Outflow tract tachycardia with R/S transition in lead V3

A novel ECG algorithm to differentiate between ventricular arrhythmia from right versus left ventricular outflow tract

AIM

The aim of this study was to evaluate the accuracy of the diagnostic criteria for determining the origin of outflow tract ventricular arrhythmia (OTVA) and develop an ECG algorithm to predict its origin.

METHOD

We analyzed the ECGs of 100 patients with OTVA who underwent successful ablation. The QRS complex was measured during sinus rhythm and ventricular arrhythmia. After the ECG algorithm was developed, it was validated in an additional 100 patients from two different hospitals.

RESULTS

In this retrospective study, among the parameters without restrictions in the transition lead, the V2S/V3R index (AUC = 0.96) was significantly better in predicting ventricular arrhythmia originating from the right ventricular outflow tract (RVOT). Further, the larger initial r wave surface area (ISA) in V1 and V2 (AUC = 0.06) was significantly better in predicting ventricular arrhythmias originating from the left ventricular outflow tract (LVOT). Among the parameters with the transition lead in V3, the V2S/V3R index (AUC = 0.82) was significantly better in predicting VAs originating from the RVOT. On the contrary, the V3 R-wave deflection interval (AUC = 0.19) was significantly better in predicting ventricular arrhythmias originating from the LVOT. The algorithm combining the V2S/V3R index and the larger ISA in V1 and V2 could predict OTVA origin with an accuracy of 95.00%, a sensitivity of 87.18%, a specificity of 100.00%, a positive predictive value (PPV) of 100.00%, and a negative predictive value (NPV) of 92.42%. In the validation study, the algorithm exhibited excellent accuracy (95.00%) and AUC (AUC = 0.95), with a sensitivity of 94.12%, a specificity of 95.45%, a PPV of 91.43%, and an NPV of 96.92%.

CONCLUSION

Our developed algorithm can reliably predict OTVA origin without restrictions in the transition lead.

Catheter Ablation of Left Ventricular Summit Arrhythmias from Adjacent Anatomic Vantage Points

Idiopathic ventricular arrhythmias (VA), particularly left ventricular outflow tract (LVOT) VA accounts for up to 10% of all VAs referred for ablative therapy. In addition to being infrequent, its intricate anatomy and its pathophysiology make catheter ablation (CA) of these arrhythmias a challenge even for experts. In this scenario, detailed right ventricular outflow tract as well as LVOT electroanatomic mapping including epicardial mapping are essential. In this article, we will emphasize our approach toward the CA technique used for LVOT VA, particularly IVS and/or LVS VA originating from intramural foci, along with its acute and long-term efficacy and safety.

A novel practical algorithm using machine learning to differentiate outflow tract ventricular arrhythmia origins

INTRODUCTION

Diagnosis of outflow tract ventricular arrhythmia (OTVA) localization by an electrocardiographic complex is key to successful catheter ablation for OTVA. However, diagnosing the origin of OTVA with a precordial transition in lead V3 (V3TZ) is challenging. This study aimed to create the best practical electrocardiogram algorithm to differentiate the left ventricular outflow tract (LVOT) from the right ventricular outflow tract (RVOT) of OTVA origin with V3TZ using machine learning.

METHODS

Of 498 consecutive patients undergoing catheter ablation for OTVA, we included 104 patients who underwent ablation for OTVA with V3TZ and identified the origin of LVOT (n = 62) and RVOT (n = 42) from the results. We analyzed the standard 12-lead electrocardiogram preoperatively and measured 128 elements in each case. The study population was randomly divided into training group (70%) and testing group (30%), and decision tree analysis was performed using the measured elements as features. The performance of the algorithm created in the training group was verified in the testing group.

RESULTS

Four measurements were identified as important features: the aVF/II R-wave ratio, the V2S/V3R index, the QRS amplitude in lead V3, and the R-wave deflection slope in lead V3. Among them, the aVF/II R-wave ratio and the V2S/V3R index had a particularly strong influence on the algorithm. The performance of this algorithm was extremely high, with an accuracy of 94.4%, precision of 91.5%, recall of 100%, and an F1-score of 0.96.

CONCLUSIONS

The novel algorithm created using machine learning is useful in diagnosing the origin of OTVA with V3TZ.

Reappraisal of electrocardiographic criteria for localization of idiopathic outflow region ventricular arrhythmias

BACKGROUND

Electrocardiographic (ECG) criteria have been proposed to localize the site of origin of outflow region ventricular arrhythmias (VAs). Many factors influence the QRS morphology of VAs and may limit the accuracy of these criteria.

OBJECTIVE

The purpose of this study was to assess the accuracy of ECG criteria that differentiate right from left outflow region VAs and localize VAs within the aortic sinus of Valsalva (ASV).

METHODS

One hundred one patients (mean age 52 ± 16 years; 55 [54%] women) undergoing catheter ablation of right ventricular outflow tract (RVOT) or ASV VAs with a left bundle branch block, inferior axis morphology were studied. ECG measurements including V₂ transition ratio, transition zone index, R-wave duration index, R/S amplitude index, V₂S/V₃R index, V_1-3 QRS morphology, R-wave amplitude in the inferior leads were tabulated for all VAs. Comparisons were made between the predicted site of origin using these criteria and the successful ablation site.

