Ventricular arrhythmias from the coronary venous system: Prevalence, mapping, and ablation

Ventricular arrhythmias originating from different portions of the communicating vein of the left ventricular summit: electrocardiographic characteristics and catheter ablation

BACKGROUND

Idiopathic ventricular arrhythmias (IVAs) arising from different portions of the communicating vein of the left ventricular summit (summit-CV) are not a rare phenomenon. Whereas its electrocardiographic (ECG) and electrophysiological characteristics are not fully investigated.

OBJECTIVE

This study aimed to identify distinct ECG and electrophysiological features of IVAs originating from different portions of summit-CV.

METHODS

Nineteen patients confirmed arising from summit-CV were included in this study.

RESULTS

The 19 patients were divided into proximal and distal portion groups based on their target sites in summit-CV. In the proximal portion group, 100% (11/11) VAs showed dominant negative (rs or QS) waves in lead I, while in the distal portion group, 87.5% (7/8) showed dominant positive waves (R, Rs or r) (p < 0.000). In lead V1, 100% (11/11) of the proximal portion group showed dominant positive waves (R or Rs), while 62.50% (5/8) of the distal portion group showed positive and negative bidirectional or negative waves (RS or rS) (p < 0.005). RI>4mV, SI<3.5mV, RV1<13mV, SV1>3.5mV, RI/SI>0.83, and RV1/SV1< 2.6 indicated a distal portion of summit-CV with the predictive value of 0.909, 1.000, 0.653, 0.972, 0.903, 0.966, respectively. A more positive wave in lead I and a more negative wave in lead V1 indicated more distal origin in summit-CV. Target sites in proximal and distal summit-CV groups showed similar electrophysiological characteristics during mapping.

CONCLUSIONS

There were significant differences in ECG characteristics of VAs at different portions of summit-CV, which could aid pre-procedure planning and facilitate radiofrequency catheter ablation (RFCA) procedures.

Case of idiopathic left ventricular summit premature ventricular contractions successfully treated by catheter ablation

Key Clinical Message

CA of LVS premature beats complexes is difficult due to anatomical limitations. We report a patient with PVCs originating from the LVS region who was successfully ablated by ablation.

Abstract

Catheter ablation (CA) of premature ventricular contractions (PVCs) arising from the left ventricular summit (LVS) presents technical challenges due to the regional anatomy and frequently intramural site of origin. Herein, we demonstrated a case of a successful CA, originating from the LVS region. We further discussed the detailed anatomical background and clinical feasibility of CA as an alternative ablation route for PVCs originating from the LVS.

Mapping and ablation of ventricular arrhythmias arising from the left ventricular summit

The left ventricular summit (LVS) refers to the highest portion of the left ventricular outflow tract (LVOT). It is an epicardially delimited triangular area by the left coronary arteries and the coronary venous circulation. Its deep myocardium correlates closely with the left coronary cusp, aortic-mitral continuity, and right ventricular outflow tract (RVOT), complicating the anatomical relationship. Ventricular arrhythmias (VAs) originating from this area are common, accounting for 14.5% of all VAs origin from left ventricle. Specific electrocardiogram (ECG) characteristics may assist in locating LVS-VAs pre-procedure and facilitate procedure planning. However, catheter ablation of LVS-VAs remains challenging because of anatomical constraints. This paper reviews the recent understanding of LVS anatomy, concludes ECG characteristics, and summarizes current mapping and ablation methods for LVS-VAs.

Anatomically Based Ablation of Left Ventricular Summit Premature Ventricular Complexes Guided by Intracardiac Echocardiography

