Suppression Of Ventricular Arrhythmias Research Articles

Impact of dapagliflozin on supraventricular and ventricular arrhythmias, assessed by Holter ECG, in patients with heart failure with reduced ejection fraction

Abstract Background & Introduction Dapagliflozin has significantly reduced morbidity & mortality in patients with heart failure with reduced ejection fraction (HFrEF) (1). Some studies reported supraventricular & ventricular arrhythmia suppression, but Holter ECG was underused, hindering precise assessment of arrhythmia burden. Purpose We aim to assess the impact of dapagliflozin on reduction of arrhythmia in HFrEF at 1 year follow-up (FU) by Holter ECG. Methods This is a single center, prospective study. We have screened 219 HFrEF patients, but only 156 patients were enrolled with LVEF <40% in sinus rhythm from December 2021 to July 2023. All patients had dapagliflozin 10 mg once/day tablet with the standard HF therapy. Clinical evaluation, NYHA evaluation, 6-minute walking test (6MWT), echocardiogram, 24-hours Holter ECG and laboratory work-up were done at baseline, and FU at 6 months and 12 months. Results Males constituted 61.5% of study population; mean± SD participants’ age was 56.8 ± 8.6 years. The most common comorbidities were: ischemic etiology (63.3%), dilated cardiomyopathy (28.1%), hypertension (27.3%), smokers (14.7%), and type II diabetes (31.4%). LVEF was ≤ 35% in 85.9% of patients. We have reported (7.69%) deaths during 1-year FU, and 4 patients (2.56%) didn't complete 1-year FU. Main clinical and echocardiographic findings (baseline vs. 1-year FU): NYHA FC III& ambulant IV dropped from (42.9 to 32.9%), P value<0.05. Distance walked in 6MWT improved from 191.52 ± 75.37 to 219.35 ± 71.51 mean± SD meters, P value<0.05. E/e improved (9.4 to 8.3 cm/s, P value <0.01), LVEF improved (31.3 to 36.4%, P value<0.05). HF emergency: [HF visits dropped (23.7 to 19.2%) and HF hospitalization dropped (11.1 to 7.8%)], P value<0.05. Holter ECG (baseline vs. 1-year FU): Supraventricular Arrhythmia: [Paroxysmal AF reduced (56.2 to 47.6%), frequent PACs (≥ 10%) dropped (3.8 to 1.4%) & Intermittent 1st degree heart block dropped (12.5 to 7.3%)] P value <0.01. Ventricular Arrhythmia: [PVCs >5%-<10% dropped (16% to 9.3%), Frequent PVCs >10% dropped (3.2 to 1.4%), and NSVT dropped (7.8 to 3.1%)], P value <0.01. Stepwise logistic regression multivariable model aiming to predict the occurrence of ventricular and supraventricular arrhythmias has indicated a direct linear correlation with male gender, smoking, body mass index, left atrial volume, and a history of myocardial infarction. Conversely, there is an inverse relationship with systolic blood pressure, 6MWT distance, LVEF, and the administration of dapagliflozin (OR 0.72 [0.61 - 1.07], P value <0.01) concerning the likelihood of supraventricular and ventricular arrhythmias. Conclusions Dapagliflozin has demonstrated significant improvement in functional and echocardiographic parameters in HFrEF patients. Furthermore, it has effectively decreased the incidence of supraventricular and ventricular arrhythmias, identified through 24-hour Holter ECG monitoring during 1-year follow-up.

Epicardial ablation in patients with Brugada syndrome: a single centre experience

