Direct Current Shock Research Articles

Rationale and study design of the international randomized control trial MYocarditis THerapy with Steroids: the MYTHS trial

Abstract Background Immunosuppression is generally suggested in patients with specific subtypes of acute myocarditis, such as eosinophilic myocarditis or giant cell myocarditis or associated with systemic autoimmune disorders. In contrast, no specific treatment for most acute myocarditis complicated by acute heart failure (HF) or cardiogenic shock is recommended beyond the management of acute HF and supportive therapy. Nevertheless, large registries commonly reported using corticosteroids in severe forms without data supporting this strategy. Purpose To assess the safety and efficacy of high-dose pulse intravenous (IV) corticosteroid therapy to treat patients with complicated/fulminant acute myocarditis based on clinical suspicion. Methods An international pragmatic investigator-initiated single-blinded randomized controlled trial that screens patients between 18 and 70 years admitted to the hospital for suspected acute myocarditis (cardiac symptoms onset within three weeks) complicated by acute HF/cardiogenic shock and left ventricular (LV) ejection fraction<41% without significant LV dilation is ongoing. Patients are randomized in a 1:1 ratio to pulsed IV methylprednisolone (1 g) in saline solution (250 mL) daily for three days or placebo (saline without methylprednisolone) on top of standard therapy and maximal supportive care. A final diagnosis of myocarditis is confirmed by histology or cardiac magnetic resonance imaging. A population of 288 patients has been planned to assess a reduction in the probability of reaching the primary endpoint from 25% in the placebo arm to 12% in the methylprednisolone arm with a power of 0.80 (Figure). The main analysis will be conducted on an intention-to-treat basis. Results The primary efficacy endpoint of the trial is defined as the time from randomization to the first event occurring within 6 months, including all-cause death, heart transplantation, or long-term LV assist device implant, or need for an upgrading of the temporary mechanical circulatory support (t-MCS), or ventricular tachycardia (VT)/fibrillation (VF) treated with direct current (DC) shock, or first rehospitalization due to HF or VT/VF, or advanced atrioventricular block. The safety endpoints include a composite of potential complications that can occur, including serious infections, acute gastrointestinal bleeding, and other complications that can be related to corticosteroid therapy or prolonged stay on t-MCS. There are 32 active centers, and 48 patients have been randomized since December 2021. The trial is expected to be completed by the end of 2028. Conclusion The results of the MYTHS trial can define the role of IV methylprednisolone in the initial treatment of patients with complicated forms of acute myocarditis that currently have an unacceptably high mortality rate.

Efficacy and Safety of Stereotactic Radiotherapy in Patients With Recurrent Ventricular Tachycardias: The Czech Experience

BackgroundStereotactic arrhythmia radiotherapy (STAR) has been proposed recently in patients with refractory ventricular tachycardia (VT). ObjectivesThe purpose of this study was to describe the efficacy and safety of STAR in the Czech Republic. MethodsVT patients were recruited in 2 expert centers after at least 1 previously failed catheter ablation (CA). A precise strategy of target volume determination and CA was used in 17 patients treated from December 2018 until June 2022 (EFFICACY cohort). This group, together with an earlier series of 19 patients with less-defined treatment strategies, composed the SAFETY cohort (n = 36). A dose of 25 Gy was delivered. ResultsIn the EFFICACY cohort, the burden of implantable cardioverter-defibrillator therapies decreased, and this drop reached significance for direct current shocks (1.9 ± 3.2 vs 0.1 ± 0.2 per month; P = 0.03). Eight patients (47%) underwent repeated CA for recurrences of VT during 13.7 ± 11.6 months. In the SAFETY cohort (32 procedures, follow-up >6 months), 8 patients (25%) presented with a progression of mitral valve regurgitation, and 3 (9%) required intervention (median follow-up of 33.5 months). Two cases of esophagitis (6%) were seen with 1 death caused by the esophago-pericardial fistula (3%). A total of 18 patients (50%) died during the median follow-up of 26.9 months. ConclusionsAlthough STAR may not be very effective in preventing VT recurrences after failed CA in an expert center, it can still modify the arrhythmogenic substrate, and when used with additional CA, reduce the number of implantable cardioverter-defibrillator shocks. Potentially serious sides effects require close follow-up.