Catheter ablation of premature ventricular contractions (PVCs) arising from the left ventricular summit (LVS) presents technical challenges due to the regional anatomy and frequent intramural site of origin (SOO). Intracardiac echocardiography (ICE) and the CARTOSOUND® (Biosense Webster, Diamond Bar, CA, USA) module allow the operator to directly reconstruct and visualize the dimensions and orientation of the LVS live and present it in relation to neighboring structures. We retrospectively reviewed consecutive cases between January 2021 and December 2022 of patients undergoing PVC ablation for a presumed LVS origin. The LVS was reconstructed by creating a three-dimensional representation of the left ventricular septum, using two-dimensional ICE sections. The earliest site in each chamber was tagged on the reconstructed LVS, and the presumed SOO was localized using a geometrical center point from all sites. Ablation was first delivered to the earliest site, except when the presence of coronary branches precluded radiofrequency delivery within the great cardiac vein. Of 20 patients (8 women, 62.4 ± 7.1 years old) with a presumed LVS origin, 12 had PVC recurrence within the monitoring period after the initial ablation for 192.5 ± 37.2 s at the earliest site. Among them, earliest activation was seen at the sinus of Valsalva (SoV), coronary venous system (CVS), and left ventricular endocardium (LVE) in four, six, and two patients, respectively. Using the reconstructed LVS, the anatomically closest site to the SOO was identified in the SoV, CVS, and LVE in four, two, and six cases, respectively. Throughout the study period (14.5 months; range, 9.3-19.7 months), 17 patients (85%) had complete elimination of PVCs as evaluated by 24-h event monitors at the 12-month visit. In 50% of cases, among patients in whom ablation at the earliest signal was unsuccessful, the site of successful ablation did not correlate with the second earliest signal or had no identifiable signal during initial activation mapping. The reconstructed LVS not only guided activation mapping but also identified sites proximal to the center point that had either a late activation signal, a low-amplitude signal, or no signal at all.

Effects of parameters on radiofrequency guidewire ablation: In vitro and in vivo experiments

BACKGROUND

A novel ablation technique with guidewire has emerged as a promising approach for mapping and ablation of arrhythmias originating from left ventricular summit. However, its biophysical characteristics have not been fully clarified.

METHODS AND RESULTS

In the in vitro experiment, guidewire ablation (GA) was performed in vessel models of 1.17 and 2.24 mm to determine the maximum safety power. Then with the maximum safety power, the predictive value of generator impedance (GI) drop on lesion radius was explored. In the in vivo experiment, the feasibility of the maximum safety power and lesion formation was verified in the living swine. It was found that in both groups, the incidence of steam pops increased along with the raise of ablation power, and the maximum safety power was 10 W for the 1.17-mm group and 15 W for the 2.24-mm group. There was a strong linear correlation between GI drop and maximum lesion radius (in 1.17 mm-10-W group: r = .961; in 2.24 mm-15-W group: r = .918). In the in vivo experiment, besides ventricular fibrillation happened once, no other complications were observed, and lesions were found at both 48-h and 8-week groups.

CONCLUSIONS

The safety power of GA should be adjusted according to the diameter of the vessel. Besides, the GI drop can predict the lesion radius during GA.

Potential Application of Pulsed Field Ablation in Ventricular Arrhythmias

Pulsed field ablation (PFA) is a new ablative method for the therapy of arrhythmia. Recent preclinical and clinical studies have already demonstrated the feasibility and safety of PFA for the treatment of atrial fibrillation (AF). However, the application of PFA may not be limited to the above fields. There are some data on the application of PFA on ventricular arrhythmias (VAs), such as ventricular fibrillation (VF) and ventricular tachycardia (VT). Further, a case report about PFA has been published recently, in which PFA was successfully applied to the ablation of premature ventricular contractions (PVCs) from the right ventricular outflow tract. Thus, we aimed to review recent research findings of PFA in ventricular ablation and evaluate the possibility of its application in VAs.

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

The left ventricular summit (LVS) is the highest point of the left ventricular epicardium, and ventricular arrhythmias originating from this area accounts for 10% to 15% of idiopathic outflow tract ventricular arrhythmias. Direct epicardial ablation of outflow tract ventricular arrhythmias arising from the LVS is successful only in a minority of patients because of close proximity to the coronary artery or thick epicardial fat. Therefore, alternative strategies should be prioritized before performing epicardial approach. When performed, electrocardiogram characteristics suggestive of the site of origin to be the accessible area within the LVS needs be evaluated to avoid ineffective epicardial approach.

Initial experience of novel over the wire type decapolar catheter for ventricular arrhythmias originating from left ventricular summit

BACKGROUND

Previously, direct monitoring of local activation at the communicating vein (CV) has been reported to be useful for the ablation of ventricular arrhythmias (VAs) originating from the left ventricular (LV) summit. In this study, we evaluated the performance of the novel over-the-wire (OTW)-type decapolar catheter for VAs originating from the LV summit.

