Focal Ventricular Arrhythmias Research Articles

Electrocardiographic imaging to guide ablation of ventricular arrhythmias shows a higher benefit in patients with low intraprocedural burden

Abstract Background and aims Electrocardiographic imaging (ECGI) provides a non-invasive activation map of focal ventricular arrhythmias that has shown good accuracy regardless of the type of cardiac source used. Pre-procedure diagnosis in cases that are expected to be difficult and management of infrequent or poorly tolerated or multiple arrhythmias are some situations that may benefit the most from having an ECGI performed before the procedure. This study aimed to assess the benefit of the ECGI in patients with low intraprocedural burden. Methods We performed 81 ECGI procedures in 64 consecutive patients referred for ablation of ventricular arrhythmias (VAs). Ablations were performed with remote magnetic navigation or manually. The localization of the VAs based on the ECGI and invasive electroanatomic mapping was performed using a segmental model of the ventricles. A perfect match (PM) was defined as a predicted location within the same anatomic segment, whereas a near match (NM) was defined as a predicted location within the same segment or a contiguous one. The agreement between the ECGI and the invasive map was evaluated. The benefit of the ECGI in the subgroup of patients with intraprocedural infrequent VAs, defined as less than 1 VA complex /min, was assessed in terms of the success of the procedure. Results The ECGI was performed with the AMYCARD 01 only, in 26 patients, with the VIVO only, in 21 patients, and with both systems in 17 patients. Fifty-one patients underwent ablation. 65 ECGI procedures were performed before ablation in those 51 patients, 37 with Amycard with a rate of PM of 79% and NM of 97%, and 28 ECGI procedures with VIVO with 82% of PM and 93% of NM, not significantly different, respectively, p=0.764 and 0.573. The overall success rate was 80%. The low intraprocedural burden group included 28 patients (2 examples shown in the figure). The success rate was 86%, higher than the overall success rate, and much higher than the previously reported in the literature for this group of patients. Conclusions The ECGI was useful in predicting the location of the VA in general but was especially helpful in cases that are usually challenging, like patients with intraprocedural infrequent VAs.

Catheter-induced right bundle branch block: Practical implications for the cardiac electrophysiologist.

The right bundle branch (RBB), due to its endocardial course, is susceptible to traumatic block caused by "bumping" during right-heart catheterization. In the era of cardiac electrophysiology, catheter-induced RBB block (CI-RBBB) has become a common phenomenon observed during electrophysiological studies and catheter ablation procedures. While typically transient, it may persist for the entire procedure time. Compared to pre-existing RBBB, the transient nature of CI-RBBB allows for comparative analysis relative to the baseline rhythm. Furthermore, unlike functional RBBB, it occurs at similar heart rates, making the comparison of conduction intervals more reliable. While CI-RBBB can provide valuable diagnostic information in various conditions, it is often overlooked by cardiac electrophysiologists. Though it is usually a benign and self-limiting conduction defect, it may occasionally lead to diagnostic difficulties, pitfalls, or undesired consequences. Avoidance of CI-RBBB is advised in the presence of baseline complete left bundle branch block and when approaching arrhythmic substrates linked to the right His-Purkinje-System, such as fasciculo-ventricular pathways, bundle branch reentry, and right-Purkinje focal ventricular arrhythmias. This article aims to provide a comprehensive practical review of the electrophysiological phenomena related to CI-RBBB and its impact on the intrinsic conduction system and various arrhythmic substrates.

Implications of the anatomy of papillary muscle connections for mapping and ablation of focal ventricular arrhythmias