RESULTS

Patients had successful ablation of 71 RVOT and 38 ASV VAs. For the differentiation of RVOT from ASV VAs, the positive predictive values and negative predictive values for all tested ECG criteria ranged from 42% to 75% and from 71% to 82%, respectively, with the V₂S/V₃R index having the largest area under the curve of 0.852. Morphological QRS criteria in leads V₁ through V₃ did not localize ASV VAs. The maximum R-wave amplitude in the inferior leads was the sole criterion demonstrating a significant difference between right ASV, right-left ASV commissure, and left ASV sites.

CONCLUSION

ECG criteria for differentiating right from left ventricular outflow region VAs and for localizing ASV VAs have a limited accuracy.

Electrocardiographic Criteria for Differentiating Left from Right Idiopathic Outflow Tract Ventricular Arrhythmias

Idiopathic ventricular arrhythmias are ventricular tachycardias or premature ventricular contractions presumably not related to myocardial scar or disorders of ion channels. Of the ventricular arrhythmias (VAs) without underlying structural heart disease, those arising from the ventricular outflow tracts (OTs) are the most common. The right ventricular outflow tract (RVOT) is the most common site of origin for OT-VAs, but these arrhythmias can, less frequently, originate from the left ventricular outflow tract (LVOT). OT-VAs are focal and have characteristic ECG features based on their anatomical origin. Radiofrequency catheter ablation (RFCA) is an effective and safe treatment strategy for OT-VAs. Prediction of the OT-VA origin according to ECG features is an essential part of the preprocedural planning for RFCA procedures. Several ECG criteria have been proposed for differentiating OT site of origin. Unfortunately, the ECG features of RVOT-VAs and LVOT-VAs are similar and could possibly lead to misdiagnosis. The authors review the ECG criteria used in clinical practice to differentiate RVOT-VAs from LVOT-VAs.

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

Introduction

Multiple 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.

Methods

We 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.

Results

The 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).

Conclusions

The 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.

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

Introduction

Multiple 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.

Methods

We 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.

Results

The 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).

Conclusions

The 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.

Lead I R-wave amplitude to distinguish ventricular arrhythmias with lead V3 transition originating from the left versus right ventricular outflow tract

BACKGROUND

The electrophysiology algorithm for localizing left or right origins of outflow tract ventricular arrhythmias (OT-VAs) with lead V₃ transition still needs further investigation in clinical practice.

HYPOTHESIS

Lead I R-wave amplitude is effective in distinguishing the left or right origin of OT-VAs with lead V₃ transition.

METHODS

We measured lead I R-wave amplitude in 82 OT-VA patients with lead V₃ transition and a positive complex in lead I who underwent successful catheter ablation from the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT). The optimal R-wave threshold was identified, compared with the V₂ S/V₃ R index, transitional zone (TZ) index, and V₂ transition ratio, and validated in a prospective cohort study.

RESULTS

Lead I R-wave amplitude for LVOT origins was significantly higher than that for RVOT origins (0.55 ± 0.13 vs. 0.32 ± 0.15 mV; p < .001). The area under the curve (AUC) for lead I R-wave amplitude as assessed by receiver operating characteristic (ROC) analysis was 0.926, with a cutoff value of ≥0.45 predicting LVOT origin with 92.9% sensitivity and 88.2% specificity, superior to the V₂ S/V₃ R index, TZ index, and V₂ transition ratio. VAs in the LVOT group mainly originated from the right coronary cusp (RCC) and left and right coronary cusp junction (L-RCC). In the prospective study, lead I R-wave amplitude identified the LVOT origin with 92.3% accuracy.

CONCLUSION

Lead I R-wave amplitude provides a useful and simple criterion to identify RCC or L-RCC origin in OT-VAs with lead V₃ transition.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Differentiation of the right versus left outflow tract ventricular arrhythmias using local activation time at the His bundle electrogram

Background

Although multiple algorithms based on surface electrocardiographic criteria have been introduced to localize idiopathic ventricular arrhythmia (VA) origins from the outflow tract (OT), their diagnostic accuracy and clinical usefulness remain limited. We evaluated whether local activation time of the His bundle region could differentiate left and right ventricular OT VA origins in the early stage of electrophysiology study.

Methods

We studied 30 patients who underwent catheter ablation for OT VAs with a left bundle branch block pattern and inferior axis QRS morphology. The interval between the local V signal on the mapping catheter placed in the RVOT and His bundle region (V(RVOT)-V(HB) interval) and the interval from QRS complex onset to the local V signal on the His bundle region (QRS-V(HB) interval) were measured during VAs.