METHODS

Overall, 17 patients who underwent catheter ablation for idiopathic VAs originating from the LV summit were included in this study. Of these, seven patients underwent mapping of the epicardial LV outflow tract with the novel 2.7 Fr OTW-type decapolar catheter (EPstar FIX AIV), and ten underwent mapping with the standard 2.0 Fr octopolar catheter (EPstar FIX 2F) procedure (AIV group = EPstar FIX AIV and control group = EPstar FIX 2F).

RESULTS

No significant differences in the baseline characteristics were observed between the two groups. In the AIV group, all patients achieved successful catheter positioning in the target CV, whereas in the control group, two patients failed to achieve the same. The novel catheter not only advanced to the target vessels using a 0.014-in guidewire but it was also used for contrast injection from the catheter lumen, which enabled accurate and safe positioning. As a result, the earliest activation time preceding QRS onset during the VA, recorded at the CV, was significantly earlier when compared with the control group (44.66 ± 11.23 ms vs. 32.16 ± 4.26 ms, P = 0.007).

CONCLUSIONS

Compared with the conventional electrode catheter, this novel multipolar electrode catheter is more effective for mapping local activation at the CV.

Endocardial ablation at the mitral valve vestibule and its surroundings for the treatment of arrhythmias linked to the greater cardiac vasculature

BACKGROUND

The role of the epicardial vasculature in supraventricular and ventricular arrhythmias was described in clinical studies as well as its treatment by intravascular point ablation or alcohol injection. We report on a case series of patients with different arrhythmias linked to an epicardial site of origin with evidence supporting transmural extensions that were targeted for ablation with successful outcomes.

METHODS

The records of patients who has catheter ablation for Supraventricular or Ventricular arrhythmias between 2015-2020 was searched for patients with (1) arrhythmias linked to the epicardial vasculature and (2) findings to support an endocardial connection to the epicardial vasculature by activation mapping, pace mapping, or differential pacing, and (3) were successfully ablated via an endocardial approach only.

RESULTS

From the data searched, we identified 5 patients with the following arrhythmias left ventricular summit ectopy, peri-mitral atrial flutter, preexcitation with inducible atrioventricular reentry tachycardia (AVRT) and a concealed left side accessory pathway with inducible AVRT that were linked to the following vessels: Great Cardiac vein, persistent left superior vena cava, left coronary cusp and left ventricular outflow tract. Endocardial connections were supported by a combination of electro anatomical activation mapping, pace-mapping, and differential pacing. Endocardial ablations performed in all patients were successful without complications CONCLUSION: : This report highlights a subset of patients with arrhythmias linked to the greater cardiac vascular system that can be safely and effectively ablated endocardially, given the limitations and possible complications of epicardial ablation within or in the proximity of the epicardial vasculature. This article is protected by copyright. All rights reserved.

Usefulness of the over-the-wire microelectrodes catheter in treatment of ventricular arrhythmia arising from the left ventricular summit

BACKGROUND

This study was aimed to investigate efficacy of the over-the-wire (OTW) microelectrodes catheter in coronary venous system (CVS) mapping and treatment of outflow tract ventricular arrhythmia (OTVA) arising from the vicinity of the left ventricular summit (LVS).

METHODS

Consecutive 62 patients with idiopathic OTVA in whom the OTW microelectrodes catheter was routinely used for CVS mapping were analyzed. CVS mapping was performed for both main trunk (from great cardiac vein to anterior interventricular vein) and branches including annular branch or septal branch.

RESULTS

The earliest activation site (EAS) was within the CVS in 21 patients. Among them, the EAS was within the main trunk of the CVS in 7 (33%) and within the branch of the CVS in 14 (67%) patients. Radiofrequency catheter ablation was started at an anatomically adjacent site to the EAS, which eliminated OTVA in 16 (76%) patients　(the endocardial LVOT in 10 and the aortic sinus of Valsalva in 6 patients). For the remaining 5 patients with unsuccessful catheter ablation at an anatomically adjacent site, targeted OTVA was eliminated by catheter ablation at the EAS within the CVS in 2 patients and by chemical ablation with ethanol injection in 1 patient, resulting in overall success rate of 90% (19/21).

