Ventricular Outflow Tract Tachycardia Research Articles

P 023: Idiopathic left fascicular ventricular tachycardia in pregnancy

Ventricular tachycardia (VT) can occasionally cause complications in pregnancy. In structurally normal heart, VT that arises in the left ventricle is uncommon and is termed as idiopathic left fascicular VT (ILVT). We report a case of 32-year-old lady, gravida 4 para 3 who presented to us at 34 weeks of pregnancy with symptomatic stable cardiac arrythmia with heart rate of 160 beats per minute. Electrocardiogram showed wide complex tachycardia with positive initial R wave at aVR and capture beats suggestive of ILVT. Echocardiogram was normal. She received IV verapamil 25 mg in total which failed to revert to sinus rhythm and hence, she underwent emergency Caesarean section followed by synchronized cardioversion urgently in operation theatre. Post cardioversion ECG showed sinus rhythm with memory T waves at chest leads. She was scheduled radiofrequency ablation later. This case highlights the importance of attaining the diagnosis of ILVT with distinctive ECG changes. Left ventricular outflow tract (LVOT) VT morphology depends on the site of origin, with either LBBB or early precordial transition in leads V1 to V2 or RBBB pattern in V1 with broad monophasic R in the precordial leads. In addition, there will be an R:S amplitude ratio of 30% or more or an R:QRS duration ratio of 50% in leads V1–2 with other features like capture beats and fusion beats. ILVT responds well with verapamil and can be cured with cardiac ablation, with success rates of more than 90%. ILVT though difficult to diagnose, it has distinctive ECG features which can lead to its diagnosis for appropriate treatment to be given accordingly. ILVT in pregnant patients generally has a good prognosis.

Fatal Cardiac Arrhythmias During Electronic Gaming in Patients With Genetically Mediated Heart Diseases

BackgroundRecently, electronic gaming has been reported as a precipitant of life-threatening cardiac arrhythmias in susceptible individuals. However, the prevalence of cardiac events in genetic heart diseases (GHDs) in the setting of electronic gaming has not been established. ObjectivesIn this study, we sought to define the prevalence of cardiac events occurring in the setting of electronic gaming in GHDs. MethodsRetrospective review of all patients evaluated and treated at Mayo Clinic’s genetic heart rhythm clinic from July 2000 to November 2022 was performed to identify patients with a history of playing electronic games at the time of their cardiac event. Cardiac event was used to define events occurring before diagnosis, and breakthrough cardiac event (BCE) was used for events occurring after diagnosis. ResultsOf the 3,370 patients with a GHD (mean age at first evaluation 27 ± 19 years, 55% female), 1,079 (32%) had a cardiac event before diagnosis, with 5 patients (0.5%) having an electronic gaming–associated event (3 catecholaminergic polymorphic ventricular tachycardia, 1 long QT syndrome, and 1 premature ventricular contraction–triggered ventricular fibrillation). After diagnosis and treatment, 431 patients (13%) experienced ≥1 BCE during follow-up, of which 1 electronic gaming–associated BCE (0.2%) occurred in a patient with catecholamine-sensitive right outflow tract ventricular tachycardia. ConclusionsAlthough anecdotal cases of electronic gaming–associated life-threatening arrhythmias have been reported, in this largest single-center study to date, we show that these are extremely rare occurrences. While electronic gaming can have adverse health consequences, the threat of electronic gaming–triggered sudden death should not be used to try to curb time spent gaming.

The long-term outcome of malignant outflow tract ventricular tachycardia in patients without structural heart disease

