Definition and management of arrhythmia-induced cardiomyopathy: findings from the European Heart Rhythm Association survey.

AIMS: Arrhythmia-induced cardiomyopathy (AiCM) represents a subtype of acute heart failure (HF) in the context of sustained arrhythmia. Clear definitions and management recommendations for AiCM are lacking. The European Heart Rhythm Association Scientific Initiatives Committee (EHRA SIC) conducted a survey to explore the current definitions and management of patients with AiCM among European and non-European electrophysiologists. METHODS AND RESULTS: A 25-item online questionnaire was developed and distributed among EP specialists on the EHRA SIC website and on social media between 4 September and 5 October 2023. Of the 206 respondents, 16% were female and 61% were between 30 and 49 years old. Most of the respondents were EP specialists (81%) working at university hospitals (47%). While most participants (67%) agreed that AiCM should be defined as a left ventricular ejection fraction (LVEF) impairment after new onset of an arrhythmia, only 35% identified a specific LVEF drop to diagnose AiCM with a wide range of values (5-20% LVEF drop). Most respondents considered all available therapies: catheter ablation (93%), electrical cardioversion (83%), antiarrhythmic drugs (76%), and adjuvant HF treatment (76%). A total of 83% of respondents indicated that adjuvant HF treatment should be started at first HF diagnosis prior to antiarrhythmic treatment, and 84% agreed it should be stopped within six months after LVEF normalization. Responses for the optimal time point for the first LVEF reassessment during follow-up varied markedly (1 day-6 months after antiarrhythmic treatment). CONCLUSION: This EHRA Survey reveals varying practices regarding AiCM among physicians, highlighting a lack of consensus and heterogenous care of these patients.

The efficacy and safety of intraoperative intravenous amiodarone in patients undergoing on-pump coronary artery bypass grafting surgery: a systemic review and PRISMA-compliant meta-analysis.

BACKGROUND: To evaluate the clinical efficacy and safety of intraoperative intravenous amiodarone for arrhythmia prevention in on-pump coronary artery bypass grafting (CABG) patients. METHODS: A meta-analysis of randomized controlled trials was conducted. Pubmed, Embase, Cochrane Library, Ovid, China National Knowledge Infrastructure, and the Wan Fang database until July 1th, 2023. The primary outcomes of interest included the incidences of intra- and post-operative atrial fibrillation (POAF), ventricular fibrillation, or any arrhythmia, including atrial fibrillation, ventricular fibrillation, ventricular tachycardia, premature ventricular contraction, and sinus bradycardia. For continuous and dichotomous variables, treatment effects were calculated as the weighted mean difference (WMD)/risk ratio (RR) and 95% confidence interval (CI). RESULTS: A database search yielded 7 randomized controlled trials including 608 patients, where three studies, including three treatments (amiodarone, lidocaine, and saline), contributed to the clinical outcome of atrial fibrillation, ventricular fibrillation, or any arrhythmia. Meta-analysis demonstrated that amiodarone can significantly reduce the incidence of POAF (RR, 0.39; 95%CI: 0.20, 0.77; P = 0.007, I2 = 0%) in patients undergoing on-pump CABG; there was no statistically significant influence on intra-operative atrial fibrillation, intra- and post-operative ventricular fibrillation, or any arrhythmia. CONCLUSIONS: The current study suggests that intraoperative administration of intravenous amiodarone may be safe and effective in preventing POAF in patients undergoing on-pump CABG. More well-designed clinical trials are needed to validate this result.

Pharmacological Approach for Symptomatic Nonsustained Ventricular Tachycardia.

Nonsustained ventricular tachycardia (NSVT) is a common arrhythmia associated with heart failure, cardiomyopathy, coronary artery disease, electrolyte imbalances, and congenital heart disorders (Foth et al., 2023). NSVT is often asymptomatic depending on its burden percentage. However, typical NSVT presentation in the emergency department (ED) includes palpitations, near-syncope, dizziness, skipped beats, chest pain, and/or dyspnea (Katritsis et al., 2012). In some instances, NSVT can present with elevated or slightly elevated troponin from demand ischemia. A definite diagnosis of NSVT is not of high complexity; nevertheless, it is not always identified on electrocardiogram (ECG) by the time the patient arrives to the ED. Identification of NSVT usually requires prolonged cardiac monitoring, mobile cardiac telemetry (MCT), and in some instances internal loop recorder placement. The purpose of this case is to discuss the typical presentation and pharmacological approach of patients with stable NSVT.

