Premature Ventricular Contractions Research Articles

Accuracy of a non-invasive mapping system for the localisation of re-entrant VT site of origin and its relationship to myocardial scar on cross-sectional imaging

Abstract Introduction View in ventricular onset (VIVO) is a non-invasive mapping system used for localising the site of earliest activation in ventricular arrhythmia, utilising a mathematical algorithm, patient specific cardiac model (constructed using cross-sectional imaging data), 3D images of the patient’s torso (for localising surface electrodes), and a 12-lead electrocardiogram (ECG).(1, 2) Several publications have examined its role in the localisation of premature ventricular contractions (PVCs), and a 5 patient case series assessed its role in scar related re-entrant VT.(1-4) However, its validity in a larger cohort and of the relationship to the relevant myocardial scar has not been investigated. Objective Assess the accuracy of the VIVO mapping system in localising the VT-SoO for patients with scar related re-entrant VT and its relationship to the relevant myocardial scar on cross-sectional imaging. Methods 20 patients with structural heart disease (18 ischaemic cardiomyopathy (ICM), 1 dilated cardiomyopathy (DCM), 1 hypertrophic cardiomyopathy (HCM)) (Male n=18, 63±14 years) and recent cross-sectional cardiac imaging, were recruited over a 16-month period (table 1). All patients had a clinical indication for VT ablation and were on optimal medical therapy, 19 had an implantable cardiac defibrillator. Invasive electro-anatomical mapping (EAM) was performed with the Advisor HD Grid multipolar catheter and maps were generated using Omnipolar electrograms (EGMs). The VT-SoO was identified using an activation- or pace-map by an experienced operator and the location defined using the American heart association’s 17 segment model of the left ventricle during the procedure.(5) VIVO maps were reviewed by a second independent operator and a segment allocated, scar segments were obtained from cross-sectional imaging. A "complete match" was defined as exact segment concordance between allocated segments, "partial match" as adjacent segments, and "no match" if it does not satisfy either of those requirements. Results Mean left ventricular ejection fraction was 35.5 ± 10.6%. Mean procedure time was 242 ± 70 minutes, with a mean ablation time of 20 ± 11.1 minutes. A total of 32 re-entrant VTs were mapped. The VT exit site was identified in all cases (11 activation-map; 21 pace-map). A complete match between the EAM and VIVO map was seen in 75% of VTs and partial match in a further 15% (table 2). The VT-SoO was located withing the myocardial scar (or directly adjacent to is) in 83% of accurately mapped VTs. Procedural success (defined as freedom from device treated episodes) was seen in 90% of patients at mean follow up of 7.3 ± 4.7 months. Conclusion VIVO non-invasive mapping system was able to accurately map the VT-SoO in scar dependent VT, and identify the relevant myocardial scar as seen on cross sectional imaging. Further research assessing its ability to accurately identify relevant ablation targets is ongoing.

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 & 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

Invasive validation of central blood pressure measurements using a suprasystolic monitor