Abstract Funding Acknowledgements Type of funding sources: None. Background Idiopathic ventricular tachycardia (VT) originating from the outflow tract (OT) is usually considered a benign condition. However, in some rare cases, patients with the malignant OT-VT suffer from syncope or even sudden cardiac death (SCD). Objectives The purpose of this study was to clarify the long-term clinical outcome of catheter ablation for malignant OT-VT with no sturctural heart disease (no SHD). Methods Fifty two consecutive patients (28 women and 24 men; mean age, 45 years; range, 20-77 years) ablated or implanted cardiac defibrillator (ICD) for malignant OT-VT were followed for median 5 years from 2001 to 2019. Primary end point defined recurrent VT/VF episodes. Result All 52 patients underwent electrophysiologic study (EPS). Among these patients, catheter ablation successfully elimiated VT focus in 37 (71.2%), partially suppressed VT in 9 (17.3%), and failed to controll VT in 6 (11.5%) [5 of 6 failed to induce clinical tachcyardia and 1 of 6 failed to ablate VT due to multipe PVC]. There was no acute procedureal complication. ICDs were implanted in 16 patients. 12 of these 16 patients were presented with VF or SCD. One of these 16 patients had recurrent VT in 3 years after ablation and three of 16 patients failed to induce clinical tachcyardia. During a mean follow up 58 months (range, 6-161 months), 19 (36.5%) of 52 patients suffered from recurrent VT/VF episodes. Among the 37 patients with successful ablation, 10 (27.0%) patients reached primary endpoints. More importantly, two patients (with only syncope and no prior VF) experienced SCD, one at 6 years after a successful ablation and the other at 3 years after partially modification of VT focus. Conclusion Catheter ablation for the malignant OT-VT in patients with no SHD showed safe and tolerable outcomes. It may consider as an early treatment option for these patients. However, even after the successful ablation, a periodical follow-up is crucial in some patients for preventing sudden cardiac deaths.

PO-04-061 A RARE CASE OF FOCAL LEFT VENTRICULAR OUTFLOW TRACT VENTRICULAR TACHYCARDIA LATE AFTER TRANSCATHETER AORTIC VALVE REPLACEMENT

Transcatheter aortic valve replacement (TAVR) is commonly used to treat severe aortic stenosis (AS). To date there is only one reported case of post-TAVR, new onset, left ventricular outflow tract (LVOT) ventricular tachycardia (VT) which was ablated above the TAVR valve. We report a case of late presenting symptomatic LVOT VT, which was successfully ablated via a trans-septal approach, without fluoroscopy, using intracardiac echocardiography (ICE) and electroanatomic mapping (EAM), thereby, avoiding catheter manipulation in the aorta above the valve. N/A A 68-year-old man underwent TAVR for severe AS with Sapien 3 valve (Edwards Lifescience). Nine months later, the patient developed worsening dyspnea. Echocardiogram showed well seated TAVR valve, and exercise nuclear stress revealed no ischemia. During the stress test, he had slow monomorphic VT at rest, during exercise, and recovery (100-120 bpm). A 24-hour Holter monitor revealed a ventricular arrhythmia burden of 55% with rates between 85 and 112 bpm. The 12-lead ECG of VT had an initial positive deflection in lead I, QS in V1 and V2, and an initial R wave in V3 taller than the sinus QRS, suggesting a septal right ventricular outflow tract (RVOT) vs. LVOT origin. There was no improvement with beta-blocker therapy. An electrophysiology study was performed using ICE and CARTO (Biosense Webster, Diamond Bar, CA). Activation mapping in the septal RVOT revealed a 20ms presystolic electrogram (far field) and an 80% pace map, despite the unipolar signal with QS complex. Radiofrequency ablation performed at this site only mildly suppressed the arrhythmia. The decision was made to map from the LVOT via transseptal access using EAM and real-time markers from Cartosound real time images to accurately visualize the ablation catheter below the TAVR. Earliest activation was beneath the left coronary cusp directly across the RVOT lesions with a sharp 22ms pre-systolic electrogram, unipolar QS, and 90% pace map match. Ablation performed here successfully eliminated the VT even after isoproterenol infusion and programmed stimulation. The patient’s symptoms have resolved, and he remains arrhythmia free. LVOT VA’s may rarely occur post TAVR, although a direct cause cannot be ascertained. This is the first report of successfully ablating the arrhythmia in a TAVR patient using a transeptal, subvalvular approach without fluoroscopy, and avoiding any risks associated with the aortic approach.