Ventricular arrhythmias (VAs) originating from papillary muscles (PAPs) can be challenging when targeted with catheter ablation. Reasons may include premature ventricular complex pleomorphism, structurally abnormal PAPs, or unusual origins of VAs from PAP-myocardial connections (PAP-MYCs). The purpose of this study was to correlate PAP anatomy with mapping and ablation of PAP VAs. In a series of 43 consecutive patients with frequent PAP arrhythmias referred for ablation, the anatomy and structure of PAPs and VA origins were analyzed using multimodality imaging. Successful ablation sites were analyzed for location on the PAP body or a PAP-MYC. In a total of 17 of 43 patients (40%), VAs originated from a PAP-MYC (in 5 of 17 patients, the PAP inserted into the mitral valve anulus); and in 41 patients, VAs originated from a PAP body. VAs from a PAP-MYC more often had delayed R-wave transition than did other PAP VAs (69% vs 28%; P < .001). Patients with failed procedures had more PAP-MYCs (24.8 ± 8 PAP-MYCs per patient vs 16 ± 7 PAP-MYCs per patient; P < .001). Multimodality imaging identifies anatomic details of PAPs that facilitate mapping and ablation of VAs. In more than a third of patients with PAP VAs, VAs originate from connections between PAPs and the surrounding myocardium or between other PAPs. VA electrocardiographic morphologies are different when VAs originate from PAP-connection sites as compared with VAs originating from the PAP body.

PO-638-02 INFLAMMATION BY FDG PET IS DISCORDANT WITH SITES OF FOCAL VENTRICULAR TACHYCARDIA IN PATIENTS WITH SUSPECTED CARDIAC SARCOIDOSIS

In pts with cardiac sarcoidosis (CS), late gadolinium enhancement by cardiac MRI predicts development of ventricular arrhythmias. Our previous analysis also suggested a relation between scar regions and focal ventricular arrhythmias (FVA) as determined by FDG PET CT. The role of active inflammation on FDG PET in focal ventricular arrhythmias (FVA) site of origin is unclear.

On the Electrophysiology and Mapping of Intramural Arrhythmic Focus.

Conventional mapping of focal ventricular arrhythmias relies on unipolar electrogram characteristics and early local activation times. Deep intramural foci are common and associated with high recurrence rates following catheter-based radiofrequency ablation. We assessed the accuracy of unipolar morphological patterns and mapping surface indices to predict the site and depth of ventricular arrhythmogenic focal sources. An experimental beating-heart model used Langendorff-perfused, healthy swine hearts. A custom 56-pole electrode array catheter was positioned on the left ventricle. A plunge needle was placed perpendicular in the center of the grid to simulate arrhythmic foci at variable depths. Unipolar electrograms and local activation times were generated. Simulation models from 2 human hearts were also included with grids positioned simultaneously on the endocardium-epicardium from multiple left ventricular, septal, and outflow tract sites. A unipolar Q or QS complex lacks specificity for superficial arrhythmic foci, as this morphology pattern occupies a large surface area and is the predominant pattern as intramural depth increases without developing a R component. There is progressive displacement from the arrhythmic focus to the surface exit as intramural focus depth increases. A shorter total activation time over the overlying electrode array, larger surface area within initial 20 ms activation, and a dual surface breakout pattern all indicate a deep focus. Displacement from the focal intramural origin to the exit site on the mapping surface could lead to erroneous lesion delivery strategies. Traditional unipolar electrogram features lack specificity to predict the intramural arrhythmic source; however, novel endocardial-epicardial mapping surface indices can be used to determine the depth of arrhythmic foci.

Anatomy of the proximal septal vein in patients with focal intramural ventricular arrhythmias.

Focal ventricular arrhythmias (VAs) originating from the intramural myocardium of the basal septum are difficult to localize and ablate. Proximal septal veins emptying into the great cardiac vein can reach close to the origin of intramural arrhythmias. To assess characteristics of proximal septal coronary veins in patients with intramural VAs. Among 84 consecutive patients with intramural VAs, 29 patients (age 60 ± 11years, 16 males, ejection fraction 47 ± 13%) underwent preprocedural cardiac computed tomographic angiography (CTA). In 14 of these patients, the intramural site of origin (SOO) was identified with multipolar catheters. The intramural SOO could not be accessed with mapping catheters in the other 15 patients while mapping the coronary venous system. The CTA identified sizable proximal septal veins in all patients in whom the SOO could be accessed with mapping catheters. In the patients in whom the intramural SOO was not identified, the proximal septal veins were often either small (<2 mm atthe branching site) or non-existent (n = 9, p = .001). The proximal septal veins in patients in whom the SOO was identified were larger than in the patients in whom the SOO could not be identified (3.0 ± 0.6 mm vs. 2.1 ± 0.9 mm, p = .01). Preprocedural imaging with CTAs can be beneficial in identifying the anatomy of proximal septal coronary veins that allow adequate mapping of patients with suspected intramural VAs.

