Recurrent Ventricular Arrhythmias Research Articles

Recurrent ventricular arrhythmia in an ICD recipient: What is the mechanism?

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Ethanol ablation for ventricular arrhythmias: A systematic review and meta-analysis.

Ethanol ablation (EA) is an alternative option for subjects with ventricular arrhythmias (VAs) refractory to conventional medical and ablative treatment. However, data on the efficacy and safety of EA remain sparse. A systematic literature search was conducted. The primary outcomes were 1) freedom from the targeted VA and 2) freedom from any VAs post-EA. Additional safety outcomes were also analyzed. Ten studies were selected accounting for a population of 174 patients (62.3 ± 12.5 years, 94% male) undergoing 185 procedures. The overall acute success rate of EA was 72.4% (confidence interval [CI95% ]: 65.6-78.4). After a mean follow-up of 11.3 ± 5.5 months, the incidence of relapse of the targeted VA was 24.4% (CI95% : 17.1-32.8), while any VAs post-EA occurred in 41.3% (CI95% : 33.7-49.1). The overall incidence of procedural complications was 14.1% (CI95% : 9.8-19.8), with pericardial complications and complete atrioventricular block being the most frequent. An anterograde transarterial approach was associated with a higher rate of VA recurrences and complications compared to a retrograde transvenous route; however, differences in the baseline population characteristics and in the targeted ventricular areas should be accounted. EA is a valuable therapeutic option for VAs refractory to conventional treatment and can result in 1-year freedom from VA recurrence in 60%-75% of the patients. However, anatomical or technical challenges preclude acute success in almost 30% of the candidates and the rate of complication is not insignificant, highlighting the importance of well-informed patient selection. The certainty of the evidence is low, and further research is necessary.

Bipolar ablation of therapy-refractory ventricular arrhythmias: application of a dedicated approach.

Bipolar radiofrequency ablation (B-RFA) has been reported as a bail-out strategy for the treatment of therapy refractory ventricular arrhythmias (VA). Currently, existing setups have not been standardized for B-RFA, while the impact of conventional B-RFA approaches on lesion formation remains unclear. (i) In a multicentre observational study, patients undergoing B-RFA for previously therapy-refractory VA using a dedicated B-RFA setup were retrospectively analysed. (ii) Additionally, in an ex vivo model lesion formation during B-RFA was evaluated using porcine hearts. In a total of 26 procedures (24 patients), acute success was achieved in all 14 ventricular tachycardia (VT) procedures and 7/12 procedures with premature ventricular contractions (PVC), with major complications occurring in 1 procedure (atrioventricular block). During a median follow-up of 211 days in 21 patients, 6/11 patients (VT) and 5/10 patients (PVC) remained arrhythmia-free. Lesion formation in the ex vivo model during energy titration from 30 to 50 W led to similar lesion volumes compared with initial high-power 50 W B-RFA. Lesion size significantly increased when combining sequential unipolar and B-RFA (1429 mm3 vs. titration 501 mm3 vs. B-RFA 50 W 423 mm3, P < 0.001), an approach used in overall 58% of procedures and more frequently applied in procedures without VA recurrence (92% vs. 36%, P = 0.009). Adipose tissue severely limited lesion formation during B-RFA. Using a dedicated device for B-RFA for therapy-refractory VA appears feasible and safe. While some patients need repeat ablation, success rates were encouraging. Sequential unipolar and B-RFA may be favourable for lesion formation.

DREAM-ICD-II Study.

Regulatory authorities of most industrialized countries recommend 6 months of private driving restriction after implantation of a secondary prevention implantable cardioverter-defibrillator (ICD). These driving restrictions result in significant inconvenience and social implications. This study aimed to assess the incidence rate of appropriate device therapies in contemporary recipients of a secondary prevention ICD. This retrospective study at 3 Canadian tertiary care centers enrolled consecutive patients with new secondary prevention ICD implants between 2016 and 2020. For a median of 760 days (324, 1190 days), 721 patients were followed up. The risk of recurrent ventricular arrhythmia was highest during the first 3 months after device insertion (34.4%) and decreased over time (10.6% between 3 and 6 months, 11.7% between 6 and 12 months). The corresponding incidence rate per 100 patient-days was 0.48 (95% CI, 0.35-0.64) at 90 days, 0.28 (95% CI, 0.17-0.45) at 180 days, and 0.21 (95% CI, 0.13-0.33) between 181 and 365 days after ICD insertion (P<0.001). The cumulative incidence of arrhythmic syncope resulting in sudden cardiac incapacitation was 1.8% within the first 90 days and subsequently dropped to 0.4% between 91 and 180 days (P<0.001) after ICD insertion. The incidence rate of appropriate therapies resulting in sudden cardiac incapacitation in contemporary recipients of a secondary prevention ICD is much lower than previously reported and declines significantly after the first 3 months. Lowering driving restrictions to 3 months after the index cardiac event seems safe, and revision of existing guidelines should be considered in countries still adhering to a 6-month period. Existing restrictions for private driving after implantation of a secondary prevention ICD should be reconsidered.