Abstract Introduction Brugada syndrome (BrS) is a rare disease associated with an increased risk of ventricular fibrillation (VF), ventricular tachycardia (VT), and sudden cardiac death (SCD). The standard prevention of SCD in patients with BrS is the implantation of an implantable cardioverter-defibrillator (ICD), especially in patients who have previously suffered cardiac arrest or arrhythmogenic syncope. Catheter ablation is an effective method to prevent recurrences of VF/VT in these patients. Purpose Retrospective analysis of the results of catheter ablation by epicardial approach and genetic testing in patients with a diagnosis of BrS and repeated adequate ICD interventions. Methods In 2013-2024, catheter ablation by epicardial approach was performed in our centre in 9 patients diagnosed with Brugada syndrome (mean age 41±6 years, nine males, left ventricular ejection fraction 57±4%). All patients had an ICD implanted for secondary prevention of SCD and presented with adequate ICD therapies (mean 9±11 shocks/patient in the last six months before catheter ablation). Before catheter ablation, two patients were treated with quinidine. Patients underwent cardiogenetic testing by next-generation sequencing of 228 genes. Results Type 1 electrocardiogram (ECG) pattern was present at baseline ECG in four (44%) patients; in five (56%) patients, type 1 was induced after ajmaline administration. Genetic testing was performed in seven patients, and only one patient (14%) was found to have a relevant pathogenic mutation in the SCN5A gene. Prior to ablation, sustained VT/VF could be induced by programmed electrical stimulation in three patients (33%). Epicardial ablation was targeted at areas of abnormal electrograms located over the right ventricular outflow tract. No complications were noted. The mean follow-up period was 25±30 months. In one patient (11%), reablation was required to suppress ventricular arrhythmias successfully. After the last ablation, no recurrence of VT/VF was observed in any patient. Conclusions Epicardial ablation is an effective method that leads to the suppression of ventricular arrhythmias in patients with a diagnosis of BrS and repeated ICD interventions. Despite the malignant arrhythmic phenotype, patients in our cohort had a rather low prevalence of signs associated with a high risk of VT/VF, such as spontaneous ECG pattern of BrS, inducibility of VT/VF during electrical programmed stimulation, or the presence of a causative genetic mutation.

Clinical profile of patients undergoing percutaneous stellate ganglion block for electrical storm and association with antiarrhythmic efficacy

Abstract Background Percutaneous stellate ganglion block (PSGB) usage for patients with refractory ventricular arrhythmias (VAs) in form of electrical storm (ES) is in quickly expanding. The clinical profile of patients and the potential association with the antiarrhythmic efficacy of the procedure are mostly unexplored. Purpose To better characterize clinical profile and potential association with antiarrhythmic efficacy of patients undergoing PSGB for ES. Methods Patients undergoing PSGB for ES in our Center from 2/2021 to 2/2024 were enrolled; all the dynamic variables were evaluated in a per procedure analysis. Results 45 patients (93% male, 64 ± 10 years) received a total of 80 PSGB performed with the lateral, ultrasound (US) guided technique; most PSGB consisted of a single bolus anesthetic injection (lidocaine + ropivacaine), 26% in an additional continuous infusion, mostly with ropivacaine. All procedures except for 3 in a single patient who had previously received left cardiac sympathetic denervation, were performed on the left side. Most of the patients (60%) suffered ischemic cardiomyopathy (CMP), including 10 with an acute coronary syndrome; the rest had non-ischemic CMP; 60% had an ICD. The type of VAs was ventricular tachycardia (VTs) only in 86% of the procedures (cycle length 404 ± 143 msec), VT and VF in 10% and VF only in 3 (4%). Most PSGB (81%) were performed in the setting of impending or manifest cardiogenic shock (SCAI classification B or more), including 20% with sepsis. Cardiac US performed before (within 12 hours) each PSGB showed a severely depressed left ventricular (LV) function (mean LVEF 22 ± 10%, mean LV outflow tract velocity time integral 12 ± 4 cm), calculated at a mean heart rate of 81 ± 16 bpm. Mean LVEDV was 252 ± 104 ml, 79% had mitral regurgitation (MR) ≥2+/4+ (including 39% severe MR), 50% had ≥ moderate diastolic dysfunction, 29% had right ventricular dysfunction (mean fractional areal change 33± 7%). Most cases (75%) experienced a complete VAs suppression (sustained or treated) in the 12 hours after PSGB; only 3/80 cases required additional urgent antiarrhythmic strategies (intra-aortic ballon pump in one case, urgent pacing in another one, urgent revascularization in the last one). None of the assessed clinical or echocardiographic characteristics was significantly associated with VT cycle length or the response to PSGB. Only 1 (1%) major complication occurred (respiratory arrest), that was quickly and effectively treated with lipid emulsion. Conclusions PSGB in our Center was mostly performed in the setting of primary impending or manifest cardiogenic shock with severely impaired cardiac function, with an excellent safety profile. None of the assessed clinical or echocardiographic variables were associated with response to PSGB. Our data, despite preliminary and requiring confirmation, suggests always considering PSGB in the urgent/emergent setting independently from patients’ characteristics.