An electrocardiographic diagnostic model for differentiating right from left ventricular outflow tract arrythmias origin

Abstract Background/Introduction Several ECG signs have been proposed to discern the focal origin of ventricular outflow tract arrhythmias with a transition ≥V3. Their independent predictive value is unclear. Purpose The aim of the study is to establish a predictive model of independent ECG parameters to obtain an acute success in right-sided catheter ablation of isolated premature ventricular contractions (PVCs) or ventricular tachycardia (VT) from the ventricular outflow tract with a transition ≥V3. Methods We included 122 patients (62 women, mean age 54±16 years) with documented PVCs or VT showing a lower axis and predominantly negative QRS complexes in V1 and V2 who underwent ablation between January 2014 and June 2020. The achievement of acute ablation success from right endocardial positions was assessed. We performed a predictive model by multivariate logistic regression analysis including the following ECG variables associated with a right origin of the ventricular focus in previous studies: Transitional Zone (TZ) index, V2 transition ratio, V2S / V3R index, R-wave duration index, R/S-wave amplitude index in V2, variable coupling interval, and the presence of QS morphology in lead I. Results Two independent predictive ECG variables were identified: the V2S / V3R index (odds ratio 1.223; 95% CI, 1.024–1.460; p=0.026) and a coupling interval variability &amp;gt;60 ms (odds ratio 0.307; 95% CI, 0.129 - 0.731; p=0.008). The area under the curve of this model was 0.733 (Picture 1). Arrhythmias with transition in V3 present a greater electroanatomic overlap and, therefore, a higher probability of right failure (59.3% vs 73.5% in arrhythmias with transitions after V3). In these, the V2 transition ratio is useful to predict the origin of the ectopy. Conclusion Two easily identifiable ECG variables (the V2S / V3R index and coupling interval variability &amp;gt;60 ms) predict the acute success of a right-sided approach in the ablation of focal ventricular arrhythmias with predominantly negative QRS complexes in V1 and V2. Funding Acknowledgement Type of funding sources: None. Predictive accuracy of the ECG model

Simulation and Visualization of the electrical Activity of the Heart with focal ventricular tachycardia in a 3D Model

Abstract Patients with focal ventricular tachycardia are at risk of hemodynamic failure and if no treatment is provided the mortality rate can exceed 30%. Therefore, medical professionals must be adequately trained in the management of these conditions. To achieve the best treatment, the origin of the abnormality should be known, as well as the course of the disease. This study provides an opportunity to visualize various focal ventricular tachycardias using the Offenburg heart rhythm model. Modeling and simulation of focal ventricular tachycardias in the Offenburg heart rhythm model was performed using CST (Computer Simulation Technology) software from Dessault Systèms. A bundle of nerve tissue in different regions in the left and right ventricle was defined as the focus in the already existing heart rhythm model. This ultimately served as the origin of the focal excitation sites. For the simulations, the heart rhythm model was divided into a mesh consisting of 5354516 tetrahedra, which is required to calculate the electric field lines. The simulations in the Offenburg heart rhythm model were able to successfully represent the progression of focal ventricular tachycardia in the heart using measured electrical field lines. The simulation results were realized as an animated sequence of images running in real time at a frame rate of 20 frames per second. By changing the frame rate, these simulations can additionally be produced at different speeds. The Offenburg heart rhythm model allows visualization of focal ventricular arrhythmias using computer simulations. By selecting the frame rate, the speed of the simulation results can be adjusted accordingly to visualize the electric field lines of focal ventricular tachycardias in more detail. The static and dynamic simulation results could be used in the future for teaching and research, including the training of medical professionals.

