Radiofrequency catheter ablation as a cure for idiopathic tachycardia of both left and right ventricular origin

Prevalence and electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias originating from the septal left ventricular summit

INTRODUCTION

The left ventricular summit (LVS) is the highest point on the epicardial surface of the left ventricle. A part of the LVS that is located between the left coronary arteries (lateral-LVS) is one of the major sites of idiopathic ventricular arrhythmia (VA) origins. Some idiopathic epicardial VAs can be ablated at endocardial sites adjacent to the epicardial area septal to the lateral-LVS (septal-LVS). This study examined the prevalence and electrocardiographic and electrophysiological characteristics of septal-LVS VAs.

METHODS

We studied consecutive patients with idiopathic VAs originating from the LVS (67 patients) and aortic root (93 patients).

RESULTS

Based on the ablation results, among 67 LVS VAs, 54 were classified as lateral and 13 as septal-LVS VAs. As compared with the lateral-LVS VAs, the septal-LVS VAs were characterized by a greater prevalence of left bundle branch block with left inferior-axis QRS pattern, later precordial transition, lower R-wave amplitude ratio in leads III to II, lower Q-wave amplitude ratio in leads aVL to aVR, and later local ventricular activation time relative to the QRS onset during VAs (V-QRS) in the great cardiac vein. The electrocardiographic and electrophysiological characteristics of the septal-LVS VAs were similar to those of the aortic root VAs. However, the V-QRS at the successful ablation site was significantly later during the septal-LVS VAs than aortic root VAs (p < .0001). The precordial transition was significantly later during the septal-LVS VAs than aortic root VAs (p < .05).

CONCLUSIONS

Septal-LVS VAs are considered a distinct subgroup of idiopathic VAs originating from the left ventricular outflow tract.

Trends Favoring an Anatomical Approach to Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Summit

BACKGROUND

Epicardial radiofrequency catheter ablation (RFCA) of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) is challenging because of the anatomic barriers. On the other hand, RFCA at the endocardial sites near the earliest epicardial activation site of LVS-VAs (anatomic approach) has proven successful. The evolving trends in the approaches and outcomes of RFCA of LVS-VAs at a single center were evaluated.

METHODS

We studied 88 consecutive patients with idiopathic LVS-VAs at our institute from 2009 to 2019. These patients were divided into 3 periods: 2009 to 2012 (early), 2013 to 2015 (middle), and 2016 to 2019 (recent). The data were compared among the 3 periods.

RESULTS

The RFCA success rate did not significantly change from the early to middle period but significantly increased from the middle to recent period (P=0.0315). The transpericardial approach usage significantly decreased over the 3 periods. The anatomic approach usage significantly increased over the 3 periods. The use of the transpericardial approach did not affect the RFCA outcomes over the 3 periods. The success rate of the anatomic RFCA tended to increase from the early to middle period and significantly increased from the middle to recent period (P=0.0412). The number of endocardial locations where RFCA was successful increased over the 3 periods.

CONCLUSIONS

Over the 10-year period, the transpericardial approach became decreasingly performed, whereas the anatomic approach became increasingly performed with a satisfactory improvement in the RFCA outcomes of LVS-VAs. The anatomic RFCA became more successful by identifying more and various endocardial locations as target sites.

Twenty-five years of catheter ablation of ventricular tachycardia: a look back and a look forward

This article will discuss the past, present, and future of ventricular tachycardia ablation and the continuing contribution of the Europace journal as the platform for publication of milestone research papers in this field of ventricular tachycardia ablation.

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.

Idiopathic Ventricular Tachycardia

Idiopathic ventricular tachycardia (VT) is an important cause of morbidity and less commonly, mortality in patients with structurally normal hearts. Appropriate diagnosis and management are predicated on an understanding of the mechanism, relevant cardiac anatomy, and associated ECG signatures. Catheter ablation is a viable strategy to adequately treat and potentially provide a cure in patients that are intolerant to medications or when these are ineffective. In this review, we discuss special approaches and considerations for effective and safe ablation of VT arising from the right ventricular outflow tract, left ventricular outflow tract, left ventricular fascicles, papillary muscles, and moderator band.