PO-04-103 WIDE COMPLEX TACHYCARDIA IN ACUTE ANTI-NMDA RECEPTOR ENCEPHALITIS

NA NA NA A 20-year-old male with no known past medical history presented with two months of episodic right-sided weakness. An extensive workup was notable for a lumbar puncture that was positive for antibodies to the N-methyl-D-aspartate (NMDA) receptor, confirming anti-NMDA receptor (NMDAR) encephalitis. Baseline cardiac workup included a transthoracic echocardiogram (TTE) that showed left ventricular (LV) hypokinesis with borderline ejection fraction (EF 52%), and an ECG showing sinus tachycardia (Figure-A). While admitted, the patient developed shock, necessitating intubation and vasopressors. Serial ECGs while in shock showed sinus tachycardia, a prolonged QTc, and broad sail-like T wave in V1 (similar to type 1 Brugada pattern), with ST elevations in aVR and diffuse ST depressions inferolaterally (Figure-B). Serial troponins were minimally elevated (0.11 ug/L) and TTE showed no regional wall motion abnormalities, so invasive coronary angiography was not pursued. During progressive shock, the patient developed a wide complex tachycardia (WCT, Figure-C), that was thought to most likely be LV outflow tract ventricular tachycardia. The patient became hemodynamically unstable with the WCT, necessitating amiodarone, lidocaine, and ultimately five cardioversions. Repeat TTE showed severe biventricular dysfunction, and the patient needed veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Ultimately, the patient’s biventricular function recovered, and he was able to be decannulated from VA-ECMO. He was managed with intravenous immunoglobulin, steroids and rituximab for his anti-NMDAR encephalitis. Cardiac arrhythmias are a known complication of anti-NMDAR encephalitis in up to one-third of patients. To the best of our knowledge, this is the first case of anti-NDMAR encephalitis associated with diffuse ST elevations suggestive of ischemia. Models suggest NMDA receptor-mediated signaling in the nervous system can alter the vagal outflow to the heart, leading to sinus brady/tachycardia. Other explanations for ECG changes in our patient include focal myocarditis/vasospasm. This is an unusual case of marked ST elevation and sustained VT in anti-NMDAR encephalitis. Pathogenesis and management of arrhythmias related to this condition warrant further study.

PO-02-225 LATE GADOLINIUM ENHANCEMENT AT CARDIAC MAGNETIC RESONANCE YIELDS HIGH NUMBER OF FALSE POSITIVE DIAGNOSES IN ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY

New diagnostic criteria have been proposed for arrhythmogenic right ventricular cardiomyopathy (ARVC). These proposed “Padua criteria” include late gadolinium enhancement (LGE) on cardiac magnetic resonance for the left ventricle (LV) and right ventricle (RV). Yet, the potential of LGE to distinguish ARVC from differential diagnoses remains unknown. Assess the diagnostic value of LGE to distinguish ARVC from its differentials. We included 130 subjects (57% male, 46±17 years) clinically diagnosed with ARVC as per 2010 Task Force Criteria (n=32, 84% PKP2 carriers), familial dilated cardiomyopathy as per World Health Organization criteria (n=25), myocarditis as per 2013 ESC position statement (n=13), sarcoidosis as per 2014 HRS expert consensus statement (n=20), biopsy-proven cardiac amyloidosis (n=19) and RV outflow tract-ventricular tachycardia (n=21). Presence and distribution of LGE was evaluated by an experienced radiologist using a 17-segment LV and 7-segment RV model. Presence of LGE was determined as per Padua criteria. Diagnostic value of RV-LGE and LV-LGE as per Padua criteria in ARVC vs. non-ARVC patients was evaluated with specificity, false positive rate (FPR) and accuracy. Distributions of LGE per subgroup are shown in the Figure. The RV-LGE criterion was equally often fulfilled in ARVC (n=16, 50%) vs. non-ARVC (n=43, 44%) patients, p=0.546. ARVC patients most often had RV-LGE in the RV inlet region (n=14/32, 44%). Consequently, the RV-LGE criterion yielded specificity 56%, FPR 44% and accuracy 55% for right-sided disease. In contrast, the LV-LGE criterion was significantly more often fulfilled in non-ARVC (n=71, 72%) vs. ARVC (n=11, 34%) patients, p<0.001. ARVC patients most often had LV-LGE in the inferolateral (n=10/11, 91%) wall, whereas it was more global in non-ARVC groups (median segments n=2 [IQR 2-6] ARVC vs. n=9 [IQR 4-15] non-ARVC, p<0.001). As such, the LV-LGE criterion yielded specificity 28%, FPR 72% and accuracy 29% for left-sided disease. LV-LGE is observed in one-third of ARVC patients, most often in the inferolateral region. RV-LGE is observed in half of ARVC patients, typically in the RV inlet region. Notably, LGE is often present in ARVC differentials. While LGE may be helpful to determine focal fibrosis, it may result in a large number of false positive diagnoses when included as a diagnostic criterion. Knowledge of LGE patterns can be useful for diagnostic classification.

