Idiopathic Outflow Tract Ventricular Tachycardia Research Articles

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

Diagnosing arrhythmogenic right ventricular cardiomyopathy by 2010 Task Force Criteria: clinical performance and simplified practical implementation.

AimsArrhythmogenic right ventricular cardiomyopathy (ARVC) is diagnosed by a complex set of clinical tests as per 2010 Task Force Criteria (TFC). Avoiding misdiagnosis is crucial to prevent sudden cardiac death as well as unnecessary implantable cardioverter-defibrillator implantations. This study aims to validate the overall performance of the TFC in a real-world cohort of patients referred for ARVC evaluation.Methods and resultsWe included patients consecutively referred to our centres for ARVC evaluation. Patients were diagnosed by consensus of three independent clinical experts. Using this as a reference standard, diagnostic performance was measured for each individual criterion as well as the overall TFC classification. Of 407 evaluated patients (age 38 ± 17 years, 51% male), the expert panel diagnosed 66 (16%) with ARVC. The clinically observed TFC was false negative in 7/66 (11%) patients and false positive in 10/69 (14%) patients. Idiopathic outflow tract ventricular tachycardia was the most common alternative diagnosis. While the TFC performed well overall (sensitivity and specificity 92%), signal-averaged electrocardiogram (SAECG, P = 0.43), and several family history criteria (P ≥ 0.17) failed to discriminate. Eliminating these criteria reduced false positives without increasing false negatives (net reclassification improvement 4.3%, P = 0.019). Furthermore, all ARVC patients met at least one electrocardiogram (ECG) or arrhythmia criterion (sensitivity 100%).ConclusionThe TFC perform well but are complex and can lead to misdiagnosis. Simplification by eliminating SAECG and several family history criteria improves diagnostic accuracy. Arrhythmogenic right ventricular cardiomyopathy can be ruled out using ECG and arrhythmia criteria alone, hence these tests may serve as a first-line screening strategy among at-risk individuals.

Association of Tp-Te/QT Ratio With Ventricular Tachycardia in Patients With Idiopathic Outflow Tract Ventricular Premature Contraction.

BackgroundIdiopathic outflow tract ventricular premature contraction (VPC) can evolve into ventricular tachycardia (VT) via triggered activity mechanism. Transmural dispersion of repolarization (TDR) might play a role in idiopathic outflow tract VT by inducing phase 2 early afterdepolarization (EAD) and serve as the functional substrate for VT. Tp-Te/QT ratio as an arrhythmogenesis index has been reported to be associated with the incidence of ventricular arrhythmia. This study aims to investigate the association between Tp-Te/QT ratio with VT incidence in idiopathic outflow tract VPC.MethodsObservational research with cross sectional design was conducted. VT episodes were retrospectively tracked from electrocardiogram (ECG), treadmill test (TMT), Holter monitor and electrophysiology study data in Sardjito Hospital of patients with idiopathic outflow tract VPC during September to October 2017. Tp-Te/QT was defined as the time from the peak of T wave to the intersection between the tangent and isoeectric line, divided with QT interval. Tp-Te/QT ratio measurement was performed in leads V4, V5 and V6 by single observer. Tp-Te/QT ratio was categorized into increased (> 0.25) and normal (< 0.25). Chi-square and logistic regression test were performed.ResultsOut of 46 patients, there were 28 patients who had VT. Increased Tp-Te/QT ratio of lead V4 was found in 11 patients, the increased ratios in leads V5 and V6 were found in 13 patients. The prevalence ratio (PR) of Tp-Te/QT ratio to VT incidence in lead V4 was 2.059 (95% CI: 1.464 - 2.895; P = 0.007), while in leads V5 and V6 was 2.200 (95% CI: 1.514 - 3.197; P = 0.002). Tp-Te/QT ratios in leads V4, V5 and V6 were not significantly different and equally strong in predicting VT events (P < 0.001; 95% CI). Adjustment of confounding factor hypertension with multivariate test gave insignificant results (PR: 1.290; 95% CI: 0.444 - 3.747).ConclusionsIncreased Tp-Te/QT ratio in idiopathic outflow tract VPC patients was associated with higher prevalence ratio for VT, although this was affected by hypertension. Leads V4, V5 and V6 were equally strong in predicting VT events.