The Outcome of Ventricular Arrhythmias Associated With Mitral Valve Prolapse After Catheter Ablation: A Systematic Review and Meta-Analysis.

The presence of mitral valve prolapse (MVP) varies from asymptomatic to life-threatening arrhythmias. Catheter ablation (CA) is widely used to treat ventricular arrhythmias (VAs) associated with MVP. Despite having high procedural success, outcome data after CA is limited, especially in a long-term setting. Therefore, this systematic review and meta-analysis were performed. Literature searching was conducted in Pubmed, EuropePMC, Proquest, and Ebsco from inception to December 2020 using keywords: ventricular arrhythmia, premature ventricular complex, ventricular tachycardia, ventricular fibrillation, mitral valve prolapse, and catheter ablation. A total of 407 potential articles were retrieved for further review. The final review resulted in six articles for systematic review and meta-analysis. The study was registered in PROSPERO (CRD42020219144). The most common origin of VAs was papillary muscle. The acute success rate of CA in the MVP group varies between 66% and 94%. Follow-up studies reported a higher percentage of VAs recurrence after CA in the MVP group (22.22%) compared with the non-MVP group (11.38%). However, the difference is not significant (P-value = 0.16). Other studies reported a 12.5%-36% rate and 40% of repeat ablation in the medium term and the long term, respectively. Episodes of sudden cardiac death during exertion could still occur following CA in patients with MVP. Distinct origin of VAs was observed during repeated ablation procedures, which may explain arrhythmic substrate progression. Diffuse left ventricular fibrosis around papillary muscle rather than local fibrosis was observed among older patients. Furthermore, the presence of mitral annular disjunction (MAD) and Filamin C mutation might increase the risk of recurrent VAs. CAn has been done as the treatment of VAs associated with MVP. The acute success rate of CA varies between studies and the number of patients requiring repeat CA varied from 12.5% to 40%. Sudden cardiac death could still occur after CA. Older age during CA, genetic predisposition, deep arrhythmic foci, multifocal VAs origin, diffuse fibrosis, and the presence of MAD may contribute to the recurrence of VAs. Further studies, stratification, and evaluation are needed to prevent fatal outcomes in VA associated with MVP, even after CA.

Predictors and Long-Term Outcome of Ablation of Discrete Pre-potentials in Patients With Idiopathic Ventricular Arrhythmias Originating From the Aortic Sinuses of Valsalva.

Background: The predictability and long-term outcome of the discrete pre-potential (DPP) of idiopathic ventricular arrhythmias (VAs) arising from the aortic sinuses of Valsalva (ASV) have not been fully identified.Methods: Of 687 consecutive patients undergoing ablation of outflow tract VAs, there were 105 (15.3%) patients with VAs originating from the ASV region who were included. Detailed mapping was performed within the ASV in all patients. Electrocardiographic, electrophysiological parameters, and long-term success rate were compared between patients with and without the DPPs.Results: A DPP was recorded in 67 of 105 (63.8%) patients, including 38 left sinus of Valsalva (LSV)-VAs (38/105, 36.2%) and 29 right sinus of Valsalva (RSV)-VAs (29/105, 27.6%). The patients with DPPs had wider QRS duration (152 ± 17 vs. 145 ± 14 ms, p < 0.001). The average of earliest activation time was significantly earlier in patients with DPPs (−38.6 ± 8.5 vs. −27.7 ± 5.7 ms, p < 0.001). Mean time from the first lesion to elimination of VAs was shorter in patients with DPPs (2.3 ± 2.1 s vs. 4.9 ± 1.0 s, p < 0.001). A stepwise logistic multivariable analysis identified only younger age as a significant predictor of DPP (age ≤ 35.5 years predicted DPP with 92.9% positive predictive value). During a follow-up duration of 42.5 ± 22.3 months, 63 (94.0%) patients with DPPs and 30 (78.9%) patients without DPPs remained free of recurrent VAs (p = 0.027).Conclusion: Discrete pre-potentials were observed in 63.8% of patients with VAs arising from the ASV. Ablation in patients with DPPs was associated with higher long-term success. DPPs were seen more commonly in younger (age ≤ 35.5 years) patients.