TREK-1 in the heart: Potential physiological and pathophysiological roles.

The TREK-1 channel belongs to the TREK subfamily of two-pore domains channels that are activated by stretch and polyunsaturated fatty acids and inactivated by Protein Kinase A phosphorylation. The activation of this potassium channel must induce a hyperpolarization of the resting membrane potential and a shortening of the action potential duration in neurons and cardiac cells, two phenomena being beneficial for these tissues in pathological situations like ischemia-reperfusion. Surprisingly, the physiological role of TREK-1 in cardiac function has never been thoroughly investigated, very likely because of the lack of a specific inhibitor. However, possible roles have been unraveled in pathological situations such as atrial fibrillation worsened by heart failure, right ventricular outflow tract tachycardia or pulmonary arterial hypertension. The inhomogeneous distribution of TREK-1 channel within the heart reinforces the idea that this stretch-activated potassium channel might play a role in cardiac areas where the mechanical constraints are important and need a particular protection afforded by TREK-1. Consequently, the main purpose of this mini review is to discuss the possible role played by TREK -1 in physiological and pathophysiological conditions and its potential role in mechano-electrical feedback. Improved understanding of the role of TREK-1 in the heart may help the development of promising treatments for challenging cardiac diseases.

Evaluation of five algorithms in predicting the sublocalisation of right ventricular outflow tract arrhythmia (RVOTA) when compared to 3D electroanatomical mapping origin

Abstract Introduction The majority of idiopathic ventricular arrythmias arise from the right ventricular outflow tract (RVOT) and they represent nearly 10% of all ventricular tachycardia (VT) admissions. It is paramount to precisely predict the origin of RVOT arrhythmias to define the appropriate approach before the ablation procedure. Conventional 12-lead electrocardiogram (ECG) is a useful tool for analysing cardiac arrhythmias, and numerous ECG algorithms for predicting the origin of RVOT arrhythmias have been reported. Purpose To compare the predictive accuracy of five different algorithms as verified by successful ablation site using 3D electroanatomical non-contact mapping in patients with symptomatic and asymptomatic but high ventricular burden right ventricular outflow tract (RVOT) tachycardias. Methods 28 consecutive patients admitted for radiofrequency catheter ablation for symptomatic and asymptomatic, but high ventricular burden idiopathic premature ventricular contractions (PVC) were recruited for this study. All patients had previous failed or intolerant to beta-blocker and/or at least one class IC anti-arrhythmic agents, and they had normal left ventricular ejection fraction. All patients had documented monomorphic PVC with left bundle branch block morphology and an inferior axis. Concordance of the arrhythmia origin based on ECG algorithm and 3D mapping system site were further evaluated. Of the five algorithms, two algorithms with easy-applicability and having a memorable design (Dixit and Joshi) and three algorithms with more complex and detailed design (Ito, Zhang, Pytkowski) were selected for comparisons. Results Assessment of the diagnostic accuracy showed that each of the five algorithms had only moderate accuracy, and the greatest accuracy was observed in the algorithm proposed by Pytkowski algorithm when assessed by a general cardiologist and Dixit and Pytkowski algorithms when evaluated by the electrophysiologist. However, when the algorithms were compared for their accuracy, specificity, sensitivity, no significant differences were found (p=0.99). Conclusions All the five published 12-lead ECG algorithms for RVOT location were similar in terms of the diagnostic accuracy, specificity, and sensitivity. In our study, Pytkowski algorithm exhibits the best accuracy and sensitivity among the algorithms, while predicting a precise location and when evaluation is performed by electrophysiologists and/or cardiologists. Funding Acknowledgement Type of funding sources: None.