Initial outcome following invasive cardiac electrophysiologic studies and radiofrequency ablation of ventricular tachycardia

Background: Cardiac electrophysiologic study (EPS) and radiofrequency (RF) ablation have become an established mode of treatment for patients with refractory arrhythmias. These procedures are carried out regularly at the cardiac catheterization laboratory of Madras Medical Mission India. Objective: The purpose of this study was to evaluate our experience with cardiac EPSs and Radiofrequency ablations (RFAs) of ventricular tachycardia (VT). Methods: This was a retrospective study carried out in the Cardiac Electrophysiology Department of the Institute of Cardiovascular Diseases, Madras Medical Mission, India. All cases diagnosed to have VT following cardiac EPS between January 2010 and April 2014 were selected for the study. The records which were obtained from the Cardiac Electrophysiology Clinical Research Office of Madras Medical Mission were reviewed. One hundred and thirteen cases were chosen for the analysis, using SPSS statistical software version 15. Results: There were 113 patients, comprised 78 males and 35 females. The mean age was 48.79 years. Common etiologic classes of VT were idiopathic outflow tract VT - 50.4%, ischemic heart disease - 20.4%, arrhythmogenic right ventricular cardiomyopathy (ACMP) - 11.5%, and idiopathic dilated cardiomyopathy (IDCM) - 12.4%. Ablation was attempted in 92 (82.1%). The initial outcome was highest in IDCM, 87.5%, and least in ACMP, 50.0%. Conclusions: Treatment of VT by RFA is comparatively effective and safe.

Unusual occurrence of ventricular tachycardia induced by single bee sting.

Sir, A 35-year-old female patient was admitted to our emergency room with palpitations, 1 h after a single bee sting in the left hand. She was previously in good health, not on any medications and did not have any past allergic reactions. Local inspection of the left hand revealed only mild erythema and swelling. Hemoglobin, thyroid-stimulating hormone, and serum electrolyte levels were within the normal range. Initial 12-lead electrocardiogram (ECG) showed short runs of the nonsustained ventricular tachycardia (VT) [Figure 1]. Only a few seconds later, she suddenly complained of chest discomfort, dizziness, and intensive palpitations. Repeat ECG showed wide QRS-complex tachycardia at a rate of 160 b.p.m. without detectable P-waves [Figure 2]. A bolus of 150 mg amiodarone i.v. was administered, which rapidly terminated VT and restored normal sinus rhythm [Figure 3]. The treatment was continued with bisoprolol 2.5 mg twice daily. Figure 1 Electrocardiogram showing standard Leads I, II, and III: Frequent ectopic ventricular beats with short runs of the nonsustained ventricular tachycardia Figure 2 Electrocardiogram showing standard Leads I, II, and III: Sustained ventricular tachycardia with the right bundle branch block pattern Figure 3 Electrocardiogram showing standard Leads I, II, and III: Regular sinus rhythm just after conversion with amiodarone Transthoracic echocardiography revealed only a mild mitral valve prolapse with mild mitral regurgitation. The patient refused to undergo further invasive investigations (namely coronary angiography and electrophysiological study) so we performed computed tomography-coronary angiography, which showed the normal anatomy of the coronary arteries and the absence of stenosis. The patient was discharged after 48 h and remained asymptomatic during the next 6 months follow-up. A 24-h-holter-ECG was performed after 1–6 months and was normal. Bee stings have been associated with a wide variety of local and systemic reactions including rarely, tachyarrhythmias, commonly occurring in individuals with preexisting heart disease such as left atrial enlargement and left ventricular failure.[1] Although the arrhythmogenic mechanism of the bee venom is still unknown, many pharmacologically active constituents of the bee venom have been isolated including histamine, serotonin, dopamine and noradrenaline, melittin, hyaluronidase, apamin, and phospholipase A2 which may induce tachyarrhythmias in the absence of anaphylaxis.[2] However, in the presence of anaphylaxis tachyarrhythmias are more common, and possible mechanisms include a direct antigen-antibody myocardial reaction, a pharmacological effect of mediators released during anaphylaxis, the effects of agents such as adrenaline used for treatment, hypoxia, hypotension, preexisting heart disease or a combination of several factors.[3] In this patient only mild mitral valve prolapse was demonstrated by transthoracic echocardiography; and to the best of our knowledge, this is the first reported case of VT in a patient with mild mitral valve prolapse-induced by single bee sting in the absence of anaphylaxis. Bee venom as a metabolic insult and resultant autonomic overactivity probably induced tachyarrhythmia in this case. Cardiac magnetic resonance imaging to look for myocardial scarring and electrophysiologic study to look for inducibility of idiopathic outflow tract VT would be indicated in the setting of purely monomorphic VT. Finally, this case implies the necessity of meticulous ECG monitoring in patients presenting with palpitations and ventricular ectopic beats after bee sting, because malignant tachyarrhythmias may occur even in the absence of anaphylaxis in the setting of only mild structural heart abnormalities, as reported here. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Malignant conversion of benign right ventricular outflow track ventricular tachycardia 18 years post-ablation

