Recurrent Ventricular Arrhythmias Research Articles

Myocardial scarring and recurrence of ventricular arrhythmia in patients surviving an out-of-hospital cardiac arrest.

Prediction of recurrent ventricular arrhythmia (VA) in survivors of an out-of-hospital cardiac arrest (OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring assessed with late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Our study aims to characterize myocardial scarring as defined by LGE-CMR in survivors of a VA-OHCA and investigate its potential role in the risk of new VA events. Between 2015 and 2022, a total of 230 VA-OHCA patients without ST-segment elevation myocardial infarction had CMR before implantable cardioverter-defibrillator implantation for secondary prevention at Copenhagen University Hospital, Rigshospitalet, and Hospital Clínic, University of Barcelona, of which n = 170 patients had a conventional (no LGE protocol) CMR and n = 60 patients had LGE-CMR (including LGE protocol). Scar tissue including core, border zone (BZ) and BZ channels were automatically detected by specialized investigational software in patients with LGE-CMR. The primary endpoint was recurrent VA. After exclusion, n = 52 VA-OHCA patients with LGE-CMR and a mean left ventricular ejection fraction of 49 ± 16% were included, of which 18 (32%) patients reached the primary endpoint of VA. Patients with recurrent VA in exhibited greater scar mass, core mass, BZ mass, and presence of BZ channels compared with patients without recurrent VA. The presence of BZ channels identified patients with recurrent VA with 67% sensitivity and 85% specificity (area under the ROC curve (AUC) 0.76; 95% CI: 0.63-0.89; p < .001) and was the strongest predictor of the primary endpoint. The presence of BZ channels was the strongest predictor of recurrent VA in patients with an out of-hospital cardiac arrest and LGE-CMR.

COVID-19 as a potential trigger for refractory arrhythmias and electrical storm in a patient with dilated cardiomyopathy: a case report

Arrhythmias occur both in the acute coronavirus disease 2019 (COVID-19) and in the post-acute period, which may be associated with the long-term SARS-CoV-2 persistence. In a case report, patient with primary dilated cardiomyopathy, an implanted cardioverter-defibrillator, recurrent ventricular arrhythmias, and an electrical storm are presented. The patient was repeatedly hospitalized in a city hospital, where electrical cardioversion, antiarrhythmic therapy, radiofrequency ablation of recurrent ventricular tachycardia regions, including emergency ("lifesaving") combined catheter radiofrequency destruction of the electrical storm substrate, was performed. Subsequently, against the background of ongoing postoperative therapy, massive pulmonary embolism (PE) suddenly developed, which led to the death. Autopsy established that the cause of the patient’s death was massive pulmonary embolism; SARS-CoV-2 and enterovirus was detected in the myocardium. Based on an autopsy study, the patient was diagnosed with primary dilated cardiomyopathy with secondary active chronic lymphocytic myocarditis.

Bilateral Cardiac Sympathetic Denervation as a Safe Therapeutic Option for Ventricular Arrhythmias.

The recurrence of ventricular arrhythmias (VAs) in patients who have already undergone treatment with antiarrhythmic medication, catheter ablation, and the insertion of implantable cardioverter defibrillators is not uncommon. Recent studies have shown that bilateral cardiac sympathetic denervation (BCSD) effectively treats VAs. However, only a limited number of studies have confirmed the safety of BCSD as a viable therapeutic option for VAs. This single-center study included 10 patients, who had a median age of 54 years (interquartile range [IQR], 45-65 years) and a median ejection fraction of 58.5% (IQR, 56.2%-60.8%), with VAs who underwent video-assisted BCSD. BCSD was executed as a single-stage surgery for 8 patients, while the remaining 2 patients initially underwent left cardiac sympathetic denervation followed by right cardiac sympathetic denervation. We evaluated postoperative complications, the duration of hospital stays, and VA-related symptoms before and after surgery. The median hospital stay after surgery was 2 days (IQR, 2-3 days). The median surgical time for BCSD was 113 minutes (IQR, 104-126 minutes). No significant complications occurred during hospitalization or after discharge. During the median follow-up period of 13.5 months (IQR, 10.5-28.0 months) from surgery, no VA-related symptoms were observed in 70% of patients. The benefits of a short postoperative hospitalization and negligible complications make BCSD a safe, alternative therapeutic option for patients suffering from refractory VAs.