Machine learning for distinguishing right from left premature ventricular contraction origin using surface electrocardiogram features

BACKGROUND

Precise localization of the site of origin of premature ventricular contractions (PVCs) before ablation can facilitate the planning and execution of the electrophysiological procedure.

OBJECTIVE

The purpose of this study was to develop a predictive model that can be used to differentiate PVCs between the left ventricular outflow tract and right ventricular outflow tract (RVOT) using surface electrocardiogram characteristics.

METHODS

A total of 851 patients undergoing radiofrequency ablation of premature ventricular beats from January 2015 to March 2022 were enrolled. Ninety-two patients were excluded. The other 759 patients were enrolled into the development (n = 605), external validation (n = 104), or prospective cohort (n = 50). The development cohort consisted of the training group (n = 423) and the internal validation group (n = 182). Machine learning algorithms were used to construct predictive models for the origin of PVCs using body surface electrocardiogram features.

RESULTS

In the development cohort, the Random Forest model showed a maximum receiver operating characteristic curve area of 0.96. In the external validation cohort, the Random Forest model surpasses 4 reported algorithms in predicting performance (accuracy 94.23%; sensitivity 97.10%; specificity 88.57%). In the prospective cohort, the Random Forest model showed good performance (accuracy 94.00%; sensitivity 85.71%; specificity 97.22%).

CONCLUSION

Random Forest algorithm has improved the accuracy of distinguishing the origin of PVCs, which surpasses 4 previous standards, and would be used to identify the origin of PVCs before the interventional procedure.

How to use pace mapping for ventricular tachycardia ablation in post-infarct patients

We aim to describe the technical aspects of pace mapping (PM), as well as the two typical patterns of pacing correlation maps during ventricular tachycardia (VT) ablation. The first main pattern is focal, with a gradual and eccentric decrease of the QRS correlation from the area with the best PM correlation. This focal pattern may be associated with two clinical situations: (1) with some endocardial points showing a good correlation compared to VT morphology: true endocardial exit of VT or endocardial breakthrough of either an intramural or an epicardial circuit; (2) without any endocardial points showing a good correlation compared to VT morphology: the VT may originate from the other ventricle, but the presence of an intramural or an epicardial circuit should be considered in patients with a structural heart disease. The second pattern is the presence of PM points exhibiting a good correlation close to other PM points showing a poor correlation compared to VT morphology: this abrupt change in paced QRS morphology over a short distance indicates divergence of activation wavefronts between these sites and suggests the presence of a slow conduction channel: the VT isthmus.

Development of a Visualization Deep Learning Model for Classifying Origins of Ventricular Arrhythmias

BACKGROUND

Several algorithms have been proposed for differentiating the right and left outflow tracts (RVOT/LVOT) arrhythmia origins from 12-lead electrocardiograms (ECGs); however, the procedure is complicated. A deep learning (DL) model, a form of artificial intelligence, can directly use ECGs and depict the importance of the leads and waveforms. This study aimed to create a visualized DL model that could classify arrhythmia origins more accurately.Methods and Results: This study enrolled 80 patients who underwent catheter ablation. A convolutional neural network-based model that could classify arrhythmia origins with 12-lead ECGs and visualize the leads that contributed to the diagnosis using a gradient-weighted class activation mapping method was developed. The average prediction results of the origins by the DL model were 89.4% (88.2-90.6) for accuracy and 95.2% (94.3-96.2) for recall, which were significantly better than when a conventional algorithm is used. The ratio of the contribution to the prediction differed between RVOT and LVOT origins. Although leads V1 to V3 and the limb leads had a focused balance in the LVOT group, the contribution ratio of leads aVR, aVL, and aVF was higher in the RVOT group.

