Ventricular arrhythmias from the mitral annulus: Patient characteristics, electrophysiological findings, ablation, and prognosis

Electrocardiographic Characteristics of Ventricular Arrhythmias Originating from Different Areas Adjacent to the Mitral Annulus

BACKGROUND

This study aimed to explore the electrocardiographic (ECG) characteristics of ventricular arrhythmias (VAs) arising from epicardial and endocardial areas adjacent to the mitral annulus (MA).

METHODS

This study involved 283 patients with MA-VAs who received radiofrequency catheter ablation at the center. The ECG characteristics of these patients were analyzed retrospectively.

RESULTS

The origin of MA-VAs was judged based on the ECG variables. Among all MA-VAs, intrinsicoid deflection time (IDT) > 77 ms or maximum deflection index (MDI) > 0.505 predicted the VAs arising from the epicardium (sensitivity of 70.20% and 73.51%, specificity of 94.70% and 82.58%, positive predictive value (PPV) of 93.81% and 82.84%, and negative predictive value (NPV) of 73.53% and 73.15%). Among all epicardial MA-VAs, the RV1/RV2 ratio > 0.87 predicted the VAs originating from the epicardial anteroseptal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 62.86%, 98.06%, 91.67%, and 88.60%, respectively. Among all endocardial MA-VAs, Q(q)R(r) morphology in lead V1 predicted the VAs arising from the endocardial septal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 92.98%, 100%, 100%, and 94.94%, respectively. Among all endocardial septal MA-VAs, a predominant positive wave in lead II and a predominant negative wave in lead III predicted the VAs arising from the endocardial midseptal portion adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 86.04%, 100%, 100%, and 70.00%, respectively.

CONCLUSION

the ECG characteristics of VAs from the different sites adjacent to the MA can enable judging the arrhythmia's origin and designing the ablation plan accordingly.

Electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias with acute successful ablation at the left ventricular basal inferoseptum recess near the mitral annulus

PURPOSE

We sought to clarify the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs), including idiopathic ventricular tachycardia (VT) and premature ventricular contractions (PVCs), with acute successful radiofrequency catheter ablation (RFCA) at the left ventricular basal inferoseptum recess near the mitral annulus (LV-BIS-MA).

METHODS

Twenty-five patients with acute successful RFCA at the LV-BIS-MA were included in this study.

RESULTS

The S-wave amplitudes on lead III during VAs were 1.54 ± 0.38 mV, significantly larger than those on lead II (0.55 ± 0.19 mV) and aVF (1.04 ± 0.31 mV) (P < 0.01). Precordial R/S > 1 transition before lead V₂ and S-waves in lead V₆ was recorded in 100% and 48.0% of patients, respectively. The earliest bipolar activation preceded the QRS onset by 32.3 ± 11.5 ms. Pace mapping demonstrated perfect QRS morphology matching in only 56.0% of patients. The RFCA start-to-effect time was 10.2 ± 5.8 seconds (s) in 21 patients (84.0%). In the remaining 4 patients (16.0%), the mean duration of successful RFCA was not well determined due to the infrequent presence of clinical VAs during ablation. The trans-septal approach was utilized in all 25 cases. Intra-cardiac echocardiography (ICE) showed that the ablation catheter tip was underneath the anterior leaflet of the mitral valve via the reversed C-curve technique. Early (within 3 days) and late (1 year) recurrence rates were 4.0% (one patient) and 12.0% (three patients), respectively. No complications during RFCA or at the 1-year follow-up.

CONCLUSIONS

LV-BIS-MA VAs are a subgroup of idiopathic VAs with distinctive ECG and EP features. RFCA via a trans-septal approach using a reversed C-curve technique is effective for better identification and targeting of the areas of VAs origin, and ICE showed that the ablation catheter tip was underneath the anterior leaflet of the mitral valve.

Premature ventricular contractions with acute successful radiofrequency catheter ablation near the atrioventricular node using reversed C curve technique

Background

We sought to clarify the electrophysiological (EP) characteristics of premature ventricular contractions (PVCs) with acute successful radiofrequency catheter ablation (RFCA) near the atrioventricular node (AVN).

Methods and results

Eighteen patients with acute successful RFCA near the AVN were included in this study. Systematic mapping was performed with two mapping methods: antegrade mapping technique (group A) and reversed C curve mapping technique (group R). RFCA was preferentially performed underneath the tricuspid valve (TV) with reversed C curve technique in all patients. The a amplitude/v amplitude ratio during sinus rhythm in group A was significantly larger than in group B (0.19 ± 0.10 vs 0.06 ± 0.02, p < 0.01). The earliest bipolar activation preceded the QRS onset in group A was significantly smaller than in group R (19.6 ± 4.9 vs 24.4 ± 6.6 ms (ms), p < 0.01). Pace mapping in group A and group R demonstrated perfect QRS morphology (12/12) match only in 5.6% (one patient) and 16.7% (3 patients) of patients, respectively. The mean duration of successful RFCA was 8.2 ± 2.4 s in 13 patients (72.2%). Early (within 3 days) and late (one-year) recurrence rates were 5.6% (one patient) and 16.7% (3 patients), respectively. No atrioventricular block occurred during RFCA or the one-year follow up.