Results

The V(RVOT)-V(HB) and QRS-V(HB) intervals were significantly shorter in patients with LVOT VAs. The area under the curve (AUC) for the V(RVOT)-V(HB) interval by receiver operating characteristic analysis was 0.865. A cutoff value of ≤ 50 ms predicted an LVOT origin of VA with sensitivity, specificity, and positive and negative predictive values of 100%, 62.5%, 40%, and 100%, respectively. The QRS-V(HB) interval showed similar diagnostic accuracy (AUC, 0.840), and a cutoff value of ≤ 15 ms predicted an LVOT origin of VA with a sensitivity, specificity, and positive and negative predictive values of 100%, 70.8%, 45.2%, and 100%, respectively.

Conclusion

The V(RVOT)-V(HB) and QRS-V(HB) intervals could differentiate left from right OT origins of VA with high sensitivity and negative predictive values.

Left ventricular summit arrhythmias with an abrupt V3 transition: Anatomy of the aortic interleaflet triangle vantage point

BACKGROUND

While early precordial electrocardiographic (ECG) characteristics are useful to differentiate left-sided from the right-sided outflow tract ventricular arrhythmia (OTVA), few patterns predict an origin from the septal margin of the left ventricular (LV) summit.

OBJECTIVE

The purpose of this study was to report mapping and ablation characteristics of a new ECG pattern with left bundle branch morphology and an abrupt R-wave transition in lead V₃ (ATV3).

METHODS

Over a 3-year period, 78 consecutive patients (mean age 57±15 years; 35% female) with OTVA were referred for mapping and ablation. Twenty patients (26%) exhibited an ATV3 pattern, of whom 65% failed prior ablation.

RESULTS

Ninety-two percent of patients with ATV3 that underwent simultaneous epicardial and endocardial mapping demonstrated an intramural or epicardial site of origin. Eighty percent of OTVA with ATV3 was eliminated by ablation from the vantage point of the interleaflet triangle below the right-left coronary junction. The ATV3 pattern showed higher sensitivity, specificity, predictive value, and accuracy than validated ECG criteria (notch or "w" pattern in lead V₁, qrS pattern in leads V₁ through V₃, and pattern break V₂) for predicting successful ablation in the region of the anterior LV ostium. At 12±11 months, freedom from ventricular arrhythmia recurrence was 89% and 82% in the ATV3 and control groups, respectively.

CONCLUSION

ATV3 is a simple and distinct ECG pattern indicative of a site of origin from the septal margin of the LV summit. The right-left aortic interleaflet triangle vantage point was effective to eliminate OTVA with ATV3 that overwhelmingly exhibited the earliest activation from the epicardium or mid-myocardium. Test characteristics for ATV3 were superior to ECG patterns validated for the anterior LV ostium.

Clinical and electrophysiological characteristics of ventricular arrhythmias arising from pulmonary cusps

Introduction

Ventricular arrhythmias (VAs) have been successfully ablated from the pulmonary sinus cusps establishing pulmonary artery (PA) as a distinct site of arrhythmic foci. The aim of the present study was to determine the clinical presentation, electrocardiographic, and ablation characteristics of PA‐VAs.

Methods

Thirty consecutive patients with right ventricular outflow tract (RVOT)‐type VAs were included in this retrospective study. Three‐dimensional electroanatomic mapping was performed in all patients. Mapping was performed initially in RVOT, and later within the PA. Mapping was performed in the PA if there was no early activation, unsatisfactory pace‐map, or ablation in RVOT were unsuccessful. All PA‐VAs were mapped and ablated by looping the catheter in a reverse U fashion.

Results

Among 30 patients, 8 (26.6%) patients VAs were successfully ablated within PA. Electrocardiography (ECG) revealed that the QRS duration was significantly wider in the PA‐VAs group compared to the RVOT‐VAs group (155 ± 14.14 vs 142.40 ± 8.12 ms, P < .01). Mapping by reversed U method of PA‐VAs revealed earlier activation (55 ± 9.66 vs 12.00 ± 8.61 ms, P < .01) in PA compared to RVOT. An isolated discrete prepotential was present at the successful site in 50% (n = 4).

Conclusion

Pulmonary artery‐VAs are an important subset of VA originating from the outflow tract. They have a wider baseline QRS duration compared to RVOT‐VAs. Presence of a prepotential aids in the identification of a successful ablation site. Mapping utilizing the reversed U method can help in localization and successful ablation of PA‐VAs.

Electrocardiographic features, mapping and ablation of idiopathic outflow tract ventricular arrhythmias

PURPOSE

Idiopathic outflow tract ventricular arrhythmias are ventricular tachycardias or premature ventricular contractions presumably not related to myocardial scar or disorders of ion channels. These arrhythmias have focal origin and display characteristic electrocardiographic features. The purpose of this article is to review the state of the art of diagnosis and treatment of idiopathic outflow tract ventricular arrhythmias.

METHODS

We systematically reviewed scientific literature about idiopathic outflow tract ventricular arrhythmias selecting the most relevant papers on this topic.

RESULTS

The right ventricle outflow tract is the most common site of origin for outflow tract ventricular arrhythmias, but also left ventricle outflow tract can harbour these arrhythmias. Outflow tract ventricular arrhythmias are generally benign and may require treatment if they are symptomatic, incessant or give rise to cardiomyopathy. Radiofrequency catheter ablation is an effective and safe therapeutic strategy. A successful procedure requires a thorough preoperative analysis of the 12-lead electrocardiogram of the spontaneous arrhythmia combined with a detailed electroanatomical mapping and intracardiac echocardiography.