CONCLUSIONS

This study diagnosed the arrhythmia origins more accurately than the conventional algorithm, and clarified which part of the 12-lead waveforms contributed to the diagnosis. The visualized DL model was convincing and may play a role in understanding the pathogenesis of arrhythmias.

Vitamin D Supplementation Replaced Catheter Ablation in a Patient with Frequent Premature Ventricular Contractions

A high premature ventricular contractions (PVC) burden can disturb the patient’s condition through fatigue during exercise or palpitations. Hence, researchers started to look for treatment options that decrease PVC burden without the side effects of antiarrhythmic drugs, and vitamin D could be a valuable solution and safe alternative to drugs or catheter ablation for high-burden PVCs. We present the case of a 24-year-old patient with high-burden PVC of >25,500/24 hours referred for urgent catheter ablation. Treatment with beta-blockers and calcium blockers did not reduce PVC burden. Under propafenone, there was a slight reduction in the number of PVCs to 21,200/24 hours, therefore the patient was referred for catheter ablation. As there was a vitamin D deficiency of 10.1 ng/mL, an attempt of vitamin D supplementation was done, with increase of vitamin D to 32.1 ng/mL and decrease of PVC burden to 9,600/24 hours. Further dietary supplementation increased 25-OH vitamin D to 50.2 ng/mL and decreased the PVC burden to 119/24 hours. Consequently, catheter ablation was canceled, and the patient remained free of antiarrhythmic drugs.

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

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.

Tp-e and (Tp-e)/QT ratio as a non-invasive risk factors for malignant ventricular arrhythmia in patients with idiopathic ventricular premature complexes

Background

To evaluate the role of Tp‐e and (Tp‐e)/QT ratio in differentiating benign ventricular premature complex (VPC) and malignant polymorphic ventricular tachycardia (PVT).

Methods

From January 2017 to December 2017, patients with documented polymorphic ventricular tachycardia (PVT) or ventricular fibrillation (VF) were consecutive included and classified as PVT/VF group. Sixty age‐ and sex‐matched healthy individuals were recruited as comparative control and subdivided into non‐VPC and VPC group. Clinical characteristics and Tp‐e and Tp‐e/QT ratio between the three groups were compared.

Results

Tp‐e and (Tp‐e)/QT ratio were significantly higher in patients of PVT/VF group compared with the other two groups (P < .001). Episodes of syncope were more frequent in patients with PVT/VF (P < .05). The sensitivity and specificity of a Tp‐e interval ≥86 ms for malignant arrhythmias triggered by VPCs were 88% and 66%, respectively, while the sensitivity and specificity of the Tp‐e/QT ratio ≥0.24 were 82% and 70%, respectively. Five patients complained recurrence of syncope in the PVT/VF group and 1 patient died with mean follow‐up of 18 months.

Conclusion

Tp‐e interval and the Tp‐Te/QT ratio is significantly increased in patients with PVT/VF and may be used as a novel non‐invasive marker of differentiating malignant and benign VPC.

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.

Catheter Ablation of Left Ventricular Summit Arrhythmia in a Patient with Critical Coronary Artery Stenosis: A Sequential Approach

The left ventricular (LV) summit is the usual source of epicardial idiopathic premature ventricular contractions (PVCs). A 56-year-old male patient presented to the cardiology outpatient clinic with palpitations and dyspnea. Twelve-lead electrocardiography performed on admission revealed monomorphic PVCs with precordial QRS transition in the V1 derivation and an rS pattern in the D1 derivation and inferior axis. An electrophysiology study and ablation procedure were planned. Activation mapping guided by a three-dimensional electroanatomic system was conducted to identify the earliest site of ventricular activation of the PVCs. During the PVCs, the earliest ventricular activation was observed within the great cardiac vein (GCV) and preceded the QRS onset by 37 ms. Coronary angiography was performed before ablation in the coronary venous system (CVS) to assess the distance from the coronary artery, which showed severe stenosis in the left circumflex artery. Then, percutaneous coronary intervention was performed to address the left circumflex artery stenosis. Anatomic catheter ablation was performed in the aortic cusp and endocardial LV outflow tract, the sites adjacent to the LV-summit PVC origin. However, successful ablation could not be achieved. Subsequently, an irrigated radiofrequency current was delivered in the GCV for 60 seconds, with the power being gradually increased to 30 W and with an irrigation flow rate of 30 mL/min. After ablation, under isoproterenol infusion and burst pacing from the right ventricle, no PVC or ventricular tachycardia was observed. Special precautions should be taken to avoid coronary artery damage during ablation from distal CVS. This approach may increase the success of ablation and avoid potential complications.