Conclusions

PVCs near the AVN are a subgroup of idiopathic PVCs with distinctive EP features. RFCA using reversed C curve technique is effective and safe for the acute elimination of these challenging AVN-PVCs.

Electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias with acute successful ablation at the superior portion of the mitral annulus

BACKGROUND

We sought to identify the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs), including idiopathic ventricular tachycardia (VT) and premature ventricular contractions (PVCs), with acute successful radiofrequency catheter ablation (RFCA) at the superior portion of the mitral annulus (SP-MA).

METHODS AND RESULTS

Among 437 consecutive patients who presented with VAs for RFCA, twenty-six patients with acute successful RFCA at the SP-MA were included in this study. The ratio of the amplitude of the first positive peak (if present) versus the nadir in the unipolar electrogram (EGM) was 0.00-0.03 (0.00) at the acute successful RFCA site. The time interval between the QRS onset and the maximum descending slope (D-Max) in the unipolar EGM (QRS-Uni) was 18.8 ± 13.6 ms. With bipolar mapping, the ventricular QRS (V-QRS) interval was 3.75-17.3 (11) ms, 6 (23.1%) patients showed the earliest V-QRS interval of 0 ms, and the other 20 patients (76.9%) showed a V-QRS interval of 10-54 ms. The RFCA start-to-effect time was 14.1 ± 7.2 s in 23 patients (88.5%). In the remaining 3 patients (11.5%), the mean duration of successful RFCA was not well defined due to the infrequent nature of clinical VAs during RFCA. Early (within 3 days) and late (1-year) recurrence rates were 23.1% (6 patients) and 26.9% (7 patients), respectively. VAs disappeared 3 days later due to delayed RFCA efficacy in 2 patients (7.7%). No complications occurred during the RFCA procedure or the one-year follow-up.

CONCLUSIONS

SP-MA VAs are a rare but distinct subgroup of VAs. Bipolar and unipolar EGM features can help to determine the optimal RFCA site, and the QRS-Uni interval may serve as a marker that could be used to guide RFCA.

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.

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.

Electrocardiographic characteristics of idiopathic ventricular arrhythmias based on anatomy

Idiopathic ventricular arrhythmia (IVA) is a term used to describe a spectrum of ventricular arrhythmia without structural heart disease (SHD). IVAs contain premature ventricular contractions (PVCs), nonsustained monomorphic ventricular tachycardia (VT), and sustained VT. Electrocardiography is a fundamental and important tool to diagnose and localize IVAs. More detailed, IVAs originating from different origins exhibit characterized ECGs due to their specific anatomic backgrounds. As catheter ablation becomes widely used to eliminate these arrhythmias, its high success rate is based on accurate localization of their origins. Therefore, these ECG characteristics show great importance for precise localization of their origins and subsequently successful ablation. This review aims to sum up ECG characteristics of IVAs based on anatomy and give brief introduction of mechanisms and treatment of IVAs.

Idiopathic basal crux ventricular arrhythmias with left bundle branch block and superior axis: A comparison with inferior-septal valvular arrhythmias

INTRODUCTION

Left bundle branch block (LBBB) with superior axis is common in patients with idiopathic-ventricular arrhythmia (VA) originating from the tricuspid annulus (TA) and rarely from the cardiac basal crux and mitral annulus (MA). We described the electrocardiography and electrophysiological findings of idiopathic-VA presenting with LBBB and superior axis.

METHODS AND RESULTS

We described 42 idiopathic-VA patients who had an LBBB and superior axis; 15 basal crux-VA, 17 TA-VA, and 10 MA-VA. No patient had a structural heart disease. Among patients with idiopathic-VA referred for ablation, we investigated the electrocardiogram and clinical characteristics of basal crux-VA as compared with other LBBB and superior axis-VA. The left ventricular ejection fraction with MA-VA was significantly lower in comparison with basal crux-VA (P = .01). All patients had a positive R wave in lead I and aVL. The maximum deflection index with basal crux-VA was significantly higher in comparison with TA-VA or MA-VA (P = .01). Patients with basal crux-VA presented with QS wave in lead II more frequently as compared with TA-VA or MA-VA (P = .001). All MA-VA patients had Rs wave in V6, and basal crux-VA, and TA-VA patients had a monophasic R wave or Rs wave in V6. Basal crux-VA patients underwent ablation in the middle cardiac vein (MCV) or coronary sinus (success rate: 94%, recurrence rate: 6%).