B-PO02-127 OUTCOMES OF CATHETER ABLATION OF VENTRICULAR ARRHYTHMIAS ORIGINATING FROM A LEFT VENTRICULAR FALSE TENDON

Left ventricular false tendons (LV-FT) are chord-like fibromuscular structures that cross the LV cavity and attach between the septum, papillary muscles (PM), or the free wall. Ventricular arrhythmias (VAs) arising from LV-FT have been described in isolated case reports, but data on larger cohorts of patients are insufficient. We investigated the prevalence, electrophysiologic features and outcomes of catheter ablation of LV-FT VAs. We screened 3719 patients undergoing ablation of VAs at our institution between January 2011 and August 2020. Diagnosis of LV-FT origin of the VA was based on detailed activation/pace-mapping guided by intracardiac echocardiography (ICE). A total of 16 (0.4%) patients (age 60±15 years, LVEF 38±16%) with LV-FT VAs were identified. Of these, 9 (56%) had focal PVC/VT from the LV-FT and 7 (44%) scar-related monomorphic VT with critical circuit elements involving the LV-FT. The most common anatomical locations of the LV-FT were between the posteromedial PM and LV septum, between the anterolateral and posteromedial PM and between the LV apex and the mid-septum. Purkinje potentials in sinus rhythm were recorded on the LV-FT at the VA target site in only 1 case. Acute ablation success was achieved in 15 (94%) patients (Figure). After a median follow-up of 1.5 years, the targeted LV-FT VA recurred in 4 (31%). The LV-FT can be a rare site of origin of focal VAs or may contain critical circuit elements of scar-related VTs. Mapping and catheter ablation guided by ICE is successful in eliminating LV-FT VAs in most cases.

Practical Approaches to Catheter Ablation of Idiopathic Ventricular Arrhythmias

In this review, we provide a practical approach to the catheter ablation of idiopathic focal ventricular arrhythmias (VAs) by summarizing the electrocardiographic (ECG) characteristics, mapping strategies, and ablation techniques for each of the major types of idiopathic VAs. We identify special considerations to be taken when treating specific forms of idiopathic VAs with catheter ablation that can increase success rates and reduce complications. Insights on ECG morphologies of VAs have led to novel criteria that can aid in accurate identification and localization of VA sites of origin. Advancements in mapping catheters and software as well as the use of intracardiac echocardiography have allowed for more precise mapping and ablation of arrhythmias arising from complex cardiac structures. Idiopathic VAs occurring in patients without overt structural heart disease can be categorized into four groups on the basis of anatomic location: (1) outflow tract VAs (which include the right ventricular outflow tract, left ventricular outflow tract, and left ventricular summit; (2) fascicular VAs; (3) papillary muscle VAs; and (4) annular VAs. Knowledge of the ECG characteristics of idiopathic VAs and the three-dimensional anatomy surrounding their sites of origin can guide pre-procedure planning, prioritization of cardiac regions for mapping, and approach for ablation.

Fluoroless catheter ablation of supraventricular and ventricular arrhythmias in pregnancy: validation of a standard approach in a large multicenter registry

Abstract Background An increasing experience in zero- (ZF) or near-zero fluoroscopy catheter ablation (CA) supports the implementation of early, fluoroless approach for recurrent, symptomatic arrhythmias in pregnancy. Purpose The aim of the study was to evaluate the feasibility, efficacy, and safety of CA with a standardized ZF approach during pregnancy. Methods Data were derived from a large prospective multicenter registry (ELEKTRO-RARE-A-CAREgistry). Between 2012 and 2019, more than 2655 CA procedures were performed in women in intention-to-treat using a ZF fluoroscopy approach. The procedures were performer using: 1) femoral access, 2) double-catheter technique, without intracardiac echocardiography, 3) electroanatomic mapping system (Ensite, Abbott, USA) for mapping and navigation, 4) conscious, light sedation. Shared decision making approach was applied, including a pregnancy heart team consultations. Results The study group consisted of 18 pregnant women (mean age: 30.3±5.0 years; range: 19–38 years; mean gestational age during CA: 21.4±9.2 weeks; range: 7–36 weeks). All pregnant women had no overt structural heart disease. Among women in reproductive age, pregnant women referred for ZF-CA approach accounted for approximately 2% of procedures. In the study group, the major indications for CA included: AVNRT (n=10); OAVRT/WPW (n=2); focal idiopathic ventricular arrhythmia (n=4), AT (n=1) and AF (n=1). Five women had double substrate for CA. In AF case general anesthesia and transesophageal echocardiography were used to monitor ZF-transseptal puncture and right-sided pulmonary vein isolation. All procedures were successfully completed without fluoroscopy, and without serious maternal or fetal complications. The procedure and ablation application times were 55.0±30.0 min and 394±338 s, respectively. In one patient second procedure for idiopathic ventricular arrhythmia was postponed after delivery. Conclusion Implementation of pregnancy heart team and a standard fluoroless protocol for CA in daily electrophysiological practice allowed an early, safe, and effective CA of maternal supraventricular tachycardia and idiopathic ventricular arrhythmias in pregnancy. Funding Acknowledgement Type of funding source: None