Recurrent ventricular arrhythmia due to aconite intoxication successfully treated with landiolol: A case report

In recent years, because of the growing desire to improve the noninvasiveness and safety of tumor treatments, sonodynamic therapy has gradually become a popular research topic. However, due to the complexity of the therapeutic process, the relevant mechanisms have not yet been fully elucidated. One of the widely accepted possibilities involves the effect of reactive oxygen species. In this review, the mechanism of reactive oxygen species production by sonodynamic therapy (SDT) and ways to enhance the sonodynamic production of reactive oxygen species are reviewed. Then, the clinical application and limitations of SDT are discussed. In conclusion, current research on sonodynamic therapy should focus on the development of sonosensitizers that efficiently produce active oxygen, exhibit biological safety, and promote the clinical transformation of sonodynamic therapy.

Emergency out-of-hours catheter ablation for ventricular arrhythmia storm: a UK and Australian experience.

There are limited data on emergency catheter ablation (CA) for ventricular arrhythmia (VA) storm. We describe the feasibility and safety of performing emergency CA in an out-of-hours setting for VA storm refractory to medical therapy at 2 tertiary hospitals. Twenty-five consecutive patients underwent out-of-hours (5pm-8am [weekday] or Friday 5pm-Monday 8am [weekend]) CA for VA storm refractory to anti-arrhythmic drugs and sedation. Baseline and procedural characteristics along with outcomes were compared to 91 consecutive patients undergoing weekday daytime-hours (8am-5pm) CA for VA storm. More patients undergoing out-of-hours CA had a left ventricular ejection fraction ≤35% (68% vs. 42%, P = 0.022), chronic kidney disease (60% vs. 20%, P < 0.001), and presented following a resuscitated out-of-hospital cardiac arrest (56% vs. 5%, P < 0.001), compared to the daytime-hours group. During median follow-up (377 [interquartile range 138-826] days), both groups experienced similar survival free from recurrent VA and VA storm. Survival free from cardiac transplant and/or mortality was lower in the out-of-hours group (44% vs. 81%, P = 0.007), but out-of-hours CA was not independently associated with increased cardiac transplant and/or mortality (hazard ratio 1.34, 95% confidence interval 0.61-2.96, P = 0.47). Of the 11 patients in the out-of-hours group who survived follow-up, VA-free survival was 91% and VA storm-free survival was 100% at 1-year after CA. Out-of-hours CA may occasionally be required to control VA storm and can be safe and efficacious in this scenario. During follow-up, cardiac transplant and/or mortality is common but undergoing out-of-hours CA was not predictive of this composite endpoint.

Left Ventricular Abnormal Substrate in Brugada Syndrome

BackgroundSlow-conductive structural abnormalities located in the epicardium of the right ventricle (RV) underlie Brugada syndrome (BrS). The extent of such substrate in the left ventricle (LV) has not been investigated. ObjectivesThis study sought to characterize the extent of epicardial substrate abnormalities in BrS. MethodsWe evaluated 22 consecutive patients (mean age 46 ± 11 years, 21 male) referred for recurrent ventricular arrhythmias (mean 10 ± 13 episodes) in the setting of BrS. The patients underwent clinical investigations and wide genetic screening to identify SCN5A mutations and common risk variants. High-density biventricular epicardial mapping was performed to detect prolonged (>70 ms) fragmented electrograms, indicating abnormal substrate area. ResultsAll patients presented with abnormal substrate in the epicardial anterior RV (27 ± 11 cm2). Abnormal substrate was also identified on the LV epicardium in 10 patients (45%), 9 at baseline and 1 after ajmaline infusion, covering 15 ± 11 cm2. Of these, 4 had severe LV fascicular blocks. Patients with LV substrate had a longer history of arrhythmia (11.4 ± 6.7 years vs 4.3 ± 4.3 years; P = 0.003), longer PR (217 ± 24 ms vs 171 ± 14 ms; P < 0.001) and HV (60 ± 12 ms vs 46 ± 5 ms; P = 0.005) intervals, and abnormal substrate also extending into the inferior RV (100% vs 33%; P = 0.001). SCN5A mutation was present in 70% of patients with LV substrate (vs 25%; P = 0.035). SCN5A BrS patients with recurrent ventricular arrhythmias present a higher polygenic risk score compared with a nonselected BrS population (median of differences: −0.86; 95% CI: −1.48 to −0.27; P = 0.02). ConclusionsA subset of patients with BrS present an abnormal substrate extending onto the LV epicardium and inferior RV that is associated with SCN5A mutations and multigenic variants.