This case report describes the rare phenomenon of malignant conversion of benign right ventricular outflow tract ventricular tachycardia into idiopathic ventricular fibrillation 18 years after successful ablation, in the absence of any type of heart disease. We review the current literature looking at predictors for this event, with the conclusion that there are no reliable risk predictors available. Until clear guidelines exist, we suggest patients be informed and monitored for the possibility of “malignant conversion” following ablation for benign idiopathic outflow tract ventricular tachycardia.

Comparison of the “Real-life” Diagnostic Value of Two Recently Published Electrocardiogram Methods for the Differential Diagnosis of Wide QRS Complex Tachycardias

The diagnostic values of the aVR lead or "Vereckei algorithm," and the lead II R-wave peak time (RWPT) criterion, recently devised for the differential diagnosis of wide QRS complex tachycardias (WCTs), were compared. A total of 212 WCTs (142 ventricular tachycardias [VTs], 62 supraventricular tachycardias [SVT], and eight preexcitation SVTs) from 145 patients with proven electrophysiologic diagnoses were retrospectively analyzed by seven examiners blinded to the electrophysiologic diagnoses. The overall test accuracy of the Vereckei algorithm was superior to that of the RWPT criterion (84.3% vs. 79.6%; p = 0.0003). The sensitivity of the Vereckei algorithm for VT diagnosis was greater than that of RWPT criterion (92.4% vs. 79.1%; p < 0.0001). The negative predictive value (NPV) for the Vereckei algorithm was also greater (77.8%; 95% confidence interval [CI] = 73.6% to 82.1%) than that of the RWPT criterion (61.6%; 95% CI = 57.6% to 65.6%). The specificity of the Vereckei algorithm was lower than that of the RWPT criterion (64.7% vs. 80.9%; p < 0.0001). The positive predictive value (PPV) was also lower for the Vereckei algorithm (86.4%; 95% CI = 84.4% to 88.4%) than for the RWPT criterion (90.9%; 95% CI = 89.1% to 92.8%). Incorrect diagnoses made by the Vereckei algorithm were mainly due to misdiagnosis of SVT as VT (65.7% of cases), and those made by the RWPT criterion were due to the more dangerous misdiagnosis of VT as SVT (72.5% of cases). The Vereckei algorithm was superior in overall test accuracy, sensitivity, and NPV for VT diagnosis and inferior in specificity and PPV to the RWPT criterion. All of these parameters were lower in "real life" than those reported by the original authors for each of the particular electrocardiographic methods.