Efficacy of Shensong Yangxin capsule combined with dronedarone in paroxysmal atrial fibrillation after ablation.

OBJECTIVE: To investigate whether postoperative administration of Shensong Yangxin capsules (SSYX) and dronedarone for atrial fibrillation (AF) can reduce the recurrence of paroxysmal AF after radiofrequency ablation, thus providing a more optimal choice of antiarrhythmic medication during the blank period. METHODS: We included 120 patients with paroxysmal AF who underwent radiofrequency ablation at our hospital between July 2020 and July 2022. They underwent routine circumferential pulmonary vein ablation and, subsequently, left and right atrial pressure monitoring to assess sinoatrial node recovery time under burst 400/300 ms stimulation. Postoperatively, the patients were randomly divided into 2 groups (60 patients each). The control group was administered dronedarone orally for 3 months and the study group was treated with SSYX combined with dronedarone. This study aimed to compare differences in clinical efficacy of the treatment between the 2 groups. RESULTS: The left and right atrial pressures in both groups were higher than those in the preoperative period (P < .05), with no statistically significant differences between the 2 groups (P > .05). Sinoatrial node recovery time under burst 400/300 ms stimulation showed no statistical difference between the 2 groups (P > .05). At 3 months and 1 year postoperatively, the AFEQT scale scores for both groups were lower than those before treatment (P < .05), with the study group scoring lower than the control group at 3 months (P < .05). However, no statistically significant difference was observed between the 2 groups at 1 year postoperatively (P > .05). At 3 months postoperatively, the sinus rhythm maintenance rate and heart rate were higher in the intervention group than in the control group (P < .05); however, these differences between the 2 groups were not statistically significant at 1 year postoperatively (P > .05). CONCLUSION SUBSECTIONS: The combination of SSYX and dronedarone could effectively reduce the early recurrence of paroxysmal AF after radiofrequency ablation, increase heart rate, and improve the quality of life.

Vericiguat suppresses ventricular tachyarrhythmias inducibility in a rabbit myocardial infarction model.

BACKGROUND: The VICTORIA trial demonstrated a significant decrease in cardiovascular events through vericiguat therapy. This study aimed to assess the potential mechanisms responsible for the reduction of cardiovascular events with vericiguat therapy in a rabbit model of myocardial infarction (MI). METHODS: A chronic MI rabbit model was created through coronary artery ligation. Following 4 weeks, the hearts were harvested and Langendorff perfused. Subsequently, electrophysiological examinations and dual voltage-calcium optical mapping studies were conducted at baseline and after administration of vericiguat at a dose of 5 µmol/L. RESULTS: Acute vericiguat therapy demonstrated a significant reduction in premature ventricular beat burden and effectively suppressed ventricular arrhythmic inducibility. The electrophysiological influences of vericiguat therapy included an increased ventricular effective refractory period, prolonged action potential duration, and accelerated intracellular calcium (Cai) homeostasis, leading to the suppression of action potential and Cai alternans. The pacing-induced ventricular arrhythmias exhibited a reentrant pattern, attributed to fixed or functional conduction block in the peri-infarct zone. Vericiguat therapy effectively mitigated the formation of cardiac alternans as well as the development of reentrant impulses, providing additional anti-arrhythmic benefits. CONCLUSIONS: In the MI rabbit model, vericiguat therapy demonstrates anti-ventricular arrhythmia effects. The vericiguat therapy reduces ventricular ectopic beats, inhibiting the initiation of ventricular arrhythmias. Furthermore, the therapy successfully suppresses cardiac alternans, preventing conduction block and, consequently, the formation of reentry circuits.

The Pharmacologic Management of Cardiac Arrest.

The effectiveness of pharmacologic management of cardiac arrest patients is widely debated; however, several studies published in the past 5 years have begun to clarify some of these issues. This article covers the current state of evidence for the effectiveness of the vasopressor epinephrine and the combination of vasopressin-steroids-epinephrine and antiarrhythmic medications amiodarone and lidocaine and reviews the role of other medications such as calcium, sodium bicarbonate, magnesium, and atropine in cardiac arrest care. We additionally review the role of ß-blockers for refractory pulseless ventricular tachycardia/ventricular fibrillation and thrombolytics in undifferentiated cardiac arrest and suspected fatal pulmonary embolism.