Comparison of Oral Procainamide and Mexiletine Treatment of Recurrent and Refractory Ventricular Tachyarrhythmias

Background: Antiarrhythmic therapy for recurrent ventricular arrhythmias (VAs) in patients having undergone catheter ablation and in whom amiodarone and/or beta-blockers were ineffective or contraindicated is a controversial issue. Purpose: The present study sought to compare the efficacy and tolerability of oral procainamide and mexiletine in patients with recurrent ventricular arrhythmias when the standard therapy strategy failed. Methods: All patients with an implantable cardioverter defibrillator (ICD) treated with oral procainamide or mexiletine for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in two cardiology divisions between January 2010 and January 2020 were enrolled. Patients were divided into group A (oral procainamide) and group B (mexiletine) and the two groups were compared to each other. The primary endpoint was the efficacy of therapy; the secondary endpoint was the discontinuation of therapy. All events that occurred during procainamide or mexiletine treatment were compared with a matched duration period before the initiation of the therapy. Antiarrhythmic therapy was considered effective when a ≥80% reduction of the sustained ventricular arrhythmias burden recorded by the ICD was achieved. Results: A total of 68 consecutive patients (61 males, 89.7%; mean age 74 ± 10 years) were included in this retrospective analysis. After a median follow-up of 19 months, 38 (56%) patients had a significant reduction in the VA burden. After multivariable adjustment, therapy with procainamide was independently associated with an almost 3-fold higher efficacy on VA suppression compared to mexiletine (HR 2.54, 95% CI 1.06–6.14, p = 0.03). Only three patients (9%) treated with procainamide presented severe side effects (dyspnea or hypotension) requiring discontinuation of therapy compared with six patients (18%) treated with mexiletine who interrupted therapy because of severe side effects (p = 0.47). Conclusions: Compared to mexiletine, oral procainamide had a higher efficacy for the treatment of recurrent and refractory VAs, and showed a good profile of tolerability.

Transseptal approach versus retrograde aortic approach in mapping and ablation of ventricular arrhythmias from anterolateral papillary muscles.

The anterior and lateral position of the anterolateral papillary muscle (ALPM) has found to be reached with better catheter stability and less mechanical bumping via the transseptal (TS) compared to the retrograde aortic (RA) approach. The aim of this study is to compare the TS and RA approaches on mapping and ablation of ventricular arrhythmias (VAs) arising from ALPMs. Thirty-two patients with ALPM-VAs undergoing mapping and ablation via the TS approach were included and compared with 31 patients via the RA approach within the same period. Acute success was compared, as well as other outcomes including misinterpreted mapping results due to bumping, radiofrequency (RF) attempts, procedural time and success rate at 12-month follow-up. Acute success was achieved in more cases in the TS group (96.4% vs. 72.0%, p = .020). During activation mapping, bump-provoked premature ventricular complexes (PVCs) misinterpreted as clinical PVCs were more common in the RA group (30.0% vs. 58.3%, p = .036), leading to more RF attempts (3.5 ± 2.7 vs. 7.2 ± 6.8, p = .006). Suppression of VAs were finally achieved in the unsuccessful cases by changing to the alternative approach, but the procedural time was significantly less in the TS group (90.0 ± 33.0 vs. 113.7 ± 41.1 min, p = .027) with less need to change the approach, although follow-up success rates were similar (75.0% vs. 71.0%, p = .718). A TS rather than RA approach as the initial approach appears to facilitate mapping and ablation of ALPM-VAs, specifically by decreasing the possibility of misleading mapping results caused by bump-provoked PVC, and increase the acute success rate thereby.

Anatomical approach to suppression of para-Hisian ventricular arrhythmias with changes in QRS morphology after ablation at the earliest activation site

BackgroundThe anatomical approach for the management of para-Hisian ventricular arrhythmias (VAs) with QRS morphological changes after catheter ablation (CA) has not been well investigated. ObjectiveWe aimed to evaluate the electrocardiographic and electrophysiological findings and ablation outcomes of para-Hisian VAs with QRS morphological changes after CA. MethodsOf the 30 patients who underwent CA for para-Hisian VAs at 4 institutions, 10 (33%) had QRS morphological changes after ablation. All 10 patients underwent an anatomical approach, targeting the site anatomically opposite to the site where the QRS morphology had been changed by ablation. We investigated the safety and efficacy of the anatomical approach. ResultsOf the 10 patients evaluated, the approach was switched from the right ventricular septum to the left ventricular septum/aortic root in 7 (70%) (RL group) whereas 3 (30%) underwent left-to-right switches (LR group). After CA, the precordial transition zone tended to be earlier in the RL group and later in the LR group. In the RL group, successful VA suppression was achieved, despite suboptimal pace map concordance from the left side or a relatively delayed earliest activation time. Of the 10 patients who underwent an anatomical approach, 8 (80%) had procedural success, and ablation was discontinued in 1 (10%) because of the risk of atrioventricular block. ConclusionThe anatomical approach showed promising results regarding safety and efficacy. Therefore, it should be considered when QRS morphological changes are observed during or after CA of para-Hisian VAs.

