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.

Predictor of A4 amplitude using preprocedural electrocardiography in patients with leadless pacemakers

BACKGROUND

Based on historical studies of leadless pacemakers (LPs), high atrioventricular synchrony (AVS) with mechanical sensing-based VDD pacing is largely influenced by A4 amplitude. A limited study investigated the predictors of A4 amplitude using clinical and echocardiographic parameters.

OBJECTIVE

The purpose of this study was to investigate the predictors of A4 amplitude preoperatively to select patients who could benefit the most from AVS among patients with VDD LPs (Micra-AV, Medtronic).

METHODS

Data from patients who received Micra-AV implantations from November 2021 to August 2023 at Tottori University Hospital were analyzed. Twelve-lead electrocardiography and transthoracic echocardiography were performed before the Micra-AV implantations. To assess the electrical indices associated with the A4 signal, electrocardiographic morphologic P-wave parameters were analyzed, including P-wave duration, P-wave amplitude, maximum deflection index (MDI), and P-wave dispersion.

RESULTS

A total of 50 patients who underwent Micra-AV implantations (median age 84 years; 64% male) were included and divided into 2 groups based on the median value of A4 amplitude, the high-A4 group (A4 amplitude >2.5 m/s2; n = 26), and low-A4 group (A4 amplitude ≤2.5 m/s2; n = 24). There was a significant difference between the high-A4 and low-A4 groups with regard to left ventricular ejection fraction (P = .01), P-wave dispersion (P = .01), and MDI (P <.001). Multivariate logistic analysis revealed that lower MDI was an independent predictor of high A4-amplitude (odds ratio 0.78; 95% confidence interval 0.67-0.92; P = 0.003).

CONCLUSION

Preoperative electrocardiographic evaluations of P-wave morphology may be useful for predicting A4 amplitude. MDI was the only independent A4 amplitude predictor that seemed promising for selecting Micra-AV patients.

Electrocardiogram Parameters That Affect the Success Rate of Radiofrequency Ablation in Patients with Outflow Tract Ventricular Premature Complexes

Objectives. The objectives of this study are to assess the efficacy of radiofrequency catheter ablation (RFCA) in patients with outflow tract (OT) ventricular premature complexes (VPCs) and to explore the electrocardiographic (ECG) features of initially successful procedures. Methods. Based on the outcome of ablation, 154 consecutive patients with OT-VPCs who underwent RFCA from January 2017 to December 2019 were divided into two groups. The rate of successful procedures and the ECG features were analyzed and compared between the two groups. Results. The highest success rate was found in patients with VPCs from the right ventricular outflow tract (RVOT), and the lowest success rate was evident among patients with complexes from both the RVOT and the left ventricular OT (LVOT). The patients with successful procedures (136) reflected a lower pseudo delta wave ratio (16.2% vs. 44.4%, $P<0.01$ ), a smaller R-wave amplitude in lead V1 (V1) ( $0.23\pm 0.24$ mV vs. $0.35\pm 0.44$  mV, $P<0.05$ ), shorter intrinsicoid deflection time in lead V2 (V2) ( $44.00\pm 18.33$ ms vs. $57.41\pm 20.67$ ms, $P<0.01$ ), a shorter RS duration in V2 ( $93.67\pm 21.33$  ms vs. $106.93\pm 18.76$  ms, $\text{P}<0.01$ ), and smaller R/S-waveratios in V2. Furthermore, multivariate analysis demonstrated that RS duration in V2 was above 109.17 ms and R/S ratio in V2 was above 0.28, forecasting a failed procedure. Conclusions. The ECG predictors of failed ablation were characterized by RS duration and R/S ratio in V2.

The RV1-V3 transition ratio: A novel electrocardiographic criterion for the differentiation of right versus left outflow tract premature ventricular complexes

Background

Several electrocardiographic (ECG) indices have been proposed to predict the origin of premature ventricular complexes (PVCs) with precordial transition in lead V₃. However, the accuracy of these algorithms is limited.

Objectives

We sought to evaluate a new ECG criterion differentiating the origin of outflow tract with precordial transition in lead V₃.

Methods

We included in our study patients exhibiting outflow tract PVCs with precordial transition in lead V₃ referred for ablation. We analyzed a novel new ECG criterion, RV₁-V₃ transition ratio, for distinguishing right from left idiopathic outflow tract PVCs with precordial transition in lead V₃. The RV₁-V₃ transition ratio was defined as (RV1+RV2+RV3) _PVC / (RV1+RV2+RV3) SR (sinus rhythm).