Arrhythmias and cardiac MRI associations in patients with established cardiac dystrophinopathy.

AIMS: Some patients with cardiac dystrophinopathy die suddenly. Whether such deaths are preventable by specific antiarrhythmic management or simply indicate heart failure overwhelming medical therapies is uncertain. The aim of this prospective, cohort study was to describe the occurrence and nature of cardiac arrhythmias recorded during prolonged continuous ECG rhythm surveillance in patients with established cardiac dystrophinopathy and relate them to abnormalities on cardiac MRI. METHODS AND RESULTS: A cohort of 10 patients (36.3 years; 3 female) with LVEF<40% due to Duchenne (3) or Becker muscular (4) dystrophy or Duchenne muscular dystrophy-gene carrying effects in females (3) were recruited, had cardiac MRI, ECG signal-averaging and ECG loop-recorder implants. All were on standard of care heart medications and none had prior history of arrhythmias.No deaths or brady arrhythmias occurred during median follow-up 30 months (range 13-35). Self-limiting episodes of asymptomatic tachyarrhythmia (range 1-29) were confirmed in 8 (80%) patients (ventricular only 2; ventricular and atrial 6). Higher ventricular arrhythmia burden correlated with extent of myocardial fibrosis (extracellular volume%, p=0.029; native T1, p=0.49; late gadolinium enhancement, p=0.49), but not with LVEF% (p=1.0) on MRI and atrial arrhythmias with left atrial dilatation. Features of VT episodes suggested various underlying arrhythmia mechanisms. CONCLUSIONS: The overall prevalence of arrhythmias was low. Even in such a small sample size, higher arrhythmia counts occurred in those with larger scar burden and greater ventricular volume, suggesting key roles for myocardial stretch as well as disease progression in arrhythmogenesis. These features overlap with the stage of left ventricular dysfunction when heart failure also becomes overt. The findings of this pilot study should help inform the design of a definitive study of specific antiarrhythmic management in dystrophinopathy. TRIAL REGISTRATION NUMBER: ISRCTN15622536.

Dronedarone for the Treatment of Atrial Arrhythmias in Adults With Congenital Heart Disease.

BACKGROUND: Atrial tachyarrhythmias are common and difficult to treat in adults with congenital heart disease. Dronedarone has proven effective in patients without congenital heart disease, but data are limited about its use in adults with congenital heart disease of moderate to great complexity. METHODS: A single-center, retrospective chart review of 21 adults with congenital heart disease of moderate to great complexity who were treated with dronedarone for atrial tachyarrhythmias was performed. RESULTS: The median (IQR) age at dronedarone initiation was 35 (27.5-39) years. Eleven patients (52%) were male. Ten patients (48%) had New York Heart Association class I disease, 10 (48%) had class II disease, and 1 (5%) had class III disease. Ejection fraction at initiation was greater than 55% in 11 patients (52%), 35% to 55% in 9 patients (43%), and less than 35% in 1 patient (5%). Prior treatments included ß-blockers (71%), sotalol (38%), amiodarone (24%), digoxin (24%), and catheter ablation (38%). Rhythm control was complete in 5 patients (24%), partial in 6 (29%), and inadequate in 10 (48%). Two patients (10%) experienced adverse events, including nausea in 1 (5%) and cardiac arrest in 1 (5%), which occurred 48 months after initiation of treatment. There were no deaths during the follow-up period. The median (IQR) follow-up time for patients with complete or partial rhythm control was 20 (1-54) months. CONCLUSION: Dronedarone can be effective for adult patients with congenital heart disease and atrial arrhythmias for whom more established therapies have failed, and with close monitoring it can be safely tolerated.

Non-paroxysmal junctional tachycardia complicating disseminated intravascular coagulation during massive surgical hemorrhage: A case report.

