Idiopathic Left Ventricular Tachycardia Originating from the Mitral Annulus

Natural increase in the efficiency of ablation of ventricular tachyarrhythmias using high-density mapping in patients with non-ischemic etiology

OBJECTIVE

This research is aimed at evaluating the efficacy and safety of ablation of ventricular tachyarrhythmias using high-density mapping in patients with non-ischemic etiology.

MATERIAL AND METHODS

This study analyzed 60 patients with ventricular tachyarrhythmias, using diagnostic tools like electrocardiography and MRI. Treatment involved epicardial ablation following the E. Sosa method, with efficacy evaluated through the SF-36 survey and MRI. Success rates were categorized, and post-treatment care included troponin monitoring and aspirin. Data was analyzed using Excel and Statistika 11.0.

RESULTS

Of the 60 patients, 30 underwent surgery at the City Cardiological Center in Almaty and 30 patients were operated on at the National Research Cardiac Surgery Center in Astana. Prior to surgery, all patients underwent a standard clinical diagnostic examination followed by ablation of ventricular tachyarrhythmias using high-density mapping. After six and 12 months from the beginning of the study, all patients underwent a follow-up examination, with an assessment of the effectiveness of the above treatment. After 12 months, follow-up examination of patients showed good results. Left ventricular ejection fraction in patients after 12 months increased from 47 ± 2.4 to 58 ± 4.5%. The end-diastolic diameter of the left ventricle decreased from 61.2 ± 2.31 to 50.1 ± 1.9 mm.

CONCLUSION

In summary, the study highlights the efficacy and safety of high-density mapping ablation in treating ventricular tachyarrhythmias, especially from the right ventricular outflow tract in patients with reduced left ventricular ejection fraction. The success rate of the procedure was 95%. This approach proves beneficial for patients unresponsive to antiarrhythmic therapy, enhancing both the quality of life and potentially reducing mortality in patients with ventricular arrhythmias.

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 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.

[Prognostic significance of premature ventricular contractions : Harmless or life-threatening?]

Premature ventricular contractions (PVC) are very common arrhythmias in cardiology. In structural normal hearts they usually represent a benign entity. If the ECG morphology is not consistent with idiopathic PVC, further diagnostic workup should be performed. They can occur due to structural heart disease and may be associated with sudden cardiac death. Polymorphic PVC or a high PVC burden should also always lead to further diagnostics and an individual risk-stratification. Therapeutic options include drug therapy and invasive catheter ablation.

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.

A novel ablation strategy of premature ventricular contractions originating from summit guided by CartoUNIVU module

Background

Premature ventricular contractions (PVCs) from left ventricular (LV) summit remain challenging for the risk of coronary artery injury. Computed tomographic or intracardiac echocardiography may be helpful, but both still have many limitations. CartoUNIVU module has rarely been used in PVC ablation.

Methods

A total of 22 patients (14 men: mean age 56.4 ± 13.3 years) with an electrocardiogram indication of summit PVCs were included in the two centers study. A novel strategy ablation with the Image Integration Module CartoUNIVUTM module was performed for all the patients with PVCs originating from LV summit area, especially to prevent the coronary artery injury.

Results

The procedure time was 78.6 ± 22.7 minutes, and the fluoroscopy time was 12.5 ± 3.1 minutes. The distance between the target and nearest coronary artery was 8.0 ± 3.1 mm. Three patients with the distance to the nearest coronary artery <5 mm. During a mean follow‐up of 11.0 ± 1.7 months, 21/22 (95.5%) patients were free from clinical PVC. No coronary artery injury was detected in the all the ablation procedures.

Conclusion

The novel strategy ablation with the Image Integration Module CartoUNIVU module is safe and effective for PVCs originating from LV summit area, especially to prevent the coronary artery injury.