Results

We included 58 patients in our study. The ratio was lower for right ventricular outflow tract origins than left ventricular outflow tract (LVOT) origins (median [interquartile range], 0.6953 [0.4818–1.0724] vs 1.5219 [1.1582–2.4313], P < .001). Receiver operating characteristic analysis revealed an area under the curve of 0.856 for the ratio, and a cut-off value of ≥0.9 predicting LVOT origin with 94% sensitivity and 73% specificity. This ratio was superior to any previously proposed ECG criterion for differentiating right from left outflow tract PVCs.

Conclusion

The RV₁-V₃ transition ratio is a simple and accurate novel ECG criterion for distinguishing right from left idiopathic outflow tract PVCs with precordial transition in lead V₃.

Electrophysiological properties and involvement of anatomical factors for the prediction of intramural origin in patients with ventricular tachyarrhythmia arising from the left ventricular outflow tract

PURPOSE

To elucidate the electrophysiological predictors of the intramural origins of left ventricular outflow tract-ventricular tachyarrhythmias (LVOT-VAs), and to clarify the involvement of anatomical factors.

METHODS

Twenty-nine successfully ablated LVOT-VAs patients with origins in the aortomitral continuity (AMC) (n = 8), aortic sinus of valsalva (ASV) (n = 9), great cardiac vein (GCV) (n = 5), and intramural myocardium (n = 7) were enrolled. Intramural origins were defined as when effective ablation from AMC and epicardium (ASV and/or GCV) was needed. The local activation time difference (LATD) was calculated as follows: (earliest AMC activation) - (earliest epicardial activation), and was presented as an absolute value. Electrophysiological parameters and anatomical factors predisposing the intramural origins were investigated.

RESULTS

LATD of intramural origins was significantly shorter than that of AMC and GCV (4.5 ± 2.6 vs. 12.1 ± 7.4 vs. 17.4 ± 4.7, P < 0.05), respectively. In multivariate logistic regression analysis, LATD was associated with intramural origins (odds ratio: 0.711, confidence interval: 0.514-0.985, P = 0.040). ROC analysis revealed LATD of 7 ms as cut-off value. In computed tomography analysis, some patients who had thick fat tissue below the GCV, and an unusual GCV running pattern might be misdiagnosed as intramural origins.

CONCLUSION

LATD ≤ 7 ms was associated with intramural origins, but with some anatomical limitations.

Radiofrequency catheter ablation of premature ventricular contractions from the mitral annulus in patients without structural heart disease

Introduction

We previously reported the clinical benefits of radiofrequency catheter ablation (RFCA) of premature ventricular contractions (PVCs) from the right ventricular outflow tract or near the His‐bundle, which can often deteriorate the clinical status. PVCs from the mitral valve (MA‐PVCs) also often deteriorate the patients’ clinical status. This study aimed to evaluate the effect of ablating MA‐PVCs with RFCA from a trans‐interatrial septal approach on the clinical status in symptomatic patients with frequent MA‐PVCs without structural heart disease.

Methods

The frequency of PVCs per the total heart beats by 24‐hours Holter monitoring and New York Heart Association (NYHA) functional class in 22 patients with MA‐PVCs were evaluated before and 6 months after RFCA.

Results

Procedural success was achieved in 20 (91%) of 22 patients. Of the 22 patients, in 15 (68%) and 1 (5%) patient, a successful RFCA on the left ventricular side of the MA using the trans‐interatrial septal approach and trans‐coronary sinus approach was achieved. Interestingly, in four (18%) patients, a successful RFCA on the left atrial (LA) side of the MA using a trans‐interatrial septal approach was achieved. Ablating MA‐PVCs readily improved the NYHA functional class compared to that before. A ≥0.62 peak deflection index and ≤30 years old may be one of the important predictors of successfully ablated MA‐PVCs from the LA side of the MA.

Conclusions

RFCA produces clinical benefits in patients with MA‐PVCs. Further, it may be necessary to initially consider a trans‐interatrial septal approach to ablate these PVCs.

Peak deflection index as a predictor of a free-wall implantation of contemporary leadless pacemakers

BACKGROUND

Leadless pacemakers are an effective treatment for bradycardia. However, some cases exhibit pericardial effusions, presumably associated with device implantations on the right ventricular free-wall. The present study was carried out to find the ECG features during ventricular pacing with a Micra, which enabled distinguishing free-wall implantations from septal implantations without using imaging modalities.