RATIONALE: Non-paroxysmal junctional tachycardia (NPJT) is a self-limiting supraventricular tachycardia associated with primary heart disease, cardiac surgery, digitalis toxicity, and metabolic or electrolyte imbalances. However, NPJT caused enhanced normal automaticity even in the absence of structural heart disease can be fatal if not managed properly. PATIENT CONCERNS: A 74-year-old hypertensive female patient was scheduled for transureteroureterostomy and right ureteroneocystostomy under general anesthesia. DIAGNOSIS: The patient developed NPJT without visible P wave and severe hypotension due to adrenergic stimulation in response to massive hemorrhage during surgery. INTERVENTIONS: NPJT with hypotension was initially converted to sinus rhythm with normotension with administration of adenosine and esmolol. However uncontrolled surgical hemorrhage and administration of large dose of vasopressors eventually perpetuated NPJT refractory to antiarrhythmic drugs. OUTCOMES: Despite intravenous fluid resuscitation and massive transfusion, the patient was deteriorated hemodynamically due to uncontrolled bleeding and persistent NPJT, which resulted in hypovolemic shock and fatal disseminated intravascular coagulation (DIC). LESSONS: NPJT can occur by enhanced automaticity due to increased catecholamine during severe surgical hemorrhage. Although NPJT is generally self-limiting, it can be refractory to antiarrhythmic agents and accelerate hypotension if the surgical bleeding is uncontrolled. Therefore, aggressive management of the primary pathologic condition is crucial for the management of NPJT and hemodynamic collapse even in the absence of structural heart disease.

The ion channel basis of pharmacological effects of amiodarone on myocardial electrophysiological properties, a comprehensive review.

Amiodarone is a benzofuran-based class III antiarrhythmic agent frequently used for the treatment of atrial and ventricular arrhythmias. The primary target of class III antiarrhythmic drugs is the cardiac human ether-a-go-go-related gene (hERG) encoded channel, KCNH2, commonly known as HERG, that conducts the rapidly activating delayed rectifier potassium current (IKr). Like other class III antiarrhythmic drugs, amiodarone exerts its physiologic effects mainly through IKr blockade, delaying the repolarization phase of the action potential and extending the effective refractory period. However, while many class III antiarrhythmics, including sotalol and dofetilide, can cause long QT syndrome (LQTS) that can progress to torsade de pointes, amiodarone displays less risk of inducing this fatal arrhythmia. This review article discusses the arrhythmogenesis in LQTS from the aspects of the development of early afterdepolarizations (EADs) associated with Ca2+ current, transmural dispersion of repolarization (TDR), as well as reverse use dependence associated with class III antiarrhythmic drugs to highlight electropharmacological effects of amiodarone on the myocardium.

Assessment of physician compliance to the CAEP 2021 Atrial Fibrillation Best Practices Checklist for rate and rhythm control in the emergency department.

OBJECTIVES: Acute atrial fibrillation and flutter (AF/AFL) are common arrhythmias treated in the emergency department (ED). The 2021 CAEP Best Practices Checklist provides clear recommendations for management of patients with acute AF/AFL. This study aimed to evaluate physician compliance to Checklist recommendations for risk assessment and ED management of AF/AFL. METHODS: This health records review assessed the management of adult patients presenting to two tertiary care EDs for management of acute AF/AFL from January to August, 2022. All ECGs demonstrating AF/AFL with a heart rate greater than 100 were compiled to capture primary and secondary causes. All visits were assessed for rate and rhythm control management, adverse events, return to ED, and safety criteria. Study physicians classified safety criteria from the Checklist into high and moderate concerns. The primary outcome was the proportion of cases with safety concerns and adverse events occurring during management in the ED. Data were analyzed using simple descriptive statistics. RESULTS: We included 429 patients with a mean age of 67.7 years and 57.1% male. ED management included rate control (20.4%), electrical (40.1%), and pharmacological (20.1%) cardioversion. Adverse events occurred in 9.5% of cases: 12.5% in rate control, 13.4% in electrical cardioversion, and 6.9% in pharmacologic cardioversion. Overall, 7.9% of cases had management safety concerns. Moderate safety concerns occurred in 4.9% of cases including failure to attain recommended heart rate at time of discharge (3.9%). Severe concerns were identified in 3.0% of cases including failure to cardiovert unstable patients (1.2%). The 30-day return-to-ED rate was 16.5% secondary to AF/AFL. CONCLUSION: ED management of AF/AFL was consistent with the CAEP Checklist and was safe overall. Opportunities for optimizing care include attaining recommended targets during rate control, avoidance of calcium channel and beta blockers in patients with systolic dysfunction, and earlier cardioversion for clinically unstable patients.