Evaluation and Management of Premature Ventricular Complexes

Premature ventricular complexes (PVCs) are extremely common, found in the majority of individuals undergoing long-term ambulatory monitoring. Increasing age, a taller height, a higher blood pressure, a history of heart disease, performance of less physical activity, and smoking each predict a greater PVC frequency. Although the fundamental causes of PVCs remain largely unknown, potential mechanisms for any given PVC include triggered activity, automaticity, and reentry. PVCs are commonly asymptomatic but can also result in palpitations, dyspnea, presyncope, and fatigue. The history, physical examination, and 12-lead ECG are each critical to the diagnosis and evaluation of a PVC. An echocardiogram is indicated in the presence of symptoms or particularly frequent PVCs, and cardiac magnetic resonance imaging is helpful when the evaluation suggests the presence of associated structural heart disease. Ambulatory monitoring is required to assess PVC frequency. The prognosis of those with PVCs is variable, with ongoing uncertainty regarding the most informative predictors of adverse outcomes. An increased PVC frequency may be a risk factor for heart failure and death, and the resolution of systolic dysfunction after successful catheter ablation of PVCs demonstrates that a causal relationship can be present. Patients with no or mild symptoms, a low PVC burden, and normal ventricular function may be best served with simple reassurance. Either medical treatment or catheter ablation are considered first-line therapies in most patients with PVCs associated with symptoms or a reduced left ventricular ejection fraction, and patient preference plays a role in determining which to try first. If medical treatment is selected, either β-blockers or nondihydropyridine calcium channel blockers are reasonable drugs in patients with normal ventricular systolic function. Other antiarrhythmic drugs should be considered if those initial drugs fail and ablation has been declined, has been unsuccessful, or has been deemed inappropriate. Catheter ablation is the most efficacious approach to eradicate PVCs but may confer increased upfront risks. Original research remains necessary to identify individuals at risk for PVC-induced cardiomyopathy and to identify preventative and therapeutic approaches targeting the root causes of PVCs to maximize effectiveness while minimizing risk.

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.

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.

Electrocardiographic landmarks of idiopathic ventricular arrhythmia origins

Idiopathic ventricular arrhythmias occur in the absence of underlying structural heart disease and less commonly in the presence of coexistent, but mechanistically unrelated, myocardial scar. These arrhythmias originate from several anatomical sites in both ventricles, with a predilection in outflow tract structures. The 12-lead surface ECG is the initial mapping tool, which is widely used to identify their origin. Specific features can predict the site of idiopathic ventricular arrhythmias, thus differentiating right from left ventricular, as well as endocardial from epicardial origins. In this review, we aim to analyse electrocardiographic landmarks for determination of idiopathic ventricular arrhythmia sources, with specific emphasis on pertinent caveats and anatomical relationships.

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.

Long-term mode and timing of premature ventricular complex recurrence following successful catheter ablation

PURPOSE

Catheter ablation of premature ventricular contractions (PVCs) is highly successful and has become the hallmark treatment for symptomatic or highly prevalent cases. However, few studies exist that evaluate the outcomes of ablation and likely mechanisms of PVC recurrence beyond 1 year of follow-up.

METHODS

This study is a retrospective analysis of patients who underwent catheter ablation for symptomatic PVCs with acute procedural success and had clinical follow-up ≥ 12 months.

RESULTS

Forty-four patients (24 women; age 53.5 ± 4.8 years) following acutely successful PVC ablation with long-term follow-up were studied. At a mean of 36 ± 6 months, overall long-term ablation success was 75% (33/44 patients). Notably, recurrence of the targeted PVC focus was low (6.8%, 3/44 patients); the majority of recurrences were from a new source location (18.2%, 8/44 patients). The time course for targeted versus de novo PVC recurrences was significantly different: recurrence of a PVC similar to the targeted PVC morphology occurred at a mean of 5.0 ± 2.0 months, while recurrence of a PVC different from the index case occurred at a mean of 35.8 ± 17.1 months (p = 0.01). Non-ischemic cardiomyopathy was associated with increased risk of PVC recurrence (odds ratio [OR] 14.50 (95% confidence interval [CI] 1.92-109.33, p = 0.01)) and was a significant negative prognostic factor in multivariate analysis for PVC recurrence survival (hazard ratio [HR] 4.63, 95% CI 1.03-20.74, p = 0.04).