Oral procainamide as pharmacological treatment of recurrent and refractory ventricular tachyarrhythmias: A single-center experience.

BackgroundAntiarrhythmic therapy for recurrent ventricular arrhythmias in patients who have undergone catheter ablation, and in whom amiodarone and/or beta-blockers were ineffective or contraindicated, is a controversial issue.ObjectiveThe present study sought to evaluate the efficacy and tolerability of oral procainamide in patients with recurrent ventricular arrhythmias when the standard therapy strategy had failed.MethodsAll patients treated with procainamide for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in our institution between January 2010 and May 2019 were enrolled. The primary endpoint was the total number of implantable cardioverter-defibrillator (ICD) interventions after the beginning of procainamide therapy. Secondary endpoints were the total number of VTs and VFs recorded on the ICDs’ controls and discontinuation of therapy. The events occurring during procainamide treatment were compared with a matched-duration period before the initiation of therapy with procainamide. Patients therefore served as self-controls.ResultsA total of 34 consecutive patients (32 male, 94.1%; mean age 74.4 ± 9.7 years) were included in the retrospective analysis. The mean time of procainamide treatment was 12.9 ± 13.7 months (median 9 [2–20] months). The mean dose of procainamide was 1207 ± 487 mg/day. Procainamide therapy significantly decreased ICD interventions (median 5 [0–22.5] vs 15.5 [3–32.25], P < .05). Procainamide also decreased the total number of VT/VF episodes (median 5.5 [0.75–30] vs 19 [7.5–30], P < .05). Only 3 patients (8.8%) presented severe side effects (dyspnea or hypotension), requiring discontinuation of therapy.ConclusionOral procainamide was associated with a significant decrease in ICD therapies and ventricular arrhythmias, showing an acceptable profile of tolerability.

Management of ventricular arrhythmias in heart failure: Current perspectives.

Congestive heart failure (HF) is a progressive affliction defined as the inability of the heart to sufficiently maintain blood flow. Ventricular arrhythmias (VAs) are common in patients with HF, and conversely, advanced HF promotes the risk of VAs. Management of VA in HF requires a systematic, multimodality approach that comprises optimization of medical therapy and use of implantable cardioverter-defibrillator and/or device combined with cardiac resynchronization therapy. Catheter ablation is one of the most important strategies with the potential to abolish or decrease the number of recurrences of VA in this population. It can be a curative strategy in arrhythmia-induced cardiomyopathy and may even save lives in cases of an electrical storm. Additionally, modulation of the autonomic nervous system and stereotactic radiotherapy have been introduced as novel methods to control refractory VAs. In patients with end-stage HF and refractory VAs, an institution of the mechanical circulatory support device and cardiac transplant may be considered. This review aims to provide an overview of current evidence regarding management strategies of VAs in HF with an emphasis on interventional treatment.

Comparison of the arrhythmogenic substrate for ventricular tachycardia in patients with ischemic vs non-ischemic cardiomyopathy - insights from high-density, multi-electrode catheter mapping.