Abstract Interest in the assessment of Central Blood Pressure (cBP) is steadily growing since it is a better predictor of myocardial infarction, stroke, or death than Peripheral Blood Pressure (pBP). However, pBP remains the first line for the diagnosis of hypertension (HTN) due to the ease and speed of the measurement. We sought to validate a new method to estimate cBP from brachial sphygmomanometer measurements. We estimated cBP using a sphygmomanometer that can record, after conventional pBP measurements, the pressure in the cuff maintained at a constant suprasystolic pressure. cBP is calculated using a method based on applying a physics-based model of the left subclavian artery to the brachial arterial branch to the suprasystolic brachial artery pressure waveforms. We compared this noninvasive estimated cBP to an invasive gold-standard measurement during cardiac catheterization. After clinically indicated cardiac catheterization requiring a haemodynamic assessment of a moderate coronary artery stenosis by Fractional Flow Reserve (FFR), the wire that incorporates a high fidelity electronic pressure transducer was positioned into the guiding catheter left in the ascending aorta. Simultaneous measurements were performed with a cuff placed on the patient's left arm. The output signals were recorded in a custom-based acquisition system. The comparison was obtained on the same 10 seconds recorded by the cuff and the pressure wire. The goal will be to reach 85 patients as recommended by the ARTERY Society Task Force. It recommends as an accuracy criterion to achieve a mean difference ≤ 5 mmHg with a standard deviation (SD) ≤ 8 mmHg, which are the standards adopted for this study. Patients with aortic stenosis, atrial fibrillation, or frequent (supra)ventricular extrasystoles were excluded. A total of 197 pairs of measured-estimated cBP were analysed in 78 patients with a mean age of 63 ± 8 yo, 75% of whom were men, 70% had hypertension, 26% fdiabetes, 93% dyslipidemia, 41% were tobacco users and 14% suffered from clinical peripheral artery diseases without history of revascularization. The median (InterQuartiles 25-75%) pBP was 123 [112 134] / 70 [64 77] mmHg. Measured cBP was 102 [92 11] / 78 [70 84] mmHg with a central augmentation index of 34 [23 44] %. The mean difference between estimated and measured systolic cBP was 4.9 ± 6.5 mmHg, while it was -3.9 ± 5.8 mmHg for diastolic cBP, meeting the prespecified accuracy criteria. In conclusion, our approach based on an exact matching and comparison of non-invasive suprasystolic arm cuff measurements and high-fidelity aortic BP validates that an estimation of central aortic blood pressure that can be easily carried out in daily practice and might improve HTN management. It remains to be demonstrated that more cardiovascular complications will be avoided by guiding the antihypertensive therapy with cBP instead of pBP measurements.Bland-Altman of estimated - measured cBP

Digital health in the EP lab: routine implementation of remote access and technical support for complex ablation procedures

Abstract Background Complex electrophysiological procedures are performed using three-dimensional (3D) electroanatomical mapping (EAM) systems, which are usually operated on site, by field technical engineers (FTE). Due to a lack of skilled personnel, the engineers usually must travel between different hospitals and the procedures have to be planed in advance. Remote access (RA) technologies were recently implemented in clinical practice, aiming to increase the flexibility in the EP lab and maximise healthcare resources use. Methods Electroanatomical mapping was performed remotely by means of an integrated audio-visual solution for RA. The operator and the FTE communicated exclusively using the RA system, while the latter worked only in home office. Consecutive procedures were prospectively enrolled and analysed in terms of indication, procedural characteristics, feasibility and saved travelled time by the FTA. Results Between September 2022 and July 2023, a total of 133 EP procedures were performed in a high volume, tertiary electrophysiological centre in Germany. The mean age was 67 (57.5, 75.5) years. Women represented 39.8% of the population. The median BMI was 26.2 (23.1, 30.3) Kg/m2. A total of 56 (42.1%) patients underwent an atrial fibrillation ablation procedure (37.5% paroxysmal), 22 (16.5%) an atrial tachycardia ablation, 13 (9.8%) cavotricuspid isthmus ablation, 15 (11.3%) supraventricular tachycardia ablation, 14 (10.5%) a premature ventricular contraction ablation, 12 (9%) ventricular tachycardia ablations and 1 patient an electrophysiological diagnostic study. The median time length of procedure was 130 (96.5, 168) minutes. The median number of radiofrequency applications was 63.5 (22.3, 109.5), while the median RF time was 14.2 (6.9, 25.1) minutes. The fluoroscopy time was 9.2 (6.5, 12.6) minutes, with a median radiation dose of 408.5 (233.0, 631.8) cGy x cm2. The median amount of contrast media was 40 (8.75, 50.0) ml and the median amount of heparin administered was 12000 (8000, 16000) UI. Protamine was used in 9 cases, with a median of 7000 (5000, 7000) UI. Except for one supraventricular procedure, where no arrhythmia induction was possible, all procedures were successful. One major complication was observed. In one case, the internet-based headphone connection was not stable. Therefore, the communication was established via a conventional smartphone. No change to on-site support was needed. The travel time reduction was available in 130 cases. In total, 290 travel hours could be saved. Conclusion The routine implementation of RA for complex EP procedures proved to be safe and efficient. This approach has the potential to increase the feasibility in case of emergency procedures, reduce travel times for FTE and streamline healthcare resources allocation.