CONCLUSIONS

The majority of long-term PVC recurrences occur late in follow-up, at locations remote from the targeted PVC source or sources. Such sites may represent ongoing substrate evolution; additional work is required to determine the precise substrate alterations which promote such arrhythmogenic changes.

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.

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.

The Surface Electrocardiograph in Ventricular Arrhythmias: Lessons in Localisation

The 12-lead electrocardiograph (ECG) is of critical importance both in the diagnosis of wide complex tachycardia and in the further classification, characterisation and management of ventricular arrhythmias. With its diligent application and interpretation, remarkable precision can be achieved in the localisation of the site of origin of ventricular arrhythmias and this may have major implications in the care of these patients. This review discusses the technical, anatomic and mechanistic basis of ECG interpretation in ventricular arrhythmias.

Localization of Ventricular Arrhythmias for Catheter Ablation: The Role of Surface Electrocardiogram

The surface ECG is a valuable mapping tool in patients with idiopathic and scar-related ventricular arrhythmias (VAs). A detailed analysis of 12-lead ECG can provide useful information in localizing the VA site of origin. This might help tailoring the ablation strategy to optimize procedural duration, increase the probability of success, and prevent complications. The aim of this article is to review the ECG features of both idiopathic and scar-related VAs and discuss their potential implications for optimizing the ablation strategy.

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.

Disappearance of Idiopathic Outflow Tract Premature Ventricular Contractions After Catheter Ablation of Overt Accessory Pathways

BACKGROUND

Multiple mechanisms have been proposed for idiopathic premature ventricular contractions (PVCs) originating from the outflow tracts (OTs). Recent observations such as the coexistence of these arrhythmias with atrioventricular nodal reentrant tachycardias and the association between discrete prepotentials and successful ablation sites of ventricular arrhythmias (VAs) from the OTs suggest a common link.

OBJECTIVE

In this case series we draw attention to a unique association between accessory pathways (APs) and idiopathic PVCs from the OTs, disappearing after AP ablation.

METHODS

We identified 6 cases in collaboration with several international electrophysiology centers, which presented with pre-excitation in association with OT, and in 1 case inflow tract (IT), PVCs on 12-lead surface ECG.

RESULTS

Six cases displayed pre-excitation and PVCs, in 5 cases originating from the right ventricular outflow tract (RVOT) and in 1 case from the right ventricular inflow tract (RVIT). In all patients, PVCs were monomorphic and had fixed coupling intervals, in 3 cases presenting in bigeminy. Catheter ablation of the AP led to the simultaneous disappearance of PVCs in 5 of 6 cases. The sites of ablation were remote from the OTs in all these cases. In most cases, the occurrence of OT PVCs was closely associated with the presence of pre-excitation.

CONCLUSION

The coexistence of pre-excitation and PVCs from the OTs and the fact that in 5 of 6 cases PVCs disappeared after AP ablation suggests a common mechanism for arrhythmia genesis.

Prevalence and Electrocardiographic and Electrophysiological Characteristics of Idiopathic Ventricular Arrhythmias Originating From Intramural Foci in the Left Ventricular Outflow Tract

Backgrounds—

Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) sometimes require catheter ablation from both the endocardial and epicardial sides for their elimination, suggesting the presence of intramural VA foci. This study investigated the prevalence and electrocardiographic and electrophysiological characteristics of these idiopathic intramural LVOT VAs when compared with the idiopathic endocardial and epicardial LVOT VAs.