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

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.

Idiopathic right ventricular arrhythmias requiring additional ablation from the left-sided outflow tract: ECG characteristics and efficacy of an anatomical approach

INTRODUCTION

Despite the characteristic electrocardiogram (ECG) findings of early activation during ventricular tachyarrhythmias (VAs) and/or excellent pacemapping in the right ventricular outflow tract (RVOT), some VAs may require additional, left-sided ablation for a cure.

METHODS AND RESULTS

This study included five patients with idiopathic VAs whose QRS morphologies were highly suggestive of an RVOT origin. The ECG characteristics and intracardiac electrocardiograms during catheter ablation were assessed. In all patients, the clinical VAs had an LBBB QRS morphology and inferior axis with a precordial R/S transition through leads V3-V5, and negative components in lead I. The earliest activation during the VAs (local electrogram-QRS interval = -34 ± 6.8 ms) and excellent pacemapping were obtained at the posterior portion of the RVOT just beneath the pulmonary valve. However, ablation at those sites failed, and the QRS morphology of the VAs changed. During left-sided OT mapping, the earliest activation was found at sites just contralateral to the initially ablated sites of the RVOT (junction of the left and right coronary cusps = 2, left coronary cusp = 3). In spite of the late activation time and poor pacemapping scores, catheter ablation at those sites cured the VAs. Those successful sites were also near the transitional zone from the great cardiac vein to the anterior interventricular vein (GCV-AIV).

CONCLUSIONS

Some VAs, highly suggestive of having RVOT origins, require catheter ablation in the left-sided OT near the initially ablated RVOT site. Those VAs have the same ECG characteristics and might have intramural origins in the superobasal LV surrounded by the RVOT, LVOT, and GCV-AIV.

Twelve-lead electrocardiographic localization of idiopathic premature ventricular contraction origins

The major sites of origins of idiopathic ventricular arrhythmias have been elucidated. Idiopathic ventricular arrhythmias most often present as premature ventricular contractions (PVCs) with a focal mechanism, and commonly occur without structural heart disease. Idiopathic ventricular arrhythmias usually originate from specific anatomical structures, commonly endocardial but sometimes epicardial and exhibit characteristic electrocardiograms (ECGs) based on their anatomical background. There are general and specific ECG characteristics that can localize the site of idiopathic PVC origins. The general ECG characteristics include the bundle branch block pattern, axis, QRS polarity in lead V6, QRS duration, precordial transition, maximal deflection index, and so forth. They can roughly localize the site of idiopathic PVC origins. Several major sites of idiopathic PVC origins are located close to each other, and specific ECG characteristics are helpful for localizing the site of origins more accurately in those PVCs. Twelve-lead surface ECG algorithms usually can localize the site of idiopathic PVC origins with a high accuracy, but their accuracy can be limited by the patients' physique, heart rotation, specific conduction properties, presence of structural heart disease, and so forth. This review describes an overview of the approaches to the 12-lead surface ECG localization of idiopathic PVCs, and also discusses their caveats and limitations.

Comparative spatial resolution of 12-lead electrocardiography and an automated algorithm

BACKGROUND

The spatial resolution of pacemapping using 12-lead electrocardiography (ECG) or PaSo software is unknown.