METHODS

Thirty-one consecutive patients who received Micra implantations in our facility were enrolled. The location of the device in the right ventricle was evaluated using echocardiography or computed tomography in order to determine whether the device was implanted on the septum (Sep group), apex (Apex group), or free-wall (FW group). The differences in the 12-lead ECG during ventricular pacing by the Micra were analyzed between the Sep and FW groups.

RESULTS

The body of the Micra was clearly identifiable in 22 patients. The location of the device was classified into Sep in 12 patients, Apex in 4, and FW in 6. The mean age was highest in the FW and lowest in the Sep group (82.7 ± 6.6 vs. 72.8 ± 8.7 years, p = 0.027). The peak deflection index (PDI) was significantly larger in the FW group than Sep/Apex group in lead V1 (Sep: 0.505 ± 0.010, Apex: 0.402 ± 0.052, FW: 0.617 ± 0.043, p = 0.004) and lead V2 (Sep: 0.450 ± 0.066, Apex: 0.409 ± 0.037, FW: 0.521 ± 0.030, p = 0.011), whereas there was no difference in the QRS duration, transitional zone, and QRS notching.

CONCLUSION

The PDI in V1 could be useful for predicting implantations of Micra devices on the free-wall and may potentially stratify the risk of postprocedural pericardial effusions.

Radiofrequency catheter ablation of premature ventricular contractions from near the His-bundle

OBJECTIVE

This study aimed to investigate the effects of radiofrequency catheter ablation (RFCA) and clinical and electrophysiological characteristics in symptomatic patients with premature ventricular contractions (PVCs) from near the His-bundle (His-PVCs).

METHODS

The patient characteristics, prevalence of complications with any life style related disease (ALSRD) including hypertension, dyslipidemia, or diabetes mellitus, and/or cardiovascular disease (CVD) including coronary artery disease, cerebrovascular disease, renal dysfunction, or cardiomyopathy, clinical status, frequency of PVCs evaluated by 24hour Holter monitoring, echocardiography including the left ventricular diastolic dysfunction (LVDD) parameters, and electrophysiological findings were evaluated in 14 consecutive symptomatic patients with His-PVCs.

RESULTS

The prevalence of males, being elderly and/or slightly obese, current and/or history of smoking, ALSRD or CVD related complications, and LVDD probably resulting from ALSRD and/or CVD complications were higher in patients with His-PVCs. RFCA of His-PVCs steadily decreased the PVC frequency and improved the systolic function, LV dilation, and clinical status, but not the LVDD. There was a significant relationship between the accordance rate of the QRS polarity between sinus rhythm and His-PVCs and the distance between the successful ablation site and His-bundle.

CONCLUSION

The analysis of the QRS duration and accordance rate of the QRS polarity between sinus rhythm and His-PVCs before the RFCA may help to determine the distance between the origin of the PVCs and His-bundle. Further, the appropriate ablation catheter may be selected during the RFCA procedure. Finally, RFCA may be one of the most effective, feasible, and safest therapies for symptomatic patients with His-PVCs.

Electrocardiographic characteristics for predicting idiopathic right ventricular outflow tract premature ventricular complex-induced cardiomyopathy

PURPOSE

In spite of several proposed predictors for premature ventricular complex (PVC)-induced cardiomyopathy (PVC-CMP), the specific ECG features of idiopathic right ventricular outflow tract (RVOT) PVC-CMP remain unknown.

METHODS

A total of 130 patients (49 males, mean age 44 years) with symptomatic and drug-refractory idiopathic RVOT PVCs undergoing radiofrequency catheter ablation (RFCA) were enrolled. The patients were categorized into two groups, including those with and without RVOT PVC-CMP (left ventricular ejection fraction (LVEF) < 50%, n = 25 and LVEF ≥ 50%, n = 105, respectively). The 12-lead PVC morphologies were assessed.