An inherited life-threatening arrhythmia model established by screening randomly mutagenized mice

Inherited arrhythmia syndromes (IASs) can cause life-threatening arrhythmias and are responsible for a significant proportion of sudden cardiac deaths (SCDs). Despite progress in the development of devices to prevent SCDs, the precise molecular mechanisms that induce detrimental arrhythmias remain to be fully investigated, and more effective therapies are desirable. In the present study, we screened a large-scale randomly mutagenized mouse library by electrocardiography to establish a disease model of IASs and consequently found one pedigree that exhibited spontaneous ventricular arrhythmias (VAs) followed by SCD within 1 y after birth. Genetic analysis successfully revealed a missense mutation (p.I4093V) of the ryanodine receptor 2 gene to be a cause of the arrhythmia. We found an age-related increase in arrhythmia frequency accompanied by cardiomegaly and decreased ventricular contractility in the Ryr2I4093V/+ mice. Ca2+ signaling analysis and a ryanodine binding assay indicated that the mutant ryanodine receptor 2 had a gain-of-function phenotype and enhanced Ca2+ sensitivity. Using this model, we detected the significant suppression of VA following flecainide or dantrolene treatment. Collectively, we established an inherited life-threatening arrhythmia mouse model from an electrocardiogram-based screen of randomly mutagenized mice. The present IAS model may prove feasible for use in investigating the mechanisms of SCD and assessing therapies.

Characteristics of Local Endograms at the Site of Successful Arrhythmia Suppression During Activation Mapping of Idiopathic Ventricular Arrhythmias Using 3D Navigation

A topical issue is the determination of the optimal values of activation time of local endograms (LE) and bipolar signal morphology during ablation in patients with idiopathic ventricular arrhythmias (VA) at the site of successful suppression, and the influence of 3D navigation on these values.
 The aim. To study earliest activation time (EAT) and LE morphology in the area of successful suppression during ablation of idiopathic VA using 3D navigation.
 Materials and methods. Analysis of the results of ablation in 57 patients with idiopathic VA was made. The patients were divided into two groups. Group I included 30 (52.6%) patients in whom mapping was performed using 3D navigation (EnSite Velocity Cardiac Mapping System). Group II included 27 (47.4%) patients who were mapped using conventional methods.
 In group I, extrasystole was found in 20 (66.7%) patients, while ventricular tachycardia was observed in 10 (33.3%) patients. In group II, extrasystole was revealed in 16 (59.3%) patients, and ventricular tachycardia in 11 (40.7%) patients.
 Group I included 21 (70%) patients with right ventricular localization of arrhythmia and 9 (30%) patients with left ventricular localization. Meanwhile, group II included 17 (63%) patients with a focus in the right ventricle and 10 (33%) patients with that in the left ventricle.
 The morphology of the LE was evaluated according to criteria such as polarity (positive or negative) and degree of signal fragmentation (monomorphic or fragmented). Polarity was determined by the initial direction of the signal during the first 10 ms, regardless of further changes in the endogram. The signal was considered fragmented if there were three or more polarity changes.
 Results. In group I, EAT of LE was -38.0±7.0 ms, while in group II it was -38.0±8.5 ms. No difference was found between the studied groups (p=0.834).
 Among all patients in both groups, the average value of EAT of LE at the site of successful arrhythmia elimination was -37.0±8.5 ms. In 92.9% cases EAT of LE was -30 ms or earlier. Only in four (7.1%) patients it was possible to achieve suppression of the arrhythmia with EAT of LE not earlier than -30 ms, while in all these cases the focus was always localized in the right ventricle. The minimum value of EAT of LE at the site of successful suppression of arrhythmia was -27 ms.
 The dominant morphology at the site of successful suppression among the patients in both groups, regardless of the type of mapping, was positive polarity of endogram.
 Conclusions. Regardless of the mapping method, in the site of successful idiopathic VA suppression LE must precede QRS by at least 27 ms.

Non-invasive Neuromodulation of Arrhythmias.

Dysfunction of the cardiac autonomic nervous system (CANS) is associated with various cardiac arrhythmias. Subsequently, invasive techniques have successfully targeted the CANS for the treatment of certain arrhythmias, such as sympathetic denervation for ventricular tachycardia storm. Non-invasive strategies capable of modulating the CANS for arrhythmia treatment have begun to gain interest due to their low-risk profile and applicability as an adjuvant therapy. This review provides an evidence-based overview of the currently studied technologies capable of non-invasively modulating CANS for the suppression of atrial fibrillation and ventricular arrhythmias.