CONCLUSIONS

Idiopathic outflow tract arrhythmias are frequent in daily clinical practice and can be successfully eliminated through discrete radiofrequency catheter ablation with low rates of complications.

V3R/V7 Index: A Novel Electrocardiographic Criterion for Differentiating Left From Right Ventricular Outflow Tract Arrhythmias Origins

BACKGROUND

Several algorithms have been proposed to predict the origin of outflow tract (OT) ventricular arrhythmias (VAs) using standard 12-lead ECG. However, the additive value of right precordial and posterior leads is unknown.

METHODS

Standard 12-lead ECG, right precordial leads ECG (V₃R, V₄R, V₅R) and posterior leads ECG (V₇, V₈, V₉) were recorded and analyzed in a development cohort of consecutive patients undergoing OT-VAs ablation at a single center. These findings informed the development of a novel algorithm incorporating right precordial and posterior leads to discriminate between left ventricular OT (LVOT) and right ventricular OT (RVOT) foci. The performance of this novel algorithm which includes the V₃R/V₇ index was prospectively tested in a validation cohort of consecutive patients undergoing OT-VA ablation at 4 centers and compared with published algorithms. The location of the foci was determined by the successful ablation site.

RESULTS

One hundred ninety-one patients were recruited, of which 94 formed the validation cohort (mean age of 45.7±15.6, 39% male, 79% RVOT foci). During OT-VAs, a QS pattern in lead V₃R and an S wave in lead V₇ were exclusively recorded in RVOT and LVOT foci, respectively. The V₃R/V₇ index of LVOT origin was significantly greater than that of RVOT (1.05±0.83 versus 0.28±0.23, P<0.001). The V₃R/V₇ index ≥0.85 predicted an LVOT origin with 87% sensitivity and 96% specificity. In the prospective evaluation, when the V₃R/V₇ index ≥0.85, an RVOT origin could be excluded with 98.6% accuracy. The area under the curve of V₃R/V₇ index (0.954) was larger than that of previously reported ECG criteria, including V₂S/V₃R (0.896), V₂ transition ratio (0.792), and transition zone index (0.666). This novel index was also accurate in both patients without obvious LVOT or RVOT origins and subgroups with cardiac rotation or lead V₃ R/S transition.

CONCLUSIONS

The V₃R/V₇ index is a novel and accurate ECG criterion that predicts OT-VAs origin.

The V1-V3 transition index as a novel electrocardiographic criterion for differentiating left from right ventricular outflow tract ventricular arrhythmias

PURPOSE

The aim of this study was to develop a new electrocardiographic criterion for differentiating the origin of outflow tract ventricular arrhythmias (OT-VAs) with precordial transition in lead V₃.

METHODS

A total of 147 consecutive patients with OT-VAs displaying precordial transition in lead V₃ who underwent successful catheter ablation in the right ventricular outflow tract (RVOT) (n = 118) or left ventricular outflow tract (LVOT) (n = 29) were included in this study. The V₁-V₃ transition index was defined as the sum of S-wave amplitude in lead V₁ and V₂ during premature ventricular contractions (PVCs) divided by the S-wave amplitude during sinus rhythm (SR), respectively, minus the sum of R-wave amplitude in lead V₁, V₂, and V₃ during PVCs divided by the R-wave amplitude during SR, respectively, i.e., [(S_PVC/S_SR)V₁ + (S_PVC/S_SR)V₂] - [(R_PVC/R_SR) V₁ + (R_PVC/R_SR)V₂ + (R_PVC/R_SR)V₃].

RESULTS

The V₁-V₃ transition index was significantly higher for RVOT origins than for LVOT origins (1.25 ± 2.48 vs. - 3.94 ± 3.11; P < 0.001). Receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.931 for the V₁-V₃ transition index, and a cutoff value of > - 1.60 predicted a RVOT origin with a 93% sensitivity and 86% specificity. With respect to AUC and accuracy, the V₁-V₃ transition index was superior to any previously proposed ECG indices for differentiating left from right OT-VAs. In 37 prospective cases, the new index was able to predict the site of a RVOT origin with 95% accuracy (35 of 37 cases).

CONCLUSIONS

The V₁-V₃ transition index is a useful novel ECG criterion for distinguishing left from right OT-VAs with precordial transition in lead V₃.