Long-Term Effect of Continuing Sports Activity in Competitive Athletes With Frequent Ventricular Premature Complexes and Apparently Normal Heart

The long-term outcome of athletes with frequent ventricular premature complexes (VPCs) and apparently normal heart has not been fully clarified. To evaluate the clinical and prognostic significance of VPCs and the influence of continuing sports activity during follow-up, we studied 120 healthy athletes (96 men; median age 16 years) in whom frequent VPCs (>100 VPCs/24 hours) were discovered by chance during preparticipation screening. All athletes were followed up for a median of 84 months. During follow-up, 96 underwent serial 24-hour Holter recording and 62 underwent serial echocardiography. The median number of VPCs/24 hours on basal Holter was 3,760. During follow-up, 81 athletes continued sports activity, whereas 39 did not. No athlete died or developed overt heart disease. The median number of VPCs/24 hours decreased in both athletes who continued sports activity and those who did not (from 3,805 to 1,124, p <0.0001 and from 5,787 to 1,298, p <0.0001, respectively). During follow-up, left ventricular ejection fraction slightly decreased to <55% in 9 of 62 athletes who, in respect to the remaining 53, had more VPCs/24 hours both in the basal state (12,000 vs 3,880) and during follow-up (10,702 vs 1,368), and a longer follow-up (95 vs 36 months). In conclusion, (1) frequent VPCs in athletes without heart disease have a long-term benign prognostic significance, (2) sporting activity does not modify this benign outcome, (3) during follow-up, the burden of VPCs decreases whether or not subjects continue sports activity, and (4) in 14.5% of athletes, ejection fraction slightly decreases over time.

The V2 Transition Ratio: A New Electrocardiographic Criterion for Distinguishing Left From Right Ventricular Outflow Tract Tachycardia Origin

We sought to develop electrocardiography (ECG) criteria for distinguishing left ventricular outflow tract (LVOT) from right ventricular outflow tract (RVOT) origin in patients with idiopathic outflow tract ventricular tachycardia (OTVT) and lead V 3 R/S transition. Several ECG criteria have been proposed for differentiating left from right OTVT origin; ventricular tachycardias (VTs) with left bundle branch block and V 3 transition remain a challenge. We analyzed the surface ECG pattern of patients with OTVT with a precordial transition in lead V 3 who underwent successful catheter ablation. Sinus and VT QRS morphologies were measured in limb and precordial leads with electronic calipers. The V 2 and V 3 transition ratios were calculated by computing the percentage R-wave during VT (R/R+S) VT divided by the percentage R-wave in sinus rhythm (R/R+S) SR . We retrospectively analyzed ECGs from 40 patients (mean age 44 ± 14 years, 21 female) with outflow tract premature ventricular contractions (PVCs)/VT. Patients with structural heart disease, paced rhythms, and bundle branch block during sinus rhythm were excluded. The V 2 transition ratio was significantly greater for LVOT PVCs compared with RVOT PVCs (1.27 ± 0.60 vs. 0.23 ± 0.16; p < 0.001) and was the only independent predictor of LVOT origin. In 21 prospective cases, a V 2 transition ratio ≥0.60 predicted an LVOT origin with 91% accuracy. A PVC precordial transition occurring later than the sinus rhythm transition excluded an LVOT origin with 100% accuracy. The V 2 transition ratio is a novel electrocardiographic measure that reliably distinguishes LVOT from RVOT origin in patients with lead V 3 precordial transition. This measure might be useful for counseling patients and planning an ablation strategy.

Left Ventricular Outflow Tract Tachycardia Including Ventricular Tachycardia from the Aortic Cusps and Epicardial Ventricular Tachycardia

Idiopathic outflow tract ventricular tachycardia (VT) can arise from the right (RVOT) or left ventricular outflow tract (LVOT). The electrocardiographic (ECG) pattern of RVOT VT is typical in most patients, showing a monomorphic left bundle branch block (LBBB) QRS morphology with an inferior axis. Radiofrequency catheter ablation can be performed with a high success rate and provides a curative therapeutic approach. However, not all VTs with LBBB and inferior axis can be ablated from the RVOT. It has become apparent that LVOT VTs including VT originating from the aortic sinus of Valsalva or epicardium represent underrecognized VT entities which are also amenable to successful catheter ablation. Twelve-lead ECG criteria can contribute to distinguish between sites of VT origin.LVOT arrhythmias represent an increasingly recognized VT entity which can be safely and successfully treated by catheter ablation. Identification of VT origin using ECG criteria and differentiation of LVOT versus RVOT origin is essential in the careful planning of the ablation strategy.