Methods and Results—

We studied 82 consecutive VAs with origins in the aortomitral continuity (n=30), LV summit (n=34), and intramural site (n=18). The maximum deflection index (the time to the maximum deflection in the precordial leads/QRS duration) was the largest in LV summit VAs (0.52±0.07), smallest in aortomitral continuity VAs (0.45±0.06), and midrange in intramural VAs (0.49±0.05). The electrocardiographic and electrophysiological characteristics of the intramural LVOT VAs were similar to those of the aortomitral continuity VAs. The intramural LVOT VAs exhibited a significantly smaller R-wave amplitude ratio in leads III to II, and ratio of the Q-wave amplitude in leads aVL to aVR, and a significantly earlier and later local ventricular activation time relative to the QRS onset at the His bundle and successful ablation sites than the LV summit VAs, respectively.

Conclusions—

Intramural sites account for a significant proportion of LVOT VAs. The electrocardiographic and electrophysiological characteristics of the idiopathic intramural LVOT VAs were midrange between those of the idiopathic endocardial and epicardial LVOT VAs, and more similar to those of the idiopathic endocardial LVOT VAs than those of the idiopathic epicardial LVOT VAs.

The "Dead-End Tract" and Its Role in Arrhythmogenesis

Idiopathic outflow tract ventricular arrhythmias (VAs) represent a significant proportion of all VAs. The mechanism is thought to be catecholamine-mediated delayed after depolarizations and triggered activity, although other etiologies should be considered. In the adult cardiac conduction system it has been demonstrated that sometimes an embryonic branch, the so-called "dead-end tract", persists beyond the bifurcation of the right and left bundle branch (LBB). Several findings suggest an involvement of this tract in idiopathic VAs (IVAs). The aim of this review is to summarize our current knowledge and the possible clinical significance of this tract.

Spot diagnosis of inferior axis and concordant R-pattern predicts left ventricular inflow tract tachycardia: Ablation from the great cardiac vein of an underdiagnosed entity

BACKGROUND

The present literature holds an enormous variation concerning origin and ablation site of idiopathic ventricular arrhythmias (VA), ranging from 2.5 to 15% for the origin within the coronary venous system (CVS). The aim of the study was to detect positive predictive ECG morphology patterns to discriminate VA stemming from the CVS.

METHODS

110 consecutive patients (P) with 111 premature ventricular capture beat (PVC) morphologies undergoing successful ablation for VA were retrospectively analyzed concerning their ECG patterns.

RESULTS

20/110 P (18%) displayed their VA origin in the CVS with anterior/anterolateral left ventricular inflow tract (LVIT) (epicardial/GCV) in 16 P (14%), anterior/anterolateral LVIT (endo- and epicardial/GCV) in 3 P (3%), and anterior interventricular vein (AIV) 1 P (<1%). ECG morphology of all GCV cases demonstrated an inferior axis and concordant R-pattern in all precordial leads resulting in 100% sensitivity. One VA demonstrating this pattern was ablated outside at the LVOT resulting in 95% specificity for origin in the anterior/anterolateral LVIT. 3/20 P that were ablated in the CVS required additional endocardial ablation from the anterior/anterolateral LVIT resulting in 80% specificity for sole successful ablation in the CVS.

CONCLUSION

An inferior axis and concordant R-pattern in all precordial leads serve as diagnostic markers for an LVIT origin in the surface ECG and suggest a high primary ablation success via the GCV.

Ablation of idiopathic ventricular tachycardia originating from posterior mitral annulus by using electroanatomical mapping

Idiopathic ventricular tachycardia (IVT) is an important type of arrhythmia, which has distinct electrocardiographic features and treatment options. Most of the cases originate from right ventricular outflow tract and less frequently from the left ventricular outflow tract. IVTs originating from mitral annulus are rare, and little is known about the efficacy of radiofrequency catheter ablation in this form. We hereby present a rare case of IVT arising from posterior mitral annulus. The electrocardiographic, electrophysiological, and electroanatomical characteristics of this tachycardia are discussed.

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.