Hybrid Epicardial Ventricular Ablation for Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes progressive fibro-fatty infiltration of the right ventricle (RV) and is associated with ventricular arrhythmias (VA). The disease progresses from the subepicardium to subendocardium; thus. epicardial ablation improves outcome in patients with recurrent VA. When percutaneous epicardial ablation is unsuccessful, a surgical approach may be required. Limited data are available for minimally invasive hybrid surgical-catheter techniques. Case: A 28-year-old man with ARVC presented with recurrent VA refractory to medical therapy following COVID-19 infection and underwent endocardial ablation with attempted epicardial ablation. He had nine or more different inducible VA morphologies at this study. Epicardial access was unsuccessful due to adhesions. Minimally invasive surgical access for epicardial ablation was scheduled as a multidisciplinary procedure in the electrophysiology suite. A left thoracoscopic approach provided intrapericardial access. Surgical ports were used to facilitate catheter placement and mapping. Relevant clinical arrhythmias were targeted, and substrate modification was performed. The patient was discharged the following morning. No subjective symptoms or implanted-device defibrillation has been required post procedure. Combined surgical and catheter-based approaches for ARVC ablation are safe and feasible. Multidisciplinary team collaboration is key for case planning and success.

Safety and efficacy of bipolar radiofrequency catheter ablation in ventricular arrhythmias of mural vs non-mural origin

Abstract Funding Acknowledgements Type of funding sources: None. Background Bipolar radiofrequency catheter ablation (B-RFA) has shown promising results in refractory ventricular arrhythmia (VA) of septal origin and underlying non-ischemic cardiomyopathy (NICM). However, its efficacy and safety in other locations such as the free wall and papillary muscles (PM) has not yet been fully determined. Purpose To describe and analyse the procedural data, safety and efficacy results of B-RFA in a cohort of patients with VA of different locations and underlying substrate. Methods We enrolled 21 patients with recurrent VA after prior failed ablation into this study, of whom 16 patients required B-RFA for effective ablation. Seven of the patients had ventricular ectopy (VE) and 9 presented with ventricular tachycardia (VT). During B-RFA, a contact-force-sensing, saline-irrigated catheter was connected to the ablation catheter connection on the radiofrequency generator and a second ablation catheter (saline-irrigated in 6 of the cases) was connected to the ground patch terminal through a custom-made switch box. This allowed visualization of both catheters on the 3D mapping system and acquisition of electrograms from both simultaneously. Procedure data, related complications and acute and long-term outcomes during follow-up were assessed. Results The VA distribution was septal (31.3%, n=5), PM (31.3%, n=5), right ventricle free wall (18.8%, n=3), left ventricle (LV) free wall (12.5%, n=2) and LV summit (6.3%, n=1). Compared to septal ablation, contact force obtained during B-RFA ablation was significantly lower in PM ablation (p=0.01), as was the impedance drop (p=0.03). There were no significant differences in the number of energy applications, their mean duration, the total ablation time, the power and the temperature among locations. Acute success was achieved in 15 patients (93.6%). Long-term success, defined as no recurrence of sustained VT or less than 1% VE burden on 24-hour Holter at 12-month follow up, was achieved in 11 patients (68.8%), and another 2 patients (12.5%) had partial success. Papillary muscle VA had lower acute and long-term success (80% and 60%, respectively) after B-RFA. On the other hand, patients with NICM appeared to have superior outcomes (figure 1). No steam pops or major peri-procedural complications were observed. However, the use of a non-irrigated indifferent electrode resulted in char formation. Conclusions B-RFA can be used successfully and safely in NICM involving the septum and free walls but has limited use for PM arrhythmias. This could be related to a lack of catheter stability and reduced energy transfer. In addition, when using B-RFA, any catheter in the circulatory system should be irrigated.