Cardiac motion in patients with ventricular tachycardia: potential implications for the treatment of patients candidates to stereotactic arrhythmia radio-ablation (STAR)

Abstract Background Stereotactic arrhythmia radio-ablation (STAR) has proven to be a valid alternative treatment for refractory ventricular tachycardia (VT) in patients who are unsuitable to undergo standard catheter ablation (CA). It consists in the application of external beam radiotherapy in a single dose of 25 Gy to the target areas. There is increased research activity on better understanding the complex and fast motion of the heart and on reducing radiation toxicity. Purpose In the context of an in silico study to evaluate the feasibility of STAR with protons in patients with VT, the initial findings related to cardiac motion on the first 10 patients are here presented. Methods Prior to CA, each patient underwent ECG gated CT scans in expiratory breath-hold, with and without contrast and reconstructed at 30% (systole) and 80% (diastole) of the cardiac R-R cycle. Contouring of the ablation target as a clinical target volume (CTV) for proton treatment planning was performed based on a standard electrophysiological study with 3D eletroanatomical mapping. Two different treatment plans were created: the first with only the diastolic CTV as target (gated treatment), the second including both diastolic and systolic CTVs to create an Internal Target Volume (ITV) in the hypothesis of non-gated treatment. Robust optimization was used to create the Planning Target Volume (PTV). Results The target volumes used for treatment planning are given in Table 1. The median CTV was 10.90 (2.93-36.94) cm3 for diastole and 14.26 (1.73-36.31) cm3 for systole. These volumes are somewhat smaller than those reported in patients treated previously with STAR: this difference may be due to the fact that no respiratory motion was included in the target contour and that the study population includes many patients referred for ventricular ectopic beats without structural heart disease, where the ablation target is expected to be smaller as compared to patients with VT in structural heart disease. Despite a small median difference between the diastolic and systolic CTV of 0.53 (0.03-9.61) cm3, the ITV approach resulted in a median increase in volume compared to the largest of the two CTVs of 29 % (1%-44%). When considering the proton range uncertainty and potential errors in patient positioning (PTV), the target is this time enlarged by a factor 2.9 (1.9-3.9). This data indicates that both cardiac motion and uncertainties in patient positioning before treatment will have a large impact on the treatment volume thus affecting the amount of surrounding tissue exposed to radiation. Conclusion The ablation target contour at systole and diastole are of similar magnitude but their non-overlap results in a large increase in treated volume when radiation delivery is not gated for cardiac motion. Further analysis shall investigate on a case-by-case basis the potential reduction in risk of healthy tissue toxicity with cardiac-gated proton delivery.Table 1

Prevalence, characteristics, and long-term outcomes of patients with mitral annular disjunction undergoing surgery for degenerative mitral regurgitation

Abstract Background Mitral valve prolapse (MVP) is associated with progressive mitral regurgitation (MR) requiring surgical repair. A subset of patients with MVP may also suffer from malignant ventricular arrhythmias (VAs), especially in the presence of mitral annular disjunction (MAD). Purpose To assess the prevalence, associated characteristics, and long-term outcomes of patients with MVP with and without MAD undergoing mitral valve surgery for degenerative MR. Methods Patients with MVP and moderate-to-severe or severe degenerative MR undergoing mitral valve surgery between 2010-2022 at a university hospital in Sweden were included. MAD length was measured on echocardiograms at end-systole from the insertion of the posterior leaflet on the detached mitral annulus to the border of the bulging left ventricle. Patient demographics and clinical outcomes were collected from medical records. The primary endpoint consisted of VAs, defined as sustained- or non-sustained ventricular tachycardia or high burden of premature ventricular complexes causing hospitalizations or ablation or identified at Holter monitoring. Other endpoints included sudden cardiac death, all-cause mortality, new onset postoperative atrial fibrillation, stroke, mitral valve reoperation, endocarditis, new or worsened heart failure, myocardial infarction and implantation of permanent pacemaker or cardiac defibrillator. Results Of 599 patients undergoing mitral valve surgery, 96 (16%) had preoperative MAD, with a median (Q1, Q3) MAD length of 8.0 (5.0-10.0) mm. Compared with patients without MAD, patients with MAD were younger (55 vs 63 years), more likely to be female (31% vs 17%), to have diffuse myxomatous valve disease (66% vs 25%) and bileaflet prolapse (57% vs 17%). Most patients underwent mitral valve repair (84% vs 80%). No patient had residual MAD after surgical repair. At a mean follow up time of 5.8 ± 3.5 years after mitral valve repair, VAs were more common in patients with pre-operative MAD (10% vs 2% (adjusted HR 4.52, 95% CI 1.57-13.0)) (Figure 1). There were no significant differences in the risks of other clinical outcomes. Conclusions MAD was associated with almost a 5-fold increased long-term risk of VAs after mitral valve repair despite successful anatomical correction of MAD. These findings highlight the importance of increased awareness of VAs in patients with MAD also after mitral valve surgery.