CONCLUSION

The OTW microelectrodes-guided ablation of OTVA from the vicinity of the LVS was effective. In maximizing the efficacy of ablation, CVS branch mapping is important since the earliest activation was commonly recorded not in the main trunk but within the branch of the CVS. This article is protected by copyright. All rights reserved.

Unipolar and bipolar electrogram characteristics of recurrent cases of idiopathic ventricular arrhythmias undergoing repeat catheter ablation

Introduction

Activation mapping guided catheter ablation (CA) of ventricular arrhythmias (VAs) is limited in some cases when it is only relied on bipolar electrogram (EGM). We hypothesized that activation mapping with use of combined bipolar and unipolar EGM facilitates to identify the focal origin of VAs and results in reduction of recurrence rate of CA of VAs.

Methods

We analyzed the data of patients undergoing repeat ablations for idiopathic out-flow tract VAs. The EGM of the 1 st and 2 nd ablations were compared for earliest local activation time (LAT), presence of discrete potentials, and polarity reversal, unipolar potential morphology (QS or non-QS), potential amplitude and activation slope.

Results

Thirty-seven patients were included. The Local activation time was significantly earlier in the 2nd ablation as compared to the 1st procedure (36.90 msec vs 31.85 msec, P < 0.01). The incidence of discrete potentials and polarity reversal were similar in both procedures (51% vs 57%, P = 0.8 and 62% in both the occasions, respectively). The unipolar voltage was similar in both occasions (6.94 mV vs 7.22 mV in repeat ablations, P = 0.7). The recurrence rate (5.7%) was significantly lower with routine use of combined unipolar and bipolar EGMs, as compared to the use of bipolar EGM alone (16.7%)

Conclusions

Use of both bipolar and unipolar electrograms helps in better delineation of the sites of earliest activation for effective ablation of VAs. Use of unipolar electrograms in addition to bipolar electrograms is associated with lower long term recurrence rate.

•

In patients undergoing redo ablations for idiopathic OTVAs, a slow-rapid initial QS morphology with its earlier timing prior to onset of QRS on unipolar EGM facilitate identification of early activation sites and improves success of CA.

•

Bipolar EGM chracteristics like polarity reversal and presence of discrete potentials have no additive efficacy in redo CA cases.

•

A slow-rapid initial QS morphology with its earlier timing to QRS onset may improve the success of CA in idiopathic OTVAs.

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.

High-power, short-duration ablation in the coronary sinus: clinical cases and preliminary observations on swine hearts

Purpose

Coronary sinus-related arrhythmias are common; however, it is difficult to perform radiofrequency (RF) ablation at these sites efficiently and safely. High-power, short-duration ablation (HPSD) is a proven alternative strategy for pulmonary vein isolation (PVI); whether it can be applied to ablation of the coronary sinus is unknown. The purpose of this preliminary study was to evaluate the feasibility and safety of HPSD ablation in the coronary sinus.

Methods

Firstly, we demonstrated 4 clinical cases of 3 types of arrhythmias who had unsuccessful ablation with standard power initially, but received successful ablations with HPSD. Secondly, RF ablation was performed in the coronary sinus ostium (CSO) and middle cardiac vein (MCV) of 4 in vitro swine hearts. Two protocols were compared: HPSD (45 W/5 S×5 rounds) and a conventional strategy that used low-power, long-duration ablation (LPLD: 25 W/10 S ×5 rounds). The total duration of HPSD protocol was 25 s, and which of LPLD was 50 s.

Results

A total of 28 lesions were created. HPSD can produce longer, wider, deeper, and larger lesions than LPLD. This difference was more pronounced when the ablation was in the MCV. One instance of steam pop occurred during LPLD in the MCV.

Conclusions

HPSD is an effective alternative strategy for ablation in coronary sinus according to clinical applications and preliminary animal study. However, the safety needs to be further evaluated based on more animal and clinical studies.

Coronary Venous Mapping and Catheter Ablation for Ventricular Arrhythmias

Catheter ablation is an effective treatment method for ventricular arrhythmias (VAs). These arrhythmias can often be mapped and targeted with ablation from the left and right ventricular endocardium. However, in some situations the VA site of origin or substrate may be intramural or epicardial in nature. In these cases, the coronary venous system (CVS) provides an effective vantage point for mapping and ablation. This review highlights situations in which CVS mapping may be helpful and discusses techniques for CVS mapping and ablation.

