain for evaluation of post-COVID-19 ventricular arrhythmia

BackgroundA relatively common complication of COVID -19 infection is arrhythmia. There is limited information about myocardial deformation and heart rate variability (HRV) in symptomatic post COVID patients presented by ventricular arrhythmia.Aim of the studyOur goal was to assess 2D-ventricular strain and heart rate variability indices (evaluated by ambulatory ECG monitoring) in post-COVID-19 patients suffering from ventricular arrhythmia.MethodsThe current observational case–control study performed on 60 patients one month after they had recovered from the COVID-19 infection. Thirty healthy volunteers served as the control group. Each participant had a full medical history review, blood tests, a 12-lead surface electrocardiogram (ECG), 24-h ambulatory ECG monitoring, and an echo-Doppler examination to evaluate the left ventricular (LV) dimensions, tissue Doppler velocities, and 2D-speckle tracking echocardiography (2D-STE) for both the LV and right ventricular (RV) strain.ResultsSymptomatic post-COVID patients with monomorphic premature ventricular contractions (PVCs) showed a substantial impairment of LV/RV systolic and diastolic functions, LV/RV myocardial performance (MPI) with reduced indices of HRV. Patients with higher versus lower ventricular burden had poorer functional status, higher levels of inflammatory biomarkers and reduced parameters of HRV (New York Heart Association (NYHA) class: 2.1 ± 0.9 vs. 1.5 ± 0.6, p < 0.001, C-reactive protein (CRP): 13.3 ± 4.1 vs. 8.3 ± 5.9 mg/L, p < 0.0001, low frequency/high frequency (LF/HF): 3.6 ± 2.4 vs. 2.2 ± 1.2, p < 0.002, the root mean square of the difference between successive normal intervals (rMSSD): 21.8 ± 4.7 vs. 29.3 ± 14.9 ms, p < 0.039 and the standard deviation of the RR interval (SDNN): 69.8 ± 19.1 vs.108.8 ± 37.4 ms, p < 0.0001). The ventricular burden positively correlated with neutrophil/lymphocyte ratio (NLR) (r = 0.33, p < 0.001), CRP (r = 0.60, p < 0.0001), while it negatively correlated with LV-global longitudinal strain (GLS) (r = -0.38, p < 0.0001), and RV-GLS (r = -0.37, p < 0.0001).ConclusionsPatients with post-COVID symptoms presented by ventricular arrhythmia had poor functional status. Patients with post-COVID symptoms and ventricular arrhythmia had subclinical myocardial damage, evidenced by speckle tracking echocardiography while having apparently preserved LV systolic function. The burden of ventricular arrhythmia in post-COVID patients significantly correlated with increased inflammatory biomarkers and reduced biventricular strain.

Clinical and electrocardiographic characteristics of immune checkpoint inhibitor-related myocarditis

BackgroundImmune checkpoint inhibitor (ICI) has become a major breakthrough in the field of tumor therapy, leading to improved survival. This study evaluated the clinical and electrocardiographic characteristics of patients with ICI-related myocarditis. MethodsPatients with ICI-related myocarditis were enrolled from 4 centers in China until September 2023. Demographic data (age, sex, comorbidity), types of ICI, clinical manifestations, electrocardiogram (ECG) and treatment were analyzed retrospectively. Arrhythmia and characteristics of ECG were compared according to prognosis and grading. ResultsA total of 29 participants (13 females with a median age of 63.25 years) with ICI-related myocarditis were enrolled. Lung cancer was the most, with a proportion of 31.03 % (9/29). The median time from the first administration of ICI to the diagnosis of myocarditis was 50 days. Camrelizumab was the main type of ICI (9/29). Most patients had non-specific symptoms, dyspnea (n = 16) and palpitation (n = 9) were common. The overall mortality rate was 37.93 % (11/29) with a median follow-up of 9(4,11) days. Compared with the survivors, P-wave abnormality was more common in participants who were dead (24.14 %vs6.90 %, p = 0.010). A total of 19 patients with severe ICI-related myocarditis were included in this study. The proportions of sinus tachycardia (34.48 %vs0.00 %, p = 0.005), premature ventricular complex (27.59 %vs0.00 %, p = 0.027) and atrioventricular block (34.48 %vs3.45 %, p = 0.044) were higher in severe ICI-related myocarditis. ConclusionsClinical manifestations of ICI-related myocarditis usually lacked specificity. ECGs can be manifested as new-onset arrhythmias, ST-T segment changes, fragmented QRS complex, abnormal P wave, prolonged QTc interval and multi‑lead low voltage.