RESULTS

Patients with RVOT PVC-CMP had a lower LVEF (42 ± 5% vs. 60 ± 7%, P < 0.01) and higher PVC burden (24 ± 14% vs. 15 ± 11%, P = 0.02) when compared to patients without RVOT PVC-CMP. The PVC features in those with PVC-CMP displayed a significantly wider QRS duration (143 ± 14 ms vs. 132 ± 17 ms, P < 0.01) and higher peak deflection index (PDI; 0.60 ± 0.07 vs. 0.55 ± 0.08, P < 0.01). A multivariate analysis demonstrated that the QRS duration (odds ratio (OR) 1.130, 95% confidence interval (CI) 1.020-1.253, P = 0.02) and PDI (OR 1.240, 95% CI 1.004-1.532, P = 0.04) were independently associated with RVOT PVC-CMP. Based on the receiver-operating characteristic analysis, a QRS duration > 139 ms and PDI > 0.57 could predict RVOT PVC-CMP (area under the curve (AUC) 0.710 and AUC 0.690, respectively). The elimination and suppression of PVCs by RFCA resulted in the recovery of the LVEF in RVOT PVC-CMP.

CONCLUSIONS

The ECG parameters, including a wider QRS duration and higher PDI, could predict the development of RVOT PVC-CMP, which could be effectively treated by RFCA.

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

OBJECTIVE

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

METHODS AND RESULTS

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

CONCLUSIONS

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

Electrocardiographic features of failed and recurrent right ventricular outflow tract catheter ablation of idiopathic ventricular arrhythmias

INTRODUCTION

Various ECG algorithms have been proposed to identify the origin of idiopathic outflow tract (OT)-ventricular arrhythmia (VA). However, electrocardiographic features of failed and recurrent right ventricular outflow tract (RVOT) ablation of idiopathic OT-VAs have not been clearly elucidated.

METHODS AND RESULTS

A total of 264 consecutive patients (mean age: 44.0 ± 13.0 years, 96 male) undergoing RVOT ablation for OT-VAs with a transition ≥V₃ , including 241 patients (91.6%) with initially successful procedures and 23 patients (8.4%) with failed ablation. Detailed clinical characteristics and ECG features were analyzed and compared between the two groups. VAs with failed RVOT ablation had larger peak deflection index (PDI), longer V₂ R wave duration (V₂ Rd), smaller V₂ S wave amplitude, higher R/S ratio in V₂ , higher V₃ R wave amplitude, and larger V₂ transition ratio than those with successful ablation. Multivariate analysis demonstrated that PDI, V₂ Rd, V₂ transition ratio, and pacemapping score acquired during mapping independently predicted failed ablation (P  =  0.01, P  =  0.01, P  =  0.01, and P < 0.001, respectively). In 31 recurrent cases (12.8%) after initially successful ablation, multivariate Cox regression analysis showed that only the earliest activation time acquired during mapping predicted the recurrences after successful ablation (P  =  0.001). The recurrent cases displayed different ECG features comparing with those with failed ablation.

CONCLUSION

The electrocardiographic features of failed RVOT ablation of idiopathic OT-VAs with a transition ≥V₃ were characterized by PDI, V₂ Rd, V₂ transition ratio, and pacemapping score acquired during mapping, unlike the recurrent RVOT ablation.

The Efficacy of Isochronal 3D Mapping-Based Ablation of Ventricular Arrhythmia

Treatment of ventricular arrhythmias (VAs) commonly involves ablating sites showing electrograms with the earliest activity relative to the VA, but there is no threshold value for prematurity guaranteeing success. Ablation of sites with great prematurity can still result in failure.We hypothesized that isochronal map area (ISCA), derived from isochrones indicating electrogram prematurity, could help identify ablation targets in VA patients, as well as predict outcome. Specifically, we hypothesized that smaller ICSA for a given prematurity value would indicate a shallower arrhythmogenic focus leading to a higher likelihood of successful ablation.We studied ICSA in 29 patients (12 males, 57 [17-65] years old) undergoing VA ablation. The VAs originated from the right and left ventricles in 11 and 18 patients, respectively. The earliest activation site of the VAs, ECG morphology of sinus beats and premature ventricular complexes (PVCs), and ISCA of activation preceding PVCs were evaluated.RF ablation at the site showing earliest prematurity resulted in VA elimination in 21 patients (success group). The 5-ms ISCA was smaller in the success group than in the failure group (0.2 [0.1-0.6] versus 1.0 [0.8-1.5] cm², respectively; P < 0.01). No significant difference was noted in prematurity itself (36 [30-45] versus 30 [29-33] ms, respectively; P = 0.07). The cut-off value of the 5 ms ISCA for successful RF ablation was 0.7 cm² with 87.5% sensitivity and 85.6% specificity.Isochrones of activity preceding PVCs appear to contain information beyond prematurity values and may help dictate suitable areas for successful ablation of VAs.