The purpose of this study was to compare the differences of arrhythmogenic substrate using high-density mapping in ventricular tachycardia (VT) patients with ischemic (ICM) vs non-ischemic cardiomyopathy (NICM). Data from patients presenting for VT ablation from December 2016 to December 2020 at Westmead Hospital were reviewed. Sixty consecutive patients with structural heart disease (ICM 57%, NICM 43%, mean age 66years) having catheter ablation of scar-related VT with pre-dominant left ventricular involvement were included. ICM was associated with larger proportion of dense scar area (bipolar; 19 [12-29]% vs 6 [3-10]%, P < 0.001, unipolar; 20 [12-32]% vs 11 [7-19]%, P = 0.01) compared with NICM. However, the scar ratio (unipolar dense scar [%]/bipolar dense scar [%]) was significantly higher in NICM patients (1.2 [0.8-1.7] vs 1.7 [1.3-2.3], P = 0.003). Larger scar area in ICM was paralleled by higher proportion of complex electrograms (6 [2-13] % vs 3 [1-5] %, P = 0.01), longer and wider voltage based conducting channels, higher incidence of late potential-based conducting channels, longer VT cycle-length (399 ± 80ms vs 359 ± 68ms, P = 0.04) and greater maximal stimulation-QRS interval among sites with good pace-map correlation (75 [51-99]ms vs 48 [31-73]ms, P = 0.02). Ventricular arrhythmia (VA) storm was more highly prevalent in ICM than NICM (50% vs 23%, P = 0.03). During the follow-up period, NICM had a significantly higher cumulative incidence for the VA recurrence than ICM (P = 0.03). High-density multi-electrode catheter mapping of left ventricular arrhythmogenic substrate of NICM tends to show smaller dense scar area and higher scar ratio, compared with ICM, suggestive the extent of epicardial/intramural substrate, with paucity of substrate targets for ablation, which results in the worse outcomes with ablation.

Abstract 11900: Quinidine as Salvage Therapy in Recurrent Monomorphic Ventricular Tachycardia

Introduction: Quinidine is an effective therapy for a subset of polymorphic ventricular tachycardias and ventricular fibrillation (VF), however the efficacy of quinidine on scar related monomorphic ventricular tachycardia (MMVT) is unclear. Hypothesis: We sought to assess the efficacy and adverse effects of quinidine in scar related MMVT. Methods: All patients with MMVT treated with quinidine from 2009-2020 at a single VT referral center were reviewed. Results: A total of 22 patients with MMVT and structural heart disease (age 66.7 ± 10.9, 20 males, 15 with ischemic cardiomyopathy, mean LVEF 22.2 ± 12.3%, 9 with left ventricular assist device (LVAD)) were treated with quinidine (14 patients on Gluconate formulation average dose 996mg±321, 8 patients on Sulfate formulation with average dose 1062mg±588). Quinidine was used in combination with other antiarrhythmics (AAD) in 18 (13 also on amiodarone). All patients previously failed &gt;1 AAD (Amiodarone 100%, mexiletine 73%, sotalol 32%, other 32%) and 8 had prior ablations (median of 1.5). Quinidine was initiated in the setting of VT storm despite other AADs (6), inability to tolerate other AADs (4), or recurrent VT despite prior therapies (12). Ventricular arrhythmias requiring ICD or external shock occurred despite quinidine in 13 (59%) patients at a median of 26 (4-240) days after quinidine initiation. In patients with recurrent MMVT, VT cycle length increased from 359ms to 434ms (p=0.02). Treatment with quinidine was associated with an increase in QTc from 527ms (413-619) to 554ms (425-725) (p=0.004). Only 6 patients remained on quinidine at 1 year with recurrence of ventricular arrhythmias in all. Of the 6 patients on long term quinidine therapy, 3 patients had no shocks but did receive successful ATP within the first year. The following adverse effects were seen: GI side effects (6), QT prolongation (2), rash (1), thrombocytopenia (1), neurologic side effects (1). One patient discontinued due to cost. Conclusions: Quinidine therapy has limited tolerability and efficacy when used in the management of amiodarone-refractory scar related MMVT. When possible, more effective therapies should be offered in patients with VT refractory to standard pharmacologic therapies.

Abstract 10092: Prophylactic Ventricular Tachycardia Ablation in Ischemic Cardiomyopathy: An Updated Meta-Analysis of Randomized Controlled Trials