Catheter ablation of idiopathic premature ventricular contractions and ventricular tachycardias originating from the vicinity of endocardial and epicardial mitral annulus

Background

Several previous reports have revealed that idiopathic ventricular arrhythmias (VAs), including premature ventricular contractions (PVCs) and ventricular tachycardias (IVTs), can originate from endocardial mitral annulus (ENDO MA). However, these data are limited to ENDO MA VAs, and little is known about the electrocardiographic (ECG) characteristics and the efficacy of radiofrequency catheter ablation (RFCA) via the coronary venous system for the VAs arising from the epicardial MA (EPI MA).

Methodology/Principal Findings

Characteristics of body surface electrocardiogram and electrophysiologic recordings were analyzed in 21 patients with symptomatic PVCs/IVTs originating from the vicinity of MA. Among 597 patients with PVCs/IVTs, the incidence of VAs originating from the ENDO and EPI MA was 3.52% (21 cases). Eleven (52%) from the ENDO MA, and 10 (48%) from the EPI MA. There were different characteristics of ECG of PVCs/VT originating from the ENDO and EPI MA. The prolonged pseudodelta wave time and intrinsicoid deflection time in lead V2 and the precordial maximum deflection index reliably differentiated EPI MA VAs from ENDO MA VAs with high sensitivity and specificity. Successful RFCA in 18 patients could be achieved (85.7% acute procedural success).

Conclusions/Significance

ECG characteristics of PVCs/VTs originating from the different portions of the MA are different, and can help regionalize the origin of these arrhythmias. RFCA within the coronary venous system was relatively effective and safe for the PVCs/IVTs and should be seen as an alternative approach, when the MA PVCs/IVTs could not be eliminated by RFCA from the endocardium.

Radiofrequency catheter ablation for ventricular tachycardia

The management of ventricular tachycardia (VT) has evolved considerably in recent times. The majority of patients with VT have structural heart disease and often implantable defibrillators. Implantable defibrillators can terminate ventricular arrhythmias and prevent sudden death but do not prevent these arrhythmias from occurring. Ventricular tachycardia may also occur in patients without structural heart disease and although these patients generally have a benign prognosis, the symptoms can be significant. Radiofrequency catheter ablation has a definite role as an alternative to anti-arrhythmic therapy in both groups of patients. This review outlines the indications, techniques and outcomes of catheter ablation in the management of patients with ventricular tachycardia.

Ventricular arrhythmias originating from the aortomitral continuity: an uncommon variant of left ventricular outflow tract tachycardia

AIMS

Ventricular arrhythmias arising from the fibrous rings have been demonstrated, but knowledge about the aortomitral continuity (AMC) as a source of the arrhytmias is still limited. The objective is to describe the characteristics of ventricular arrhythmias originating from the AMC in patients without structural heart disease.

METHODS AND RESULTS

Ten patients with ventricular tachycardia (VT) and/or premature ventricular contractions, who had been successfully treated by catheter ablation at the AMC beneath the aortic valve, were enrolled. Clinical data and electrocardiographic characteristics were analysed. Three of the 10 patients had previously registered episodes of supraventricular tachycardia and had undergone catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT). In four patients with anterior AMC location, early R/S wave transition was found in the precordial leads, with equal R and S amplitudes in V2, rS in V1, and R in V3. In six patients whose VT arose from the middle part of the AMC, we demonstrated a special ('rebound') transition pattern, with which equal R and S amplitudes occurred in V2, and high R waves in V1 and V3. In the anterior AMC location, the S/R ratios in leads V1 and V2 were >1 and statistically significantly higher than those located in the middle (V1: 1.59 vs. 0.23, P< 0.001; V2: 1.52 vs. 0.41, P< 0.01).

CONCLUSIONS

We report a series of ventricular arrhythmias arising from the AMC with different R/S wave transition patterns in the precordial leads on the electrocardiogram. There may be a relationship between ventricular arrhythmias from AMC and AVNRT.