OBJECTIVE

The purpose of this study was to determine the spatial resolution of traditional ECG pacemapping and pacemapping using the PaSo coefficients.

METHODS

Seventeen patients undergoing ablation of supraventricular tachycardias or atrioventricular node were included. After ablation, chamber (right ventricular outflow tract/rest of the right ventricle/left ventricle) geometry was created with Carto 3. Pacingwas performed from any point in these cardiac regions, the QRS morphology being the template and the point being considered as arrhythmia "origin." Subsequently, pacing was performed from points around the "origin" (1538 points). The QRS of these tagged points were compared by traditional ECG pacemapping and PaSo coefficients. The spatial resolution was calculated using correlations between the distance away from the origin (measured by 3 computational methods) and traditional ECG pacemapping and PaSo coefficients, independently.

RESULTS

A 0.01-unit decrease in the PaSo coefficient resulted in 1.1 mm increased Cartesian distance (95% confidence interval [CI] 0.9-1.3 mm; P < .001) and 2.4 mm increased geodesic distance (95% CI 1.9-2.9 mm; P < .001) and 664 mm³ increase in convex hull volume (95% CI 423-906 mm³; P < .0001). For traditional ECG pacemapping, each decrease in lead match resulted in 1.7 mm increased Cartesian distance (95% CI 1.5-2.0 mm; P < .001) and 3.4 mm increased geodesic distance (95% CI 2.8-4.1 mm; P < .001) and 712 mm³ increase in convex hull volume (95% CI 599-830 mm³; P < .0001). Both PaSo coefficients and traditional pacemapping showed a significant inverse linear correlation with distance from the "origin."

CONCLUSION

The resolution of mapping using the Paso software is better than that of traditional pacemapping.

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.

Ventricular Arrhythmias

Ventricular tachycardia is commonly seen in medical practice. It may be completely benign or portend high risk for sudden cardiac death. Therefore, it is important that clinicians be familiar with and able to promptly recognize and manage ventricular tachycardia when confronted with it clinically. In many cases, curative therapy for a given ventricular arrhythmia may be provided after a thorough understanding of the underlying substrate and mechanism. In this article, the authors broadly review the current classification of the different ventricular arrhythmias encountered in medical practice, provide brief background regarding the different mechanisms, and discuss practical diagnosis and management scenarios.

Ventricular Tachycardia in Structural Heart Disease

Patients with structural heart disease (SHD) are at risk of ventricular tachycardia (VT), which can be difficult to manage clinically. Many treatment options are currently available, but no single approach can be applied with 100% perfect results; often, a combination of therapies is required to achieve good control of ventricular arrhythmias. Coronary artery disease with previous myocardial infarction (MI) is the most common form of SHD presenting with VT, with scar-mediated reentry being the predominant mechanism. Other cardiomyopathies such as arrhythmogenic right ventricular cardiomyopathy, sarcoidosis, Chagas disease, and repaired congenital heart disease can also present in conjunction with ventricular arrhythmias. A thorough analysis of the patient’s history, 12-lead electrocardiogram, and imaging findings are essential for understanding the mechanism and guiding localization of the site of origin of the arrhythmia and the presence of underlying heart disease, which will improve outcomes following catheter ablation if such is indicated. Separately, antiarrhythmic drugs have not been shown to decrease mortality in this patient population but can help to reduce the VT burden and subsequently the need for implantable cardioverter-defibrillator therapy. Unfortunately, most antiarrhythmic agents are negative inotropes, with the possibility of worsening heart failure. This review aims to discuss the current options available for the management of VT in SHD.

Eccentric Activation Patterns in the Left Ventricular Outflow Tract during Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Summit

Background:

Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) can be ablated from the great cardiac vein and remote endocardial sites. The ablation sites are determined by mapping in the great cardiac vein and left ventricular outflow tract. This study investigated whether that mapping could accurately predict the sites of LVS-VA origins.