Haemodynamic Responses Following Lidocaine Infusion on Hypertensive Patient Undergoing Laparoscopic Cholecystectomy

Many pharmacological methods have been evaluated to attenuate the adverse haemodynamic responses resulting from airway manipulation and pneumoperitoneum. Intravenous lidocaine infusion is one of them; bolus dose of intravenous lidocaine is used to reduce haemodynamic changes resulting from intubation and extubation reflex whereas intraoperative infusion of lidocaine has been used for post-operative analgesia in laparoscopic cholecystectomy. This randomized controlled trial was conducted to observe the effectiveness of lidocaine infusion in obtundation of haemodynamic responses on hypertensive patient undergoing laparoscopic cholecystectomy. A total number of 80 patients were enrolled in this study. Patients were allocated into two groups by computer generated random chart according to a 1:1 ratio. The patients of group A were given general anaesthesia with placebo normal saline infusion and the patients of group B were given general anaesthesia with lidocaine infusion (1.5mg/kg). Mean differences of blood pressure (SBP &amp; MAP) and heart rate at different time periods from baseline were compared between two groups. The demographic profiles were almost similar between the groups (p&gt;0.05). In comparison between two groups, heart rate, systolic blood pressure and mean arterial pressure rise from baseline value was more in normal saline group (group A) than lidocaine test group (group B) during peri-intubation, pneumoperitoneum and peri-extubation period. Statistical difference was significant between two groups (p&lt;0.05) in different haemodynamic parameters. Adverse events such as tachycardia premature ventricular contraction (PVC) and hypertension were observed much more in group A, which was higher than that of group B. We observed that administration of lidocaine infusion attenuates haemodynamic responses of hypertensive patient during laparoscopic cholecystectomy. CBMJ 2024 July: vol. 13 no. 02 P: 148-157

Cytokines as markers of non-functional overstrain in rowing athletes

BACKGROUND: Regular high-intensity exercise, combined with other stressors and lack of adequate recovery time, can cause a sustained pro-inflammatory response, leading to systemic inflammation and immune dysregulation. AIM: The aim of this study is to establish the prognostic effectiveness of proinflammatory IL-1β, TNFα, IL-8, anti-inflammatory cytokine IL-4 and myokine IL-6 as markers of dysfunctional overstrain and overtraining in rowing athletes. MATERIALS AND METHODS: A total of 47 male athletes aged 18–22 years were examined, specializing in rowing, 1st category, candidates for master of sports. Of these, 28 were dynamic (4 times). The control group included 24 healthy donors, men aged 18–22 years. Cardiac overstrain was diagnosed based on 24-hour ECG data: identification of ventricular and supraventricular extrasystoles in the absence of organic changes in the heart. The content of cytokines in blood serum was determined using the Human Cytokine/Chemokine Magnetic Bead Panel 1 reagents (Merck, Millipore) on a MagPix device. The research results were processed using parametric statistics methods. RESULTS: Rowing athletes show an increase in pro-inflammatory cytokines, which can be both a consequence of adaptive changes and a sign of long-term systemic inflammation. Determination of IL-6, IL-8, TNFα may be useful for assessing the body’s adaptation to training loads. The greatest changes in the level of pro-inflammatory cytokines are observed during the competitive period, and it should be taken into account that an increase in the anti-inflammatory cytokine IL-4 occurs in response to high levels of pro-inflammatory cytokines and is a sign of good adaptation. CONCLUSIONS: The greatest importance in the diagnosis of non-functional cardiac overstrain in rowing athletes should be given to an increase in IL-1α and IL-6 and an increase in TNFα against the background of a decrease in IL-4.