Navigating the Uncommon: Case Report of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Successfully Managed with Implantable Cardioverter Defibrillator (ICD)

With a high risk of sudden cardiac mortality, arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited cardiomyopathy characterized by right ventricular dysfunction and ventricular arrhythmias (VA). In this case study, a 35-year-old presented with palpitations and revealed epsilon waves on the right precordial electrocardiogram (ECG) leads which led to the suspicion of ARVC. A 24-hour Holter monitoring revealed frequent ventricular extrasystoles (>500 per 24 hours), a CMRI revealed RV dyskinesia and transmural LGE in the apical RV, and an electrophysiologic study detected spontaneous polymorphic ventricular tachycardia (VT) despite the presence of induction ventricle fibrillation (VF). These results validated the diagnosis of ARVC and indicated that an implantable cardioverter defibrillator was necessary treatment. The ability to identify potential ARVC’s ECG abnormalities, the timing to pursue further studies, and determining necessary treatment execution are critical. The evaluation of cardiac, electrophysiological, and clinical imaging parameters is essential for the risk stratification, diagnosis, and management of patients with ARVC.

Treatment of Systemic Sclerosis Complicated By Cardiac Arrhythmia: A Case Report

Cardiac manifestations are occasionally observed in Systemic Sclerosis patients. Primary cardiac involvement may occur as a direct consequence of the disease. Arrhythmias are also thought to be a direct result from conduction system fibrosis. Early diagnosis and treatment of arrhythmia can be rewarding for this patient as if intreated may lead to a fatal outcome. Beta blockers used to treat arrythmia may worsen Raynaud’s symptom in systemic sclerosis. So there has been a controversy regarding the treatment of arrhythmia in Systemic Sclerosis. Here we are reporting a case of Systemic Sclerosis who presented with palpitation and digital gangrene. Her resting ECG showed multiple premature ventricular complexes whereas echocardiogram did not show any significant abnormality. Then She was treated with non-selective beta blocker without any progression of her Raynaud’s. For her digital gangrene, along with other conventional treatment (like nifedipine & tadalafil) she was treated with endothelin receptor antagonist (bosentan) and showed good response. J Dhaka Med Coll. 2023; 32(1) : 92-95

Post-Exercise Syncope in a Previously Healthy 67-Year-Old Man: The Bezold–Jarisch Reflex and the Role of Autonomic Nervous System Dysfunction

A 67-year-old man started treatment due to frequent asymptomatic premature ventricular complexes (PVCs) accidentally being registered during a preventive examination by a specialist, because of which he was referred to cardiologist. During the initial 24-hour (h) ECG monitoring, 4.5% PVCs and one episode of asymptomatic non-sustained ventricular tachycardia (NSVT) with three PVCs in row, at a frequency of 150 beats per minute (bpm), were detected. After the introduction of beta blockers into therapy, a lower number of PVCs, without NSVT, were recorded in the control 24 h Holter ECG, while transthoracic echocardiography (TTE) showed normal left ventricular (LV) systolic function without cardiomyopathy. So, an exercise test was indicated, and it was interrupted in the third minute at 120 beats per minute (bpm) due to fatigue and pain in the hips, without malignant arrhythmias, angina or dyspneic complaints. During the rest period, a significant inferolateral depression of the ST junction was observed, which recovered in the ninth minute. Immediately after the ECG monitoring stopped, the patient lost consciousness; his pulse was not palpable, but breathing was audible, so cardiac massage was started. After he had regained consciousness, the ECG showed alternating sinus and junctional rhythm with the lowest frequency of 33 bpm, which was accompanied by marked hypotension (80/50 mmHg). The patient was immediately hospitalized; coronary angiography and repeated TTE were completely normal, while continuous ECG monitoring did not confirm malignant rhythm disorders or asystole. It was concluded that it was vasovagal syncope (VVS), most likely caused by the Bezold–Jarisch reflex (BJR).

