Episodes Of Ventricular Fibrillation Research Articles

Electrocardiographic characteristics and catheter ablation of premature ventricular complex- mediated ventricular fibrillation

Abstract Background Premature ventricular contractions (PVCs) can trigger ventricular fibrillation (VF) in patients with/or without structural heart disease. There are limited data on coexisting electrocardiographic (ECG) features and catheter ablation outcomes in these patients which could suggest the concomitant presence of an abnormal electrical and structural substrate. Purpose We investigated ECG and electroanatomic characteristics and clinical outcomes in patents who underwent catheter ablation of PVCs triggering VF. Methods We analyzed data from a consecutive series of patients who underwent catheter ablation between 08/2019 and 04/2023 for PVCs triggering VF. On the 12-lead ECG, we assessed the following abnormalities: (a) Early repolarization (ER) pattern in either inferior or lateral leads (Figure 1), or (b) QRS Notching of either the native sinus beat or PVC (Figure 2). Post-ablation follow up outcomes were collected using a combination of ICD interrogation, remote transmission and clinical follow up. Results The cohort included 15 patients: age 52.1±16.8 years, 46.7% females, and 26.7% presenting with VF storm. On average, there were 3.8 HV shocks/per patient from an ICD prior to the index ablation procedure (range: 0-19 shocks). On the 12-lead ECG, the mean coupling interval of the PVC leading to VF was 204±82 ms, and an overall narrow PVC morphology with a mean QRS duration of 107±17 ms. We observed early repolarization (ER) in 6 (40%) of the cohort. In most patients (n=11; 73.3%), at least one of the 2 ECG abnormalities were present. An endocardial-only approach was adequate in all patients, and during catheter ablation, Purkinje potentials were targeted in 10 (66%) of the patients. Based on activation and pace-mapping, the PVCs were localized to the following sites: (a) left ventricular (LV) septum in 11 (73.3%), (b) papillary muscles in 2 (13.3%), and (c) other sites such as the Moderator band and right ventricular outflow tract in the remaining 2 (13.3%) patients. The ablation locations on the LV septum extended from basal to mid-septum. After an average of 1.7 ablation procedures targeting PVC-triggering VF, 12 (80%) patients remained free of sustained ventricular arrhythmias and ICD shocks, over a mean follow up of 479±395 days. Conclusion In most patients with PVCs-triggering VF, there was an evidence of an ECG abnormality either in the form of an ER pattern or notching of either the Sinus QRS or the PVC complex on pre-ablation ECG. During ablation, Purkinje potentials and PVCs were mapped to and ablated in the region of the LV interventricular septum and papillary muscles. Over long-term follow up, catheter ablation seemed durable and effective in reducing VF episodes and ICD shocks.Presence of Early Repolarization patternPresence of a notching pattern in the Si

CARDIOPULMONARY SUPPORT WITH EXTRACORPOREAL MEMBRANE OXYGENATION (ECMO) DURING CATHETER ABLATION OF VENTRICULAR FIBRILLATION: A CASE REPORT

Abstract The clinical case deals with a 46–year–old man, severely obese and suffering from type II diabetes mellitus and arterial hypertension, a smoker. He was admitted to our department for iterative ventricular fibrillation (VF) following a recent acute myocardial infarction with ST–segment elevation treated with percutaneous coronary angioplasty (PTCA) and implantation of drug–eluting stents on the anterior interventricular. Control coronary angiography showed good results of previous PTCA. On the echocardiogram, left ventricular pump function moderately reduced (EF 45%) with district alterations of the kinetics and aneurysmal dilatation of the ascending aorta. During hospitalization, iterative episodes of VF despite maximal antiarrhythmic therapy, promptly treated with DC shock. Continuous telemetry monitoring showed frequent early premature ventricular complex (PVC) triggering VF episodes. A 12–lead Holter ECG was performed to better identify the morphology of these PVC, documenting PVC of morphology compatible with origin from Purkinjie fibres. An electrophysiological study and mapping of the left ventricle were performed with extracorporeal membrane oxygenation (ECMO) support. During mapping of the middle left interventricular septum, VF occurred several times and was promptly treated with DC shock. In this area have been documented Purkinje fibers and low voltage and multifragmented areas; ablation was then performed by delivering radiofrequency in this area until the all potentials were completely eliminated. After ablation, no more ventricular arrhythmias were induced. Cardiac magnetic resonance imaging was performed which showed large areas of late gadolinium enhancement. The patient underwent automatic defibrillator implantation. Ventricular arrhythmias were no longer documented during telemetric monitoring. In this complex case of significant arrhythmic instability in ischemic heart disease with moderate left ventricular pump dysfunction, ECMO assistance allowed us to effectively and safely perform the ablation of the arrhythmic substrate triggering the iterative episodes of VF.