Coronary Artery Bypass Grafting for Refractory Ventricular fibrillation after the Release of the Aortic Cross-Clamp in Patients Undergoing Aortic Valve Replacement: A Case Report

Background: Ventricular fibrillation (VF) is a known complication after the release of the aortic cross-clamp (ACC) during cardiopulmonary bypass (CPB) surgery. Various factors contribute to persistent refractory VF, making its management challenging. This case report describes the successful treatment of postoperative refractory VF by coronary artery bypass grafting (CABG) in a patient undergoing aortic valve replacement (AVR) with ACC release. Case Presentation: A 52-year-old woman with a history of hypertension and ischemic cerebral infarction presented with symptoms of chest tightness, dyspnoea and palpitations. She underwent a modified maze procedure of radiofrequency ablation, mitral repair, left atrial appendage closure and mechanical AVR under a CPB procedure. Following the ACC release, the patient experienced recurrent VF that was unresponsive to standard interventions such as lidocaine, amiodarone and direct current shocks. The suspicion of right coronary artery (RCA) insufficiency led to the decision to perform CABG using the great saphenous vein. After the CABG procedure, the patient's heart rhythm gradually returned to sinus rhythm, and she had an uneventful recovery. Discussion and Conclusions: Refractory VF after the ACC release can pose diagnostic and treatment challenges. In this case, RCA insufficiency was suspected as the cause of refractory VF. The absence of blood flow in the proximal RCA and the presence of distal blood return during cardiac surface exploration supported this suspicion. Coronary artery bypass grafting using the great saphenous vein successfully restored normal sinus rhythm, confirming the diagnosis. This case emphasises the importance of considering coronary artery stenosis or occlusion as a potential cause of refractory VF after the ACC release during CPB, with CABG serving as a viable alternative treatment.

Surgical ablation of long-standing persistent atrial fibrillation: 1-year outcomes from the CArdioSurgEry Atrial Fibrillation (CASE-AF) registry.

The CArdioSurgEry Atrial Fibrillation (CASE-AF) registry is a prospective, multicentre study for collecting and analysing real-world data of surgical atrial fibrillation (AF) treatment. This study aimed to evaluate outcomes of surgery for long-standing persistent AF at 1 year. In total, 17 centres consecutively include all eligible patients with continuous AF lasting for ≥1 year. Exclusion criteria are missing informed consent or age <18 years. For patient-reported outcomes measures, the European Heart Rhythm Association score was used. No presence of AF (based on ECG findings including Holter ECG and/or implanted devices), no re-ablation, no further cardioversion and no rehospitalization due to AF after a 3-month blanking period defined no AF recurrence at 1 year. From January 2017 to January 2020, a total of 1115 patients were enrolled in CASE-AF. Of them, 202 patients (mean age 69.7 ± 7.8 years, 27.2% female) underwent surgical ablation of long-standing persistent AF (study cohort), mostly accompanied by left atrial appendage closure (n = 180 [89%], resection n = 75 [42%]) and predominantly performed as concomitant (n = 174 [86%]) and left atrial only procedure (n = 144 [71%]). Early mortality (30 days) was 2.0% and morbidity was low. At follow-up (median 14.4 months, interquartile range, 12.7-17.6 months, 100% complete), 106 patients (56%) had no AF recurrence and 93% of them were asymptomatic. AF recurrence was accompanied by AF-related rehospitalization (n = 12, P = 0.003), direct current shock cardioversion (n = 23, P < 0.001), AF ablation (n = 7, P = 0.003) and stroke (n = 3, P = 0.059). Multivariable analysis identified cryoablation, predominantly performed endocardially including additional left atrial (74%) and biatrial (42%) lesions, as a significant factor for freedom from AF recurrence (odds ratio 2.7, 95% confidence interval 1.07-6.79, P = 0.035). According to CASE-AF, surgical ablation of long-standing persistent AF is most effective when concomitantly performed using endocardial cryoablation. Ongoing follow-up allows further elucidation of efficacious treatment strategies.