Introduction: Catheter ablation of the arrhythmogenic substrate reduces the recurrence of ventricular tachycardia (VT) in patients with ischemic cardiomyopathy and implantable cardioverter-defibrillator (ICD). However, the all-cause mortality benefit in this population is unclear. Hypothesis: Prophylactic ablation of the arrhythmogenic substrate decreases all-cause mortality and prevents the recurrence of VT/ventricular fibrillation (VF) in patients with ischemic cardiomyopathy. Methods: We searched the MEDLINE and EMBASE databases from inception through May 2021. We included randomized controlled trials that compared all-cause mortality and ventricular arrhythmia recurrence in patients with ischemic cardiomyopathy who underwent ICD implantation with and without prophylactic ablation. The data from each study was combined using a fixed effects model to calculate the hazard ratio and 95% confidence interval (CI). Results: Four randomized controlled trials during 2007-2020 involving 505 patients (249 patients with and 256 patients without prophylactic VT ablation) were included in our meta-analysis. Compared with control, prophylactic VT ablation did not decrease the all-cause mortality (pooled hazard ratio = 0.94, 95% CI 0.54-1.63, p = 0.818, I2 = 5.8%). However, prophylactic VT ablation significantly decreased appropriate ICD therapy (pooled hazard ratio = 0.58, 95% CI 0.41-0.82, p = 0.002, I 2 = 26.1%) and VT/VF recurrence (pooled hazard ratio = 0.70, 95% CI 0.52-0.93, p = 0.015, I 2 = 0.0%). Conclusions: Prophylactic VT ablation in patients with ischemic cardiomyopathy did not decrease all-cause mortality; however, it did lead to decreased appropriate ICD therapy and VT/VF recurrence.

Lessons learned from catheter ablation of ventricular arrhythmias in patients with a fully magnetically levitated left ventricular assist device

IntroductionData on catheter ablation of ventricular arrhythmias (VA) are scarce in patients with left ventricular assist devices (LVADs) and current evidence predominantly consists of case reports with outdated LVAD. This prospective observational study reports our experience in terms of catheter ablation of VAs in patients with novel 3rd generation LVADs.Methods and resultsBetween 2018 and 2020, nine consecutive patients undergoing a total number of ten ablation procedures for VAs were analyzed. The mean duration between LVAD implantation and catheter ablation was 23 ± 16 months. Acute procedural success was achieved in all patients. VA substrates were not related to the LVAD scarring (cannula) site in the majority of patients. All procedures were conducted without any relevant procedure-related complications. In terms of follow-up, only one patient presented with a repeat episode of electrical storm requiring ICD-shocks 16 months after the initial ablation procedure. Four patients suffered of singular VA effectively treated with antitachycardia pacing via their ICD. The remainder were free of any VA relapse (n = 4). Two non-procedure-related deaths occurred during follow-up.ConclusionsCatheter ablation of VAs in patients with 3rd generation LVAD is feasible and leads to satisfying clinical results in terms of freedom from VA recurrence and quality of life. The majority of arrhythmia substrates in these patients are not directly related to the LVAD cannulation site and may represent a progress of heart failure.Graphic abstract

Long-Term Efficacy and Impact on Mortality of Remote Magnetic Navigation Guided Catheter Ablation of Ventricular Arrhythmias.

Remote magnetic navigation (RMN) facilitates ventricular arrhythmia (VA) ablation. This study aimed to evaluate the long-term efficacy of RMN-guided ablation for ventricular tachycardia (VT) and premature ventricular contractions (PVC). A total of 176 consecutive patients (mean age 53.23 ± 17.55 years, 37% female) underwent VA ablation for PVC (132 patients, 75%) or VT (44 patients, 25%). The cohort consisted of 119 patients (68%) with idiopathic VA, 31 (18%) with ischemic (ICM), and 26 (15%) with dilated cardiomyopathy (DCM). VA recurrence was observed in 69 patients (39%, mean age 51.71 ± 19.91 years, 23% female) during a follow-up period of 5.48 years (first quartile 770.50 days, second quartile 1101.50 days, third quartile 1615.50 days). Left ventricular ejection fraction <40% lead to a significantly increased risk for VA (p = 0.031*). Multivariate analyses found DCM to be an independent predictor (IP) for VA recurrence (p < 0.001*, hazard ratio (HR) 3.74, confidence interval (CI) 1.58–8.88). ICM resulted in a lower increase in VA recurrence (p = 0.221, HR 1.49, CI 0.79–2.81). Class I/III/IV antiarrhythmic drug therapy (AADs) was also identified as IP for recurrence (p = 0.030*, HR 2.48, CI 1.11–5.68). A total of 16 patients (9%) died within the observational period. RMN-guided ablation of VA lead to acceptable long-term results. An impaired LV function, DCM, and AADs were associated with a significant risk for VA recurrence. Personalized paths are needed to improve efficacy and outcome.