Strategies for Catheter Ablation of Left Ventricular Papillary Muscle Arrhythmias: AnInstitutional Experience.

This study sought to address whether technological innovations such as contact force sensing (CFS) can improve acute and long-term ablation outcomes of left ventricular papillary muscle (LV PAP) ventricular arrhythmias (VAs). Catheter ablation of LV PAP VAs has been less efficacious than another focal VAs. It remains unclear whether technological innovations such as CFS can improve acute and long-term ablation outcomes of LV PAP VA. From January 2015 to December 2019, a total of 137 patients underwent LV PAP VA ablation. VA site of origin (SOO) was identified using activation and pace-mapping guided by intracardiac echocardiography. Radiofrequency energy (20 to 50W for 60 to 90 s) was delivered by irrigated catheter with or without CFS. We defined acute success as complete suppression of targeted VA≥30min post ablation and clinical success as ≥80% VA burden reduction at outpatient follow-up. VA manifested as premature ventricular complexes in 98 (71%), nonsustained ventricular tachycardia in 18 (13%), sustained ventricular tachycardia in 12 (9%) and premature ventricular complexes induced ventricular fibrillation in 9 (7%). VA SOO was anterolateral PAP in 51 (37%), posteromedial PAP in 73 (53%), and both PAPs in 13 (10%). VAs were targeted using CFS in 97 (71%) and non-CFS in 40 (29%). After a single procedure, acute success was achieved in 130 (95%) and clinical success was achieved in 112 (82%); neither was impacted by VA SOO and/or CFS. Complications occurred in 5 patients (3.6%). Independent of CFS technology, intracardiac echocardiography-guided catheter ablation is highly efficacious and may be considered as first-line therapy in the management of LV PAP VA.

Special considerations in mapping and ablation of focal ventricular arrhythmias originating from the left ventricular outflow tract in patients with a transcatheter aortic valve replacement.

Transcatheter aortic valve replacements (TAVRs) have been increasingly performed in high-risk patients with severe aortic stenosis. Focal ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) can occur after a TAVR, and radiofrequency catheter ablation (RFCA) should be considered as a treatment option when those VAs are drug-refractory. There are specific challenges in the RFCA of LVOT VAs after a TAVR because the tubular structure of the TAVR device sits in the LVOT. However, if the anatomical background of the TAVR and LVOT VAs are well understood and the anatomical relationship between the TAVR device and LVOT is sufficiently evaluated, RFCA of LVOT VAs in patients with a TAVR should be safe and highly successful.

GW29-e1352 Unipolar electrogram based quantitative criteria improves specificity for predicting arrhythmogenic site in focal idiopathic outflow tract ventricular arrhythmia mapping and ablation

GW29-e1352 Unipolar electrogram based quantitative criteria improves specificity for predicting arrhythmogenic site in focal idiopathic outflow tract ventricular arrhythmia mapping and ablation

Catheter Ablation of Ventricular Arrhythmia for Ebstein's Anomaly in Unoperated and Post-Surgical Patients.