Safety and Efficacy of Ultrasound-Guided Sympathetic Blockade by Proximal Intercostal Block in Electrical Storm Patients

BackgroundElectrical storm (ES) patients who fail standard therapies have a high mortality rate. Previous studies report effective management of ES with bedside, ultrasound-guided percutaneous stellate ganglion block (SGB). We report our experience with sympathetic blockade administered via a novel alternative approach: proximal intercostal block (PICB). Compared with SGB, this technique targets an area typically free of other catheters and support devices, and may pose less strict requirements for anticoagulation interruption, along with lower risk of focal neurological side effects. ObjectivesThe authors sought to describe the safety and efficacy of PICB in patients with refractory ES. MethodsWe reviewed our institutional data on ES patients who underwent PICB between January 2018 and February 2023 to analyze procedural safety and short- and long-term outcomes. ResultsA total of 15 consecutive patients with ES underwent PICB during this period. Of those, 11 patients (73.3%) were maintained on PICB alone, and 4 patients (26.6%) were maintained on combined block with SGB and PICB. Overall, 72.7% patients who were maintained on PICB alone and 77.8% patients who were maintained on bilateral PICB had excellent arrhythmia suppression. After PICB, implantable cardioverter-defibrillator therapies were significantly reduced (P < 0.05), with 93.3% of patients receiving PICB having no implantable cardioverter-defibrillator shock until discharge or heart transplant. Anticoagulation was continued in all patients and there were no procedure-related complications. Apart from mild transient neurological symptoms seen in 3 patients, no significant neurological or hemodynamic sequelae were observed. ConclusionsIn patients with refractory ES, continuous PICB provided safe and effective sympathetic block (77.8% ventricular arrhythmia suppression), achievable without interruption of anticoagulation, and without significant side effects.

Abstract 16745: Continuous Stellate Ganglion Block for Ventricular Arrhythmias: Case Series, Systematic Review and Comparison With Epidural Anesthesia

Background: Percutaneous single bolus injection left stellate ganglion block (PLSGB) and thoracic epidural anesthesia (TEA) have been proposed for the acute management of refractory ventricular arrhythmias (VAs). Data on continuous PLSGB (C-PLSGB) are scant. Objectives: to report our single center experience with C-PLSGB and perform a systematic review on C-PLSGB and TEA to preliminary compare these 2 techniques. Methods: consecutive patients receiving C-PLSGB were enrolled. The systematic literature review was performed following the latest PRISMA criteria. Results: our single-center case series (8 pts, 88% male, 60 ±16 years, all with structural heart disease) supports that C-PLSGB is feasible and safe, even on fully anticoagulated patients and leads to a complete VAs suppression in half and to an overall clinical benefit in all patients. Overall, considering previously published data, 34 patients received C-PLSGB, and 18 TEA for refractory VAs. Most (61%) in the TEA group were on general anesthesia, as opposed to 24% in the C-PLSGB group (p=0.01); 52% of patients were on full anticoagulation at C-PLSGB, none at TEA (p&lt;0.01). C-PLSGB and TEA efficacy was not significantly different (31/34 versus 13/18 had a complete or at least partial response, p=0.1). No major complications occurred, yet the discontinuation rate was significantly higher in the TEA compared to C-PLSGB (22% versus 3%, p=0.037). Conclusions: C-PLSGB seems feasible, safe and effective for the acute management of refractory VAs. C-PLSGB efficacy seems to be not significantly different to that of TEA and may be accomplished with less concerns of anticoagulation, and lower discontinuation rate.

Post-ablation augmentation of skin sympathetic nerve activity predicts a poor outcome of idiopathic ventricular arrhythmias

BackgroundThe neuromodulation effect after ventricular arrhythmia (VA) ablation is unclear. The study aimed to investigate skin sympathetic nerve activity (SKNA) changes in patients receiving catheter ablations for idiopathic VA. MethodsOf 43 patients with drug-refractory symptomatic VA receiving ablation, SKNA was continuously recorded for 10 min during resting from electrocardiogram lead I configuration and bipolar electrodes on the right arm 1 day before and 1 day after ablation. ResultsTwenty-two patients with acute procedure success and no recurrence during follow-ups were classified as sustained success group (group 1). Other 21 patients were classified as failed ablation group (group 2). Baseline SKNA showed no significant difference between the two groups. Post-ablation SKNA in group 2 was significantly higher than in group 1. In patients with ablation involved right ventricular outflow tract (RVOT), the post-ablation SKNA was also significantly higher in group 2. In contrast, there was no difference in post-ablation SKNA between groups in patients receiving non-RVOT ablation. ConclusionThe neuromodulation response after RVOT ablation may correspond to the sympathetic nerve distribution at RVOT. Augmentation of sympathetic activity after VA ablation indicates an unsuccessful VA suppression, especially in patients receiving ablation of RVOT VA.