ABSTRAIT: OBJECTIFS: La fibrillation auriculaire aiguë et le flutter (FA/FAT) sont des arythmies courantes traitées aux urgences (SU). La liste de vérification des pratiques exemplaires 2021 du CAEP fournit des recommandations claires pour la prise en charge des patients atteints de FA/FAT aiguës. Cette étude visait à évaluer la conformité des médecins aux recommandations de la liste de contrôle pour l'évaluation des risques et la gestion de la FA/FAT. MéTHODES: Cet examen des dossiers de santé a évalué la prise en charge des patients adultes qui se sont présentés à deux urgences de soins tertiaires pour la prise en charge des FA/FAT aiguës de janvier à août 2022. Tous les ECG démontrant une FA/FAT avec une fréquence cardiaque supérieure à 100 ont été compilés pour capturer les causes primaires et secondaires. Toutes les visites ont été évaluées pour la gestion du contrôle des taux et du rythme, les événements indésirables, le retour à l'urgence et les critères de sécurité. Les médecins de l'étude ont classé les critères d'innocuité de la liste de contrôle en préoccupations élevées et modérées. Le résultat principal était la proportion de cas présentant des préoccupations en matière de sécurité et des événements indésirables survenant pendant la prise en charge à l'urgence. Les données ont été analysées à l'aide de statistiques descriptives simples. RéSULTATS: Nous avons inclus 429 patients avec un âge moyen de 67.7 ans et 57.1% d'hommes. La prise en charge de l'urgence comprenait une cardioversion contrôlée (20.4 %), électrique (40.1 %) et pharmacologique (20.1 %). Des événements indésirables se sont produits dans 9.5% des cas : 12.5% dans le contrôle du taux, 13.4% dans la cardioversion électrique et 6.9% dans la cardioversion pharmacologique. Dans l'ensemble, 7.9 % des cas concernaient la sécurité de la direction. Des problèmes de sécurité modérés sont survenus dans 4.9 % des cas, y compris l'incapacité d'atteindre la fréquence cardiaque recommandée au moment du congé (3.9 %). Des préoccupations graves ont été identifiées dans 3.0 % des cas, y compris l'échec à cardiovert patients instables (1.2 %). Le taux de retour aux urgences après 30 jours était de 16,5 % secondaire aux FA/FAT. CONCLUSION: La gestion de l'AF/AFL par le DG était conforme à la liste de vérification du CAEP et était sécuritaire dans l'ensemble. Les possibilités d'optimisation des soins comprennent l'atteinte des cibles recommandées lors du contrôle des taux, l'évitement du canal calcique et des bêtabloquants chez les patients présentant une dysfonction systolique et une cardioversion antérieure pour les patients cliniquement instables.

Diagnosis and Management of Paroxysmal Supraventricular Tachycardia.

Importance: Paroxysmal supraventricular tachycardia (PSVT), defined as tachyarrhythmias that originate from or conduct through the atria or atrioventricular node with abrupt onset, affects 168 to 332 per 100 000 individuals. Untreated PSVT is associated with adverse outcomes including high symptom burden and tachycardia-mediated cardiomyopathy. Observations: Approximately 50% of patients with PSVT are aged 45 to 64 years and 67.5% are female. Most common symptoms include palpitations (86%), chest discomfort (47%), and dyspnea (38%). Patients may rarely develop tachycardia-mediated cardiomyopathy (1%) due to PSVT. Diagnosis is made on electrocardiogram during an arrhythmic event or using ambulatory monitoring. First-line acute therapy for hemodynamically stable patients includes vagal maneuvers such as the modified Valsalva maneuver (43% effective) and intravenous adenosine (91% effective). Emergent cardioversion is recommended for patients who are hemodynamically unstable. Catheter ablation is safe, highly effective, and recommended as first-line therapy to prevent recurrence of PSVT. Meta-analysis of observational studies shows single catheter ablation procedure success rates of 94.3% to 98.5%. Evidence is limited for the effectiveness of long-term pharmacotherapy to prevent PSVT. Nonetheless, guidelines recommend therapies including calcium channel blockers, ß-blockers, and antiarrhythmic agents as management options. Conclusion and Relevance: Paroxysmal SVT affects both adult and pediatric populations and is generally a benign condition. Catheter ablation is the most effective therapy to prevent recurrent PSVT. Pharmacotherapy is an important component of acute and long-term management of PSVT.