Clinical features and outcomes of patients with refractory out-of-hospital cardiac arrest and an initial shockable rhythm

Abstract Background Clinical features of patients presenting with refractory out-of-hospital cardiac arrest (OHCA) and initial shockable rhythms of ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) remain poorly described. Purpose This study evaluated clinical characteristics, angiographic findings, and short-term outcomes among patients with refractory OHCA (defined as incessant VF/pVT after ≥3 direct-current shocks) compared to those without refractory OHCA. Methods Of 761 consecutive patients hospitalized for OHCA between 2014–2018 at two large tertiary health services in Victoria, Australia, 204 (27%) had an initial shockable rhythm and were stratified by the presence (n=74, 36%) or absence (n=130, 64%) of refractory OHCA. Primary outcome was in-hospital mortality. Multivariable logistic regression was performed to evaluate independent predictors of in-hospital mortality. Results The majority of patients were male (77%) and the median age was 62 years [IQR 52–72]. Refractory OHCA patients had longer cardiopulmonary resuscitation (23 vs 15 minutes), more frequently required ≥450 mg of amiodarone (34% vs 3.8%), had cardiogenic shock (80% vs 55%) necessitating higher adrenaline dose (4.0 vs 1.0 mg) and higher rates of mechanical ventilation (92% vs 74%) (all p&amp;lt;0.01). A total of 167 patients (82%) underwent coronary angiography, and refractory OHCA patients were less likely to be selected (74% vs 86%, p=0.035). No difference in door-to-needle times between those with and without refractory OHCA was noted (103 vs 99 minutes, p=0.586). Significant coronary artery disease (≥1 major vessel with &amp;gt;70% stenosis) was present in &amp;gt;70% of patients. Refractory OHCA group frequently had acute coronary occlusion (64% vs 47%), especially of the left circumflex artery (20% vs 6.4%) and graft vessel (7.3% vs 0.9%), and often had complex coronary lesions (type B2 or C) (57% vs 39%) compared to those without refractory OHCA (all p&amp;lt;0.05). Patients with both refractory OHCA and ST-elevation on electrocardiogram had the highest prevalence of acute coronary occlusion (85%, 22/26). Refractory OHCA group had higher rates of in-hospital mortality (45% vs 30%) and new requirement for dialysis (18% vs 6.3%) (all p&amp;lt;0.05). After adjustment, refractory OHCA heightened the risk of in-hospital mortality by over two-fold (OR 2.28, 95% CI 1.06–4.89, p=0.034) (Figure 1). Among those with refractory OHCA, higher cumulative prehospital adrenaline dose (OR 1.38, 95% CI 1.01–1.89 per 1 mg increase), and increased number of direct-current shocks (1.13, 1.00–1.27 per 1 additional shock) were independent predictors of in-hospital mortality, whereas undergoing coronary revascularization (0.28, 0.09–0.94) diminished this risk (all p&amp;lt;0.05) (Figure 2). Conclusion Refractory VF/pVT OHCA was associated with more intensive resuscitation, higher rates of acute coronary occlusion and poorer in-hospital outcomes, underscoring the need for future studies in this extreme-risk subgroup.Figure 1Figure 2

Redox imbalance in patients with heart failure and ICD/CRT-D intervention. Can it be an underappreciated and overlooked arrhythmogenic factor? A first preliminary clinical study.

Introduction: Redox imbalance and oxidative stress are involved in the pathogenesis of arrhythmias. They also play a significant role in pathogenesis of heart failure (HF). In patients with HFand implanted cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D), the direct current shocks may be responsible for additional redox disturbances and additionally increase arrhythmia risk. However, the precise role of oxidative stress in potentially fatal arrhythmias and shock induction remains unclear. Methods: 36 patients with diagnosed HF and implanted ICD/CRT-D were included in this study. Patients were qualified to the study group in case of registered ventricular arrhythmia and adequate ICD/CRT-D intervention. The control group consisted of patients without arrhythmia with elective replacement indicator (ERI) status. Activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH) in erythrocyte (RBC), SOD, GPx activity and reactive oxygen/nitrogen species (ROS/RNS) concentration in plasma were determined. The values were correlated with glucose, TSH, uric acid, Mg and ion concentrations. Results: In the perishock period, we found a significant decrease in RBC and extracellular (EC) SOD and RBC CAT activity (p = 0.0110, p = 0.0055 and p = 0.0002, respectively). EC GPx activity was also lower (p = 0.0313). In all patients, a decrease in the concentration of all forms of glutathione was observed compared to the ERI group. Important association between ROS/RNS and GSH, Mg, TSH and uric acid was shown. A relationship between the activity of GSH and antioxidant enzymes was found. Furthermore, an association between oxidative stress and ionic imbalance has also been demonstrated. The patients had an unchanged de Haan antioxidant ratio and glutathione redox potential. Conclusion: Here we show significant redox disturbances in patients with HF and ICD/CRT-D interventions. Oxidative stress may be an additional risk factor for the development of arrhythmia in patients with HF. The detailed role of oxidative stress in ventricular arrhythmias requires further research already undertaken by our team.