Prevalence of frequent premature ventricular contractions and left-ventricular systolic dysfunction in patients receiving Holter monitoring.

Premature ventricular contractions (PVCs) are frequently observed with left ventricular (LV) systolic dysfunction, although the prevalence of these associated conditions in the general population remains unknown. We sought to understand the prevalence of frequent PVCs (defined PVCs > 5%) and high burden PVCs (defined PVCs > 10%) and LV systolic dysfunction in patients receiving ambulatory Holter monitors (HM). A prospective multicenter (eight US medical centers) cross-sectional study collected demographic and PVC burden data from consecutive patients undergoing 24-h, 48-h, and 14-day HM (July 2018-June 2020). Left ventricle ejection fraction (LVEF) data was collected if obtained within 6 months of HM. Four PVC burden groups were analyzed (<1%, 1%-5%, 5.1%-10%, and >10% burden) and stratified by normal LVEF (≥50%) or presence LVEF < 50%. The prevalence of PVC burden of 5.1%-10% and >10% was 4% and 5%, respectively in the population undergoing HM (n = 6529). Age was significantly different between PVC groups (p < .001). In those with LVEF assessment (n = 3713), the prevalence of LVEF < 50% and both LVEF < 50% and PVC > 5% was 16.4% and 4.2%, respectively. The prevalence of PVC > 5% and PVC > 10% in patients with LVEF < 50% was 26% and 16%, respectively. PVC > 5% were more prevalent in older, male, and Caucasians (p < .001). Females had a lower prevalence of PVC > 5% than males (6% vs. 11%; p < .001), but not among those with LVEF < 50% (24% vs. 26%, p = .10). PVC > 5% and PVC > 10% and LVEF < 50% are prevalent in patients undergoing HM. PVC > 5% are associated with older age. Females have a lower prevalence of PVC > 5% than males but similar combined PVC > 5% and LVEF < 50%. gov identifier: NCT03228823.

A multi-adaptive neuro-fuzzy inference system with variable thresholds for heartbeat classification

Various heart disorders are non-invasively diagnosed using electrocardiograms (ECGs). An ECG records a variety of waveforms, including P, QRS, and T waves, which represent the electrical activity of the human heart. Cardiovascular diseases are diagnosed by examining the length, form, and spacing of these waveforms. This research develops a multi-adaptive, neuro-fuzzy inference system (MANFIS), enhanced by a variable threshold approach, to enhance heartbeat classification accuracy. The MIT-BIH arrhythmia database was utilized, and seven features were extracted from each record. A subtractive clustering method was employed to prepare the inputs for the MANFIS, enabling heartbeat classification. By applying a variable threshold to the MANFIS outputs, classification accuracy was further enhanced. The proposed method, termed variable-threshold MANFIS, can separately detect normal sinus rhythm, left bundle branch block, right bundle branch block, premature ventricular contraction, atrial premature condition, and paced beat. This is achieved using six different ANFIS classifiers, each with its own threshold. The system was evaluated, achieving an accuracy of 98.33%, a sensitivity of 93.12%, a specificity of 99.66%, a precision of 98.33, and an F1-score of 95.44. A distinct feature of this machine-learning-based model is its controllable threshold, which delivers promising results across all training, testing, and validation datasets. The proposed diagnostic system is applicable in new automated medical instrumentation and serves as a valuable tool in cardiology.

Functional Ventricular Undersensing After Ventricular Ectopic Beats Due to ICD Dynamic Sensitivity.

An 80-year-old patient, previously implanted for idiopathic sustained ventricular tachycardia with a Rivacor VR-T DX implantable cardioverter defibrillator (ICD Biotronik, Berlin, Germany), came to our pacemaker clinic for palpitations. Electrocardiogram (ECG) showed sinus bradycardia with interpolated ventricular ectopic beats. A ventricular-paced event occurred with a coupling interval shorter than the expected one suggesting ventricular undersensing. The phenomenon can be explained by the default ICD sensitivity setting proposed by the manufacturer.