Ventricular Arrhythmias After Primary Percutaneous Coronary Intervention for STEMI

Currently, mortality risk for patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) with an uncomplicated postprocedure course is low. Less is known regarding the risk of in-hospital ventricular tachycardia (VT) and ventricular fibrillation (VF). To evaluate the risk of late VT and VF after primary PCI for STEMI. This cohort study included adults aged 18 years or older with STEMI treated with primary PCI between January 1, 2015, and December 31, 2018, identified in the US National Cardiovascular Data Registry Chest Pain-MI Registry. Data were analyzed from April to December 2020. Multivariable logistic regression was used to evaluate the risk of late VT (≥7 beat run of VT during STEMI hospitalization ≥1 day after PCI) or VF (any episode of VF≥1 day after PCI) associated with cardiac arrest and associations between late VT or VF and in-hospital mortality in the overall cohort and a cohort with uncomplicated STEMI without prior myocardial infarction or heart failure, systolic blood pressure less than 90 mm Hg, cardiogenic shock, cardiac arrest, reinfarction, or left ventricular ejection fraction (LVEF) less than 40%. A total of 174 126 eligible patients with STEMI were treated with primary PCI at 814 sites in the study; 15 460 (8.9%) had VT or VF after primary PCI, and 4156 (2.4%) had late VT or VF. Among the eligible patients, 99 905 (57.4%) at 807 sites had uncomplicated STEMI. The median age for patients with late VT or VF overall was 63 years (IQR, 55-73 years), and 75.5% were men; the median age for patients with late VT or VF with uncomplicated STEMI was 60 years (IQR, 53-69 years), and 77.7% were men. The median length of stay was 3 days (IQR, 2-7 days) for the overall cohort with late VT or VF and 3 days (IQR, 2-4 days) for the cohort with uncomplicated STEMI with late VT or VF. The risk of late VT or VF was 2.4% (overall) and 1.7% (uncomplicated STEMI). Late VT or VF with cardiac arrest occurred in 674 patients overall (0.4%) and in 117 with uncomplicated STEMI (0.1%). LVEF was the most significant factor associated with late VT or VF with cardiac arrest (adjusted odds ratio [AOR] for every 5-unit decrease ≤40%: 1.67; 95% CI, 1.54-1.85). Late VT or VF events were associated with increased odds of in-hospital mortality in the overall cohort (AOR, 6.40; 95% CI, 5.63-7.29) and the cohort with uncomplicated STEMI (AOR, 8.74; 95% CI, 6.53-11.70). In this study, a small proportion of patients with STEMI treated with primary PCI had late VT or VF. However, late VT or VF with cardiac arrest was rare, particularly in the cohort with uncomplicated STEMI. This information may be useful when determining the optimal timing for hospital discharge after STEMI.

Extravascular Implantable Cardioverter-Defibrillator Sensing and Detection in a Large Global Population.

The extravascular (EV) implantable cardioverter-defibrillator (ICD) includes features to address sensing and arrhythmia detection challenges presented by its substernal lead location. In this study, the authors sought to evaluate sensing and detection performance in 299 patients discharged with an EV-ICD in the global pivotal study. We reviewed and adjudicated all induced ventricular fibrillation (VF) episodes and spontaneous device-stored episodes that satisfied rate and duration criteria in a programmed ventricular tachycardia (VT)/VF therapy zone. At implantation, all EV-ICDs detected induced VF at the programmed sensitivity; 95.9% detected VF with a 3× safety margin. In follow-up, EV-ICDs detected all 59 VT/VF episodes that sustained until therapy. Of 1,034 non-VT/VF episodes, oversensing caused 87.9% and supraventricular tachycardia caused 12.1%. Therapy was withheld in 80.9%, aborted in 10.6%, and delivered in 8.5%. The most common causes of oversensing were myopotentials (61.2%) and P-wave oversensing (PWOS) (19.9%). Inappropriate shocks occurred in only 3.2% of myopotential episodes, but in 21.8% of PWOS episodes. Myopotential oversensing was more common with Ring-Can sensing (P< 0.0001) and correlated with low R-wave amplitude (P< 0.0001). PWOS occurred almost exclusively with Ring1-Ring2 sensing (P=0.0001) and began with transient decrease in R-wave or increase in P-wave amplitude (P< 0.0001). In software emulation, a new PWOS discriminator significantly reduced total inappropriate detections. In a global population, EV-ICD detected induced and spontaneous VT/VF accurately. Although discriminators withheld detection from most non-VT/VF episodes, inappropriate shocks were common. The most common cause was PWOS, which may be reduced by optimizing sensing at implantation and incorporation of the PWOS discriminator, which is now in the current device. (Extravascular ICD Pivotal Study [EV ICD]; NCT04060680).