Stellate ganglion blockade for treatment of ventricular arrhythmia storm: a meta-analysis

Abstract Background Autonomic neuromodulation and particularly stellate ganglion blockade (SGB) has been tested in ventricular arrhythmia (VA) storm, but there is so far no robust evidence to inform clinical practice and its use remains limited. Purpose We aimed to summarize the efficacy and safety of SGB in patients with VA storm. Methods We searched PubMed, the Cochrane Library and Scopus from inception to 15th March 2022, for studies performing either pharmacological or electrical SGB in the context of drug-refractory VA storm. Case series with less than 10 patients were excluded. We performed a single-arm random effects meta-analysis of studies to calculate the pooled proportion estimate of freedom from VA recurrence after SBG and the overall mean change of VA burden from baseline. Results Of 409 articles identified and screened, we considered eligible six studies comprising a total of 106 patients. The mean age was 61.6±13.9 years, 79.2% were male, the mean left ventricular ejection fraction was 28.8±12.7%, and 47.1% had underlying ischemic cardiomyopathy. In five trials the patients received pharmacological SGB with bupivacaine, ropivacaine, or/and lidocaine (left-sided or bilateral), while in one study transcutaneous magnetic stimulation of the left stellate ganglion was used. The pooled proportion of patients free of VA recurrences was 65% (95% CI 51–78%, I2=46%) at the first 24 hours post-SGB (Figure 1A), and 54% (95% CI 43–64%, I2=0%) at 72 hours (Figure 1B). The number of VA episodes was significantly reduced from a mean baseline of 7.01±8.34 episodes/24h before SGB to 0.93±1.64 episodes/24h after SGB. The mean absolute reduction of VA episodes was 5.44 (95% CI 2.83–8.05, I2=88%) (Figure 1C) while the mean absolute reduction of external or internal defibrillation events was 3.36 (95% CI 0.62–6.09, I2=84%) (Figure 1D). No serious procedure-related complications were reported. The overall in-hospital mortality was 28.4%. Conclusions SGB appears an effective and safe treatment in patients with VA storm with approximately 1 in 2 patients exhibiting complete suppression of VA for 72 hours and an approximately 80% mean relative reduction in VA burden. Funding Acknowledgement Type of funding sources: None.

Safety and Efficacy of Cryoablation forRight Ventricular Moderator Band-Papillary Muscle Complex Ventricular Arrhythmias.

The right ventricular moderator band and papillary muscle (RV MB-PM) complex is an uncommon source of ventricular arrhythmias (VAs). Success rates following the ablation of intracavity structures are lower than for other sites of origin of VAs because of challenging catheter stability and a tendency for hemodynamically unstable automaticity when radiofrequency (RF) is delivered. This study sought to describe the institutional experience of RV MB-PM VAs across a 2-year period and compare the outcomes from ablations performed using RF ablation and cryoablation. Electronic health records of patients who underwent catheter ablation of RV MB-PM arrhythmias between January 2018 and November 2021 were reviewed, including imaging, intraprocedural data, and follow-up. Eleven patients underwent ablation of RV MB-PM arrhythmias throughout the duration of the study. Five patients underwent catheter ablation with RF, and 6 patients underwent cryoablation. Three patients in the cryoablation group had previous attempted ablation with RF. Four patients in the RF group and 4 patients in the cryoablation group had structurally abnormal hearts. Acute VA suppression was achieved in 4 of 5 patients with RF and 6 of 6 patients with cryoablation. During follow-up, the rate of arrhythmia recurrence was lower in the cryoablation group (HR: 0.12; 95%CI: 0.016-0.90; P = 0.0396). Compared to RF, cryoablation offers improved catheter stability and reduced propensity for automaticity during ablation. The use of cryoablation as a first-line strategy is reasonable when RV MB-PM origin of premature ventricular contractions is suspected.