3D Map Combined with Transthoracic Echocardiography for Ablation of Premature Ventricular Contractions/Ventricular Arrhythmia from Papillary Muscle: A Technical Report.

Ventricular arrhythmias originating from the papillary muscle of the ventricles are complex clinical problems. Catheter ablation has the potential to cure these arrhythmias. However, the procedure is usually challenging due to the specific anatomy, catheter instability and difficulty in localization of the origin of the arrhythmias. Intracardiac echocardiography (ICE) has been reported to be the suitable imaging method for assessing the location of focus in papillary muscles. We used transthoracic echocardiography (TTE), as a noninvasive cost-effective imaging supporting modality, in combination with 3D mapping to guide the exact localization and successful ablation of papillary muscle-originating premature ventricular contractions (PVCs).

Predicting long-term risk of sudden cardiac death with automatic computer-interpretations of electrocardiogram.

Computer-interpreted electrocardiogram (CIE) data is provided by almost all commercial software used to capture and store digital electrocardiograms. CIE is widely available, inexpensive, and accurate. We tested the potential of CIE in long-term sudden cardiac death (SCD) risk prediction. This is a retrospective of 8,568 consecutive patients treated for acute coronary syndrome. The primary endpoint was five-year occurrence of SCDs or equivalent events (SCDs aborted by successful resuscitation or adequate ICD therapy). CIE statements were extracted from summary statements and measurements made by the GE Muse 12SL algorithm from ECGs taken during admission. Three supervised machine learning algorithms (logistic regression, extreme gradient boosting, and random forest) were then used for analysis to find risk features using a random 70/30% split for discovery and validation cohorts. Five-year SCD occurrence rate was 3.3% (n = 287). Regardless of the used ML algorithm, the most significant risk ECG risk features detected by the CIE included known risk features such as QRS duration and factors associated with QRS duration, heart rate-corrected QT time (QTc), and the presence of premature ventricular contractions (PVCs). Risk score formed by using most significant CIE features associated with the risk of SCD despite adjusting for any clinical risk factor (including left ventricular ejection fraction). Sensitivity of CIE data to correctly identify patients with high risk of SCD (over 10% 5-year risk of SCD) was usually low, but specificity and negative prediction value reached up to 96.9% and 97.3% when selecting only the most significant features identified by logistic regression modeling (p-value threshold <0.01 for accepting features in the model). Overall, CIE data showed a modest overall performance for identifying high risk individuals with area under the receiver operating characteristic curve values ranging between 0.652 and 0.693 (highest for extreme gradient boosting and lowest for logistic regression). This proof-of-concept study shows that automatic interpretation of ECG identifies previously validated risk features for SCD.

Screening for Life-Threatening Arrhythmia in Asymptomatic Patients After Paediatric Cardiac Surgery: A Single-Centre Retrospective Analysis of 790 Pre-hospital-discharge 24-h Holter Electocardiogram Recordings.

Severe arrhythmias may occur early after open heart surgery. Because younger patients do not usually show any specific symptoms, presently Holter monitoring is routinely performed for 24h predischarge at our centre to prevent adverse outcomes. It is unknown whether this test is truly justified in this patient population. Retrospective single-centre analysis of all consecutive patients younger than 19years old after open heart surgery 2013-2019 who underwent routine Holter monitoring before hospital discharge. Patients with permanent pacemakers and patients who died during this hospital stay were excluded. The cohort was divided into two groups depending on whether severe arrhythmia occurred or not. The study includes 790 Holter recordings from 666 patients with a median age of 0.5years (IQR 0.23-3.08), performed at a median time of 8days (IQR 6-15) postoperatively. Postoperative arrhythmia was detected in 554 of 790 24-h Holter recordings (70%); in 47 of 790 (6%), this arrhythmia was classified as severe. The most common severe arrhythmias were premature ventricular contractions (n = 26/47) and long pauses (n = 14/47). A longer aortic cross-clamp time (mean 94.5 (SD ± 53.0) versus 68.1 (SD ± 51.9) min, p = 0.001) was associated with the occurrence of severe postoperative arrhythmia. Severe arrhythmias are rare in predischarge assessments after open heart surgery in children. In current postoperative monitoring at our centre, the diagnostic yield of ECG Holter monitoring for 24h is too low to justify routine screening in all paediatric patients after open heart surgery.