A case of early repolarization syndrome in which hyponatremia and coronary vasospasms induced ventricular fibrillation

A 60-year-old man was referred to our hospital presenting with unconsciousness due to severe hyponatremia. The twelve‑lead ECG on admission exhibited prominent J waves in the inferolateral leads. During the treatment for hyponatremia, ventricular fibrillation (VF) occurred and the electrogram (ECG) after the VF incident exhibited marked ST elevation in the inferolateral leads. An Ach provocation test induced vasospasms in the right and left coronary arteries and J wave augmentation, suggesting a high risk for vasospastic angina. Finally, a subcutaneous implantable cardioverter defibrillator was implanted in the patient. We hereby discuss the possible contribution of hyponatremia to VF episodes in early repolarization syndrome based on the present case.

Chronic congestion with oral feeds in the presence of subglottic stenosis: a case report

Abstract Background Subglottic stenosis is the narrowing of the airway below the vocal folds. It can present as a congenital or acquired condition. The primary clinical presentation is often noted as noisy breathing, also known as stridor. Diagnosis in the infant pediatric population poses challenges due to age-related factors and symptom variability. This case report highlights a pediatric patient whose predominant symptom was congestion during oral feeds. Case presentation A 3-month-old pre-term male, intubated following an episode of ventricular fibrillation with underlying viral infection, presented with prolonged, persistent congestion with oral feeds. Given persistent congestion, the differential diagnosis included aspiration, recovery from a viral illness, reflux, and an anatomical stricture. A videofluoroscopic swallow study was completed and ruled out oropharyngeal dysphagia from the differential. Despite this exclusion and the patient’s eventual recovery from his viral illness, congestion with oral feeds continued to worsen. A fiberoptic endoscopic evaluation was completed and revealed Grade 2 subglottic stenosis. The patient required immediate intervention via balloon dilation in the operating room. Conclusions Acquired subglottic stenosis is often a consequence of intubation. Symptoms are variable and can be difficult to diagnose in pediatric patients. Timely intervention is essential to prevent life-threatening conditions.

Prediction and Detection of Ventricular Fibrillation Using Complex Features and AI-Based Classification

We analyzed the possibility of detecting and predicting ventricular fibrillation (VF), a medical emergency that may put people’s lives at risk, as the medical prognosis depends on the time in which medical personnel intervene. Therefore, besides immediate detection of VF, the possibility of predicting VF 40 or even 50 min in advance was analyzed. For testing the proposed algorithm, we used ECG signals taken from the MIT-BIH database, namely, Malignant Ventricular Ectopy Database, Sudden Cardiac Death Holter Database and Normal Sinus Rhythm Database. The presented method is based on features extracted from the ECG signals in the time domain, frequency domain and complexity measures. For VF detection, the possibility of identifying the VF episode in the first 3 s after its occurrence was tested. For this, the first 3 s immediately after the appearance of VF were cut out and the features were computed on these sections. For VF prediction, 3 min of the ECG signal clipped 40 or 50 min before VF onset was used. Then, on these pieces of ECG signal, the specific features were calculated for 1 s segments. For the normal signal situation, 3 min was randomly selected from the database with normal ECGs. For the classification or detection stage, both an MLP-type neural network and the classifiers from the Machine Learning toolbox of the MATLAB® environment were used. The results obtained for both detection and classification are over 94% in both cases. The novelty of our results compared to those previously obtained is the time interval with which the possibility of prediction was analyzed, namely, 50 min in advance of the VF installation date. This means that the patient will be informed that it is possible to suffer a VF and has time to take the necessary measures to overcome a possible medical emergency.

1-dimensional convolutional neural networks for predicting sudden cardiac

&lt;span&gt;Sudden cardiac arrest (SCA) is a serious heart problem that occurs without symptoms or warning. SCA causes high mortality. Therefore, it is important to estimate the incidence of SCA. Current methods for predicting ventricular fibrillation (VF) episodes require monitoring patients over time, resulting in no complications. New technologies, especially machine learning, are gaining popularity due to the benefits they provide. However, most existing systems rely on manual processes, which can lead to inefficiencies in disseminating patient information. On the other hand, existing deep learning methods rely on large data sets that are not publicly available. In this study, we propose a deep learning method based on one-dimensional convolutional neural networks to learn to use discrete fourier transform (DFT) features in raw electrocardiogram (ECG) signals. The results showed that our method was able to accurately predict the onset of SCA with an accuracy of 96% approximately 90 minutes before it occurred. Predictions can save many lives. That is, optimized deep learning models can outperform manual models in analyzing long-term signals.&lt;/span&gt;

Sex- and age-dependent susceptibility to ventricular arrhythmias in the rat heart ex vivo