Abstract Mo072: Sustained Biological Pacemaker Activity Induced by AAV9-hTBX18

Background: Sinoatrial node (SAN) dysfunction is a clinical disorder characterized by the inability of the SAN to maintain an appropriate heart rate (HR). Patients with this condition often need an electronic pacemaker. Although it is the current standard of care, devices can have complications. A biological pacemaker has been created by adenovirus expressing TBX18 as an alternative. Hypothesis: However, adenoviruses are immunogenic, limiting the duration of expression. We hypothesized that an AAV9 would promote prolonged TBX18 expression, induce somatic reprogramming in vivo, and sustained pacemaker activity. Methods: AAV9 containing GFP or TBX18 was directly injected into the myocardium of eight-week-old male Sprague Dawley rats (n=70) at low (1x10 9 GC), mid (1x10 10 GC) and high (1x10 11 GC) doses. Transient AV block was induced by tail vein injection of adenosine. A permanent complete AV block was induced by ablation of the his bundle. Hearts were harvested for optical mapping and mRNA analysis. Results: Six weeks after injection, all doses of AAV9-TBX18 had increased HR (low: 104±4, p=0.04; mid: 106±3.4, p=0.008; high: 103±4.1, p=0.04; vs GFP: 89±3 bpm) compared to AAV9-GFP when we induced AV block using adenosine. AAV9-GFP and -TBX18 mid dose injected rats underwent surgery to induce complete AV block. TBX18 group presented superior HR over the 24 hours monitored. 6-lead EKG analysis of the QRS axis in the frontal plane revealed that the ventricular ectopic beats from the AAV9-TBX18-injected group originated from the injection site. Activation maps further confirmed that the injection site originated those beats in TBX18-injected rats only. Successful reprogramming of adult ventricular myocytes into SAN-like cells was confirmed by transcriptional profiles with increased expression of TBX18 (2.2±0.5 FC, p&lt;0.0001) and Hcn2 (25.2±1.1 FC, p=0.02), and reduced Gja1 (-10.8±0.7 FC, p=0.005), Scn5a (-1.1±0.8 FC, p=0.01) and Nkx2.5 (-2.0±0.6 FC, p=0.004) relative to GFP. Conclusion: Collectively, these data indicate that the AAV-based somatic reprogramming induced by TBX18 leads to sustained biological pacemaker activity in rats with AV block. Long-term studies are needed to characterize the long-term effects of sustained TBX18 expression.

Abstract Tu060: Unveiling Arrhythmogenic Right Ventricular Dysplasia In Pregnancy

Introduction: Arrhythmogenic right ventricular dysplasia (ARVD) is a rare autosomal dominant disease, caused by desmosomal gene mutations, and characterized by fibrofatty replacement of right ventricular (RV) myocardium with left ventricular (LV) involvement in advanced stages. It is mostly diagnosed between the second and forth decades of life and can present with ventricular tachycardia and arrhythmic sudden death. Here we present a case of ARVD diagnosis in a female in her forth pregnancy. Case description: A 28-year-old female, on her 27 th week of gestation (G4P3) was admitted to the hospital with preterm premature rupture of membranes. She also endorsed intermittent chest pressure, palpitations and shortness of breath. Her vital signs were stable, and electrocardiogram (ECG) revealed normal sinus rhythm with frequent premature ventricular contractions (PVCs) and T wave inversions in leads V1- V3. Laboratory studies showed normal troponin and D-dimer levels, and slightly elevated brain natriuretic peptide 240 pg/mL. Patient notably had frequent runs of monomorphic non-sustained ventricular tachycardia (NSVT) arising from RV apical territory, with left bundle branch morphology on telemetry. An echocardiogram revealed a dilated right atrium and RV with hypokinesis of RV; LV size and function were normal. Overall, patient met the revised task force diagnostic criteria for ARVD based on PVC morphology, abnormal ECG and dilated and hypokinetic RV. She had no sustained or hemodynamically unstable VT, no history of syncope or family history of sudden cardiac death and did not meet class I indication for implantable cardioverter defibrillator. She was started on oral metoprolol succinate 25 mg daily with which her arrhythmias significantly improved. She was recommended a cardiac magnetic resonance imaging and genetic testing for confirmation and to assess familial implications. Conclusion: Recognition of ARVD during pregnancy is challenging given the overlapping symptoms of normal pregnancy-related changes. Hormonal surge and sympathetic drive may have driven the increased frequency of NSVT in our patient and beta blocker was effective in managing these. Early recognition and tailored management are crucial to ensure the well-being of both the mother and the fetus. A close follow-up is necessary to understand the long-term implications for the patient and potential genetic predisposition in the family.