Clinical Features and Outcomes Among Patients With Refractory Out-of-Hospital Cardiac Arrest and an Initial Shockable Rhythm.

Clinical features among patients with refractory out-of-hospital cardiac arrest (OHCA) and initial shockable rhythms of ventricular fibrillation/pulseless ventricular tachycardia are not well-characterized. We compared clinical characteristics and coronary angiographic findings between patients with refractory OHCA (incessant ventricular fibrillation/pulseless ventricular tachycardia after ≥3 direct-current shocks) and those without refractory OHCA. Between 2014 and 2018, a total of 204 patients with ventricular fibrillation/pulseless ventricular tachycardia OHCA (median age 62; males 78%) were divided into groups with (36%, 74/204) and without refractory arrest (64%, 130/204). Refractory OHCA patients had longer cardiopulmonary resuscitation (23 versus 15 minutes), more frequently required ≥450 mg amiodarone (34% versus 3.8%), and had cardiogenic shock (80% versus 55%) necessitating higher adrenaline dose (4.0 versus 1.0 mg) and higher rates of mechanical ventilation (92% versus 74%; all P<0.01). Of 167 patients (82%) selected for coronary angiography, 33% (n=55) had refractory OHCA (P=0.035). Significant coronary artery disease (≥1 major vessel with >70% stenosis) was present in >70% of patients. Refractory OHCA patients frequently had acute coronary occlusion (64% versus 47%), especially left circumflex (20% versus 6.4%) and graft vessel (7.3% versus 0.9%; all P<0.05) compared with those without refractory OHCA. Refractory OHCA group had higher in-hospital mortality (45% versus 30%, P=0.036) and greater new requirement for dialysis (18% versus 6.3%, P=0.011). After adjustment, refractory OHCA was associated with over 2-fold higher odds of in-hospital mortality (odds ratio, 2.28 [95% CI, 1.06-4.89]; P=0.034). Refractory ventricular fibrillation/pulseless ventricular tachycardia OHCA was associated with more intensive resuscitation, higher rates of acute coronary occlusion, and poorer in-hospital outcomes, underscoring the need for future studies in this extreme-risk subgroup.

The electrophysiology of electrocution.

Electrocution is a death caused by an application of electrical current to the human body. Our present understanding of electrocution-as the induction of ventricular fibrillation (VF)-followed a nearly century-long path of misunderstandings and speculation primarily focused on hypotheses of asphyxia as well as central nervous system trauma. It is hard for us today to appreciate the past mystery of an unexpected sudden death usually bereft of visible trauma. Even today, a false dogma exists that direct-current shocks can cause asystole instead of VF. A lightning discharge (up to 500 megavolts) is differentiated because it can cause substantial acute and chronic neural effects leading to other cardiac arrest rhythms. The human heart is exquisitely sensitive to alternating currents, and VF can be induced with currents of one-eighth that required for mere pacing. Because of these low currents, this effect obtains only in the TQ interval, and low-power electrocution does not involve the vulnerable period. If a current is strong enough to electrocute, generally it will do so in 1-2 seconds; longer shocks do not tend to be more dangerous. Regardless of concomitant drug dosing, the electrocution cardiac arrest rhythm is still VF, suggesting that electrocution is a stand-alone cause of death; the electrical current does not potentiate the effects of the drug. The experimental and clinical data supporting VF as the mechanism for electrocution are provided.