Surface unipolar electrogram characteristics to predict site of origin of outflow tract arrhythmias using noninvasive mapping

BACKGROUND

Noninvasive electroanatomic mapping (NIEAM) demonstrate patterns of depolarization that are useful in identifying the chamber of origin (COO) in outflow tract ventricular arrhythmias (OTVA). However, its use in predicting exact site of origin (SOO) has not yet been validated.

METHODS

NIEAMs (CardioInsight, Medtronic) from 40 patients (age 62.5 ± 2.6) undergoing ablation for OTVA were reviewed for diagnostic accuracy in predicting the SOO. Earliest arrhythmia breakout and directionality of earliest instantaneous unipolar electrograms (uEGMs) on NIEAMs were evaluated subjectively by two observers for quality and amplitude. Sites with most negative earliest uEGMs on right and left ventricular outflow tracts, as well as epicardial surface were manually identified. Using NIEAM-based activation timing of the lateral mitral annulus and basal septum COO was identified for each OTVA. Predictions of SOO using NIEAMs was compared with true SOO from invasive study. NIEAMs SOO predictions were compared with subjective 12 lead electrocardiogram (ECG) review by two observers.

RESULTS

Review of arrhythmia breakout and signal directionality had poor diagnostic value in predicting SOO in OTVA (50.6% and 49.4%, 56.6% and 43.4%, respectively) and underperformed compared with ECG interpretation (59.1% and 80.5%). After excluding uEGMs with poor characteristics, the uEGM with most negative amplitude at the COO was predictive of the true SOO with 96.4% sensitivity and specificity.

CONCLUSION

We propose a stepwise approach when interpreting NIEAMs for OTVA where patterns of activation are evaluated first to determine the COO, followed by identification of the site with most negative amplitude instantaneous uEGM to determine SOO.

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.

Epicardial Ablation via Arterial and Venous Systems

The intracoronary artery and venous routes provide unique roadmaps for mapping and interventions for ventricular arrhythmias and certain atrial arrhythmias. The unique anatomic location of these vessels on the epicardial surface enables mapping/interventions without the need to access the pericardial space. These anatomic routes also track deep into certain intramural regions, with interventions that are not accessible from either epicardial or endocardial routes. To map smaller vessels, multipolar catheters and wires are used to record local electrograms. Endocardial/epicardial ablation at adjacent sites is sometimes required to enhance successful outcomes. This article describes tools, techniques, and site-specific mapping and interventions.

Epicardial Ablation of Idiopathic Ventricular Tachycardia

Ventricular arrhythmias (VAs) occurring in the absence of structural heart disease or ion channelopathies are referred to as idiopathic. They can clinically present with frequent monomorphic premature ventricular contractions, nonsustained ventricular tachycardia (VT), or sustained VT, and generally share a benign prognosis. Approximately 4% to 10% of idiopathic VAs have an epicardial site of origin, represented in most cases by the left ventricular summit and, less frequently, by the cardiac crux. Epicardial foci can be addressed by catheter ablation via the coronary venous system tributaries. In rarer instances, a direct epicardial access from a subxiphoid approach is needed.

Electrocardiographic localization of ventricular arrhythmias successfully ablated from the distal great cardiac vein

BACKGROUND

Idiopathic ventricular arrhythmias (IVAs) from the left ventricular (LV) summit may be successfully ablated from the distal great cardiac vein (dGCV). Using a 12-lead electrocardiogram (ECG) to localize IVAs that can be ablated from the dGCV is valuable for ablation planning.

OBJECTIVE

To determine if a "w" wave, a notch in the Q wave in lead I, and other ECG features can identify IVAs that can be successfully ablated from the dGCV.

METHODS

We reviewed outflow tract premature ventricular contraction (PVC) ablations performed at two centers between September 2010 and June 2018. Successful PVC ablations, in which the PVCs were mapped from the right ventricular outflow tract, coronary cusps, commissures, endocardial LV, and the coronary venous system including the dGCV were included. ECG characteristics were compared between patients with successful ablations in the dGCV and non-dGCV sites.