The Diagnostic Utility of Holter Monitoring in Catecholaminergic Polymorphic Ventricular Tachycardia.

Holter monitoring may raise suspicion of an underlying catecholaminergic polymorphic ventricular tachycardia (CPVT) diagnosis. Although not a primary investigation for CPVT, Holter monitoring is ubiquitously used as a diagnostic tool in the heart rhythm clinic. The objective of this study was to explore Holter monitoring in CPVT diagnosis. This retrospective cohort study analyzed off-therapy Holter monitoring from 13 ryanodine receptor 2-positive CPVT and 34 healthy patients from the Canadian Hearts in Rhythm Organization national registry. Using the Edwards method, the ratio of ambient-maximum heart rate during Holter monitoring was correlated with exertion level to separate premature ventricular contractions (PVCs) during periods of adrenergic and nonadrenergic stress. A receiver operating characteristic curve analysis determined the optimal threshold for isolating CPVT-induced PVCs during adrenergic states. PVC burden differed between groups (P=0.001) but was within population norm, suggesting ambient PVCs are uncommon in CPVT. CPVT patients had higher PVC counts than healthy controls (P=0.002), with a different distribution based on adrenergic state. The optimal threshold for separating PVCs into periods of adrenergic and nonadrenergic stress in CPVT patients was 76% of the maximum heart rate during the monitoring period. Compared with healthy controls, CPVT patients had a higher PVC count, limited to periods of adrenergic stress, defined by >76% maximum heart rate threshold (P=0.002; area under the receiver operating characteristic curve: 0.84). Below this threshold, there was no significant PVC difference (P=0.604). Holter monitor PVC counts alone are inadequate for CPVT diagnosis, owing to the adrenergic nature of the disease. Quantifying PVC prevalence at a heart rate threshold >76% identified CPVT with moderate sensitivity (69%) and high specificity (94%).

Premature ventricular complexes after catheter ablation for atrial fibrillation: Accounting for regression to the mean.

Prior studies have indicated that the frequency of premature ventricular complexes (PVC) increases after catheter ablation for atrial fibrillation (AF). However, these studies have primarily focused on patients whose PVC burden increased rather than including the full spectrum of outcomes. We performed a single-center retrospective cohort study of consecutive patients who underwent first-time AF ablation from 1/2018 to 12/2022 for paroxysmal or persistent AF and had both preablation and postablation rhythm monitoring within 6 months of the procedure. Patients were excluded if they had prior AF or PVC ablation or were prescribed a class I or III antiarrhythmic medication. Among 2945 patients who underwent AF ablation during the study period, 130 patients underwent first-time AF ablation and received both pre and post ambulatory monitoring. The median PVC burden before ablation was <1%. Most patients (63%) had no change in PVC burden after AF ablation compared with preablation, and patients who had an increase in PVC burden were offset by those with reductions in PVCs. A paired analysis pre- and post-AF ablation showed no significant change in PVC burden (p = .495). Although an elevated PVC burden after AF ablation may be seen clinically, the majority of patients have no change in burden. Studies that suggest an increase in PVC burden after AF ablation may suffer from incomplete sample selection and thus omit the important effect of regression to the mean.

A "strange" premature ventricular complex: from ECG evaluation to genetics

A "strange" premature ventricular complex: from ECG evaluation to genetics