Mark E Josephson: Clinical Investigator

Mark E Josephson entered the world of clinical cardiac electrophysiology (EP) almost at its inception (1972); with so much to learn and so many directions one could take, he dived into the field with unbridled enthusiasm and an uncommon - perhaps almost unique - aptitude for asking questions and finding ways to answer them. Few aspects of EP escaped his indelible influence. In this short paper, I will attempt to touch on some of the high points of his astounding career as a clinical investigator.

[Catheter ablation of ventricular extrasystoles and ventricular tachycardia in the elderly]

BACKGROUND

The prevalence of structural heart disease increases with higher age, and thereby the basis for ventricular arrhythmias is created. Catheter ablation has been shown to be an effective therapy option that is very safe and achieves good long-term results in patients with recurrent ventricular tachycardia (VT). Data regarding ablation in patients older than 75 years is sparse, although this patient group was included as a minority in most published VT ablation studies. Data from younger patient collectives may not be transferable to older patient cohorts due to differences in patient comorbidities and baseline characteristics.

METHODS

Studies with patient collectives ≥75 years or even ≥80 years show comparable efficacy of catheter ablation for VT; however, the complication rate is higher, mainly due to groin complications, increases. Catheter ablation of ischemic VT appears effective and safe even in ≥75 year olds; however, extensive data for other structural heart diseases are lacking. Epicardial procedures are also possible and safe in older patients (≥80 years). Due to the significant challenges of VT ablation in older patients, including the consideration of complex comorbidities, these should be performed in specialized centers with high expertise.

CONCLUSION

The aim of catheter ablation in older patients is, above all, to improve quality of life and morbidity. Long-term survival is significantly lower due to the "near end of life" situation than in younger patients. Careful consideration of alternative therapy options, chances for success of the catheter ablation, and their risks, taking into account specific patient conditions and symptoms, is crucial in these patients.

Catheter Ablation of Idiopathic Ventricular Arrhythmias Arising From the Cardiac Outflow Tracts - Recent Insights and Techniques for the Successful Treatment of Common and Challenging Cases

Ventricular arrhythmias (VA), like premature ventricular contractions (PVC) and ventricular tachycardia (VT) in patients without structural heart disease (idiopathic VA), mainly arise from the right and left ventricular outflow tracts (RVOT/LVOT). The prognosis for OT VA is generally good in the majority of patients, but there is potential for developing dilated cardiomyopathies from the high burden of VA, as well as a certain risk for sudden cardiac death because of fast monomorphic VT or polymorphic VT triggered by short-coupling PVC. Radiofrequency catheter ablation (RFCA) has evolved into a widely accepted treatment strategy for patients suffering from VAs. A detailed knowledge of surface ECGs and complex cardiac anatomy, especially within the ventricular OTs, is essential for the understanding of cardiac OT-VAs and highly related to safe and successful RFCA procedures. This review article focuses on RFCA of idiopathic VA arising from the cardiac OT as well as adjacent regions and will illustrate recent insights and technical issues. (Circ J 2016; 80: 1073-1086).

Ventricular Arrhythmias from the Left Ventricular Summit: Critical Importance of Anatomy, Imaging, and Detailed Mapping to Allow Safe and Effective Ablation

Ventricular arrhythmias arising from the region of the left ventricular summit can be challenging for catheter-based percutaneous ablation. A detailed knowledge of the anatomy of this region and the need of high-density mapping of surrounding structures are critical in ensuring safe and effective ablation. This case-based review focuses on the particular challenges with ablation in this region.

Development of a magnetocardiography-based algorithm for discrimination between ventricular arrhythmias originating from the right ventricular outflow tract and those originating from the aortic sinus cusp: a pilot study

BACKGROUND

Although several reports address characteristic 12-lead electrocardiographic findings of outflow tract ventricular arrhythmias (OT-VAs), the accuracy of electrocardiogram-based algorithms to predict the OT-VA origin is sometimes limited.

OBJECTIVE

This study aimed to develop a magnetocardiography (MCG)-based algorithm using a novel adaptive spatial filter to differentiate between VAs originating from the aortic sinus cusp (ASC-VAs) and those originating from the right ventricular outflow tract (RVOT-VAs).