The incidence of life-threatening ventricular arrhythmias, the most common cause of sudden cardiac death (SCD), depends largely on the arrhythmic substrate that develops in the myocardium during the aging process. There is a large deficit of comparative studies on the development of this substrate in both sexes, with a particular paucity of studies in females. To identify the substrates of arrhythmia, fibrosis, cardiomyocyte hypertrophy, mitochondrial density, oxidative stress, antioxidant defense and intracellular Ca2+ signaling in isolated cardiomyocytes were measured in the hearts of 3- and 24-month-old female and male rats. Arrhythmia susceptibility was assessed in ex vivo perfused hearts after exposure to isoproterenol (ISO) and hydrogen peroxide (H2O2). The number of ventricular premature beats (PVBs), ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes, as well as intrinsic heart rate, QRS and QT duration, were measured in ECG signals recorded from the surfaces of the beating hearts. After ISO administration, VT/VFs were formed only in the hearts of males, mainly older ones. In contrast, H2O2 led to VT/VF formation in the hearts of rats of both sexes but much more frequently in older males. We identified several components of the arrhythmia substrate that develop in the myocardium during the aging process, including high spontaneous ryanodine receptor activity in cardiomyocytes, fibrosis of varying severity in different layers of the myocardium (nonheterogenic fibrosis), and high levels of oxidative stress as measured by nitrated tyrosine levels. All of these elements appeared at a much greater intensity in male individuals during the aging process. On the other hand, in aging females, antioxidant defense at the level of H2O2 detoxification, measured as glutathione peroxidase expression, was weaker than that in males of the same age. We showed that sex has a significant effect on the development of an arrhythmic substrate during aging. This substrate determines the incidence of life-threatening ventricular arrhythmias in the presence of additional stimuli with proarrhythmic potential, such as catecholamine stimulation or oxidative stress, which are constant elements in the pathomechanism of most cardiovascular diseases.

Spontaneous Coronary Artery Dissection Presenting as Electrical Storm: A Case Report.

Spontaneous coronary artery dissection (SCAD) is an important cause of myocardial infarction in patients of younger age without typical atherosclerotic risk factors and can present with ventricular arrhythmia such as ventricular tachycardia (VT) or ventricular fibrillation (VF). Electrical storm (ES) is defined as greater than or equal to 3 episodes of VT or VF occurring within 24 hours. A healthy 38-year-old-male developed chest pain while exercising at the gym and presented to the emergency department unresponsive in a ventricular arrhythmia defined as ES. The patient's cardiac arrest was initially refractory to standard defibrillation and Advanced Cardiac Life Support medications. He was ultimately diagnosed with SCAD of the left anterior descending artery, which was stented. The patient survived neurologically intact after a 13-day hospital stay. Spontaneous coronary artery dissection is a significant cause of acute coronary syndrome and occurs in healthier patients without cardiac risk factors. Electrical storm represents a unique manifestation of SCAD. Emergency physicians should maintain a heightened suspicion for SCAD for accurate diagnosis and treatment.

Clinical characteristics of electrical storm in patients with early repolarization syndrome

BackgroundEarly repolarization syndrome (ERS) is an idiopathic ventricular fibrillation (VF) associated with inferolateral J waves. While electrical storm (ES) in ERS is not rare, their characteristics and risk factors are not fully understood. ObjectiveThis study aimed to clarify the significance of ES in ERS. MethodsWe evaluated 44 patients with ERS who experienced VF/sudden cardiac death or arrhythmic syncope. We assessed clinical characteristics to identify the risk factors for ES. ResultsIn total, 13 patients (30%) experienced ES (ES group). Of these, 11 patients (85%) experienced ES during the acute phase of initial VF episodes and 2 patients (2%) experienced ES during follow-up. VF associated with ES occurred during therapeutic hypothermia in 6 of 13 patients (46%). The J-wave voltage during therapeutic hypothermia was higher in the ES group than that in the patients without ES. Isoproterenol was used in 5 patients (38%), which decreased J-wave voltage and relieved ES. Among the clinical markers, shorter QT and QTp intervals (the interval from QRS onset to the peak of T wave), pilsicainide-induced ST elevation, and high scores on the Shanghai Score System were associated with ES. Although pilsicainide induced ST elevation in 6 of 34 patients (18%), spontaneous Brugada electrocardiographic patterns did not appear to be associated with VF. Therapeutic hypothermia was also a risk factor for acute phase ES. ConclusionPatients with ERS in the ES group frequently had short QT and QTp intervals, pilsicainide-induced ST elevations, and high Shanghai Score System scores. Therapeutic hypothermia was also associated with acute phase ES.

High-risk Brugada syndrome: factors associated with arrhythmia recurrence and benefits of epicardial ablation in addition to implantable cardioverter defibrillator implantation.