[Premature ventricular contractions and tachycardia in a structurally normal heart : Idiopathic PVC and VT]

Premature ventricular contractions (PVC) are a common, often incidental and mostly benign finding. Treatment is indicated in frequent and symptomatic PVC or in cases of worsening of left ventricular function. Idiopathic ventricular tachycardia (VT) is mostly found in patients with a structurally healthy heart. These PVC/VT usually have a focal origin. The most likely mechanism is delayed post-depolarization. Localization of the origin is based on the creation of an activation map with or without combination of pace mapping. Idiopathic PVC/VT are most frequently located on the outflow tracts of the right and left ventricles, including the aortic root. Other typical locations include the annulus of the tricuspid or mitral valve, papillary muscles and Purkinje fibers. Catheter ablation is an alternative to antiarrhythmic medication in symptomatic monomorphic PVC/VT. The success rate is good whereby mapping and ablation can often represent a challenge. This article is the fifth part of a series dedicated to specific advanced training in the field of special rhythmology and invasive electrophysiology. It describes the pathophysiological principles, types and typical findings that can be obtained during an electrophysiological investigation.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

High-density mapping for catheter ablation of premature ventricular complexes originating from left ventricular papillary muscles: A case series

PURPOSE

Ablation of premature ventricular complexes (PVCs) originating from left-sided papillary muscles is challenging. We tested a new approach by performing high-density mapping of PVC.

METHODS AND RESULTS

We used a 20-pole deflectable spiral catheter during ablation procedures in four consecutive patients. Three presented with mitral valve prolapse, one with dilated cardiomyopathy. PVC burden was 24 ± 13%. The procedures lasted 182 ± 55.4 minutes, including 10 ± 3.2 minutes of radiofrequency. In all patients, mapping evidenced internal primary activation relative to the left ventricle shell (mean distance 21.3 ± 5.1 mm). Endocavitary prematurity was -38.3 ± 4.8 ms. Primary ablation success was achieved for all patients.

CONCLUSIONS

High-density mapping of the papillary muscles in the left ventricle using a spiral catheter may be feasible. We identified the PVC foci away from the left ventricular shell. This consolidates the assumption for the origin of these ectopic beats at the junction between the chordae tendineae and the papillary muscles.

An electrocardiographic diagnostic model for differentiating left from right ventricular outflow tract tachycardia origin

INTRODUCTION

Although several electrocardiographic (ECG) algorithms have been proposed for differentiating the origins of outflow tract ventricular arrhythmias, the most optimal one has not been agreed on. The purpose of this study was to establish an ECG diagnostic model based on the previous ECG algorithms.

METHODS AND RESULTS

The following ECG diagnostic model, Y=-1.15×( TZ )-0.494×(V2S/V3R), was developed by standard 12-lead ECG algorithms in 488 patients with idiopathic premature ventricular contractions or ventricular tachycardia with a left bundle branch block pattern and inferior axis QRS morphology. Binary logistic regression analysis was performed to establish the ECG diagnostic model. The ECG diagnostic model consisted of two ECG algorithms-the transition zone (TZ) index and V2S/V3R index. The area under the curve by receiver operating characteristic curve analysis for the ECG diagnostic model was 0.88, with a cut-off value of ≥ -0.76 predicting a left ventricular outflow tract (LVOT) origin with a sensitivity of 82% and a specificity of 86%, which was higher than other ECG algorithms in this study. The predictive accuracy of the ECG diagnostic model was also the best among all ECG algorithms in patients with a lead V3 precordial transition. This model was tested prospectively in 207 patients with a sensitivity of 90%, a specificity of 87%, and Youden index of 0.77.

CONCLUSIONS

A highly accurate ECG diagnostic model for correctly differentiating LVOT origin from right ventricular outflow tract origin was developed.

Recurrence after successful catheter ablation for ventricular arrhythmia from the aortic root

OBJECTIVE

The mechanism underlying recurrence after successful ablation of ventricular arrhythmias (VAs) was unclear. Spectrum analysis can help to identify near-field activation. The purpose of this study was to quantify the changes of near-field activation in response to ablation at the VAs origin in the aortic root (AR-VAs) and to assess its relationship with late ablation outcome.

METHODS AND RESULTS

Patients who underwent acutely successful ablation for AR-VAs were analysed. Ventricular electrograms acquired before and after ablation at VAs origin were subjected to spectrum analysis. The area under the curve of the high frequency component (HFC, 50-200 Hz) and the low frequency component (LFC, 0-50 Hz) was measured. The proportion of HFC to the frequency spectrum of 0-200 Hz was defined as the HFC ratio (HFCR). The reduction of HFC and HFCR in response to ablation was defined as HFC pre-post and HFCR pre-post, respectively. Documentation of VAs with the same morphology after an acute successful procedure was defined as recurrence. Fifty-six patients were analysed, and VAs recurred in 17 patients. HFCR pre-post, HFC pre-post, and HFC pre-ablation were significantly higher in patients without recurrence. And HFCR pre-post has the highest predictive value (area under the receiver-operating characteristic curve: 0.975). A HFCR pre-post of 1.0% differentiated two groups (sensitivity = 84.6%, specificity = 100%). Higher HFCR pre-post was correlated with shorter VAs termination time (correlation coefficient = -0.399, p = .009).

CONCLUSIONS

HFCR pre-post can quantify the near-field activation change during ablation. Incomplete destruction to the VAs foci could underlie recurrence after successful ablation.