METHODS

This study comprised 51 patients with an OT-VA as the target of catheter ablation. An algorithm was developed by correlating MCG findings with the successful ablation site. The arrhythmias were classified as RVOT-VAs or ASC-VAs. Three parameters were obtained from 3-dimensional MCG imaging: depth of the origin of the OT-VA in the anteroposterior direction; distance between the earliest atrial activation site, that is, sinus node, and the origin of the OT-VA; and orientation of the arrhythmia propagation at the QRS peak. The distance was indexed to the patient's body surface area (in mm/m2).

RESULTS

Origins of ASC-VAs were significantly deeper (81 ± 6 mm/m(2) vs. 68 ± 8 mm/m(2); P < .01) and farther from the sinus node (55 ± 9 mm/m2 vs. 41 ± 9 mm/m(2); P < .01) than those of RVOT-VAs. ASC-VA propagation had a tendency toward rightward axis. Receiver operating characteristic analyses determined that the depth of the origin was the most powerful predictor, with a sensitivity of 90% and a specificity of 73% (area under the curve = 0.90; P < .01). Discriminant analysis combining all 3 parameters revealed the accuracy of the localization to be 94%.

CONCLUSION

This MCG-based algorithm appeared to precisely discriminate ASC-VAs from RVOT-VAs. Further investigation is required to validate the clinical value of this technique.

Ventricular Arrhythmias Arising From the Left Ventricular Outflow Tract Below the Aortic Sinus Cusps

Background—

Ventricular arrhythmias (VAs) originating from the anterosuperior left ventricular outflow tract (LVOT) represent a challenging location for catheter ablation. This study investigates mapping and ablation of VA from anterosuperior LVOT via a transseptal approach.

Methods and Results—

This study included 27 patients with symptomatic VA, of which 13 patients had previous failed ablations. LVOT endocardial 3-dimensional mapping via retrograde transaortic and antegrade transseptal approaches was performed. Previous ECG markers for procedure failure were analyzed. In all patients, earliest activation with low-amplitude potentials was identified at the anterosuperior LVOT 5.1±2.8 mm below the aortic cusp and preceded the QRS onset by 39.5±7.7 ms only via an antegrade transseptal approach using a reversed S curve. In all patients, pace mapping failed to demonstrate perfect QRS morphology match. The anatomic location was below the left coronary cusp in 16, below the left coronary cusp/right coronary cusp junction in 8, and below the right coronary cusp in 3 patients. Radiofrequency energy resulted in rapid disappearance of VAs in all patients. ECG analysis showed aVL/aVR Q-wave amplitude ratio >1.4 in 7, lead III/II R-wave amplitude ratio >1.1 in 10, and peak deflection index >0.6 in 11 patients. There were no complications or clinical VA recurrence during a mean follow-up of 8.4±2.5 months.

Conclusions—

The anterosuperior LVOT can be reached via a transseptal approach with a reversed S curve of the ablation catheter. The rapid effect from radiofrequency energy indicates that the VA is most likely located under the endocardium. Also, previous ECG markers for procedure failure need further investigation.

Discrete Prepotential as an Indicator of Successful Ablation in Patients With Coronary Cusp Ventricular Arrhythmia

Background—

Although coronary cusp (CC) ventricular arrhythmia (VA) can be treated by catheter ablation, reliable indicators of successful ablation sites have not been fully identified.

Methods and Results—

This study comprised 392 patients undergoing radiofrequency catheter ablation for outflow tract-VA at 3 institutions from January 2007 to August 2012. The successful ablation site was on the left CC or right CC in 35 (8.9%) of the 392 patients. In 9 (26%) of these 35 patients, a discrete prepotential was recognized, 5 of whom had left CC-VAs and 4 of whom had right CC-VAs. Radiofrequency catheter ablation was successful at the site of the prepotential in all 9 of these patients. The duration of the isoelectric line between the end of the discrete prepotential and the onset of the ventricular electrogram was 27±13 ms. The time from onset of the discrete prepotential at the successful ablation site on the CC to the QRS onset (activation time) was 69±20 ms (range, 50–98 ms). Pace mapping was graded as excellent at the successful ablation site in only 1 patient. No discrete prepotential was recorded in any successful right outflow tract-VA ablation case in this study.

Conclusions—

A discrete prepotential was seen in 9 (26%) of 35 patients with CC-VA. In left and right CC-VA, the site of a discrete prepotential with ≥50 ms activation time may indicate a successful ablation site.