Connexin43, A Promising Target to Reduce Cardiac Arrhythmia Burden in Pulmonary Arterial Hypertension.

While essential hypertension (HTN) is very prevalent, pulmonary arterial hypertension (PAH) is very rare in the general population. However, due to progressive heart failure, prognoses and survival rates are much worse in PAH. Patients with PAH are at a higher risk of developing supraventricular arrhythmias and malignant ventricular arrhythmias. The latter underlie sudden cardiac death regardless of the mechanical cardiac dysfunction. Systemic chronic inflammation and oxidative stress are causal factors that increase the risk of the occurrence of cardiac arrhythmias in hypertension. These stressful factors contribute to endothelial dysfunction and arterial pressure overload, resulting in the development of cardiac pro-arrhythmic conditions, including myocardial structural, ion channel and connexin43 (Cx43) channel remodeling and their dysfunction. Myocardial fibrosis appears to be a crucial proarrhythmic substrate linked with myocardial electrical instability due to the downregulation and abnormal topology of electrical coupling protein Cx43. Furthermore, these conditions promote ventricular mechanical dysfunction and heart failure. The treatment algorithm in HTN is superior to PAH, likely due to the paucity of comprehensive pathomechanisms and causal factors for a multitargeted approach in PAH. The intention of this review is to provide information regarding the role of Cx43 in the development of cardiac arrhythmias in hypertensive heart disease. Furthermore, information on the progress of therapy in terms of its cardioprotective and potentially antiarrhythmic effects is included. Specifically, the benefits of sodium glucose co-transporter inhibitors (SGLT2i), as well as sotatercept, pirfenidone, ranolazine, nintedanib, mirabegron and melatonin are discussed. Discovering novel therapeutic and antiarrhythmic strategies may be challenging for further research. Undoubtedly, such research should include protection of the heart from inflammation and oxidative stress, as these are primary pro-arrhythmic factors that jeopardize cardiac Cx43 homeostasis, the integrity of intercalated disk and extracellular matrix, and, thereby, heart function.

One-year outcomes of pulmonary vein isolation with a novel cryoballoon: Primary results of the FROZEN AF trial.

INTRODUCTION: Cryoablation therapy for pulmonary vein isolation (PVI) to treat paroxysmal atrial fibrillation (PAF) is well established. A novel 28 mm cryoballoon system designed to operate under low pressure to safely reach a lower nadir temperature and maintain constant balloon size during cooling has not been prospectively studied in a large patient population for safety and efficacy. The FROZEN AF (NCT04133168) trial was an international multicenter, open-label, prospective, single-arm study on the safety and performance of a novel cryoballoon system for treatment of PAF. METHODS AND RESULTS: The study enrolled patients at 44 sites in 10 countries across North America, Europe, and Asia. Subjects were indicated for PVI treatment of PAF and had failed or were intolerant of one or more antiarrhythmic drugs. Procedural outcomes were defined based on the 2017 HRS consensus statement. Follow-up was performed at 7 days, 3, 6, and 12 months. Data are reported as mean ± SD or median (IQR). PVI was performed with a 28 mm cryoballoon in 325 drug refractory PAF patients. Complete PVI was achieved in 95.7% of patients. In cryoablation lesions longer than 60 s, 60.1% of PV isolations required only a single cryoballoon application. Procedure related complications included: phrenic nerve palsy [temporary 4 (1.2%), persistent 0 (0.0%)], cardiac tamponade/perforation 2 (0.6%), and air embolism 1 (0.3%). Freedom from documented atrial arrhythmia recurrence at 12 months was 79.9% (AF 82.7%, AFL 96.5%, AT 98.1%), antiarrhythmic drugs (AAD) were continued or re-initiated in 26.8% of patients after the 3-month blanking period. Additionally, an extension arm enrolled 50 pts for treatment with 28/31 mm variable size cryoballoon. A single temporary PNP occurred in this group, which resolved before discharge. Freedom from documented recurrence at 12 months in these pts was 82.0%. CONCLUSIONS: This novel cryoballoon may facilitate PVI to treat PAF, providing more options to address the variety of anatomies present in patients with PAF. This cryoballoon system proved to be safe and effective for treatment of patients with drug refractory or drug intolerant PAF.