CONCLUSIONS

We could distinguish basal crux-VA, TA-VA, and MA-VA, using a combination of clinical and electrocardiographic findings. These findings might be useful for counseling patients about an ablation strategy. Ablation via the MCV is effective for eliminating basal crux-VA.

[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.

Electrocardiographic and Electrophysiologic Characteristics of Idiopathic Ventricular Arrhythmias Originating From the Basal Inferoseptal Left Ventricle

OBJECTIVES

This study sought to characterize ventricular arrhythmia (VA) ablated from the basal inferoseptal left ventricular endocardium (BIS-LVe) and identify electrocardiographic characteristics to differentiate from inferobasal crux (IBC) VA.

BACKGROUND

The inferior basal septum is an uncommon source of idiopathic VAs, which can arise from its endocardial or epicardial (crux) aspect. Because the latter are often targeted from the coronary venous system or epicardium, distinguishing between the 2 is important for successful ablation.

METHODS

Consecutive patients undergoing ablation of idiopathic VA from the BIS-LVe or IBC from 2009 to 2018 were identified and clinical characteristics and electrocardiographs of VA were compared.

RESULTS

Of 931 patients undergoing idiopathic VA ablation, Virginia was eliminated from the BIS-LVe in 19 patients (2%) (17 male, age 63.7 ± 9.2 years, LV ejection fraction: 45.0 ± 9.3%). QRS complexes typically manifested right bundle branch block morphology with "reverse V₂ pattern break" and left superior axis (more negative in lead III than II). VA elimination was achieved after median of 2 lesions (interquartile range [IQR]: 1-6; range 1 to 20) (radiofrequency ablation time: 123 s [IQR: 75-311]). Compared with 7 patients with IBC VA (3 male, age 51.9 ± 20.1 years, LV ejection fraction: 51.4 ± 17.7%), BIS-LVe VA less frequently had initial negative forces (QS pattern) in leads II, III, and/or aVF (p < 0.001), R-S ratio <1 in lead V₁ (p = 0.005), and notching in lead II (p = 0.006) were narrower (QRS duration: 178.2 ± 22.4 vs. 221.1 ± 41.9 ms; p = 0.04) and more frequently had maximum deflection index of <0.55 (p < 0.001).

CONCLUSIONS

The BIS-LVe region is an uncommon source of idiopathic VA. Distinguishing these from IBC VA is important for procedural planning and ablation success.

Catheter Ablation of Idiopathic Ventricular Arrhythmias

Ventricular arrhythmias (VA) are observed in the setting of structural heart disease. However, in a proportion of patients presenting with VT, the routine diagnostic modalities fail to demonstrate overt myocardial abnormality. These arrhythmias have been called idiopathic VAs. They consist of various subtypes that have been defined by their anatomic location of origin within the heart and/or their underlying mechanism. While the majority of patients are asymptomatic, some experience debilitating symptoms and may develop reversible ventricular dysfunction. Catheter ablation has been traditionally reserved for patients with incapacitating symptoms or progressive ventricular dysfunction. However, as many patients are young, and catheter ablation can be curative in >90% of cases with a low risk (<1%) of serious complications, it is increasingly being offered as a first-line treatment in symptomatic patients. The approach to arrhythmia mapping is guided by the 12-lead electrocardiograph (ECG) morphology of the ventricular tachycardia (VT). Use of three dimensional (3D) electroanatomic mapping systems and intra-cardiac echocardiography are helpful in localising sites for successful ablation.

Ventricular Arrhythmias in the Patient with a Structurally Normal Heart

Ventricular arrhythmias (VAs) are among the most common cardiac rhythm disturbances encountered in clinical practice. Patients presenting with frequent ventricular ectopy or sustained ventricular tachycardia represent a challenging and worrisome clinical scenario for many practitioners because of concerning symptoms, frequent associated acute hemodynamic compromise, and the adverse prognostic implications inherent to these cases. While an underlying structural or functional cardiac abnormality, metabolic derangement, or medication toxicity is often readily apparent, many patients have no obvious underlying condition, despite a comprehensive diagnostic evaluation. Such patients are diagnosed as having an idiopathic VA, which is a label with specific implications regarding arrhythmia origin, prognosis, and potential for pharmacologic and invasive management. Further, a subset of patients with otherwise benign idiopathic ventricular ectopy can present with polymorphic ventricular tachycardia and ventricular fibrillation, adding a layer of complexity to a clinical syndrome previously felt to have a benign clinical course. Thus, this review seeks to highlight the most common types of idiopathic VAs with a focus on their prognostic implications, underlying electrophysiologic mechanisms, unique electrocardiographic signatures, and considerations for invasive electrophysiologic study and catheter ablation. We further address some of the data regarding idiopathic ventricular fibrillation with respect to the heterogeneous nature of this diagnosis.