RESULTS

Of the 120 patients (age 56.8 ± 13.8 years, 45% female) that met the inclusion criteria, the dGCV was the successful ablation site in 18 patients (15%). Multivariate analysis with binary logistic regression showed that a "w" in lead I in combination with an early precordial pattern break and a maximum deflection index (MDI) ≥ 0.5 had sensitivity and specificity for a successful ablation in the dGCV of 94.4% and 96.1%, respectively.

CONCLUSION

Combining a "w" wave in lead I with an early precordial pattern break and an MDI ≥ 0.5 is highly sensitive and specific for identifying the dGCV as a successful ablation site for PVCs.

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.

Unique features of epicardial ventricular arrhythmias/premature ventricular complexes ablated from coronary venous system in veteran population

Introduction

Ventricular arrhythmias/premature ventricular complexes (VA/PVCs) that can be ablated from within the coronary venous system (CVS) have not been described in the United States Veterans Health Administration (VHA) population. We retrospectively studied the VA/PVCs ablations that were performed in the VHA population.

Methods

Data from 42 consecutive patients who underwent VA/PVCs ablation at Veterans Affairs Hospital, Indianapolis, IN, with 44 VA/PVCs was included in the study. Patients were divided into two groups (CVS group [n = 10], and non-CVS group [n = 32]) based on where the earliest pre-systolic activation was seen with >95% pacematch.

Results

The mean age in CVS group was 65 ± 8 years versus 64 ± 12 years (p = 0.69) in non-CVS group. Overall there was a statistically significant reduction in PVC burden post ablation (27.7% (pre-ablation) versus 4.7% (post-ablation). In the 10 patients in the CVS group, either ablation or catheter-related mechanical trauma resulted in complete (n = 6 [60%]) or partial (n = 4 [40%]) long-term suppression of VA/PVCs. Right bundle branch block-type VA/PVC (9/11: 82%) was the most common morphology in the CVS group, whereas in the non-CVS group, this type was seen in only 3/33 (9%). The CVS group (25% of total VA/PVCs) had shorter activation time compared to non CVS group.

Conclusion

In our experience VA/PVCs with electrocardiograms suggestive of epicardial origin can often be safely and successfully ablated within the coronary venous system. These arrhythmias have unique features in Veterans patient population.

An electrocardiographic sign of idiopathic ventricular tachycardia ablatable from the distal great cardiac vein

BACKGROUND

Idiopathic ventricular arrhythmias (IVAs) can originate from the distal great cardiac vein (DGCV). However, inadequate distinction sometimes occurs when electrocardiographic (ECG) characteristics are used to distinguish ventricular arrhythmias (VAs) arising from the DGCV from those arising from the adjacent left ventricular endocardium (LV ENDO).

OBJECTIVE

The purpose of this study was to identify distinct ECG features in patients with idiopathic IVAs originating from the DGCV.

METHODS

A total of 32 patients with IVAs originating from the DGCV were identified from a consecutive group of 874 patients undergoing IVAs ablation. Patients with IVAs from the DGCV were compared with a consecutively chosen series of 40 patients with IVAs in whom the site of origin was the adjacent LV ENDO.

RESULTS

Of the 32 patients with IVAs arising from the DGCV, 13 had distinct ECG characteristics compared with the LV ENDO group. Notches in both the upstroke and downstroke of the R wave in lead III were found in all 13 patients. However, the characteristic ECG pattern in lead III was found in 1 of 40 patients in the LV ENDO group. The ECG characteristic of both early notch and late notches in lead III has sensitivity of 40.6%, specificity of 97.5%, negative predictive value of 67.2%, and positive predictive value of 92.9% to predict VAs arising from the DGCV.

CONCLUSION

The distinct ECG characteristics of VAs originating from the DGCV can help differentiate from adjacent LV ENDO sites of origin.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Idiopathic Outflow Tract Ventricular Arrhythmia Ablation: Pearls and Pitfalls

Idiopathic outflow tract ventricular arrhythmias (VAs) occur typically in patients without structural heart disease. They are often symptomatic and can sometimes lead to left ventricular systolic dysfunction. Both activation and pace mapping are utilised for successful ablation of these arrhythmias. Pace mapping is particularly helpful when the VA is infrequent and/or cannot be elucidated during the ablation procedure. VAs originating from different sites in the outflow tract region have distinct QRS patterns on the 12-lead ECG and careful analysis of the latter can help predict the site of origin of these arrhythmias. Successful ablation of these VAs requires understanding of the detailed anatomy of the OT region, which can be accomplished through electroanatomic mapping tools and intracardiac echocardiography.