This study aims to evaluate the prognostic impact of the arrhythmogenic substrate size in symptomatic Brugada syndrome (BrS) as well as to validate the long-term safety and effectiveness of epicardial radiofrequency ablation (RFA) compared with no-RFA group. In this prospective investigational long-term registry study, 257 selected symptomatic BrS patients with implantable cardioverter defibrillator (ICD) implantation were included. Among them, 206 patients underwent epicardial RFA and were monitored for over 5 years post-ablation (RFA group), while 51 patients received only ICD implantation declining RFA. Primary endpoints included risk factors for ventricular fibrillation (VF) events pre-ablation and freedom from VF events post-ablation. In the RFA group, BrS substrates were identified in the epicardial surface of the right ventricle. During the pre-RFA follow-up period (median 27 months), VF episodes and VF storms were experienced by 53 patients. Independent risk factors included substrate size [hazard ratio (HR), 1.13; 95% confidence interval (CI), 1.08-1.18; P < 0.001], aborted cardiac arrest (HR, 2.98; 95% CI, 1.68-5.28; P < 0.001), and SCN5A variants (HR, 2.22; 95% CI, 1.15-4.27; P = 0.017). In the post-RFA follow-up (median 40 months), the RFA group demonstrated superior outcomes compared with no-RFA (P < 0.001) without major procedure-related complications. Our study underscores the role of BrS substrate extent as a crucial prognostic factor for recurrent VF and validates the safety and efficacy of RFA when compared with a no-RFA group. Our findings highlight the importance of ajmaline in guiding epicardial mapping/ablation in symptomatic BrS patients, laying the groundwork for further exploration of non-invasive methods to guide informed clinical decision-making.

Multiple Implantable Cardioverter-Defibrillator Shocks in Ischemic Cardiomyopathy Compels Coronary Vascularization Reassessment

Abstract The increasing number of patients with heart failure and implantable cardioverter-defibrillators (ICD) has led to a growing of the emergency presentations for ICD internal shocks. Appropriate shocks are sometimes caused by acute events in the course of disease and could be one of the earliest symptoms contributing to the diagnosis and timely treatment of these acute conditions. We present the case of a 64-year-old male patient with ischemic cardiomyopathy, ICD carrier, who presented to the emergency department for recurrent appropriate ICD shocks caused by episodes of polymorphic ventricular tachycardia and ventricular fibrillation. Even if he did not have chest pain, he was referred to cath lab, where the coronary angiography has shown a severe stenosis at the origin of the left anterior descending artery and a moderate stenosis at the proximal left circumflex artery. The percutaneous revascularization of both lesions resulted in the eradication of the sustained ventricular arrhythmias and the improvement of the clinical status. The case argues for the need for coronary vascularization assessment in ICD carrier patients with ischemic heart failure and adequate recurrent shocks, also emphasizing the importance of remote monitoring in early diagnosis of acute conditions in these patients.

Immediate, early and late ventricular fibrillation complicating acute myocardial infarction: insights from a real life registry

Abstract Background Conflicting data exist on the prognosis of ventricular fibrillation (VF) based on its timing in relation to coronary occlusion in acute myocardial infarction (AMI). Purpose To describe the patient profile and prognostic impact of VF during AMI according to its time of occurrence. Methods Data from three nationwide French cohorts carried out 5 years apart from 2005 to 2015 were analysed (FAST-MI program). All consecutive patients with AMI (STEMI and Non-STEMI) over a 1-month period were enrolled and followed 5 years. The present analysis focused on patients who presented with VF according to its time of occurrence defined as: immediate (out-of-hospital cardiac arrest), early (&amp;lt;48h at admission) and late (≥48h after admission). Results Out of 13 125 patients admitted for AMI (66±14 years, 71% men, 52% ST-elevation myocardial infarction-STEMI), 406 (3.1%) presented with VF including 205 immediate (50.5%), 147 early (36.2%) and 54 late (13.3%) VF episodes. Immediate and early VF were most frequent during STEMI (respectively 2.3% and 1.8% vs. 0.8% and 0.4% in non-STEMI, p&amp;lt;0.001), while late VF incidence was as frequent in ST-elevation and non-STEMI (0.5% vs 0.4%, p value). The proportion of immediate, early and late VF in AMI were similar in 2005, 2010 and 2015. Patients with immediate (61.6±13.2 yo) or early (62.4±14.2 yo) VF were younger than those with no VF (66.1±14.1 yo, p&amp;lt;0.001) while patients with late VF patients were the oldest (70.5±13.6 yo). LVEF was lower in patients with early (48±10%) or late (48±13%), compared with patients without VF (52±11%) or those with immediate VF (51±12%) (p&amp;lt;0.001). In-hospital mortality was particularly high in patients who developed immediate (24.9%) and late (37.0%) VF, intermediate in early VF patients (10.9%) and lowest in non-VF patients (3.0%) (p&amp;lt;0.001). Among patients alived at hospital discharge, and compared with patients with no VF (4.2%), the six-month mortality was considerably increased in the late VF subgroup (17.6%, adjusted HR: 6.04 [2.69-13.58], P&amp;lt;0.001), moderately increased in immediate VF (5.2%, HR:2.15 [1.06-4.34, P=0.03) ) and did not differ in early VF (1.5%, HR: 0.52 [0.13-2.11 P=0.36). At five years, mortality was also significantly higher in patients with late VF (38.2%, adjusted HR 1.72 [1.01-2.91]), with no significant difference between immediate, early, and non VF patients (14.2%, 11.5% and 19.3% respectively). Conclusions Patients with immediate, early and late VF during AMI do present with significantly different profiles. Still, only late VF (≥48h after admission) was associated with poorer outcome after the index hospitalisation, especially within the initial 6 months. By contrast with current guidelines based on relatively old data from the 2000s in secondary prevention in ischemic or non-ischemic settings, the extent to which patients with late VF would benefit from rapid cardioverter defibrillator implantation is questionable.3 months survival after VF in AMI5 year survival after VF in AMI