Methods:

We studied 26 consecutive patients with idiopathic LVS-VA origins that were identified in the basal and apical LVS in 15 and 11 patients, respectively.

Results:

Radiofrequency catheter ablation of the apical LVS-VAs was successful in the great cardiac vein in 9 patients and in the apical LV outflow tract in 2. That of the basal LVS-VAs was successful in the aortomitral continuity in 9 patients, at the junction of the left and right coronary cusps in 4, and in the left coronary cusp in 2. Three apical LVS-VAs exhibited an eccentric endocardial activation pattern that was from the basal to apical LV outflow tract. In 11 basal LVS-VAs, the activation pattern was eccentric because the ventricular activation within the great cardiac vein in the apical LVS was earlier than that in the basal LV outflow tract. In 2 basal LVS-VAs, the activation pattern was eccentric because a relatively early ventricular activation was recorded at multiple sites away from the successful ablation site.

Conclusions:

Eccentric activation patterns often occurred during idiopathic LVS-VAs, which could mislead the catheter ablation of those VAs. Understanding such eccentric activation patterns was suggested to be able to improve the outcomes of the catheter ablation of those VAs by the anatomic approach.

[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: Executive summary

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.

Catheter ablation of ventricular arrhythmias originating from the junction of the pulmonary sinus cusp via a nonreversed U curve approach

BACKGROUND

Ventricular arrhythmias (VAs) can originate from the pulmonary sinus cusp, and reversed U curve ablation has been highly efficient treatment.

OBJECTIVE

The purpose of this study was to clarify the characteristics of VAs originating from the pulmonary sinus junction (PSJ): left cusp-anterior cusp (LC-AC), right cusp-left cusp (RC-LC), and right cusp-anterior cusp (RC-AC).

METHODS

One hundred twenty-five consecutive patients with right ventricular outflow (RVOT)-type VAs were enrolled in the study and analyzed.

RESULTS

Seventeen RVOT-type VAs (13.6%) had an anatomic origin at the PSJ (9 at LC-AC, 6 at RC-LC, 4 at RC-AC). For PSJ-VA patients, the earliest activation site was identified at the PSJ 22.65 ± 2.47 mm above the pulmonary sinus base and preceded QRS onset by 35.7 ± 12.7 ms (P <.001). Fourteen of the 17 PSJ-VA patients underwent successful ablation via a nonreversed U curve after failed reversed U curve ablation. The bipolar proximal potential was earlier, equal to, or later than the distal potential when the reversed U curve catheter tip was positioned at the bottom, middle, or junction region of individual sinus. Electrocardiographic analysis revealed a lower amplitude of RC-AC than LC-AC and RC-LC VAs (P <.001).

CONCLUSION

The PSJ is a nonrare but distinct origin of RVOT-type VAs. The nonreversed U curve approach is a more feasible alternative for PSJ-VAs than the reversed U curve approach.

Usefulness of Reversed U-Curve Technique to EnhanceMapping and Ablation Efficiency in the Treatment ofPulmonary Sinus Cusp-Derived Ventricular Arrhythmias

Reversed U-curve and nonreversed U-curve (conventional technique) were both reported to be effective in treating pulmonary sinus cusp (PSC)-derived ventricular arrhythmia (VA). The aim of this study was to evaluate the characteristics between two methods. We enrolled 37 consecutive patients with PSC-derived VA who underwent radiofrequency catheter ablation using a contact force (CF)-sensing catheter. Reversed U-curve and conventional method were routinely used for each patient. For the 37 patients with PSC-VA (14 cases in left cusp [LC], 12 in right cusp, and 11 in anterior cusp), only 7 patients from the LC were ablated using conventional method whereas the others underwent successful reversed U-curve ablation. For the reversed U-curve mapping, presence of a near-field sharp potential and QS wave at the best mapping site were observed with a higher frequency; CF in 3 sinuses was always higher except for LC (p <0.001, p <0.001, and p = 0.18, respectively); the bipolar potential amplitude was significantly higher (1.52 ± 1.75 mV vs 1.02± 2.37 mV, p <0.001), and increased with CF (p <0.001). In conclusion, reversed U-curve technique allows for sufficient contact and better catheter stability, enhancing mapping and ablation efficiency in the treatment of PSC-derived VA, particularly for right and anterior sinuses.