P120 NEW MALIGNANT MUTATION IN HYPERTROPHIC CARDIOMYOPATHY

Abstract A 62–year–old man diagnosed with non–obstructive hypertrophic cardiomyopathy and dual–chamber pacemaker wearer since the age of 40, for third–degree atrioventricular block, came to our attention for atrial fibrillation (AF) episodes (one complicated by cardiogenic shock and multiorgan failure) and flutter with high ventricular response. For a progressive worsening of the systolic function, and the onset of multiple episodes of sustained ventricular tachycardia, an upgrade to the defibrillator was performed, which, in the following months, intervened appropriately for recurrences of ventricular arrhythmias. The patient was admitted to our ward for exacerbation of heart failure. The echocardiography showed moderate concentric hypertrophy with mild ventricular dilatation and ejection fraction 33%, inferior and inferoseptal wall, and apex akinesia with thrombotic apposition. Due to a sudden deterioration of the clinical conditions, the patient died. After genetic counseling the patient‘s family agreed to genetic testing in the proband. This highlighted the presence of a missense mutation, i.e. the substitution of the cysteine ​​residue with a serine, in the codon 905 of the MYH7 gene, encoding the cardiac isoform of myosin heavy chain. The mutation is probably pathogenetic as it falls in the region where most of the missense variants are clustered and statistically associated with the HCM phenotype. Only in one previous case of HCM was detected a mutation of the same codon, Cys905Phe. Several studies have reported that AF tends to be more prevalent in patients carrying MYH7 mutations and is associated with a substantial risk of heart failure–related mortality, stroke, and severe functional disability. Knowledge of the entire spectrum of MYH7 mutations, especially those related to a high arrhythmic burden or SCD, combined with an accurate clinical and molecular characterization of the patient, can improve the genotype–phenotype correlation by clarifying the mechanism of HCM and allowing a better clinical and therapeutic decision–making of patients.

PO-04-029 TRIANGULATING THE LV SUMMIT: A NOVEL BIPOLAR RADIOFREQUENCY CATHETER ABLATION STRATEGY

Bipolar radiofrequency catheter ablation (RFCA) is an off-label strategy used to target ventricular arrhythmias (VA) from difficult substrates such as the LV summit. To achieve greater transmural RFCA lesions in challenging anatomy with a novel bipolar RFCA strategy. N/A A 51-year-old male with familial HCM and prior catheter ablation for persistent AF presented with pallor and palpitations in the setting of wide complex tachycardia of 210 BPM (Figure A). The patient was given a bolus of IV amiodarone and externally cardioverted. Amiodarone was discontinued given his history of amiodarone-induced hyperthyroidism. During the hospitalization, he had recurrences of sustained VAs that were suppressed with lidocaine. Cardiac MRI was obtained, which showed LVEF 42% and an extensive LGE in the LV (Figure B). The patient was brought to the EP lab for VT ablation. Extensive mapping in the RVOT, distal CS, and peri-aortic area was performed. The best pacemap was achieved with the 2F EPstar catheter (Baylis Medical) in the AIV. The ablation catheter was not able to be advanced into the distal branch in the coronary sinus. A total of 17 unipolar RFCA lesions were delivered from endocardial LV but the clinical VA remained easily inducible. A second ablation catheter was advanced to the posteroseptal RVOT on the opposite side of the septum for bipolar RFCA. The 2F EPstar catheter was positioned in the AIV near the region of best pacemap for tripolar effect (Figure C). A significant difference in the ablation impedance decline was noted between unipolar and bipolar ablations utilizing this novel strategy (Figure D top - unipolar, D bottom - bipolar). Following five bipolar RCFA lesions, the clinical VA was no longer inducible. The patient tolerated the procedure well with no further recurrence of VAs. Bipolar RFCA with a mapping catheter triangulating the target may help achieve deeper lesions.