A very wide complex tachycardia

A 74-year-old woman with a history of persistent atrial fibrillation, hypertension, and hyperlipidemia presented to the emergency department (ED) after 3 days of intermittent palpitations and presyncope. She had been treated for atrial fibrillation with flecainide (150 mg twice daily) and metoprolol succinate (25 mg daily) for more than 20 years. In the ED, her heart rate was 150 bpm, and her blood pressure was 102/87. The electrocardiogram (ECG) is shown in Figure 1. The ECG obtained after a 150-mg bolus of intravenous amiodarone followed by a 200-J biphasic direct current shock is shown in Figure 2A . The ECG recorded soon after administration of 100 mEq of hypertonic sodium bicarbonate is shown in Figure 2B. What is the most likely cause of the wide complex tachycardia (WCT)? Figure 2A: Electrocardiogram with normal sinus rhythm and prolonged PR, QRS, and corrected QT intervals following direct current cardioversion. B: Electrocardiogram after treatment. View Large Image Figure Viewer Download Hi-res image

P224 THE SHARK–FIN THAT EMERGES AND IMMERGES: A CASE REPORT OF TRANSIENT AND REPETITIVE TRIANGULAR QRS–ST–T

Abstract Introduction Shark fin sign, also known as triangular QRS–ST–T waveform (TW), is characterized by a giant R wave (amplitude ≥ 1 mV) resulting from the fusion of the QRS complex, the ST–segment and the T wave and showing triangular morphology. TW pattern is quite uncommon and reveals a life–threatening condition that needs aggressive management. Case presentation: A 45–year–old black man with history of arterial hypertension and without known comorbidities arrived at our emergency department (ED) with out–of–hospital cardiac arrest (OHCA). Return of spontaneous circulation occurred after 11 minutes and 2 direct current shocks. At arrival in the ED, he was hemodynamically stable, electrocardiogram showed atrial fibrillation without repolarization abnormalities, and echocardiogram revealed left ventricular hypertrophy and hypokinesia of the mid–basal inferior wall. Plasma level of electrolytes and high–sensitivity troponin were in range. Sedation in the ED was needed due to psychomotor agitation. He was transferred to the cardiac intensive care unit; no arrhythmias were noted. During the night, electrocardiogram monitoring revealed a progressive ST segment elevation in inferior leads up to a triangular QRS–ST–T giant waveform (“Shark fin sign”), confirmed at 12–lead electrocardiogram. After 3 minutes the electrocardiogram showed a progressive and complete resolution of ST–elevation. Akinesia of the inferior wall was confirmed at echocardiogram. The episode repeated 5 more times in the following 40 minutes, while waiting for the arrival of the Cath lab personnel. Coronary angiography revealed a sub–occlusive mid right coronary artery (RCA) stenosis. Percutaneous coronary intervention with the implantation of one drug eluting stent was performed. After the procedure the patient was hemodynamically stable, and the ECG did not show any other abnormality and no episodes of recurrent ST–elevation occurred. Conclusion The shark fin sign refers to the abrupt total deprivation of blood flow in large areas of myocardium that are seen during coronary thrombotic occlusion or vasospasm. In our case we assisted to transient but repetitive inferior triangular ST–elevation, probably the expression of RCA plaque coronary vasospasm that cause the ECG shark fin sign and OHCA. This sign correlates with high risk of cardiogenic shock, electrical instability, and cardiac arrest, thus requiring prompt and aggressive management.

Extremely dangerous hypopituitarism related long QT syndrome and transient ST-segment elevation: A case report

Acquired long QT syndrome caused by hypopituitarism and transient ST-segment elevation has not been reported in cardiac arrest patients. We report a case of extremely dangerous acquired long QT syndrome and transient ST-segment elevation. A 44-year-old Chinese woman with renal failure experienced sudden cardiac arrest in the haemodialysis room. Subsequent electrocardiogram showed QT prolongation and transient ST-segment elevation. This patient's medical history, subsequent laboratory results and pituitary magnetic resonance imaging suggested hypopituitarism. Transient ST-segment elevation on the electrocardiogram was considered to be caused by repeated direct current shocks. The patient was diagnosed with acquired long QT syndrome and was not taking any antiarrhythmic drugs. Her corrected QT interval normalized after hormone replacement therapy. This case highlights the importance of the awareness of hypopituitarism; early identification and intervention can prevent the occurrence of this life-threatening arrhythmia. ST-segment elevation is not always due to acute myocardial infarction, and a variety of other causes, especially electrical cardioversion, should be considered.