PO-682-05 USE OF DRY SUCTION WATER SEAL DRAINAGE FOR PERICARDIAL FLUID MANAGEMENT DURING EPICARDIAL VT ABLATION

Epicardial ablation is less common but often critical approach for suppression of ventricular arrhythmias (VA), particularly in patients with arrhythmogenic cardiomyopathies. The use of irrigated ablation catheters in this space requires manual aspiration of fluid to prevent tamponade, creating frequent interruptions that prolong procedure time.

Suppression of ventricular arrhythmias by targeting late L-type Ca2+ current.

Ventricular arrhythmias, a leading cause of sudden cardiac death, can be triggered by cardiomyocyte early afterdepolarizations (EADs). EADs can result from an abnormal late activation of L-type Ca2+ channels (LTCCs). Current LTCC blockers (class IV antiarrhythmics), while effective at suppressing EADs, block both early and late components of ICa,L, compromising inotropy. However, computational studies have recently demonstrated that selective reduction of late ICa,L (Ca2+ influx during late phases of the action potential) is sufficient to potently suppress EADs, suggesting that effective antiarrhythmic action can be achieved without blocking the early peak ICa,L, which is essential for proper excitation-contraction coupling. We tested this new strategy using a purine analogue, roscovitine, which reduces late ICa,L with minimal effect on peak current. Scaling our investigation from a human CaV1.2 channel clone to rabbit ventricular myocytes and rat and rabbit perfused hearts, we demonstrate that (1) roscovitine selectively reduces ICa,L noninactivating component in a human CaV1.2 channel clone and in ventricular myocytes native current, (2) the pharmacological reduction of late ICa,L suppresses EADs and EATs (early after Ca2+ transients) induced by oxidative stress and hypokalemia in isolated myocytes, largely preserving cell shortening and normal Ca2+ transient, and (3) late ICa,L reduction prevents/suppresses ventricular tachycardia/fibrillation in ex vivo rabbit and rat hearts subjected to hypokalemia and/or oxidative stress. These results support the value of an antiarrhythmic strategy based on the selective reduction of late ICa,L to suppress EAD-mediated arrhythmias. Antiarrhythmic therapies based on this idea would modify the gating properties of CaV1.2 channels rather than blocking their pore, largely preserving contractility.

Quinidine in the Management of Recurrent Ventricular Arrhythmias: A Reappraisal.

This study aimed to review the utility of quinidine in patients presenting with recurrent sustained ventricular arrhythmia (VA) and limited antiarrhythmic drug (AAD) options. Therapeutic options are often limited in patients with structural heart disease and recurrent VAs. Quinidine has an established role in rare arrhythmic syndromes, but its potential use in other difficult VAs has not been assessed in the present era. We performed a retrospective analysis of 37 patients who had in-hospital quinidine initiation after multiple other therapies failed for VA suppression at our tertiary referral center. Clinical data and outcomes were obtained from the medical record. Of 30 patients with in-hospital quantifiable VA episodes, quinidine reduced acute VA from a median of 3 episodes (interquartile range [IQR]: 2 to 7.5) to 0 (IQR: 0 to 0.5) during medians of 3days before and 4days after quinidine initiation (p<0.001). VA events decreased from a median of 10.5 episodes per day (IQR: 5 to 15) to 0.5 episodes (IQR: 0 to 4) after quinidine initiation in the 12 patients presenting with electrical storm (p=0.004). Among the 24 patients discharged on quinidine, 13 (54.2%) had VA recurrence during a median of 138days. Adverse effects in 9 of the 37 patients (24.3%) led to drug discontinuation, most commonly gastrointestinal intolerance. In patients with recurrent VAs and structural heart disease who have limited treatment options,quinidine can be useful, particularly as a short-term therapy.

Mechanism of angiotensin receptor-neprilysin inhibitor in suppression of ventricular arrhythmia