Conventional mapping and ablation of focal ventricular tachycardias in the healthy heart

Ventricular tachycardias (VT) in the healthy heart, also known as idiopathic VTs, often have a focal origin. Triggered activity due to delayed after-depolarization is the most likely mechanism of focal VTs. Localization of the site of origin of focal VTs is based on activation mapping with or without combination with pace mapping. The characteristic anatomic site of origin of idiopathic VTs is the right and left outflow tract. Other sites include the tricuspid and mitral annulus, the papillary muscles, and Purkinje fibers. Catheter ablation is indicated for monomorphic symptomatic VT and can be an alternative to antiarrhythmic drugs. Success rates are high, but mapping and ablation can be challenging. We review the main electrophysiological findings and the important clues for ablation of focal VTs. Specific considerations for each location are considered.

Value of a Posterior Electrocardiographic Lead for Localization of Ventricular Outflow Tract Arrhythmias: The V4/V8 Ratio

OBJECTIVES

This study sought to prospectively evaluate the value of a dedicated electrocardiographic posterior lead to create an anteroposterior ratio to localize premature ventricular complexes (PVCs) between the right ventricular outflow tract and left ventricular outflow tract for catheter ablation.

BACKGROUND

The anteroposterior relationship between the right and left outflow tract has not been explored for electrocardiographic localization of ventricular arrhythmia.

METHODS

Standard V₅ and V₆ leads were placed posteriorly and ablation was performed with activation mapping. The site of successful ablation was correlated with the ratio of the R-wave in V₄ to the R-wave in V₈. Normalization of the V₄/V₈ ratio to a V₄/V₈ index was achieved by dividing the V₄/V₈ ratio by sinus V₄/V₈. After determination of optimal cutoffs, comparison with V₂ transition ratio and V_2S/V_3R was subsequently performed using receiver operating characteristic curves in a prospective validation cohort.

RESULTS

A total of 134 patients underwent ablation of PVCs with 2 modified posterior leads. PVCs successfully ablated from the left side had a statistically significantly higher V₄/V₈ ratio compared with right-sided PVCs (11.7 ± 10.6 vs. 2.3 ± 2.4, p < 0.001). At a cutoff of >3, the V₄/V₈ ratio had a sensitivity of 88% with a specificity of 77% for left-sided locations. At a cutoff of >2.28, the V₄/V₈ index had a sensitivity of 67% with a specificity of 98%. In the prospective validation cohort (n = 40), the V₄/V₈ ratio exhibited the highest sensitivity of 75% with a negative predictive value of 89% compared with the V₄/V₈ index, V₂ transition ratio, and V_2S/V_3R. The V₄/V₈ index had the highest specificity of 96% with positive predictive value of 89% compared to the other predictive ratios. When analyzing cases with a V₃ transition, the V₄/V₈ index demonstrated 100% specificity and positive predictive value.

CONCLUSIONS

A simple modification of V₅ to V₈ posteriorly may provide incremental diagnostic value for localizing PVCs arising from the outflow tracts. Normalizing PVC localization criteria to the sinus rhythm results in the highest specificity when compared with other validated criteria.

Effects of Age-Related Aortic Root Anatomic Changes on Left Ventricular Outflow Tract Pace-Mapping Morphologies: A Cardiac Magnetic Resonance Imaging Validation Study

INTRODUCTION

Outflow tract ventricular arrhythmias (OT VAs) are common and catheter ablation is an effective treatment option. We sought to investigate the relationship between age-related anatomic aortic root changes and QRS morphology during left ventricular outflow tract (LVOT) pace-mapping using cardiac magnetic resonance (CMR) imaging.

METHODS AND RESULTS

Fifty-one patients undergoing CMR imaging were divided into 3 groups based on age (<40, 40-60, >60 years). We measured the angle of the aortic root, the aorta to ventricular septal angle, the distance between the right coronary cusp (RCC) and left coronary cusp (LCC), and the distance between the ascending and descending aorta. Additionally, we evaluated the QRS morphologies obtained during pace-mapping from the LVOT. In older patients, LCC was more superior to the RCC (P < 0.01). Age was positively correlated with the aortic root angle (r² = 0.481, P < 0.01) as well as the distances between the ascending and descending aorta at a level below the arch (r² = 0.569, P < 0.01). In older patients, LVOT pace-mapping (performed in 16 patients) demonstrated higher maximal R-wave amplitude, and was greater when pacing from the LCC versus the RCC in lead III (1.8 ± 0.7 vs. 1.0 ± 0.5 mV, P = 0.02).

CONCLUSION

The anatomy of the aortic root changes with age, and age-related aortic root changes may affect the QRS morphology during pace-mapping. Understanding the potential anatomic changes that accompany aging is important to maximize the efficacy of catheter ablation of OT VAs.

How To Identify & Treat Epicardial Origin Of Outflow Tract Tachycardias

The right ventricle outflow tract (RVOT) is the most common site of origin of idiopathic ventricular arrhythmias. The typical outflow tract arrhythmias pattern on ECG is an inferior axis deviation and left bundle branch block when originated on the RVOT and right bundle branch block morphology when originated on the left ventricular outflow tract (LVOT). There are several ECG tricks for different locations of origin. An increased Maximum Deflection Index (MDI) suggests epicardial origin of arrhythmia. In general the result of ablation is very good, but sometimes there are difficult and unsuccessful procedures. The origin in the aortic cusps and epicardium are the reason for failure in some cases. When they are epicardial, the arrhythmias can be accessed by the venous system or by subxiphoid epicardial mapping.