PO-04-232 PERCUTANEOUS STELLATE GANGLION BLOCKADE FOR ELECTRICAL STORM: LARGE SINGLE CENTRE EXPERIENCE

Electrical storm (ES) is defined as three or more episodes of ventricular arrhythmia requiring defibrilltaion or anti tachycardia pacing within a day.Some times electrical storm may not respond to anti-arrhythmic drugs alone.Increased sympathetic activity plays significant role in electrical storm.Stellate ganglion blockade reduces sympathetic activity and helpful in reduction of ventricular arrhythmias. We aimed to study the effectiveness and outcomes of percutaneous stellate ganglion blockade (SGB) in the patients with drug-refractory electrical storm. The study included patients with a drug-refractory electrical storm. Before giving SGB, at least two anti-arrhythmic drugs(AAD) were given before SGB. Bupivacaine was injected in the vicinity of the stellate ganglion under Ultrasound quidance. A total of 83 procedures were performed on 56 patients (71% males, 60+6 years).Fourty three patients (76%) had ischemic heart disease. Nearly 66%(37/56) of patients were free from ventricular arrhythmias(VA) at 24 hours after left SGB and 51%(29/56) were arrhythmia free at 72 hours. Bilateral SGB was done in 16 patients who had failed left-sided SGB with a success rate of 36%. Heart failure and shock were documented in 65% and 55% respectively. Twenty Five (44%) patients were on both Intra-aortic balloon counterpulsation and inotrope support. All-cause mortality was 32% (18/56). Cardiovascular mortality was 28% (16/56). Septic shock in one patient and Ischemic brain stroke was the cause of death in the other patient. VA recurrence, poor left ventricular ejection fraction, and failed stellate ganglion blockade were associated with increased mortality. Procedure-related complications like transient bradycardia(16%), hematoma(14%), hoarseness of voice (10%), persistent ptosis(5%), and monoparesis(3.5%) were noted, all of which were resolved within two weeks of post-procedure. SGB helps to stabilize the hemodynamic status of the patients with electrical storm. It also provides time for

PO-04-233 MULTIDISCIPLINARY APPROACHES TO TREAT VENTRICULAR ARRHYTHMIAS WITH RADIOABLATION AND CARDIAC SYMPATHECTOMY (MAVERICS)

Ventricular arrhythmias (VAs) are the most lethal arrhythmias. Established therapies to prevent occurrence of VAs include anti-arrhythmic drugs (AADs) and catheter ablation (CA). For patients with recurrent VAs despite AADs and CA, there exist novel treatment modalities such as cardiac sympathetic denervation (CSD) via percutaneous and surgical approach and stereotactic body radiation therapy (SBRT). The current study reports the outcomes of CSD and SBRT from a tertiary care academic center. To report outcomes of CSD and SBRT for treatment of VAs refractory to conventional treatment with AADs and CA. Study comprises all patients undergoing CSD or SBRT at our center from 10/2018 to 10/2021. Patients with less than 2 months of available follow-up data were excluded. Retrospective chart review was performed to collate data for demographics, clinical characteristics, arrhythmia burden before and after novel therapies (maximum 12 months), and complications during study period. Burden of VAs in the form of episodes of anti-tachycardia pacing (ATP) and defibrillator shocks per month were assessed as primary efficacy outcome. Complications during CSD and SBRT were assessed as primary safety outcome. Overall, 25 patients underwent novel therapies for VAs. Thirteen were excluded due to insufficient follow up data. Of 12 included patients, a total of 4, 5, and 3 patients underwent SBRT, CSD, and both CSD/SBRT, respectively. Median age of the study population was 66 years (55-72). The majority of the patients (10/12) were male. Median left ventricular ejection fraction was 30% (25%-34%). Eight patients had non-ischemic cardiomyopathy. Median number of AADs and CA prior to novel therapies was 3 (2-5) and 1 (0-2), respectively. Follow up was available for a median of 12 (12-12) months before and 12 (9-12) months after intervention. Overall, 11 of 12 patients demonstrated a reduction in VA burden. Mean number of ATP and shock episodes was significantly lower after novel therapies (39±43 vs 3±6; p= 0.008). No procedure-related complications were observed during the study period. Incorporation of novel VA treatment modalities is associated with a reduced arrhythmia burden in this single center study. Further studies are warranted to validate these findings.