BackgroundThe mechanisms underlying angiotensin receptor-neprilysin inhibitor (ARNi) suppression of ventricular arrhythmia (VA) are unclear. This study aimed to investigate the mechanism of ARNi-related suppression of VA in a heart failure (HF) model. MethodsNew Zealand white rabbits (n = 6 per group) were assigned to normal, HF [4 weeks of left ascending artery (LAD) ligation], angiotensin receptor blocker (ARB, valsartan at 27 mg/kg/day for 3 weeks after 1 week of LAD ligation), and ARNi (sacubitril at 34 mg/kg/day and valsartan at 27 mg/kg/day for 3 weeks after 1 week of LAD ligation) groups. Experiments involving echocardiogram, optical mapping, histological of trichrome stain and immunostain, and flow cytometry were performed. ResultsHF group had larger left ventricular (LV) internal dimensions in diastole and systole, and lower LV ejection fraction and fractional shortening than normal, ARB, and ARNi groups. HF group had a prolonged action potential duration (APD) and decreased conduction velocity (CV), which was mitigated in ARB and ARNi groups. HF group had a prolonged QRS duration, QT and QTc intervals, which was reversed in ARB and ARNi groups. HF group had a steeper maximum slope of APD restitutions, which was attenuated in normal, ARB, and ARNi groups. HF group had increased number of phase singularities (PSs) and VA inducibility than normal, ARB, and ARNi groups. A higher content of fibrosis was found in HF group than that in normal, ARB, and ARNi groups. Compared to ARB group, ARNi had a lower context of fibrosis. HF group had more peripheral blood CD4+ and CD8+ cells count than normal, ARB, and ARNi group. ConclusionsIn a rabbit model of ischemic HF, ventricular arrhythmogenesis could be suppressed by ARNi treatment. This appears to be mediated by reversing changes in the APD, CV, maximum slope of the APDR, PSs, fibrosis, and inflammation.

Malignant arrythmic storm, stellate ganglion and diabetes mellitus

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Malignant arrhythmic storm (MAS) increases mortality more than three-fold according to current data. In the acute setting, besides resolving reversible causes, antiarrhythmics are the mainstay of treatment. The role of suppressing the local sympathetic nervous system activity, using stellate ganglion block (SGB) for example, is still being investigated. Purpose To show short-term efficacy of SGB in suppressing the ventricular arrhythmia recurrence in MAS. To identify subgroups of patients with better clinical response after SGB. Methods All consecutive patients with MAS, with standard treatment failure and ventricular arrhythmia recurrence, treated with ultrasound guided SGB, instilating 7ml of 0,5% Bupivacain. 58 MAS treated with SGB durin 2017 – 2020. There were 49 men (84,5%), average age 68,7 +/- 11,4, with average left ventricular EF 28,9 +/- 8,43%. There were 17 diabetics (29,3%). Results When we compare the numbers of defibrillations for sustained ventricular tachycardia 48 hours before and 48 hours after SGB, being the primary therapeutic endpoint in MAS, we see a 96,7% reduction (p &amp;lt; 0,001). When we evaluate ventricular arrhythmias treated with both antitachycardia pacing and shocks, then we see 90% reduction (p &amp;lt; 0,001). The effect of SGB in ventricular arrhythmia suppression was statistically significant during the entire follow-up of 8 days. When we analyzed the cohort, looking for groups showing better response after SGB in terms of ventricular arrhythmia reduction, the only group showing statistical significance in this regard are patients with diabetes mellitus. Conclusions In our cohort, stellate ganglion block is exceptionally effective in the treatment algorithm of malignant arrhythmic storm. SGB shows significantly higher efficacy in the subgroup of patients with diabetes mellitus. Abstract Figure. VA before and after BSG

Quinidine in the Management of Recurrent Ventricular Arrhythmias: A Reappraisal

OBJECTIVE: We aimed to study quinidine's utility in patients presenting with recurrent sustained VA and limited AAD options. \ BACKGROUND: Antiarrhythmic drug (AAD) options are often limited in patients with structural heart disease and recurrent ventricular arrhythmias (VA). Quinidine has an established role in rare arrhythmic syndromes, but its potential use in other difficult VA has not been assessed in the present era. METHODS: We performed a retrospective analysis of 37 patients who had in-hospital quinidine initiation after multiple other therapies failed for VA suppression at our tertiary referral center. Clinical data and outcomes were obtained from the medical record. RESULTS: Of 30 patients with in-hospital quantifiable VA episodes, quinidine reduced acute VA from a median of 3 episodes (interquartile range [IQR] 2 - 7.5) to 0 (IQR 0 - 0.5), during a median of 3 days before, and 4 days after quinidine initiation (P < 0.001). VA events decreased from a median of 10.5 episodes (IQR 5-15) to 0.5 episodes (IQR 0-4) after quinidine initiation in the 12 patients presenting with electrical storm (P = 0.004). Among the 24 patients discharged on quinidine, 13 patients (54.2%) had VA recurrence during a median of 138 days. Adverse effects in 9 of the 37 (24.3%) patients led to drug discontinuation, most commonly gastrointestinal (GI) intolerance. CONCLUSION: In patients with recurrent VA and structural heart disease who have limited treatment options, quinidine can be useful, particularly as a short-term therapy.