Differentiating the origin of outflow tract ventricular arrhythmia using a simple, novel approach

BACKGROUND

Numerous electrocardiographic (ECG) criteria have been proposed to identify localization of outflow tract ventricular arrhythmias (OT-VAs); however, in some cases, it is difficult to accurately localize the origin of OT-VA using the surface ECG.

OBJECTIVE

The purpose of this study was to assess a simple criterion for localization of OT-VAs during electrophysiology study.

METHODS

We measured the interval from the onset of the earliest QRS complex of premature ventricular contractions (PVCs) to the distal right ventricular apical signal (the QRS-RVA interval) in 66 patients (31 men aged 53.3 ± 14.0 years; right ventricular outflow tract [RVOT] origin in 37) referred for ablation of symptomatic outflow tract PVCs. We prospectively validated this criterion in 39 patients (22 men aged 52 ± 15 years; RVOT origin in 19).

RESULTS

Compared with patients with RVOT PVCs, the QRS-RVA interval was significantly longer in patients with left ventricular outflow tract (LVOT) PVCs (70 ± 14 vs 33.4±10 ms, P < .001). Receiver operating characteristic analysis showed that a QRS-RVA interval ≥49 ms had sensitivity, specificity, and positive and negative predictive values of 100%, 94.6%, 93.5%, and 100%, respectively, for prediction of an LVOT origin. The same analysis in the validation cohort showed sensitivity, specificity, and positive and negative predictive values of 94.7%, 95%, 95%, and 94.7%, respectively. When these data were combined, a QRS-RVA interval ≥49 ms had sensitivity, specificity, and positive and negative predictive values of 98%, 94.6%, 94.1%, and 98.1%, respectively, for prediction of an LVOT origin.

CONCLUSION

A QRS-RVA interval ≥49 ms suggests an LVOT origin. The QRS-RVA interval is a simple and accurate criterion for differentiating the origin of outflow tract arrhythmia during electrophysiology study; however, the accuracy of this criterion in identifying OT-VA from the right coronary cusp is limited.

Percutaneous Epicardial Ablation of Ventricular Arrhythmias Arising From the Left Ventricular Summit

Background—

Percutaneous epicardial ablation of ventricular arrhythmias arising from the left ventricular summit is limited by the presence of major coronary vessels and epicardial fat. We report the outcomes of percutaneous epicardial mapping and ablation of ventricular arrhythmias arising from the left ventricular summit and the ECG features associated with successful ablation.

Methods and Results—

Between January 2003 and December 2012, a total of 23 consecutive patients (49±14 years; 39% men) with ventricular arrhythmias arising from the left ventricular summit underwent percutaneous epicardial instrumentation for mapping and ablation because of unsuccessful ablation from the coronary venous system and multiple endocardial LV/right ventricular sites. Successful epicardial ablation was achieved in 5 (22%) patients. In the remaining 18 (78%) cases, ablation was aborted for either close proximity to major coronary arteries or poor energy delivery over epicardial fat. The Q-wave amplitude ratio in aVL/aVR was higher in the successful group, with a ratio of >1.85 present in 4 (80%) patients in the successful group versus 2 (11%) in the unsuccessful group ( P =0.008). The ratio of R/S wave in V1 was greater in the successful group, with 4 (80%) patients in the successful group having a R/S ratio of >2 in V1 versus 5 (28%) in the unsuccessful group ( P =0.056). None of the patients in the successful group had an initial q wave in lead V1, as opposed to 6 (33%) in the unsuccessful group. The presence of at least 2 of the 3 ECG criteria above predicted successful ablation with 100% sensitivity and 72% specificity.

Conclusions—

Epicardial instrumentation for mapping and ablation of ventricular arrhythmias arising from the left ventricular summit is successful only in a minority of patients because of close proximity to major coronary arteries and epicardial fat. A Q-wave ratio of >1.85 in aVL/aVR, a R/S ratio of >2 in V1, and absence of q waves in lead V1 help identify appropriate candidates for epicardial ablation.

Which Is The Appropriate Arrhythmia Burden To Offer RF Ablation For RVOT Tachycardias?

Premature ventricular complexes (PVCs) and ventricular tachycardia (VT) in patients with structurally normal hearts originate from the right ventricular outflow tract (RVOT) in the majority of cases. In the last few decades catheter ablation of these arrhythmias has been proven to be effective. RVOT VT/PVCs may cause disabling symptoms or arrhythmia induced cardiomyopathy. However, the PVC burden at which catheter ablation should be recommended is still controversial. What adds to the controversy is why some patients with only a low number of PVCs can be highly symptomatic and may even develop arrhythmia induced cardiomyopathy, whilst others may have a higher PVC/VT burden and remain asymptomatic and do not develop cardiomyopathy for a long period of time. Therefore, although catheter ablation of RVOT PVCs has high success and low complication rates, the time point of when ablation should be recommended is currently still under debate. This review discusses the treatment strategies and prognosis for RVOT tachycardias and focuses on the question of which arrhythmia burden is appropriate to offer RF ablation.