CE-452779-4 DOFETILIDE FOR TREATMENT OF PREMATURE VENTRICULAR COMPLEXES AND VENTRICULAR TACHYCARDIA

Dofetilide is a class III antiarrhythmic agent approved for the treatment of atrial fibrillation and atrial flutter. Given the efficacy of other class III agents, it is used off-label for the treatment of premature ventricular complexes (PVCs) and ventricular tachycardia (VT), however its ability to suppress recurrent ventricular arrhythmia has not been well examined. In this study, we examined the use of dofetilide for the treatment of PVCs and VT. This was a single-center retrospective cohort study of patients admitted to the University of Michigan between 2015 and 2020 for dofetilide initiation. In patients for whom dofetilide was initiated for PVCs, VT or both, additional descriptive information was collected until date of last clinical follow-up. Successful PVC suppression was defined as 80% reduction in PVC burden compared to pre-dofetilide initiation. A total of 50 patients were admitted for dofetilide initiation for treatment of PVCs (18), VT (27) or both (5). Average left-ventricular ejection fraction was 32.0 +/- 17.2% with 32.7% of patients having ischemic cardiomyopathy and 67.3% of patients having non ischemic cardiomyopathy. A majority (90%) of patients in the cohort had an internal cardioverter defibrillator (ICD). Prior to dofetilide initiation, 40% of patients had undergone ventricular ablations. Previous antiarrhythmic treatments included amiodarone (54.0%), sotalol (28%) and mexilitine (36.0%). Dofetilide was stopped in 8 patients (16%) during index hospitalization for QT prolongation with 3 patients experiencing Torsades de Pointes. In an additional 24 patients, dofetilide was discontinued at a median of 3.3 months for inefficacy (50%) or QT prolongation (50%). Median follow was 36.3 months (range of 3.9 months to 84.8 months). Dofetilide dosing was 500 (35.7%), 250 (45.2%), 125 (19.1%) micrograms. In patients treated for PVCs, PVC frequency decreased from an average of 21.7% to 9.0% (p<.001) with 35.7% of patients meeting criteria for successful suppression. In patients with VT, 80.0% had recurrent ICD shocks after dofetilide (average 1.6 shocks/year of follow-up). 7 patients died over the follow-up period. Treatment with dofetilide was associated with a decrease in PVCs, however clinically significant suppression occurred in a minority of patients. Dofetilide failed to suppress ICD shocks in a majority of patients and was associated with significant toxicities requiring discontinuation in 40% of patients during the follow-up period.

PO-04-190 LONG TERM OUTCOMES OF VENTRICULAR TACHYCARDIA ABLATION IN DESMOPLAKIN ARRHYTHMOGENIC CARDIOMYOPATHY – A MULTICENTER STUDY

Desmoplakin (DSP) pathogenic/likely pathogenic (P/LP) variants have been associated with the development of highly arrhyhtmogenic phenotypes of the spectrum of the arrhythmogenic cardiomyopathy (DSP-ACM). Data addressing arrhythmic outcomes after ventricular tachycardia (VT) ablation in patients (pts) with DSP-ACM are scarce. To report on long-term outcomes of pts with DSP-ACM undergoing VT-ablation All pts with P/LP DSP variant at 8 tertiary academic institutions in North America and Europe undergoing VT ablation were included in the study. Demographic, clinical, and instrumental data, as well as all arrhythmic events including per patient rates of VA episodes/year were collected. Sustained ventricular arrhythmia (VA) episodes (defined as a combination of sustained VT, proper implantable cardioverter defibrillator (ICD) intervention, and ventricular fibrillation episodes) after index procedure were the primary outcome of the study and reported with Kaplan Meyer curves. A per-pt pre- and post- VT ablation paired comparison of VA episodes/year rates was performed as well. Nineteen DSP-ACM pts (29 [25–36] y.o.; 68.4% male; 94.7% probands) referred for VT ablation were included. At the time of index procedures, all patients had a highly arrhythmic profile with a high PVC burden and over 30 different VT morphologies (56.6% right bundle branch block (BBBB); 26.6% left BBB; 16.8% unknown)(Table1). VT ablation targets were located in the LV in 7/19 pts, the RV in 7/19 pts, and both ventricles in 5/19 pts. An epicardial ablation was needed in 14/19 pts. Over a median follow-up of 27 [20–72] months, 10/19 (52.6%) pts experienced recurrent VA episodes (Figure1-PanelA). A significant reduction in per-patient event/year pre- and post- VT ablation was observed (0.50 0.25–0.94] vs 0.14 [0–0.40]; Matched Pair Wilcoxon p=0.009) (Figure1-Panel B). VT ablation in DSP-ACM is effective in significantly reducing the VA burden of the disease. However, it is not uncommon for pts to experience VA recurrences during follow up.

Combination of Intracardiac Echocardiography and Contact Force Sensing for Left Ventricular Papillary Muscle Arrhythmias.