Unique electrocardiographic pattern "w" wave in lead I of idiopathic ventricular arrhythmias arising from the distal great cardiac vein

Background

The ECG characteristics of the distal coronary venous system ventricular arrhythmias (VAs) share common features with VAs arising from the aortic cusps or the endocardial left ventricular outflow tract (LVOT) beneath the cusps. The purpose of this study was to identify specific electrocardiographic and electrophysiological characteristics of VAs originating from the distal great cardiac vein (GCV).

Methods

Based on the successful ablation site, patients with idiopathic VAs from the distal GCV, left coronary cusp (LCC) or the subvalvular left ventricular outflow tract (LVOT) area were included in the present study.

Results

The final population consisted of 39 patients (35 males, mean age 51 ± 23 years). All VAs displayed a right bundle branch block (RBBB) morphology with inferior axis. Among these patients, 15 were successfully ablated at the GCV, 15 at the LCC and 9 at the subvalvular region. A “w” pattern in lead I was present in 12 out of 15 (80%) VAs originating from the distal GCV compared to none of VAs arising from the other two sites (p < 0.01). VAs with a GCV origin exhibited more commonly increased intrinsicoid deflection time, higher maximum deflection index and wider QRS duration compared to LCC and subvalvular sites (p < 0.05). Acceptable pace mapping at the successful ablation site was achieved in 10 patients. After an average of 36 ± 24 months follow up, 14 (93.3%) patients were free from VAs recurrence.

Conclusion

A “w” pattern in lead I may distinguish distal GCV VAs from VAs arising from the LCC or the subvalvular region.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1064-9) contains supplementary material, which is available to authorized users.

Effect of radiofrequency on epicardial myocardium after ablation of ventricular arrhythmias from within coronary sinus

BACKGROUND

Radiofrequency (RF) ablation of idiopathic ventricular arrhythmias (IVA) from the coronary venous system (CVS) has been increasingly performed, but real effect of ablation lesions from CVS on epicardial myocardium has not been studied.

OBJECTIVE

To compare effects of RF delivered inside the distal CVS during ablation of IVAs originating from left ventricular summit (LVS) with IVAs ablated from right ventricular outflow tract (RVOT) using cardiac magnetic resonance imaging (CMRI).

METHODS

Twenty consecutive patients with IVAs who underwent acutely successful RF ablation at initial appropriate sites, i.e., distal CVS (Group 1, n = 10) or RVOT (Group 2; n = 10) were enrolled. Detailed contrast-enhanced CMRI of each patient was performed 3 months later. Presence and location of scars, distance of CVS to epicardial ventricular myocardium were measured and analyzed.

RESULTS

Group 1 consisted of 10 and Group 2 consisted of 10 patients. Three months after the ablation, only three patients in Group 1 had detectable late gadolinium enhancement (LGE) on CMRI while nine out of 10 patients in Group 2 had evident LGE on CMRI (P: 0.02). The mean distance of distal CVS to epicardial anterobasal myocardium was measured to be 8.8 ± 1.6 mm in Group 1. In three cases that had detectable scar on superior anterobasal LV epicardium, the mean distance was 7.4 ± 1.1 mm.

CONCLUSIONS

RF delivery inside the CVS is less likely to produce detectable LGE on CMRI compared to RVOT. This may partially explain less than ideal long-term results after ablation of LVS IVAs from within the great cardiac vein/anterior interventricular vein.

Idiopathic premature ventricular complexes originating from the distal great cardiac vein: Clinical, cardiac and electrophysiological characteristics and catheter ablation outcome

AIMS

Although catheter ablation for idiopathic ventricular arrhythmia (VA) has been generally well-established, VA originating from the great cardiac vein (GCV) may be clinically challenging due to its epicardial origin, proximity to coronary arteries and limited accessibility. The purpose of this study was to explore its electrophysiological characteristics and identify effective mapping/ablation strategies for idiopathic premature ventricular complexes (PVCs) originating from the GCV.