Assessment of palpitations in patients with frequent premature ventricular contractions.

In patients with frequent premature ventricular contractions (PVCs), palpitations may not always be directly caused by PVCs, and therefore, it is essential to establish symptom-rhythm correlations to determine the appropriate treatment. This study aims to analyze the palpitations and related factors in patients with frequent PVCs. The study enrolled patients with frequent PVCs who were not combined with other arrhythmias or structural heart disease. Through face-to-face consultation, patients were divided into symptomatic and asymptomatic groups. For symptomatic patients, the correlation between palpitations and PVC was further evaluated based on the temporal consistency of symptom onset and PVC occurrence. The demographic, clinical, and electrocardiogram features of the patients in each group were compared. Of the 214 patients enrolled, 124(57.9%) experienced palpitations. Compared to the asymptomatic group, the symptomatic group had a higher proportion of females (63.7% vs. 47.8%; p = .020) and a higher proportion of subjects with anxiety (44.4% vs.14.4%; p = .000). Within the symptomatic patients, 72 (33.60%) who had palpitations that were clearly correlated with PVCs were classified as the PVC-relevant group. In this group, the PVC CI ratios were significantly lower (55% [52% -60%] vs. 62% [55% -67%]; p = .001) and the Post-PVC CI were longer (1170 [1027-1270] vs. 1083 [960-1180] ms; p = .018) than in the PVC-irrelevant group. A direct relationship between palpitations and PVCs could be established only in a minority of patients with frequent PVCs. PVCs with a relatively short PVC CI and a long post-PVC CI were more likely to cause palpitations, whereas palpitations lasting only a few seconds were more likely to be directly relevant to PVCs.

Source Localization and Classification of Pulmonary Valve-Originated Electrocardiograms Using Volume Conductor Modeling with Anatomical Models.

Premature ventricular contractions (PVCs) are a common arrhythmia characterized by ectopic excitations within the ventricles. Accurately estimating the ablation site using an electrocardiogram (ECG) is crucial for the initial classification of PVC origins, typically focusing on the right and left ventricular outflow tracts. However, finer classification, specifically identifying the left cusp (LC), anterior cusp (AC), and right cusp (RC), is essential for detailed preoperative planning. This study aims to improve the accuracy of cardiac waveform source estimation and classification in 27 patients with PVCs originating from the pulmonary valve. We utilized an anatomical human model and electromagnetic simulations to estimate wave source positions from 12-lead ECG data. Time-series source points were identified for each measured ECG waveform, focusing on the moment when the distance between the estimated wave source and the pulmonary valve was minimal. Computational analysis revealed that the distance between the estimated wave source and the pulmonary valve was reduced to less than 1 cm, with LC localization achieving errors under 5 mm. Additionally, 74.1% of the subjects were accurately classified into the correct origin (LC, AC, or RC), with each origin demonstrating the highest percentage of subjects corresponding to the targeted excitation origin. Our findings underscore the novel potential of this source localization method as a valuable complement to traditional waveform classification, offering enhanced diagnostic precision and improved preoperative planning for PVC ablation procedures.

Machine Learning for Localization of Premature Ventricular Contraction Origins: A Review.

Premature ventricular contraction (PVC) is one of the most common arrhythmias, originating from ectopic beats in the ventricles. Precision in localizing the origin of PVCs has long been a focal point in electrophysiology research. Machine learning (ML) has developed rapidly in the past two decades with increasingly widespread applications. With the increase of clinical data such as electrocardiograms (ECGs), computed tomography (CT), and magnetic resonance imaging (MRI), ML and its subfields, deep learning (DL), have become powerful analytical tools, playing an increasingly important role in electrophysiological research. In this review, we mainly provide an overview of the development of ML in the localization of PVC origins, including its applications, advantages, disadvantages, and future research directions. This information is intended to serve as a reference for clinicians and researchers, aiding them in better-utilizing ML techniques for the diagnosis and study of PVC origins.

Clinical implication of R wave in aVR during ventricular tachycardia or premature ventricular contraction

Clinical implication of R wave in aVR during ventricular tachycardia or premature ventricular contraction

"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.