The catheter ablation of ventricular arrhythmias (VAs) arising from the left ventricular (LV) papillary muscles (PMs) is challenging. This study sought to address whether the combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) can improve the acute and long-term ablation outcomes of left ventricular papillary muscle arrhythmias. From May 2015 to August 2022, a total of thirty-three patients underwent catheter ablation for LV PM arrhythmias: VAs were located in anterolateral PMs in 11 and posteromedial PMs in 22. A combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) was used in 21 of the 33 procedures. A mean of 6.93 ± 4.91 for lesions was used per patient, comparable between the CFS/ICE and no ICE/CFS (4.90 ± 2.23 vs. 10.17 ± 5.89; p = 0.011). The mean CF achieved in the ICE/CFS group was 7.52 ± 3.31 g. Less X-ray time was used in the combination group (CFS/ICE: 165.67 ± 47.80 S vs. no ICE/CFS: 365.00 ± 183.73 S; p < 0.001). An acute success rate of 100% was achieved for the ICE/CFS group (n = 22) and 66.67% for the no ICE/CFS group (n = 8). VA recurrence at the 11.21 ± 7.21-month follow-up was 14.2% for the ICE/CFS group and 50% for the no ICE/CFS group (p = 0.04). No severe complications occurred in all patients. The combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) could provide precise geometries of cardiac endocavitary structures and accurate contact information for the catheter during ablation, which improved acute and long-term ablation outcomes. The routine adoption of this strategy should be considered to improve the outcomes of LV PM VA ablation.

The Brugada syndrome: pharmacological therapy.

Brugada syndrome is an inherited channelopathy with an increased risk of sudden cardiac death (SCD) due to ventricular arrhythmias (VA) and an increased incidence of supraventricular arrhythmias, as compared with the general population. For the prevention of SCD, the guidelines recommend the implantable cardioverter-defibrillator (ICD); however, ICD does not prevent VA. In this article, we provide a brief review of the literature on the Brugada syndrome pharmacological therapy, mainly focusing on quinidine treatment. The efficacy of quinidine therapy in the prevention of VA in Brugada syndrome has been demonstrated by several small studies in patients with ICD and recurrent shocks or in asymptomatic patients with inducible ventricular fibrillation (VF) at electrophysiological study. Quinidine has also been tested for the prophylaxis of supraventricular arrhythmias, especially atrial fibrillation/flutter, and in paediatric patients. In these studies, quinidine proved highly effective in preventing re-induction of VF and spontaneous recurrences of both ventricular and supraventricular arrhythmias. Unfortunately, this therapy is burdened by a high incidence of side effects, which may lead to drug discontinuation.

Catheter Ablation of Ventricular Arrhythmia in Patients With an Implantable Cardioverter-Defibrillator: A Systematic Review and Meta-analysis.

Implantable cardioverter-defibrillator (ICD) shocks are associated with higher rates of mortality and reduced quality of life. In this study we aimed to investigate the effectiveness of catheter ablation (CA) of ventricular tachycardia in patients with an ICD. An electronic literature search was conducted to identify randomized controlled trials that compared CA vs control. The primary outcomes were recurrence of ventricular arrhythmia (ventricular tachycardia or ventricular fibrillation) and mortality. Kaplan-Meier curves for these outcomes were digitized to obtain individual patient data, which were pooled in a 1-stage meta-analysis to determine hazard ratios (HRs) and 95% confidence intervals (CIs). Secondary outcomes included cardiac hospitalization, electrical storm, syncope, appropriate ICD therapies, appropriate ICD shocks, and inappropriate shocks. For these, study-level HRs or risk ratios were obtained and pooled in random effects meta-analyses. Subgroup analysis was performed for trials that investigated prophylactic CA (before or during ICD implantation). Data on 9 studies and 1103 patients were retrieved. CA significantly reduced ventricular tachycardia/ventricular fibrillation recurrence compared with control (shared frailty HR, 0.63; 95% CI, 0.49-0.81; P < 0.001) but not mortality (shared frailty HR, 0.84; 95% CI, 0.57-1.23; P= 0.361). CA was associated with significantly lower rates of cardiac hospitalization, electrical storm, appropriate ICD therapies and shocks, but not syncope or inappropriate shocks. Subgroup analysis showed similar results for prophylactic CA except that no significant difference was observed for cardiac hospitalizations. CA is associated with reduced ventricular arrhythmia recurrence, appropriate ICD therapies/shocks, electrical storm, and cardiac hospitalization, and might be effective in preventing future morbidity. Future trials are needed to support the continued benefit of these promising results, and to investigate the optimal timing of ablation.