Etiology, Clinical Profile, and 1-Year Outcome of Patients Presenting with Nonischemic Ventricular Tachycardia

Background: Although ventricular tachycardia and the ventricular fibrillation occur more often in adults with coronary artery disease, These ventricular arrhythmias may appear in young people, often early and late after surgery for congential heart disease or in association with a variety of cardiac disease, autonomic imbalance, drugs, as well as in the absence of detectable cardiac desease, when serious ventricular tachyarrhythmias occur in the young they may be misdiagnosed as aberrantly conducting supraventricular tachycardias because of their presumed infrequency. Information on clinical characteristics and outcome of patients with NIVT in our patient population is limited. Aims and Objectives: This prospective observational study was aimed at patients presenting with NIVT to our tertiary care center and to analyze their clinical features, electrocardiogram (ECG) characteristics, underlying disease, management and clinical outcome at one year of follow up. Methods: It is an observational prospective study of 50 patients who presented with nonischaemic VT (NIVT) to our tertiary care center. History, physical examination, chest X-RAY, electrocardiogram (ECG) and echocardiography were done. Details of electrophysiological studies and radio frequency ablation were collected. Antiarrhythmic drug history was noted. Patients were followed for a period of one year for their clinical outcome and their response to different modalities of treatment was noted. clinical Events defined as death, hospitalizations, DC shocks and recurrence of disease and time to event was also noted. Results: Among the total 50 patients, 27(54%) were males and 23(46%) were females. The mean age of presentation was 31 to 40 years. Most common presenting symptom was syncope (75%). Most common etiology was found to be idiopathic dilated cardiomyopathy with severe LV dysfunction (26%) followed by inflammatory cardiomyopathy (10%). post valvular replacement surgery for rheumatic heart disease, hypertrophic cardiomyopathy, idiopathic right ventricular outflow tract tachycardia were found in 6 percent of patients in each category. LBBB and RBBB morphology of VT in ECG seen in 37 and 44% of patients respectively. Immediate mortality rate was 12%, mainly seen in patients with electrolyte imbalance secondary to systemic infections and myocarditis related to covid 19 infection. Mean survival time in our study is 39.16 weeks with 95% confidence interval. Events have occurred in 30% of our patients most commonly in patients with idiopathic DCMP. Recurrent episodes of VT are more common in patients with DCMP ejection fraction less than 35 percent and also in ARVD patients after LV involvement. Conclusion: NIVT requires aggressive management to prevent mortality and morbidity. Recurrent episodes of VT can occur after disease progression in DCMP and these patients have poor prognosis. Aggressive management like cervical sympathetic denervation may be required in these patients when presented with VT storm. A comprehensive evaluation of patients with NIVT will allow recognition of underlying etiology and selection of appropriate treatment strategies like cervical sympathetic denervation, radiofrequency ablation and AICD implantation apart from drug therapy for effective control of VT.

Catheter ablation of sustained idiopathic right ventricular outflow tract tachycardia in a pregnant patient without fluoroscopy

In 2020, our department has performed 739 operations on nonpregnant patients. Additionally, 545 highly successful nonfluoroscopic catheter ablation of cardiac arrhythmias were routinely performed using a three-dimensional navigation system, including 47 patients with idiopathic ventricular tachycardia (VT) from the right ventricular outflow tract (RVOT).&#x0D; A 38-year-old female patient with a structurally normal heart was admitted to our hospital in 1011 weeks of her third pregnancy because she sustained recurrent 166 regular heartbeats per minute, wide QRS-complex tachycardia with left bundle branch morphology, and frequent premature ventricular contractions on Holter monitoring with complaints of presyncope and dyspnea. Standard antiarrhythmic drugs failed to control tachycardia. This case report presents our initial successful experience of the rescue zero-fluoroscopy catheter ablation of sustained poorly tolerated idiopathic RVOT tachycardia in a pregnant patient. Our result suggests that this technique may be considered in the few rare cases in which drug-resistant, sustained frequent VT is accompanied by hemodynamic compromise with fluoroscopy contraindication.&#x0D; AIM: Diagnostic algorithm of idiopathic sustained drug-resistant, poorly tolerated VT and the possibility of radiofrequency catheter ablation in the most vulnerable first trimester of pregnancy without fluoroscopy were presented in our case report.