Efficacy and safety of percutaneous left stellate ganglion block in patients with refractory electrical storm: our five years experience

Abstract Background Neuromodulation by percutaneous stellate ganglion block (PSGB) with local anaesthetic has proven its antiarrhythmic effect suitable for an emergency setting. Purpose To assess the efficacy and safety of PSGB performed with an anterior anatomical approach in patients with refractory electrical storm. Methods Patients with electrical storm were enrolled from November 2017 to December 2022. Left PSGB (PLSGB) was performed after failure of at least one intravenous antiarrhythmic drug. Its repetition or a continuous infusion of the local anaesthetic were considered in selected cases. Clinical data, characteristics of the block and complications were collected. The efficacy was evaluated by comparing the number of arrhythmias treated with ATP or DC-shocks by external or internal defibrillator in the hour before the block with that in the hour after the block. Per-patient efficacy was assessed by comparing the number of ATP/shocks in the 12 hours before the first procedure with that in the 12 hours after the last one. Results 37 patients were enrolled: 76% male, mean age 65 years; 11 with dilated cardiomyopathy, 18 with chronic ischemic heart disease, 11 with ST-elevation myocardial infarction, 3 with non-ST-elevation myocardial infarction, 1 with arrhythmogenic right ventricular cardiomyopathy and 1 with drug intoxication. A total of 62 PLSGBs were performed: 19 for ventricular tachycardia (VT), 26 for ventricular fibrillation (VF) and 17 for both VT and VF episodes; 15 on intubated patients, 4 in extracorporeal circulation, 14 in refractory cardiac arrest, 7 in cardiogenic/septic shock, 28 on patients on single antiplatelet therapy, 11 on dual antiplatelet therapy, 33 on anticoagulant therapy. PLSGBs were performed during intravenous infusion of antiarrhythmics (amiodarone in 30, lidocaine in 37 procedures). The local anaesthetic used was lidocaine in 27/62 PLSGB, bupivacaine in 6/62 and both in 29/62. The per-procedure analysis showed a significant reduction of the number of ATP/shocks in the hour after PLSGB compared with the hour before [0 (0-0) vs 5 (1-8) p&amp;lt;0.001]. Similarly, in the per-patient analysis, the number of ATP/shocks significantly decreased in the 12 hours after the PLSGB compared with that in the 12 hours before [0 (0-1.3) vs 7 (4.8-12.5) p&amp;lt;0.001]. No complications occurred. Conclusions This case series reports our five years experience in performing PLSGB for antiarrhythmic purpose and it confirms its efficacy and safety in the treatment of refractory electrical storm. In particular, the anatomical approach requires few tools and can be easily performed at the bedside.

Outcomes of catheter ablation in high-risk patients with Brugada syndrome refusing an implantable cardioverter defibrillator implantation.

The aim of this study was to investigate the outcomes of catheter ablation (CA) in preventing arrhythmic events among patients with symptomatic Brugada syndrome (BrS) who declined implantable cardioverter defibrillator (ICD) implantation. A total of 40 patients with symptomatic BrS were included in the study, of which 18 refused ICD implantation and underwent CA, while 22 patients received ICD implantation. The study employed substrate modification (including endocardial and epicardial approaches) and ventricular fibrillation (VF)-triggering pre-mature ventricular contraction (PVC) ablation strategies. The primary outcomes were a composite endpoint consisting of episodes of VF and sudden cardiac death during the follow-up period. The study population had a mean age of 43.8 ± 9.6 years, with 36 (90.0%) of them being male. All patients exhibited the typical Type 1 BrS electrocardiogram pattern, and 16 (40.0%) were carriers of an SCN5A mutation. The Shanghai risk scores were comparable between the CA and the ICD groups (7.05 ± 0.80 vs. 6.71 ± 0.86, P = 0.351). Ventricular fibrillation-triggering PVCs were ablated in 3 patients (16.7%), while VF substrates were ablated in 15 patients (83.3%). Epicardial ablation was performed in 12 patients (66.7%). During a median follow-up of 46.2 (17.5-73.7) months, the primary outcomes occurred more frequently in the ICD group than in the CA group (5.6 vs. 54.5%, Log-rank P = 0.012). Catheter ablation is an effective alternative therapy for improving arrhythmic outcomes in patients with symptomatic BrS who decline ICD implantation. Our findings support the consideration of CA as an alternative treatment option in this population.