Outcomes of Catheter Ablation of Left Ventricular Summit Arrhythmias.

The left ventricular summit (LVS) is the area in the highest portion of the left ventricular epicardium, bounded by the left coronary arteries and the coronary venous circulation, and can be surrounded by thick epicardial fat that may preclude epicardial ablation. Ablation of LVS ventricular arrhythmias (VA) can be achieved from adjacent structures with good success rates. The long-term freedom from LVS VA recurrence remains variable. This article reviews the spatial and anatomic relationship of the structures surrounding the LVS, which provide vantage points for ablation, and the acute and long-term outcomes of different ablation approaches in LVS VA ablation.

Stellate ganglion instrumentation for pharmacological blockade, nerve recording, and stimulation in patients with ventricular arrhythmias: Preliminary experience

Stellate ganglion blockade (SGB) can control ventricular arrhythmias (VAs), but outcomes are unclear. Percutaneous stellate ganglion (SG) recording and stimulation in humans has not been reported. The purpose of this study was to assess the outcomes of SGB and the feasibility of SG stimulation and recording in humans with VA. Two patient cohorts were included-group 1: patients undergoing SGB for drug-refractory VA. SGB was performed by injection of liposomal bupivacaine. Incidence of VA at 24 and 72 hours and clinical outcomes were collected; group 2: patients undergoing SG stimulation and recording during VA ablation; a 2-F octapolar catheter was placed at the SG at the C7 level. Recording (30 kHz sampling, 0.5-2 kHz filter) and stimulation (up to 80 mA output, 50 Hz, 2 ms pulse width for 20-30 seconds) was performed. Group 1 included 25 patients (mean age 59.2 ± 12.8 years; 76% men) who underwent SGB for VAs. Nineteen patients (76.0%) were free of VA up to 72 hours postprocedure. However, 15 (60.0%) had VA recurrence for a mean of 5.47 ± 4.52 days. Group 2 included 11 patients (mean age 63 ± 12.7 years; 82.7% men). SG stimulation caused consistent increases in systolic blood pressure. We recorded unequivocal signals with temporal association with arrhythmias in 4 of 11 patients. SGB provides short-term VA control, but has no benefit in the absence of definitive VA therapies. SG recording and stimulation is feasible and may have value to elicit VA and understand neural mechanisms of VA in the electrophysiology laboratory.

Efficacy and safety of catheter ablation as first-line therapy for the management of ventricular tachycardia

BackgroundVentricular tachycardia (VT) is associated with significantly increased morbidity and mortality. Catheter ablation (CA) in line with an implantable cardioverter-defibrillator (ICD) is highly effective in VT management; however, it is unknown if CA should be considered as first-line therapy. The aim of this study is to verify the efficacy and safety of CA as first-line therapy for the first VT presentation (as adjunctive to ICD insertion), compared to initial ICD insertion and anti-arrhythmic drug (AAD) therapy.MethodsData from patients with the first presentation for VT from January 2017 to January 2021 was reviewed. Patients were classified as “ablation first” vs “ICD first” groups and compared the clinical outcomes between groups.ResultsOne hundred and eighty-four consecutive patients presented with VT; 34 underwent CA as first-line therapy prior to ICD insertion, and 150 had ICD insertion/AAD therapy as first‐line. During the median follow-up of 625 days, patients who underwent CA as first-line therapy had significantly higher ventricular arrhythmia (VA)-free survival (91% vs 59%, log-rank P = 0.002) and composite of VA recurrence, cardiovascular hospitalization, transplant, and death (84% vs 54%, log-rank P = 0.01) compared to those who did not undergo CA. Multivariate analysis revealed that first-line CA was the only protective predictor of VA recurrence (hazard ratio (HR) 0.20, P = 0.003). There were 3 (9%) peri-procedural complications with no peri-procedural deaths.ConclusionReal-world data supports the efficacy and safety of CA as first-line therapy at the time of the first VT hospitalization, compared to the initial ICD implant and AAD therapy.