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.

Ventricular arrhythmias originating from the cardiac crux and the basal inferior segment of the interventricular septum in the patients with structural heart diseases: characteristics, mapping, and electrophysiological properties

PURPOSE

There are few reports describing ventricular arrhythmias (VAs) from the crux and the corresponding endocardial site, i.e., the basal inferior segment of the interventricular septum (IVS). We aimed to investigate a distinct clinical group of VAs arising from the endocardium at this area in patients with structural heart diseases (SHD).

METHODS

We included 17 patients with SHD and clinically documented VAs. Thirteen patients underwent endocardial mapping only. Three patients underwent both epicardial and endocardial approaches and one had only epicardial mapping. Eighteen VAs were identified, 14 focal and 4 reentrant VAs, confirmed by entrainment.

RESULTS

There were 2 VAs from the crux, 5 VAs from the corresponding endocardial site in the right ventricle (RV), and 11 from the site in the left ventricle (LV). Compared with the VAs from RV endocardium, VAs from LV endocardium had a higher R wave in V3 than V2 (V2R/V3R ratio, 1.83 ± 0.84 vs. 0.86 ± 0.38, P = 0.008) and a higher V3 transition ratio percentage (2.16 ± 2.07 vs. 0.58 ± 0.62, P = 0.008). Combining all 16 patients with endocardial mapping, there were also lower bipolar voltages (1.21 ± 1.05 vs. 3.10 ± 2.65 mv, P < 0.0001), lower unipolar voltages (4.05 ± 1.92 vs. 5.75 ± 2.90 mv, P < 0.0001), and longer local electrocardiogram (EGM) lateness (157.6 ± 47.9 vs.140.3 ± 52.5 ms, P = 0.0001) in the dominant chambers.

CONCLUSIONS

In VAs from the crux and the corresponding endocardial site, the complete ECG V2R/V3R ratio and V3 transition ratio percentage could differentiate the VAs from the RV or LV endocardium. The lower unipolar, bipolar voltage mapping, and longer EGM lateness are helpful to identify the abnormal substrate in the endocardium in these patients.

Ablation Outcomes and Predictors of Mortality Following Catheter Ablation for Ventricular Tachycardia: Data From the German Multicenter Ablation Registry

Background

Ventricular tachycardia (VT) causes significant morbidity and mortality. Implantable cardioverter‐defibrillator shocks terminate VT but confer a significant morbidity and mortality risk. Therefore, VT ablation is increasingly common. Patients with structural heart disease (SHD) and patients with structurally normal hearts as well as the subgroup with and without ischemic heart disease were assessed for predictors of mortality and nonfatal VT recurrence. We present the first multicenter, prospective German VT registry.

Methods and Results

In 334 patients, 118 structurally normal hearts and 216 SHD (74.5% ischemic heart disease), referred for VT ablation in 38 centers, long‐term follow‐up was assessed for a minimum of 12 months and analyzed for factors predicting VT recurrence rates and mortality. The VTs in SHD patients were more frequently hemodynamically unstable (34.7% versus 12.7%, P<0.0001) or incessant (9.7% versus 2.7%, P<0.05). More SHD patients underwent substrate modification than patients with structurally normal hearts who had more focal ablations. Ablation failure was 9% in both groups. Two‐year mortality was higher in patients with SHD (18.7% versus 3.5%, P<0.001). Predictors of mortality include age >60 years, incessant VT, left ventricular ejection fraction ≤30%, procedural failure, and Class I and III anti‐arrhythmic drug use at discharge. Only procedural failure is a predictor of nonfatal VT recurrence.