Slow flow or prolonged arterial phase in coronary arteries is the cause of ischemia or sudden death in patients with dilated cardiomyopathy

Abstract Background In patients with dilated cardiomyopathy (DCM), the patients could be symptomatic or presented with recurrent fluid overload, syncope or sudden cardiac death (SCD) while the coronary arteries were patent. The aim of our study was to use the coronary flow abnormalities to stratify the high risk symptomatic versus the low risk asymptomatic patient with DCM. Methods Consecutive patients with DCM were enrolled. Twenty patients with normal ejection fraction (EF) without coronary artery disease served as control. The study patients were checked for symptoms (fluid overload, syncope, SCD) and re-admission. All patients underwent a new coronary angiographic technique with injection of contrast until all the coronary arteries were completely filled. As the injection of contrast stopped, the blood in white color moved in and the blood movement could be clearly observed. The angiogram was recorded from the entry of blood flow until all the contrast was cleared. During the review, the investigators downloaded, selected the angiogram from the electronic medical record, tapped on the Key Image and used the Up and Down arrow to move the images, frame-by-frame. Each frame represented a 0.06-second recording. The duration of the arterial phase was calculated starting the time when the blood entered the ostium of the index artery until all the contrast disappeared from the distal vasculature. At the same time, an AI program was trained to measure the length of the arterial phase by Machine learning, supervised and unsupervised Deep Learning and Convoluted Neural Networks. (Figure 1) The AI programs compared the time when the arteries were full with contrast until there was no contrast left in the distal vasculature. (Figure 2) Results One hundred patients with DCM were consecutively enrolled. Twenty patients served as control. In the control group with normal flow and EF, the duration of the arterial phase was 24–30 frames (1.44 to 2 seconds). In the study group, seventy patients had extremely prolonged arterial phase (average of 120 frames or &amp;gt;8 seconds (p&amp;lt;0.05). These patients were very symptomatic and had recurrent hospitalizations. Thirty patients had normal arterial phase of &amp;lt;2 seconds. These patients had shorter length of stay (&amp;lt;3 days), became asymptomatic after only 2 days of treatment and had rare readmission. (p&amp;lt;0.05) The AI programs confirmed the results of the arterial phases calculated manually by junior investigators. Conclusions In patients with DCM, the extreme prolonged arterial phase caused ischemia in the myocardium even there was no coronary artery disease. This ischemic burden triggered recurrent ventricular dysfunction, arrhythmia, syncope and SCD. The patients with normal arterial phase became asymptomatic after optimal medical treatment. With these results, more effective prevention and management could be achieved for high risk symptomatic patients with high mortality and readmissions. Funding Acknowledgement Type of funding sources: None. U Net architectureArterial Phase

Clinical characteristics, management, and outcomes of patients with electrical storm: single centre experience

Abstract Background Electrical storm (ES) is a life-threatening condition caused by recurrent malignant ventricular arrhythmia (≥3 episodes of ventricular tachycardia (VT) or ventricular fibrillation within 24 hours). ES patient management is challenging and can involve antiarrhythmic medication, sedation, and invasive procedures such as catheter ablation. Purpose The aim of this study is to report the clinical profile and management of ES patients who attended an arrhythmia reference centre. Methods Patients who presented with ES at our centre over a five-year period were consecutively enrolled. Patient data were retrospectively collected from hospital records. Patients with in-hospital death were excluded form data analysis. Results Seventy-six patients were included (84% male, mean age 73±10 years). 55% of patients had ischemic heart disease. The mean left ventricle ejection fraction (LVEF) was 33±4%, with 22% of patients having a severe reduction in systolic ventricular function (EF &amp;lt;35%). Baseline characteristics are reported in Table 1. During hospitalisation, 30% of patients underwent coronary angiography and 30% of these had percutaneous coronary revascularization. Patients were managed with pharmacological treatment, including continuous infusion of antiarrhythmic drugs (45% of patients received at least one antiarrhythmic), sedation (12%), and electrolytic solutions (38%). More details on ES management are reported in Table 2. All patients were evaluated for transcatheter ablation. After a mean of 6 days, 25% underwent transcatheter VT ablation during hospitalisation. In 7 patients (9%), catheter ablation was planned and performed during a subsequent hospitalisation. At discharge, 93% of patients received beta blockers and 68% received amiodarone. Overall, 65% were discharged with at least two antiarrhythmic drugs. The mean length of hospitalisation was 10±9 days, with 6±4 days spent in the intensive care unit. Eighteen patients (23%) had at least one subsequent hospitalisation for ES. After a mean follow-up of 20 months, the cumulative mortality rate was 27%, without a significant difference in mortality rates between ablated and non-ablated patients (27% and 28%, respectively). Baseline mean creatinine levels were higher (1.73±1.1 vs. 1.27±0.1 mg/dl, p&amp;lt;0.05), and LVEF was lower (27±3% vs. 35±17%, p&amp;lt;0.05) in patients who died during follow-up as compared to survivors. A trend toward a longer QTc interval duration (482±47 vs. 467±28 ms) and longer QRS duration (139±36 vs. 131±7 ms) was also found among patients who died during follow-up. Conclusion In our centre, ischemic heart disease was the most common heart disease in patients presenting with ES. In more than one third of patients, VT transcatheter ablation was performed as a therapeutic strategy in addition to drug therapy. Among patients who died during the follow-up, baseline creatinine levels were higher and LVEF was lower compared with survivors. Funding Acknowledgement Type of funding sources: None. Table 1Table 2