Lower Recurrence Rates of Atrial Fibrillation and MACE Events After Early Compared to Late Ablation: A Danish Nationwide Register Study.

BACKGROUND: Guidelines recommend prioritizing treatment with antiarrhythmic drugs before referral of patients with atrial fibrillation to ablation, delaying a potential subsequent ablation. However, delaying ablation may affect ablation outcomes. We sought to investigate the impact of duration from diagnosis to ablation on the risk of atrial fibrillation recurrence and adverse events. METHODS AND RESULTS: Using Danish nationwide registries, all patients with first-time ablation for atrial fibrillation were identified and included from 2010 to 2018. Patients were divided into 4 groups by diagnosis-to-ablation time: <1.0 year (early ablation), 1.0 to 1.9 years, 2.0 to 2.9 years, and >2.9 years (late ablation). The primary end point was atrial fibrillation recurrence after the 90-day blanking period, defined by admission for atrial fibrillation, cardioversions, use of antiarrhythmic drugs, or repeat atrial fibrillation ablations. The secondary end point was a composite end point of heart failure, ischemic stroke, or death, and each event individually. The study cohort consisted of 7705 patients. The 5-year cumulative incidence of atrial fibrillation recurrence in the 4 groups was 42.9%, 54.8%, 55.9%, and 58.4%, respectively. Hazard ratios were 1.20 (95% CI, 1.07-1.35), 1.29 (95% CI, 1.13-1.47), and 1.40 (95% CI, 1.28-1.53), respectively, with the early ablation group as reference. The hazard ratio for the combined secondary end point was 1.22 (95% CI, 1.04-1.44) in the late ablation group compared with the early ablation group. CONCLUSIONS: In patients undergoing ablation for atrial fibrillation, early ablation was associated with a significantly lower risk of atrial fibrillation recurrence. Furthermore, the associated risk of heart failure, ischemic stroke, or death was significantly lower in early-compared with late-ablation patients.

Utilizing Human-Induced Pluripotent Stem Cells to Study Cardiac Electroporation Pulsed-Field Ablation.

BACKGROUND: Electroporation is a promising nonthermal ablation method for cardiac arrhythmia treatment. Although initial clinical studies found electroporation pulsed-field ablation (PFA) both safe and efficacious, there are significant knowledge gaps concerning the mechanistic nature and electrophysiological consequences of cardiomyocyte electroporation, contributed by the paucity of suitable human in vitro models. Here, we aimed to establish and characterize a functional in vitro model based on human-induced pluripotent stem cells (hiPSCs)-derived cardiac tissue, and to study the fundamentals of cardiac PFA. METHODS: hiPSC-derived cardiomyocytes were seeded as circular cell sheets and subjected to different PFA protocols. Detailed optical mapping, cellular, and molecular characterizations were performed to study PFA mechanisms and electrophysiological outcomes. RESULTS: PFA generated electrically silenced lesions within the hiPSC-derived cardiac circular cell sheets, resulting in areas of conduction block. Both reversible and irreversible electroporation components were identified. Significant electroporation reversibility was documented within 5 to 15-minutes post-PFA. Irreversibly electroporated regions persisted at 24-hours post-PFA. Per single pulse, high-frequency PFA was less efficacious than standard (monophasic) PFA, whereas increasing pulse-number augmented lesion size and diminished reversible electroporation. PFA augmentation could also be achieved by increasing extracellular Ca2+ levels. Flow-cytometry experiments revealed that regulated cell death played an important role following PFA. Assessing for PFA antiarrhythmic properties, sustainable lines of conduction block could be generated using PFA, which could either terminate or isolate arrhythmic activity in the hiPSC-derived cardiac circular cell sheets. CONCLUSIONS: Cardiac electroporation may be studied using hiPSC-derived cardiac tissue, providing novel insights into PFA temporal and electrophysiological characteristics, facilitating electroporation protocol optimization, screening for potential PFA-sensitizers, and investigating the mechanistic nature of PFA antiarrhythmic properties.