Idiopathic Ventricular Arrhythmia Originating From the Cardiac Crux or Inferior Septum

Background—

Idiopathic ventricular arrhythmia (VA) can arise from the epicardium near the posteroseptal region (cardiac crux). There are only 2 prior reports describing idiopathic VA from the cardiac crux. The purpose of this study was to characterize the clinical and the electrocardiographic features of idiopathic crux VA.

Methods and Results—

Crux VA was identified in 18 patients undergoing catheter ablation. We divided patients into 2 groups, those with VA originating from the apical crux (n=9) and the basal crux (n=9). We described the clinical and electrocardiographic characteristics of crux VA as well as the ablation results. Furthermore, we compared clinical features of crux VA with other sites of idiopathic VA. Fifteen crux VA patients (83%) had sustained ventricular tachycardia and 3 patients required implantable cardioverter defibrillator implantation because of syncope. All patients had a left superior axis and 16 patients had R>S wave in V2. In apical crux VA, all patients had a deep S wave in V6 and 8 patients (89%) had R>S wave in aVR. All apical crux patients underwent attempted ablation in the middle cardiac vein without success. In 4 of these patients, epicardial ablation with subxiphoid approach was performed successfully. All basal crux VA patients had either negative or isoelectric pattern in V1 and had R>S in V6. Patients had successful ablation within the middle cardiac vein.

Conclusions—

Apical versus basal crux VA is identified as a new category of idiopathic VA with distinctive electrocardiographic characteristics; ablation via the middle cardiac vein is effective for eliminating basal crux VA, whereas apical crux VA often requires a subxiphoid epicardial approach.

Coupling interval variability differentiates ventricular ectopic complexes arising in the aortic sinus of valsalva and great cardiac vein from other sources: mechanistic and arrhythmic risk implications

OBJECTIVES

The objective of this study was to determine whether premature ventricular contractions (PVCs) arising from the aortic sinuses of Valsalva (SOV) and great cardiac vein (GCV) have coupling interval (CI) characteristics that differentiate them from other ectopic foci.

BACKGROUND

PVCs occur at relatively fixed CI from the preceding normal QRS complex in most patients. However, we observed patients with PVCs originating in unusual areas (SOV and GCV) in whom the PVC CI was highly variable. We hypothesized that PVCs from these areas occur seemingly randomly because of the lack of electrotonic effects of the surrounding myocardium.

METHODS

Seventy-three consecutive patients referred for PVC ablation were assessed. Twelve consecutive PVC CIs were recorded. The ΔCI (maximum - minimum CI) was measured.

RESULTS

We studied 73 patients (age 50 ± 16 years, 47% male). The PVC origin was right ventricular (RV) in 29 (40%), left ventricular (LV) in 17 (23%), SOV in 21 (29%), and GCV in 6 (8%). There was a significant difference between the mean ΔCI of RV/LV PVCs compared with SOV/GCV PVCs (33 ± 15 ms vs. 116 ± 52 ms, p < 0.0001). A ΔCI of >60 ms demonstrated a sensitivity of 89%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 94%. Cardiac events were more common in the SOV/GCV group versus the RV/LV group (7 of 27 [26%] vs. 2 of 46 [4%], p < 0.02).

CONCLUSIONS

ΔCI is more pronounced in PVCs originating from the SOV or GCV. A ΔCI of 60 ms helps discriminate the origin of PVCs before diagnostic electrophysiological study and may be associated with increased frequency of cardiac events.

Estimation of the origin of ventricular outflow tract arrhythmia using synthesized right-sided chest leads

AIMS

For successful ablation of ventricular outflow tract arrhythmia, estimation of its origin prior to the procedure can be useful. Morphology and lead placement in the right thoracic area may be useful for this purpose. Electrocardiography using synthesized right-sided chest leads (Syn-V3R, Syn-V4R, and Syn-V5R) is performed using standard leads without any additional leads. This study evaluated the usefulness of synthesized right-sided chest leads in estimating the origin of ventricular outflow tract arrhythmia.

METHODS AND RESULTS

This retrospective study included 63 patients in whom successful ablation of ventricular outflow tract arrhythmia was performed. Numbers of arrhythmias originating from the left ventricle, the septum of the right ventricle, and the free wall of the right ventricle were 11, 40, and 13, respectively. In one patient, two different left ventricular outflow tract origins were found. Electrocardiographic recordings from right-sided chest leads were divided into three types as follows: those in which an R > S concordance, a transitional zone, or an R < S concordance were detected. In all left arrhythmia cases, R > S concordance was observed. A transitional zone was evident in 34 of 40 cases of right ventricular outflow tract arrhythmia originating in the ventricular septum, and an R < S concordance was observed in 6 of the 40 cases. However, an R < S concordance was found in all cases of right ventricular outflow tract arrhythmia originating in the free wall.

CONCLUSION

Synthesized right-sided chest lead electrocardiography may be useful for estimating the origin of ventricular outflow tract arrhythmia.