Implantable cardioverter-defibrillator therapy after resuscitation from cardiac arrest in vasospastic angina

Abstract Background Patients with vasospastic angina (VSA) who are resuscitated from sudden cardiac arrest (SCA) are at high risk of recurrent cardiovascular events. However, there are no recommendations for implantable cardioverter-defibrillator (ICD) therapy in the VSA and SCA patient guidelines. Purpose This study investigated the prognostic impact of ICD therapy on patients with VSA and SCA. Methods The present multi-center registry included 280 patients who were resuscitated from SCA and received ICD implantation as secondary prophylaxis. The patients were divided into two groups according to the presence of VSA. The primary endpoint was a composite of all-cause death and appropriate ICD therapy, including appropriate anti-tachycardia pacing and shock for recurrent ventricular arrhythmias. Results Of 280 patients, 51 (18%) had VSA. Among those without VSA, ischemic cardiomyopathy was the leading cause of SCA (38%), followed by non-ischemic cardiomyopathies and Brugada syndrome (Table 1). During the median follow-up period of 3.8 years, 23 (8%) patients died, and 72 (26%) underwent appropriate ICD therapy. The incidence of the primary endpoint was not significantly different between patients with and without VSA (24% vs 33%, p=0.19). Further, the incidence of the primary endpoint was not significantly different among the etiologies (Figure 1) Conclusions In a cohort of patients who underwent ICD implantation as secondary prophylaxis, long-term clinical outcomes were comparable between those with VSA and those with other cardiac diseases after SCA. The results suggest that ICD therapy may be considered in patients with VSA and those with other etiologies after resuscitation from SCA. Funding Acknowledgement Type of funding sources: None. Table 1. Patient characteristics and outcomesFigure 1. Incidence of the primary endpoint

Real-world evaluation of follow up strategies after implantable cardiac-defibrillator therapies in patients with ventricular tachycardia (REFINE-VT)

Abstract Introduction Implantable cardiac-defibrillators (ICD) can prevent sudden cardiac death but the risk of recurrent ventricular arrhythmia (VA) and ICD therapies persists. Established strategies to minimize such risks include medication optimization, device reprogramming or ventricular tachycardia (VT) catheter ablation (CA). However, the timing and choice of these strategies at ICD follow-up may not be as consistent in the real-world as the regulated conditions of clinical trials. Furthermore, whether these decisions at follow-up are influenced by the type of arrhythmia, ICD therapy or patient characteristics remain unclear. Purpose We evaluated ICD follow-up strategies in patients with ischaemic (ICM) and non-ischaemic cardiomyopathy (NICM) to refine the outpatient management of these complex patients and ultimately improve overall patient outcome. Methods REFINE-VT is a retrospective study of 514 patients with ICD/CRT-D who attended ICD follow-up between June 2018 to September 2019 at the University Hospital Coventry &amp; Warwickshire (UHCW) tertiary cardiology department. All follow-ups were face-to-face. Patients were divided into 2 groups according to the absence or presence of sustained VA (e.g. &amp;gt;30 seconds of VT and/or appropriate ICD therapy), described as “negative event” and “positive event” groups respectively. The type of strategy employed in response to a positive event were categorized into 4 groups: (1) Medication change only (2) Device programming +/− medication (3) Referral for VT CA (4) No intervention Results 514 consecutive patients with ICD (52%) or CRT-D (48%) were analysed. Overall mean age was 67±14 years with 79% male patients. ICM was diagnosed in 329 (64%) patient and NICM in 185 (36%). 437 (85%) patients had no significant VA and/or ICD therapy referred to as the negative group. A total of 77 patients (15%) suffered VA and/or ICD therapies, of whom 22 patients (26%) experienced a second event. 31% (n=24) of this positive event group received no preventative strategy (Table 1). We observed an inconsistent approach to the choice of strategies across different types of arrhythmias and ICD therapies. E.g. the odds of intervening were significantly higher if ICD shock was detected compared to anti-tachycardia pacing (OR 8.4, 95% CI 1.7–39.6, p=0.007). Even in patients with two events, the rate of referral for VT ablation and escalation of antiarrhythmics were similarly as low as patients with a single event (Table 2). Conclusion This is the first contemporary study that has evaluated how strategies that reduce the risk of recurrent ICD events are executed in a real-world population. We have demonstrated that the decision to intervene and choices of strategy remain inconsistent and partially biased by the type of arrhythmia and ICD therapy at follow-up. This supports the need for an evidence-driven multi-disciplinary VT clinic to refine and standardize our approach to this heterogeneous population. Funding Acknowledgement Type of funding sources: None.