MATERIALS AND METHODS

Between January 2013 to January 2018, 12 patients (who were diagnosed with PVCs originating from the GCV) among the 305 patients with idiopathic left ventricular outflow tract tachycardia were included. The origin of the ectopy was localized by mapping, the characteristics of the electrocardiogram (ECG) were analyzed, and all the patients with PVCs originating from GCV were treated by radiofrequency catheter ablation (RFCA). The safety and efficacy of RFCA were evaluated.

KEY FINDINGS

The origin of the ectopy was successfully localized in GCV for all 12 patients by mapping, and access to GCV via the coronary sinus was feasible. Successful RFCA was achieved in 11 of 12 patients (91.67% acute procedural success) without perioperative complications. During a median follow-up of 12.6 ± 6.5 months, only one patient had recurrent VA (recurrence rate: 9.1%).

SIGNIFICANCE

ECG characteristics may be helpful for identifying patients with PVCs originating from the GCV. RFCA within the coronary venous system appears to be safe and effective for these patients, and should be considered when routine RFCA from the endocardium or aortic sinus of the Valsalva is not effective.

Catheter Ablation of Ventricular Tachycardia in Structurally Normal Hearts: Indications, Strategies, and Outcomes-Part I

Catheter ablation of ventricular tachycardia (VT) is being increasingly performed; yet, there is often confusion regarding indications, outcomes, and how to identify those patient populations most likely to benefit. The management strategy differs between those with structural heart disease and those without. For the former, an implantable cardioverter-defibrillator (ICD) is typically required due to an elevated risk for sudden cardiac death, and catheter ablation can be used as adjunctive therapy to treat or prevent repetitive ICD therapies. In contrast, VT or premature ventricular contractions in the setting of a structurally normal heart carries a low risk for sudden cardiac death; accordingly, there is typically no indication for an ICD. In these patients, catheter ablation is considered for symptom management or to treat tachycardiomyopathy and is potentially curative. Here, the authors discuss the pathophysiology, mechanism, and management of VT that occurs in the setting of a structurally normal heart and the role of catheter ablation.

Retrograde Coronary Venous Ethanol Infusion for Ablation of Refractory Ventricular Tachycardia

BACKGROUND

Radiofrequency ablation (RFA) of ventricular tachycardia (VT) can fail because of inaccessibility to the VT substrate. Transarterial coronary ethanol ablation can be effective but entails arterial instrumentation risk. We hypothesized that retrograde coronary venous ethanol ablation can be an alternative bail-out approach to failed VT RFA.

METHODS AND RESULTS

Out of 334 consecutive patients undergoing VT/premature ventricular contraction ablation, 7 patients underwent retrograde coronary venous ethanol ablation. Six out of 7 patients had failed RFA attempts (including epicardial in 3). Coronary venogram-guided venous mapping was performed using a 4F quadripolar catheter or an alligator-clip-connected angioplasty wire. Targeted veins included those with early presystolic potentials and pace-maps matching VT/premature ventricular contraction. An angioplasty balloon (1.5-2×6 mm) was used to deliver 1 to 4 cc of 98% ethanol into a septal branch of the anterior interventricular vein in 5 patients with left ventricular summit VT, a septal branch of the middle cardiac vein, and a posterolateral coronary vein (n=1 each). The clinical VT was successfully ablated acutely in all patients. There were no complications of retrograde coronary venous ethanol ablation, but 1 patient developed pericardial and pleural effusion attributed to pericardial instrumentation. On follow-up of 590±722 days, VT recurred in 4 out of 7 patients, 3 of whom were successfully reablated with RFA.

CONCLUSIONS

Retrograde coronary venous ethanol ablation is safe and feasible as a bail-out approach to failed VT RFA, particularly those originating from the left ventricular summit.

Catheter ablation of epicardial ventricular tachycardia from the coronary venous system: Is endocardial mapping always required?

Endocardial mapping is typically considered as the first step of VT ablation procedures. Nevertheless, when the electrocardiogram is highly suggestive of an epicardial VT, a minimally invasive procedure performed exclusively via the coronary sinus might be considered. This straightforward approach avoids all potential complications associated with access to the left ventricular endocardium, the aortic root, and the pericardial space.