Epicardial Adipose Tissue Thickness is Higher in Right Ventricular Outflow Tract Tachycardia

ABSTRACT Introduction: Idiopathic ventricular arrhythmias, which occur in the absence of structural heart disease, are commonly originating from the outflow tract, and 80% of the them arise from the right ventricle. Epicardial adipose tissue (EAT), which originates from the splanchnopleuric mesoderm, has been shown to be an important source of inflammatory mediators and plays an important role in cardiac autonomic function by epicardial ganglionated plexuses. EAT may potentially contribute to the pathophysiology of idiopathic right ventricular outflow tract (RVOT) tachycardia by different mechanisms. In this study, we aimed to investigate the relationship between EAT thickness and RVOT tachycardia. Methods: This study included 55 patients (32 male, 23 female) with RVOT tachycardia and 60 control subjects (38 male, 22 female). Patients who had more than three consecutive ventricular beats over 100 bpm with specific morphological features on the electrocardiogram (ECG) were diagnosed with RVOT tachycardia. EAT thickness was measured by transthoracic echocardiography. Results: EAT thickness was significantly higher in the RVOT tachycardia group (p &lt;0.05). Ejection fraction (EF), and the thickness of the posterior wall of the left ventricle and of the interventricular septum were significantly lower, and left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left atrial diameter were significantly higher in patients who had RVOT tachycardia compared to normal subjects (p &lt;0.05). Conclusion: Patients who were diagnosed with RVOT tachycardia had increased EAT thickness compared to normal subjects. The underlying mechanism of the condition could be mechanical, metabolic, infiltrative, or autonomic effects of the EAT.

Fast repetitive response as a useful predictor of long-term success of radiofrequency ablation of right ventricular outflow tract ventricular tachycardia

Purpuse: Idiopathic right ventricular outflow tract ventricular tachycardia (RVOT-VT) is the most frequent type of ventricular arrhythmia in patients without structural heart disease and is frequently treated using radiofrequency ablation (RFA). Fast non-sustained ventricular arrhythmia showing the same morphology as initial arrhythmia, the so-called fast repetitive response (FRR), is sometimes observed during ablation of the desired region. In this study, we evaluated the prognostic impact of FRR in patients after successful RFA of RVOT- VT.&#x0D; Methods: A prospective observational case-control design was selected for the study. We included patients with successful RFA of previously registered RVOT- VT. Patients with provoked FRR during RFA were assigned to the FRR group and 33 patients displaying no FRR to the control group. Overall, 33 patients in both groups were monitored for the subsequent 24 months. Parameters of the procedure, such as duration, energy application as well as long-term success, were compared between the two groups.&#x0D; Results: We observed significantly shorter duration of procedure performance (120±29 min vs. 70±16 min; P&lt;0.001) with a markedly smaller number of applied lesions [Please note that I am unsure what the author means by 'applied lesions' here.] (21.6±15.6 vs. 13.4±12.5; P=0.02) in the FRR group. After 24 months, the adjusted odds ratio of relapse for patients from the FRR group vs. control group was 0.19 (95% CI 0.05–0.83; P=0.03).&#x0D; Conclusion: In patients with induced FRR during RFA of RVOT-VT, the procedure tended to be drastically shorter and more successful in the long-term.

Tachycardia and Anxiety in a 14-year-old Boy

Tachycardia and Anxiety in a 14-year-old Boy

Ventricular Tachycardia in Neonates: A Report of Two Cases and Review of the Literature

In the case of hemodynamically stable broad complex tachycardia, it is essential to evaluate the causes and to diagnose correctly in the selection of appropriate management and drugs. We report two neonates diagnosed with idiopathic ventricular tachycardia, which is extraordinarily rare. One presented with idiopathic fascicular ventricular tachycardia (right bundle branch block pattern with a superior axis), and the other presented with right ventricular outflow tract ventricular tachycardia (left bundle branch block pattern with an inferior axis). These two forms are representative of benign ventricular tachycardia. No features of cardiovascular shock were observed. While the recommended initial drug treatments are different, the conditions were well controlled by propranolol without the development of any adverse events. There was no recurrence of arrhythmia for several months in the outpatient clinic.