Efficacy and tolerability of quinidine as salvage therapy for monomorphic ventricular tachycardia in patients with structural heart disease.

Quinidine is an effective therapy for a subset of polymorphic ventricular tachycardia and ventricular fibrillation (VF) syndromes; however, the efficacy of quinidine in scar-related monomorphic ventricular tachycardia (MMVT) is unclear. Between 2009 and 2020 a single VT referral center, a total of 23 patients with MMVT and structural heart disease (age 66.7 ± 10.9, 20 males, 15 with ischemic cardiomyopathy, mean LVEF 22.2 ± 12.3%, 9 with left ventricular assist device [LVAD]) were treated with quinidine (14 quinidine gluconate; 996 ± 321 mg, 8 quinidine sulfate; 1062 ± 588 mg). Quinidine was used in combination with other antiarrhythmics (AAD) in 19 (13 also on amiodarone). All patients previously failed >1 AAD (amiodarone 100%, mexiletine 73%, sotalol 32%, other 32%) and eight had prior ablations (median of 1.5). Quinidine was initiated in the setting of VT storm despite AADs (6), inability to tolerate other AADs (4), or recurrent VT(12). Ventricular arrhythmias recurred despite quinidine in 13 (59%) patients at a median of 26 (4-240) days after quinidine initiation. In patients with recurrent MMVT, VT cycle length increased from 359 to 434 ms (p = .02). Six (27.3%) patients remained on quinidine at 1 year with recurrence of ventricular arrhythmias in all. The following adverse effects were seen: gastrointestinal side effects (6), QT prolongation (2), rash (1), thrombocytopenia (1), neurologic side effects (1). One patient discontinued due to cost. Quinidine therapy has limited tolerability and long-term efficacy when used in the management of amiodarone-refractory scar-related MMVT.

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.

Stellate Ganglion Phototherapy Using Low-Level Laser

This study investigates the effect of stellate ganglion (SG) phototherapy in healthy participants and assesses its efficacy in suppressing electrical storm (ES) refractory to antiarrhythmic drugs and catheter ablation.Modulation of the autonomic nervous system has been shown to be an effective adjunctive therapy for ES.Ten-minute SG phototherapy was performed twice weekly for 4 weeks in 20 healthy volunteers. To evaluate the acute and chronic effects of SG phototherapy, heart rate variability and serum concentrations of adrenaline, noradrenaline, and dopamine were obtained before phototherapy, immediately after the first phototherapy session, after 8 sessions of phototherapy, and 3 months after the first phototherapy session. In addition, the efficacy of SG phototherapy was evaluated in 11 patients with ES refractory to medication, sedation, and catheter ablation.In healthy participants, serum adrenaline concentration significantly decreased after phototherapy, whereas low-frequency power/high-frequency power significantly decreased during phototherapy. Moreover, the effect on heart rate variability did not last beyond 3 months. In the clinical pilot study, 7 patients had a suppression of ES after SG phototherapy; however, without maintenance therapy, 2 patients had a recurrence of ventricular arrhythmias. Furthermore, it did not control ES in 4 patients.SG phototherapy reduced sympathetic activity and may be a safe and effective adjunctive therapy to control ES in some patients, but its long-term efficacy remains unknown. Chronic phototherapy might help reduce ES recurrence.