Barriers and challenges to multiple-casualty management systems: a single-centre, cross-sectional study at the Nasser Medical Complex, Gaza Strip

BackgroundDuring a multiple-casualty incident, a large casualty caseload adversely affects the quality of care given to patients. From a trauma care perspective, the goal of the hospital emergency department plan is to simultaneously provide severely injured patients with a standard of care that approximates the care given to similar patients under normal conditions. This study highlights the barriers and challenges associated with implementing the emergency plans at the Nasser Medical Complex, Gaza Strip, occupied Palestinian territory, during a multiple-casualty incident, with the aim of facilitating appropriate staff training to address any deficiencies identified. MethodsA self-administered 70-item questionnaire reflecting the local major incident protocol (the Multiple Casualty Management System) was designed by the authors for completion by health-care staff. The questionnaire was divided into eight sections to assess knowledge and awareness and to specify deficiencies. Answers were analysed as frequencies and percentage points in terms of guideline adherence. Descriptive analysis were done on SPSS version 23. Findings70 questionnaires were completed by trauma team members (25 emergency doctors, 25 nurses, 15 surgeons, and five intensive care clinicians). The concepts of mass casualty and triage according to risk were understood by 40 (57%) of 70 participants, with most (65 ;93%) believing that the task of triage was to provide maximum care for the largest number of potential survivors. Only 50 (71%) reported competency in basic emergency skills like direct-current shock, chest tube insertion, cardiopulmonary resuscitation, nasogastric tube, and intravenous catheter insertion. Although 49 (70%) participants found the triage system very important, only 40 (57%) were able to apply it correctly. The biggest challenge was public acceptance of the concept of triage; only 5 (7%) participants believed that patients and relatives would accept a less urgent category. Furthermore, only 11 (16%) participants found that resources and equipment were adequate in case of mass casualty. Communication within the team was another struggle, with 45 participants were considering it unsatisfactory. However, 13 (19%) participants believed that the post-accident strategies with assessment plan to detect positive and negative points and clinical finding after the incident were satisfactory. Participants found the most important obstacles to efficient implementation of the emergency plan to be overcrowding in emergency department (63 [90%]), poor knowledge of the public regarding the importance of hospital triaging (59 [84%]), shortage of medical staff (57 [81%]), scarcity of resources (52 [74%]), ineffective security (52 [74%]), and insufficient staff training (41 [59%]). We also noticed that nearly all the emergency doctors were general practitioners without any specialised training. An emergency residency programme was started after the conclusion of this study, but results on the effects on multiple-casualty incident management are not yet available. InterpretationThis small study identified areas of weakness in the Multiple Casualty Management System, some due to poor resources and others to poor communication within the team or with the public. One important factor identified was the unawareness of the public of the importance of effective triage in this situation. Therefore, these areas should be addressed by staff feedback and training and by public awareness campaigns on the avoidance of overcrowding, the importance of non-threatening behaviour, and the purpose of triage in emergency department. Such interventions might also lead to improvement in day-to-day work at the emergency department, even outside the context of mass incidents. FundingNone.

External cardioversion of atrial fibrillation and flutter in patients with cardiac implantable electrical devices