Anti-desmoglein2 autoantibodies are present in patients with cardiac sarcoidosis and correlate with cardiac inflammation

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The Zurich ACM Program is supported by generous grants from the Georg and Bertha Schwyzer-Winniker Foundation, the Baugarten Foundation, Swiss National Science Foundation, Swiss Heart Foundation and Wild Foundation. This work is also supported by a Canadian Institutes of Health Research grant (FRN: 162402) and the Labatt Heart Centre and Waugh Family Innovation Funds, Caitlin Elizabeth Morris Memorial Fund, Alex Corrance Memorial Foundation and Meredith Cartwright. BACKGROUND Arrhythmogenic right ventricular cardiomyopathy (ARVC) has several phenocopies such as cardiac sarcoidosis (CS), idiopathic outflow tract ventricular tachycardia (OT-VT) and myocarditis. Differentiation between these entities can be challenging. Recently, we have identified diagnostic anti-desmoglein-2 autoantibodies (anti-DSG2 Abs) in patients with ARVC. PURPOSE We sought to examine whether anti-DSG2 Abs are also present in clinical phenocopies of ARVC. METHODS Anti-DSG2 Abs in sera of 25, 19 and 22 patients with sarcoidosis, OT-VT and myocarditis, respectively, were assessed by western blots and ELISA. Clinical and imaging parameters, as well as conventional biomarkers were correlated to detected anti-DSG2 Ab intensity levels. RESULTS Anti-DSG2 Abs, at various intensities, were identified in 6/25 (24%) patients with sarcoidosis, all presenting with CS, but were absent in patients with OT-VT and myocarditis. Cardiac 18F- fluorodeoxyglucose positron emission tomography (18F-FDG PET) was positive in all sarcoidosis patients with positive anti-DSG2 Abs, corresponding to a median PET maximum standardized uptake value (SUVmax) of 5.65 [IQR: 5.15 – 10.9]. In sarcoidosis patients without anti-DSG2 Abs, the SUVmax values were significantly lower with a median of 0 [IQR: 0 – 4] (p = 0.011). The Pearson correlation coefficient (R) was 0.188 (p = 0.039) indicating a positive correlation between cardiac 18F-FDG uptake and anti-DSG2 Abs. No significant correlation was detected for any of the other clinical parameters and biomarkers. CONCLUSIONS In addition to being present in ARVC, anti-DSG2 Abs are also found in CS, a common phenocopy of ARVC; conversely, anti-DSG2 Abs are absent in idiopathic OT-VT and myocarditis. Anti-DSG2 Ab levels positively correlate with myocardial disease activity in CS as indicated by cardiac 18F-FDG PET scanning. Abstract Figure. Central illustration

A High-Precision Machine Learning Algorithm to Classify Left and Right Outflow Tract Ventricular Tachycardia

IntroductionMultiple algorithms based on 12-lead ECG measurements have been proposed to identify the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT) locations from which ventricular tachycardia (VT) and frequent premature ventricular complex (PVC) originate. However, a clinical-grade machine learning algorithm that automatically analyzes characteristics of 12-lead ECGs and predicts RVOT or LVOT origins of VT and PVC is not currently available. The effective ablation sites of RVOT and LVOT, confirmed by a successful ablation procedure, provide evidence to create RVOT and LVOT labels for the machine learning model.MethodsWe randomly sampled training, validation, and testing data sets from 420 patients who underwent successful catheter ablation (CA) to treat VT or PVC, containing 340 (81%), 38 (9%), and 42 (10%) patients, respectively. We iteratively trained a machine learning algorithm supplied with 1,600,800 features extracted via our proprietary algorithm from 12-lead ECGs of the patients in the training cohort. The area under the curve (AUC) of the receiver operating characteristic curve was calculated from the internal validation data set to choose an optimal discretization cutoff threshold.ResultsThe proposed approach attained the following performance: accuracy (ACC) of 97.62 (87.44–99.99), weighted F1-score of 98.46 (90–100), AUC of 98.99 (96.89–100), sensitivity (SE) of 96.97 (82.54–99.89), and specificity (SP) of 100 (62.97–100).ConclusionsThe proposed multistage diagnostic scheme attained clinical-grade precision of prediction for LVOT and RVOT locations of VT origin with fewer applicability restrictions than prior studies.

Incidence of outflow tract ventricular tachycardia long after surgical aortic valve replacement.