Triggers of Ventricular Fibrillation in Patients With Inferolateral J-Wave Syndrome

BackgroundThere are few data on ventricular fibrillation (VF) initiation in patients with inferolateral J waves. ObjectivesThis multicenter study investigated the characteristics of triggers initiating spontaneous VF in inferolateral J-wave syndrome. MethodsA total of 31 patients (age 37 ± 14 years, 24 male) with spontaneous VF episodes associated with inferolateral J waves were evaluated to determine the origin and characteristics of triggers. The J-wave pattern was recorded in inferior leads in 11 patients, lateral leads in 3, and inferolateral leads in 17. ResultsThe VF triggers (n = 37) exhibited varying QRS durations (176 ± 21 milliseconds, range 119-219 milliseconds) and coupling intervals (339 ± 46 milliseconds, range 250-508 milliseconds) with a right (70%) or left (30%) bundle branch block (BBB) pattern. Trigger patterns were associated with J-wave location: left BBB triggers with inferior J waves and right BBB triggers with lateral J waves. Electrophysiologic study was performed for 22 VF triggers in 19 patients. They originated from the left or right Purkinje system in 6 and from the ventricular myocardium in 10 and were undetermined in 6. Purkinje vs myocardial triggers showed distinct electrocardiographic characteristics in coupling interval and QRS-complex duration and morphology. Abnormal epicardial substrate associated with fragmented electrograms was identified in 9 patients, with triggers originating from the same region in 7 patients. Catheter ablation resulted in VF suppression in 15 patients (79%). ConclusionsVF initiation in inferolateral J-wave syndrome is associated with significant individual heterogeneity in trigger characteristics. Myocardial triggers have electrocardiographic features distinct from Purkinje triggers, and their origin often colocalizes with an abnormal epicardial substrate.

Ventricular Tachycardia.

This scenario was developed to educate emergency medicine residents on the diagnosis and management of ventricular tachycardia (VT) that is refractory to single dose anti-arrhythmic management. Electrical storm, defined as three or more episodes of sustained VT, ventricular fibrillation, or appropriate shocks from an implantable cardioverter defibrillator within 24 hours,1 has a mortality rate up to 14% in the first 48 hours.2 Ventricular tachycardia may present in a heterogenous fashion, not only with stable versus unstable clinical presentations, but also with different electrocardiographic morphologies and etiologies.1 Understanding how to rapidly diagnose, treat, and utilize second or third-line treatments is vital in the setting of refractory ventricular tachycardia rather than relying on the success of first-line agents. Appreciation for what medications are readily available in your crash cart and medication dispensing cabinet is critical for timely management for refractory ventricular tachycardia. At the conclusion of the simulation session, learners will be able to: 1) identify the different etiologies of VT, including structural heart disease, acute ischemia, and acquired or congenital QT syndrome; 2) describe confounding factors of VT, such as electrolyte abnormalities and sympathetic surge; 3) describe how to troubleshoot an unsuccessful synchronized cardioversion, including checking equipment connections, increasing delivered energy, and changing pad placement; 4) compare and contrast treatments of VT based on suspected underlying etiology; 5) describe reasons to activate the cardiac catheterization lab other than occlusive myocardial infarction; and 6) identify appropriate disposition of the patient to the cardiac catheterization lab. This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on the diagnosis, differential diagnosis, and management of VT. Debriefing methods may be left to the discretion of participants, but the authors have utilized advocacy-inquiry techniques. This scenario may also be run as an oral board case. Our residents are provided a survey at the completion of the debriefing session so they may rate different aspects of the simulation, as well as provide qualitative feedback on the scenario. The local institution's simulation center's electronic feedback form is based on the Center of Medical Simulation's Debriefing Assessment for Simulation in Healthcare (DASH) Student Version Short Form3 with the inclusion of required qualitative feedback if an element was scored less than a 6 or 7. Twelve learners completed a feedback form. This session received 6 and 7 scores (consistently effective/very good and extremely effective/outstanding, respectively) other than three isolated 5 scores. The lowest average score was 6.67 for "Before the simulation, the instructor set the stage for an engaging learning experience." The highest average score was 7 for "The instructor helped me see how to improve or how to sustain good performance." The form also includes an area for general feedback about the case at the end. Illustrative examples of feedback include: "Excellent care and debrief." Specific scores are available upon request. This is a cost-effective method for reviewing VT diagnosis and management. The case may be modified for appropriate audiences, such as describing what medications may be readily available in a free-standing emergency department or pre-hospital setting. Medical simulation, ventricular tachycardia, cardiac emergencies, dysrhythmias, cardiology, emergency medicine.