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Atrial tachyarrhythmias are often treated with external cardioversion (ECV) with direct current shocks in patients with potentially electrically sensitive cardiovascular implantable electronic devices (CIED). Long-term follow-up data on contemporary pacemakers and implantable cardioverter defibrillators (ICD) undergoing ECV is sparsely described. This study investigated shock-related complications and impact on CIEDs. Methods All ECV procedures of atrial fibrillation and flutter from 2010 to 2020 in patients with CIED performed at a tertiary hospital (Denmark) were identified in the Danish National Patient Registry. Data on device interrogation before and after ECV and procedure-related complications were retrieved retrospectively by review of medical records. Results We analysed 664 ECV-events performed in 362 CIEDs, median implant time 1.5 year. Mean age of patients at first ECV-event were 69.4±9.7 years and 72.2% were men. We identified two cases of major programming changes and two cases of premature battery depletion (≤3 years after generator implant) following ECV. Minor shock-related device changes were found for impedances, atrial sensing values and pacing thresholds of right ventricle lead. In two cases increased pacing threshold of right ventricle leads following ECV triggered exit-blocks after few months. No patients died due to shock-related device dysfunctions. Conclusion Following external cardioversion with transthoracic direct current shocks, sporadic (&amp;lt;1%) but potentially critical changes in device function were identified in patients with contemporary pacemakers and implantable cardioverter-defibrillators. The present study suggests that routine post-cardioversion device interrogation is imperative for patient safety.

Congenital junctional ectopic tachycardia in the paediatric emergency department.

Congenital junctional ectopic tachycardia is a rare but serious cardiac arrhythmia seen in neonates and young infants. It is frequently resistant and refractory to first-line treatment options such as cardioversion with adenosine and direct current shock, and it carries a high morbidity and mortality rate. The aim of this article is to present the case of congenital junctional ectopic tachycardia observed in a 14-day-old neonate, highlighting the role of ivabradine in the management, followed by a discussion about current approaches to treatment.

Toward radiofrequency catheter ablation of atrial fibrillation.

Curative treatments of supraventricular arrhythmias—that is, aiming at the elimination of arrhythmic substrate—were initially performed in the 1970s during cardiac surgery as a last resort. A tandem team of surgeons and electrophysiologists intervened, as the individual location of substrate required mapping guidance of the electrical anomaly. In the early 1980s, catheter ablation began using direct current (DC) shocks, with most procedures being palliative as they aimed at interrupting atrioventricular (AV) conduction in patients with uncontrolled ventricular rate associated with atrial fibrillation (AF) or AV nodal reentrant tachycardia (AVNRT).

T Wave Alternans and Long QT Syndrome

A previously healthy 52-year-old woman who was gasping for air was brought to the emergency department. Cardiopulmonary resuscitation was initiated immediately, and the patient was simultaneously intubated. The ECG monitor showed Torsade de Pointes, which was cardioverted with direct current shock. An intravenous bolus of magnesium sulfate was also given immediately. Postcardioversion, her blood pressure was 102/62 mm Hg, pulse rate was 84 beats/min, and SaO2 was 98%. The systemic examination was unremarkable.

Premature atrial contractions with multiple patterns of aberrant conduction followed by torsade de pointes in a patient with polymyalgia rheumatica

Rationale:Recent studies have shown that QT interval prolongation is associated with disease severity and predicts mortality in systemic inflammatory diseases, particularly rheumatoid arthritis. Systemic pro-inflammatory cytokines released from synovial tissues in rheumatoid arthritis, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, could have direct effects on cardiac electrophysiology, particularly changes in the expression and function of potassium and calcium channels, resulting in QT interval prolongation on surface electrocardiogram (ECG) and an increased predisposition to develop lethal ventricular arrhythmias. However, reports on torsade de pointes (TdP) due to acquired long QT syndrome in patients with polymyalgia rheumatica (PMR) are limited.Patient concerns:An 85-year-old Japanese woman with active PMR developed first syncope.Diagnosis:Frequent premature atrial contractions (PACs) with multiple patterns of aberrant conduction, QT interval prolongation, and morphological T-U wave variability followed by TdP were documented. PACs were the first beat of TdP.Interventions:Amiodarone, together with magnesium and potassium, was intravenously administered. However, TdP resulted in a ventricular arrhythmic storm, for which sedation with mechanical ventilatory support, temporary overdrive cardiac pacing, and intravenous landiolol administration in addition to multiple direct current shocks were effective.Outcomes:Approximately 2 years later, the patient was treated with amiodarone, propranolol, and prednisolone. She did not undergo implantable cardioverter-defibrillator implantation and was quite well, with no recurrence of ventricular tachyarrhythmia.Lessons:IL-6 hyperproduction in inflamed tissues has been widely confirmed in PMR. Frequent PACs with various patterns of aberrant conduction, QT interval prolongation, and morphological T-U wave variability followed by TdP, for which IL-6-mediated enhancement of L-type Ca2+ current and inhibition of the rapid component of the delayed rectifier K+ current are the most likely mechanisms, were documented in an elderly Japanese woman with PMR. ECG may be recorded once in patients with active PMR even when these patients do not complain of palpitation or syncope. If QT interval prolongation or arrhythmia, including even PACs, is observed, follow-up ECG may be warranted, particularly for patients with some risk factors for QT prolongation that could lead to TdP, such as advanced age, female sex, hypopotassemia, and polypharmacy.