BackgroundThe peri‐outflow tract region could be the origin of ventricular tachycardia (VT) after aortic valve replacement (AVR). However, the clinical characteristics of outflow tract ventricular tachycardias (OTVTs) after AVR are yet to be clarified. This study investigated the incidence, risk factors, and clinical characteristics of patients with OTVTs after AVR.MethodsWe retrospectively analyzed the clinical course of 120 patients who had undergone surgical AVR (SAVR) between April 1980 and October 2018. The patients had no ischemic or diagnosed cardiomyopathies other than primary aortic valve diseases.ResultsSix patients (5.0%) developed OTVTs after SAVR. The average onset was at 10.8 ± 5.7 years after SAVR. All cases of VT arose from the inferior axis and included left and right bundle branch block configuration. Two patients who underwent cardiac magnetic resonance imaging (MRI) had late gadolinium enhancement (LGE) in the midlayer of the left ventricle basal anteroseptal wall. Patients with periaortic VTs had significantly larger left ventricular (LV) diameter at systole, lower LV ejection fraction, higher positive rates of signal‐averaged electrocardiogram (SAECG), and nonsustained VTs on Holter monitoring. On ablation, local fragmented potentials with low voltage zones were observed in accordance with the LGE distribution. Multiple VTs originating from the periaortic region were provoked in the sessions.ConclusionsAcute OTVT was found in 5% of patients after SAVR. Arrhythmia risk stratification by SAECG, Holter ECG, and cardiac MRI should be considered for a long period in patients after SAVR.

Catheter ablation of an antidromic atrioventricular reentrant tachycardia using a slow, decrementally conducting accessory pathway in the great cardiac vein

The inability to ablate left accessory pathways (APs) from endocardial approaches may suggest an epicardial location. We report on a 43-year-old woman presenting with a wide QRS tachycardia with Right Bundle Branch Block (RBBB) morphology, right inferior axis, and the "pattern break" appearance in V2 resembled the outflow tract ventricular tachycardia. An electrophysiology study confirmed an antidromic atrioventricular reentrant tachycardia using an antegrade slow, decrementally conducting AP that was successfully ablated in the great cardiac vein-anterior interventricular vein junction after failure of endocardial approach.

A Simplified Two-Stepwise Electrocardiographic Algorithm to Distinguish Left from Right Ventricular Outflow Tract Tachycardia Origin

Background: There are several electrocardiographic algorithms to predict the origin of idiopathic outflow tract ventricular arrhythmias (OT-VAs). This study aimed to develop a more accurate and efficient stepwise electrocardiographic algorithm to discriminate left ventricular outflow tract (LVOT) from right ventricular outflow tract (RVOT) origin. Methods and Results: We analyzed 12-lead electrocardiographic characteristics of 173 consecutive OT-VAs patients who underwent successful radiofrequency catheter ablation in the RVOT (n = 124) or LVOT (n = 49). Based on the areas under the receiver operating characteristic curves, the combination of transitional zone (TZ) index <0 and V2S/V3R index ≤1.5 exhibited 93.5% sensitivity, 85.9% specificity, and 87.3% accuracy. A further analysis was performed in the 71 OT-VAs with a V3-lead precordial transition. The sensitivity, specificity, and accuracy of the integration of V2S/V3R index ≤1.5 and R-wave deflection interval in lead V3 >80 ms were 91.7, 83.1, and 85.9%, respectively. In the prospective evaluation, the combination of TZ index and V2S/V3R index could identify the correct origin sites with 91.2% accuracy in the overall analysis, and the integration of V2S/V3R index ≤1.5 and R-wave deflection interval in lead V3 >80 ms exhibited 94% accuracy in V3-lead precordial transition. Conclusions: The combination of TZ index <0 and V2S/V3R index ≤1.5 is a simple and efficient stepwise electrocardiographic algorithm for predicting LVOT origin. For the OT-VAs with a V3-lead precordial transition, the integration of V2S/V3R index ≤1.5 and R-wave deflection interval in lead V3 >80 ms would be a better choice.

Right ventricular outflow tract ventricular tachycardia as a result of uncontrolled hyperthyroidism

Right ventricular outflow tract ventricular tachycardia as a result of uncontrolled hyperthyroidism