Catheter Ablation for Atrial Fibrillation in Patients with Left Ventricular Ejection Fraction ≤ 45%: A Meta-Analysis of Randomized Controlled Trials. / Ablação por Cateter para Fibrilação Atrial em Pacientes com Fração de Ejeção do Ventrículo Esquerdo ≤ 45%: Uma Metanálise de Ensaios Clínicos Randomizados.

BACKGROUND: Atrial fibrillation (AF) and heart failure (HF) frequently coexist, resulting in adverse outcomes. However, controversies remain regarding the efficacy of catheter ablation (CA) in AF patients with severe left ventricular dysfunction. OBJECTIVES: The purpose of this study was to perform a meta-analysis of prospective randomized controlled trials to evaluate the efficacy of CA versus medical therapy (MT) in AF patients with left ventricular ejection fraction (LVEF) ≤45%. METHODS: We searched the literature for studies that compared CA to MT in AF patients with LVEF ≤45%. A meta-analysis of 7 clinical trials was performed, including 1163 patients with AF and HF. Subgroup analysis was performed based on baseline LVEF. All tests were 2-sided; only the p-value <0.05 was considered statistically significant. RESULTS: We found that CA was associated with lower all-cause mortality (risk ratio: 0.52, 95% CI: 0.37 to 0.72; p<0.01) and greater improvements in LVEF (mean difference: 4.80%, 95% CI: 2.29% to 7.31%; p<0.01) compared to MT. Patients in the CA group had a lower risk of HF hospitalization and AF recurrence and a significantly better quality of life than those in the MT group. The results of subgroup analysis indicated that patients with milder left ventricular dysfunction improved LVEF after AF ablation (mean difference: 6.53%, 95% CI: 6.18% to 6.88%; p<0.01) compared to patients with more severe disease (mean difference: 2.02%, 95% CI: 0.87% to 3.16%; p<0.01). CONCLUSIONS: Our meta-analysis demonstrated that CA was associated with significant improvements in outcomes of AF patients with LVEF ≤45%. Additionally, AF patients with milder left ventricular dysfunction could benefit more from CA.

FUNDAMENTO: A fibrilação atrial (FA) e a insuficiência cardíaca (IC) coexistem frequentemente, resultando em desfechos adversos. No entanto, permanecem controvérsias quanto à eficácia da ablação por cateter (AC) em pacientes com FA com disfunção ventricular esquerda grave. OBJETIVOS: O objetivo deste estudo foi realizar uma metanálise de ensaios prospectivos randomizados e controlados para avaliar a eficácia da AC versus terapia médica (TM) em pacientes com FA com fração de ejeção do ventrículo esquerdo (FEVE) ≤45%. MÉTODOS: Procuramos na literatura estudos que comparassem AC com TM em pacientes com FA com FEVE ≤45%. Foi realizada uma metanálise de 7 ensaios clínicos, incluindo 1.163 pacientes com FA e IC. A análise de subgrupo foi realizada com base na FEVE basal. Todos os testes foram bilaterais; apenas o valor p <0,05 foi considerado estatisticamente significativo. RESULTADOS: Descobrimos que a AC estava associada a menor mortalidade por todas as causas (taxa de risco: 0,52, IC 95%: 0,37 a 0,72; p<0,01) e maiores melhorias na FEVE (diferença média: 4,80%, IC 95%: 2,29% a 7,31%; p<0,01) em comparação com TM. Os pacientes do grupo AC apresentaram menor risco de hospitalização por IC e recorrência de FA e qualidade de vida significativamente melhor do que aqueles do grupo TM. Os resultados da análise de subgrupo indicaram que pacientes com disfunção ventricular esquerda mais leve melhoraram a FEVE após a ablação de FA (diferença média: 6,53%, IC 95%: 6,18% a 6,88%; p<0,01) em comparação com pacientes com doença mais grave (diferença média : 2,02%, IC 95%: 0,87% a 3,16%; p<0,01). CONCLUSÕES: Nossa metanálise demonstrou que a AC foi associada a melhorias significativas nos resultados de pacientes com FA com FEVE ≤45%. Além disso, pacientes com FA com disfunção ventricular esquerda mais leve poderiam se beneficiar mais com a AC.