Ablation of Left Ventricular Epicardial Outflow Tract Tachycardia From the Distal Great Cardiac Vein

The purpose of this study was to examine the feasibility and safety of ablation of idiopathic outflow tract ventricular tachycardia (OTVT) from the distal ramifications of the coronary sinus (CS). A significant minority of patients presenting with idiopathic OTVT have an epicardial focus, the standard approach to which involves ablation from within one of the aortic valve cusps (AVCs). We describe the successful ablation of idiopathic epicardial OTVT from within the CS in the distal great cardiac vein (GCV). Ablation from the distal GCV was performed in 5 patients with idiopathic OTVT who had unfavorable mapping, in some cases unsuccessful ablation from various endocardial and epicardial sites including the AVCs, and in 1 patient via the direct epicardial approach. An electroanatomic mapping system (Carto) was used in 3 patients, and conventional mapping was performed in 2 patients, and in 3 patients cryothermal ablation was performed. In all patients, the first ablation lesion in the GCV successfully eliminated the arrhythmia. All patients have remained free of VT after a mean follow-up of 24 (7 to 44) months. There were no immediate or long-term complications. Idiopathic epicardial OTVT can be successfully ablated from the distal GCV, and should be seen as an alternative to ablation from the aortic valve cusps.

Prevalence and characteristics of idiopathic outflow tract tachycardia with QRS alteration following catheter ablation requiring additional radiofrequency ablation at a different point in the outflow tract.

Subtle variations in QRS morphology occurs during idiopathic outflow tract ventricular tachycardia (OTVT), but no studies have clarified the prevalence and characteristics of the OTVT with altered QRS morphology following radiofrequency catheter ablation (RFA), which then require an additional RF application at a different portion of the outflow tract to abolish OTVT. Of 202 patients with a monomorphic VT or premature ventricular contraction (PVC) originating from the outflow tract, 6 (3%) showed changes in QRS morphology in the OTVT following RFA, requiring an additional RF application to the outflow tract at a different portion. In all six patients, RFA was applied for the first or second OTVT to a right or left ventricular endocardial site, with the other site being the left sinus of Valsalva. In each patient, OTVT before or after the changes in QRS morphology had characteristic ECG findings originating from a particular portion of the outflow tract. Changes in QRS morphology consistently included an increase or decrease in R wave amplitude in all inferior leads. Detailed continuous observation of QRS morphology in OTVT, especially R wave amplitude in inferior leads, is important for identifying changes of QRS morphology during catheter ablation. Mapping and ablation at a different portion of the outflow tract is then needed for cure.

Coincidence of idiopathic ventricular outflow tract tachycardia and atrioventricular nodal reentrant tachycardia.

Tachycardia-induced tachycardia appears to be a relatively rare condition. In such cases an important question arises whether catheter ablation of one arrhythmia may prevent the occurrence of another. This paper reviews single-centre experience with coincident idiopathic outflow tract ventricular tachycardia (VT) and atrioventricular (AV) nodal reentry tachycardia (AVNRT), and strategy of treatment. Seven of 46 patients (15%) with clinically documented idiopathic outflow tract VT were found to have reproducibly inducible AVNRT at the time of an electrophysiological study. There were two men and five women (mean age 35+/-9 years, range 20-44) without structural heart disease. During the study, AVNRT spontaneously triggered VT in three cases. Radiofrequency catheter ablation of the slow pathway did not suppress subsequent inducibility of VT in any of them. Successful catheter ablation of VT did not prevent clinical recurrence of AVNRT in one patient, and led to transition of VT into typical AVNRT in another. Coincidence of idiopathic outflow tract VT and AVNRT was found in 15% of cases of clinically documented idiopathic VT. Catheter ablation of one arrhythmia substrate did not prevent inducibility or clinical recurrence of the other. These data support the strategy of performing catheter ablation of both arrhythmia substrates during one session.