Conclusions

Procedural failure was the sole independent predictor for nonfatal VT recurrence for our study cohort. This emphasizes the importance of a successful ablation procedure in experienced hands to reduce long‐term mortality and nonfatal VT recurrence.

Idiopathic Ventricular Arrhythmias Originating From the Parietal Band

Backgrounds—

The parietal band is one of the muscle bands in the right ventricle. This study investigated the electrocardiographic and electrophysiological characteristics and ablation outcome of idiopathic ventricular arrhythmias (VAs) originating from the parietal band.

Methods and Results—

We studied 14 patients with idiopathic VA origins in the parietal band among 294 consecutive patients with VA origins in the right ventricle. The QRS morphologies of the parietal band VAs were characterized by a left bundle branch block and left inferior (n=12) or superior (n=2) axis pattern with the presence of a notch in the middle of the QRS in all cases, precordial transition at ≤lead V3 in 7 patients, and a slow QRS onset in 4 patients. During parietal band VAs, a far-field ventricular electrogram with an early activation was always recorded in the His bundle region, regardless of the location of the VA origins. During the catheter ablation, a mean number of 10.4±7.4 radiofrequency applications with a duration of 1099±1034 seconds were delivered. Catheter ablation was successful in 10 patients, and VAs recurred in 4 during a mean follow-up period of 41±24 months. A change in the QRS morphology was observed spontaneously in 4 patients, immediately after the ablation in 4, and at the time of a VA recurrence in 2.

Conclusions—

Idiopathic VAs rarely originated from the parietal band. The catheter ablation of the parietal band VAs was always challenging, requiring a large amount of the radiofrequency energy delivery for a successful ablation with a relatively high recurrence rate.

Efficacy of an Anatomical Approach in Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Outflow Tract

Background—

When anatomic obstacles preclude radiofrequency catheter ablation of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT), an alternative approach from the anatomically opposite side (endocardial versus epicardial or above versus below the aortic valve) may be considered (anatomic ablation). The purpose of this study was to investigate the efficacy of an anatomic ablation in idiopathic LVOT VAs.

Methods and Results—

We studied 229 consecutive patients with idiopathic LVOT VAs. Radiofrequency ablation from the first suitable site was successful in 190 patients, and in the remaining 39 patients, it was unsuccessful or had to be abandoned because of anatomic obstacles. In 22 of these 39 patients, an anatomic ablation was successful, and the VA origins were located in the intramural LVOT in 17 patients, basal left ventricular summit in 4, and LVOT septum near the His bundle in 1. The anatomic ablation was highly successful for idiopathic VAs originating from the intramural LVOT (>75%) and lateral LVOT, whereas it was unlikely to be successful for idiopathic VAs originating from the basal left ventricular summit (25%) and sepal LVOT.

Conclusions—

When a standard catheter ablation targeting the best electrophysiological measure of idiopathic LVOT VAs was unsuccessful or had to be abandoned because of anatomic obstacles, an anatomic ablation was moderately successful. These idiopathic LVOT VAs with a successful anatomic ablation commonly arose from the intramural LVOT among the left coronary cusp, aortomitral continuity, and epicardium, occasionally the basal left ventricular summit, and rarely the LVOT septum near the His bundle.

Pace Mapping to Localize the Critical Isthmus of Ventricular Tachycardia

Most postinfarct ventricular tachycardias (VT) are sustained by a reentrant mechanism. The "protected isthmus" of the reentrant circuit is critical for the maintenance of VTs and the target for catheter ablation. In this article, the authors describe the technique of pace-mapping during sinus rhythm to unmask postinfarct VT isthmuses. A pace-mapping map should be considered as the surrogate of an activation map during VT, in both patients with a normal heart and patients with a structural heart disease. Pace mapping is useful to unmask VT isthmuses in patients with postinfarct reentrant VTs.