Destabilization of the Organized Structure of Ventricular Fibrillation During Reperfusion

Aim: to study the effect of reperfusion on the organized frequency-amplitude structure of ventricular fibrillation (VF) in the dog heart.Materials and methods. We conducted 4 experiments on 8 dogs. In each experiment, the isolated heart of one dog was perfused with the blood of the second (supporting) dog. In 4 experiments on an isolated artificially perfused heart, 6 episodes of 3 min ischemia and 10 min reperfusion of the heart were performed in VF (1–2 episodes of ischemia-reperfusion in one experiment). Each episode of 3 min ischemia in VF was preceded by a 10 min perfusion of the heart in VF. Ventricular electrogram was recorded during VF episodes. A frequencyamplitude (spectral) analysis of 1 sec segments of the electrogram was performed, and the proportion (in %) of 0.5–15 Hz frequency oscillations in 10 sec segments of the electrogram was determined in 6 episodes of perfusion, ischemia and reperfusion in VF (M±m, N=60). The VF frequency-amplitude structures during ischemia and reperfusion were compared with the stable VF frequency-amplitude structure during perfusion taken as the control. The nonparametric Welch criterion in the «The R Project for Statistical Computing» software environment was used to compare the VF parameters during perfusion, ischemia and reperfusion. Results. 9–10 Hz frequency oscillations dominated in the VF frequency-amplitude structure during heart perfusion, taken as the control. In the first 30 sec of ischemia, the frequency and amplitude of the dominant oscillations did not significantly change vs VF control obtained during cardiac perfusion. A decrease of dominant oscillations frequency up to 6.5–7.5 Hz, and of the proportion of oscillations — up to 26% was documented at the 3rd min of ischemia. At the 1st min of reperfusion, the frequency of dominant oscillations increased to 13.5–14.5 Hz, but the proportion of oscillations remained reduced to 26%, as at the 3rd min of ischemia. At the 2nd min of reperfusion, the frequency of dominant oscillations decreased to 9.5–10.5 Hz, and the proportion of dominant oscillations increased to 33%. The frequency and amplitude of the dominant oscillations stabilized at 3–10 min of reperfusion: oscillations at 9–10 Hz frequency accounted for 32–33% of the spectral power.Conclusion. Reperfusion in VF is characterized by transient destabilization of VF organized structure at the 1st min of the procedure. VF organized structure regains stabilization within 2–10 min of reperfusion. Cardiac perfusion in intentionally induced VF can be used instead of cardioplegia during major cardiac surgery to boost cardiac resistance to ischemia and prevent or reduce reperfusion complications.

Real-world evidence for the use of subcutaneous implantable cardioverter-defibrillators in China: Asingle-center experience.

Subcutaneous implantable cardioverter-defibrillators (S-ICDs) have been shown to be non-inferior to transvenous ICDs in the prevention of sudden cardiac death (SCD), but there is still alack of evidence from clinical trials in China. We investigated whether S‑ICD implantation in the Chinese population is safe and feasible and should be promoted in the future. Consecutive patients undergoing S‑ICD implantation at our center were enrolled in this retrospective study. Data were collected within the median follow-up period of 554days. Data concerning patient selection, implantation procedures, complications, and episodes of shock were analyzed. In total, 70.2% of all 47patients (median age = 39years) were included for secondary prevention of SCD with different etiologies. Vector screening showed that 98% of patients were with > 1 appropriate vector in all postures. An intraoperative defibrillation test was not performed on six patients because of the high risk of disease deterioration, while all episodes of ventricular fibrillation induced post implantation were terminated by one shock. As expected, no severe complications (e.g., infection and device-related complications) were observed, except for one case of delayed healing of the incision. Overall, 15patients (31.9%) experienced appropriate shocks (AS) with all episodes terminated by one shock. Two patients (4.3%) experienced inappropriate shocks (IAS) due to noise oversensing, resulting in ahigh Kaplan-Meier IAS-free rate of 95.7%. Based on appropriate patient selection and standardized implantation procedures, this real-world study confirmed the safety and efficacy of S‑ICD in Chinese patients, indicating that it may help to promote the prevention of SCD in China.