Idiopathic ventricular arrhythmias arising from the posterior septum of tricuspid and mitral annuli: comparison of electrocardiographic characteristics and outcomes of catheter ablation

PURPOSE

Ventricular arrhythmia (VA) arising from the tricuspid annulus in the posterior septum (PS) (TAPS-VA) has similar electrocardiographic characteristics as VA arising from the mitral annulus in the PS (MAPS-VA) because the two locations are adjacent. We examined the electrocardiographic characteristics that differentiate MAPS-VA from TAPS-VA and the efficacy of catheter ablation.

METHODS

We studied 13 patients whose VAs were successfully ablated in the TAPS (n = 7) and MAPS (n = 6).

RESULTS

QRS morphologies of both groups were characterized by left and right bundle block morphologies in lead V1, superior axis deviation, and precordial transition at ≤ lead V3 in nine patients. Compared with TAPS-VA, MAPS-VA had (1) R < S wave in lead II, (2) precordial transition in lead V2, (3) s-wave in lead V6, and (4) slurred initial part of the QRS complex in the precordial leads, e.g., [4a] pseudo delta wave ≥ 34 ms, [4b] intrinsicoid deflection time ≥ 85 ms, and [4c] maximum deflection index ≥ 0.55. Patients who met ≥ 2 of (1)-(3) and any of [4a]-[4c] could be classified as having MAPS-VA, with a sensitivity and specificity of 100%. VA recurred in one patient in the TAPS group during the median follow-up of 7 (interquartile range 6 to 15.5) months.

CONCLUSIONS

VA arising from the PS has superior axis deviation, and left and right bundle block morphologies with relatively early precordial transition. MAPS-VA can be differentiated from TAPS-VA based on electrocardiographic characteristics. This study provides useful information for treatment involving catheter ablation for VA arising from the PS.

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.

Mapping and ablation procedures for the treatment of ventricular tachycardia

INTRODUCTION

Ventricular tachycardia (VT) may occur in the presence or absence of structural heart disease. Given that the management of VT hinges on the presence of symptoms and risk of sudden cardiac death (SCD), the main treatment goals are elimination of symptoms (including frequent implantable cardioverter defibrillator [ICD] therapies) and prevention of SCD. Unfortunately, medical management is suboptimal in a significant proportion of patients. As such, ablative therapy plays a prominent role in the treatment of ventricular tachycardia.

AREAS COVERED

In this review, we will discuss various VT disorders that are encountered in patients with and without structural heart disease. Further, we will highlight salient features regarding mapping and ablation of the various VT syndromes. Finally, we will discuss what lies on the horizon for VT ablation. Expert commentary: Meticulous mapping should aim to find the region that is most likely to be successful and least likely to result in a complication. Although recognition of the various mechanisms of VT, familiarity with different methods to mapping and ablation, and awareness of potential limitations of current approaches is critical, a thorough understanding of the fundamental principles and nuances of each facet within EP is required to ensure optimal outcomes for our patients.

Unifying mechanism of sustained idiopathic atrial and ventricular annular tachycardia

BACKGROUND

Based on the current understanding of cardiac conduction system development and the observation that arrhythmogenic foci can originate in areas near the atrioventricular annuli, we hypothesized that focal annular tachycardias, whether atrial or ventricular, share a common mechanism. We, therefore, prospectively evaluated this hypothesis in patients with sustained atrial and ventricular tachycardia originating from the peri-tricuspid and mitral annuli.

METHODS AND RESULTS

Forty-nine consecutive patients with sustained, focal annular tachycardia comprised the study group. All underwent electrophysiological evaluation and the mode of tachycardia initiation, termination, sensitivity to catecholamine infusion, and response to adenosine/verapamil were evaluated. Electroanatomical activation maps identified the sites of arrhythmia origin. Tachycardias could be initiated or terminated or both with programmed stimulation in 46 of 46 patients and most (70%) were catecholamine facilitated. Of the 9 patients with sustained annular ventricular tachycardia, 3 were localized to the tricuspid annulus, and 6 to the mitral annulus. All the 9 ventricular tachycardias (100%) terminated with adenosine, 2 of 2 terminated with verapamil, and 2 of 2 terminated with Valsalva. Of the 40 patients with annular atrial tachycardia, 4 tachycardias were localized to the mitral annulus and 37 to the tricuspid annulus (including 9 para-Hisian), and all were adenosine sensitive.

CONCLUSIONS

Peri-annular atrial and ventricular tissue correspond to a region enriched with arrhythmogenic foci, which may reflect a common developmental origin. Furthermore, the sensitivity of these tachycardias to adenosine provides evidence for a shared arrhythmia mechanism, consistent with intracellular calcium overload and triggered activity.