A perfect refractory electrical storm by acute toxicity of accidental aconitine intake

A 51-years-old male presented with drooling, hematemesis and diarrhea in emergency department after accidental ingestion of homemade aconitine tincture. Examination revealed shock and initial ECG showed atrial fibrillation. The patient suddenly developed a pulseless wide QRS complex tachycardia requiring resuscitation maneuvers. The rhythm varied from monomorphic ventricular tachycardia to torsade de point to ventricular fibrillation. Repeated direct-current cardioversions were unsuccessful. After intravenous electrolyte correction and anti-arrhythmic drugs administration, a last direct-current shock was finally successful. Bradycardia and ventricular excitability persisted over 12 hours with gradual normalization. Patient was discharged in normal sinus rhythm without any medication and on follow-up he was totally asymptomatic.&#x0D; With the increasing popularity of traditional medicine, clinicians should be alerted to the risk of herbal substances with low margins of safety like Aconitum in order to allow correct diagnosis and treatment. The general public should be educated that herbal medicine is not always safe.

The efficacy of synchronized direct current shock in reverting long standing persistent atrial fibrillation in to sinus rhythm. What help to achieve high success rate?

Background: Atrial fibrillation is the most frequent cardiac arrhythmia encountered in general medicine and cardiology practice. Synchronized direct current shock is a known safe and effective procedure to revert long standing persistent atrial fibrillation into sinus rhythm.&#x0D; Patients and Methods: Patients with long-standing atrial fibrillation who were seen at the author’s private clinic and Al-Hassani Heart Center in Sulaimanya from April 2018 to December 2020 were chosen for rhythm control subjected to synchronized direct current cardioversion under heavy sedation applying a modified anterolateral paddles position with 200J and 300J successively according to the reversion dose required.&#x0D; Objectives: The Objective of current study was to assess the efficacy of synchronized direct current shock in reverting long-standing persistent atrial fibrillation into sinus rhythm and recognizing factors that help in achieving high success rate.&#x0D; Results: In this case series study 61 patients were included thirty-one males 30 females The success rate was 89%. Even patients with atrial fibrillation duration more than 2 years showed a success rate of 84%. The recurrence rate of atrial fibrillation was 30% within a follow up period of one month to 2 years. The modified paddles position has helped in achieving high reversion rate where success increased from 62% to 85% and failure rate decreased from 38% to 15%. The shock dose needed for reversion ranged from 200J to 300 J. There was no correlation between the needed dose for reversion and body weight where patients with body weight of 71-80kg, more than 80% reverted with 200J. Pre shock antiarrhythmic drugs did not facilitate the conversion, the reversion rate in patients with or without antiarrhythmic drugs were 85% and 82% successively. No per procedure complications were seen. &#x0D; Conclusion: Electrical cardioversion of atrial fibrillation with modified paddles position is a safe, effective and smooth procedure with significantly high success rate and very low incidence of complications even with very long-standing atrial fibrillation.

Accessory pathway recording and ablation

Beginning in the mid-1970s, surgical ablation of accessory atrioventricular (AV) pathways (APs) was performed at a limited number of centers. The potential to target APs by catheter ablation became apparent in 1982, when Scheinman and coworkers introduced catheter ablation of the AV junction using high-energy direct current (DC) shocks from a defibrillator to produce AV block as palliative therapy for drug-resistant supraventricular tachyarrhythmias. Early attempts at DC shock ablation of APs were associated with some success,1 but the large area of barotrauma limited focused ablation and was associated with risk of cardiac perforation, AV block, and coronary artery injury.