The purpose of this study was to determine the ventricular arrhythmia (VA) substrates in patients with unoperated and post-surgical Ebstein's Anomaly (EA). EA is associated with variable atrialization of the right ventricle and a propensity for VA and sudden death. There are scant data on catheter ablation for VA in this population. This was a retrospective study involving 11 congenital heart disease centers. A total of 24 patients (median age 17 [interquartile range (IQR): 11 to 37] years; age range 1 to 68 years; 42% men) with EA undergoing catheter ablation were identified. Prior tricuspid valve (TV) surgery had been performed in 12 (50%). Presenting symptoms were palpitations in 15, syncope in 4, aborted cardiac arrest in 4, and none in 1. At procedure, 28 VA substrates were encountered and 25 were completely characterized (median 1 per patient; cycle length 305 [IQR: 268 to 400] ms). In 3 cases, premature ventricular contraction (PVC) foci were targeted (1 with a history of PVC-induced ventricular fibrillation). VA mechanisms were focal in 15 and macro-re-entrant in 10, and did not differ significantly between those with and those without prior TV surgery (p= 0.7). Focal VAs predominantly localized to the atrialized right ventricle ARV in unoperated patients and to diseased myocardium or Purkinje tissue after TV surgery. Macro-re-entry was related to isolated scar or split potentials in the ARV in unoperated patients, and larger, more diffuse scar after TV surgery. Complete success was achieved in 22 (92%). There were 2 of 13 complications in patients<18 years of age and none in patients >18 years of age. There was a single recurrence over a median follow-up of 3.4 years. VA in EA may be either focal or macro-re-entrant. In the absence of surgery, substrates chiefly involve the ARV. After surgery, focal VA involves injured myocardium or Purkinje tissue and re-entrant ventricular tachycardia is related to post-surgical scar. Catheter ablation is a reasonable therapeutic approach for these patients.

Catheter ablation of papillary muscle arrhythmias: Implications of mitral valve prolapse and systolic dysfunction.

The left ventricular (LV) papillary muscles are important components of the mitral valve apparatus. Catheter ablation of ventricular arrhythmias from these sites is challenging. We aim to describe the association between LV papillary muscle ventricular arrhythmias (VAs) and mitral valve prolapse (MVP), and to determine the outcomes of ablation in these patients with a focus on those with MVP and cardiomyopathy. A total of 152 patients underwent 170 consecutive procedures for ablation of focal VAs. MVP and cardiomyopathy were diagnosed by echocardiography. Outcomes following ablation were assessed in three groups: (1) LV papillary muscle VAs versus other sites, (2) LV papillary muscle VAs by the presence of MVP, and (3) LV papillary muscle VAs in the setting of cardiomyopathy. Nine of 23 (39%) patients undergoing ablation of LV papillary muscle VAs had MVP compared to none of 129 (0%) patients at other sites (P<0.001). In the former group, acute procedural success was achieved in 60% and 80% of those with and without MVP, respectively (P=0.28). Medium-term outcomes were comparable (P=0.75). In patients with cardiomyopathy, the median LV ejection fraction improved from 40% to 54% following ablation (P=0.007). Although MVP is strongly associated with LV papillary muscle VAs, MVP does not adversely affect the acute or medium-term outcomes of ablation. Systolic function can improve following ablation in patients with ectopy-mediated cardiomyopathy due to papillary muscle VAs.

Assessment of a conduction-repolarisation metric to predict Arrhythmogenesis in right ventricular disorders

BackgroundThe re-entry vulnerability index (RVI) is a recently proposed activation-repolarization metric designed to quantify tissue susceptibility to re-entry. This study aimed to test feasibility of an RVI-based algorithm to predict the earliest endocardial activation site of ventricular tachycardia (VT) during electrophysiological studies and occurrence of haemodynamically significant ventricular arrhythmias in follow-up. MethodsPatients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) (n = 11), Brugada Syndrome (BrS) (n = 13) and focal RV outflow tract VT (n = 9) underwent programmed stimulation with unipolar electrograms recorded from a non-contact array in the RV. ResultsLowest values of RVI co-localised with VT earliest activation site in ARVC/BrS but not in focal VT. The distance between region of lowest RVI and site of VT earliest site (Dmin) was lower in ARVC/BrS than in focal VT (6.8 ± 6.7 mm vs 26.9 ± 13.3 mm, p = 0.005). ARVC/BrS patients with inducible VT had lower Global-RVI (RVIG) than those who were non-inducible (−54.9 ± 13.0 ms vs −35.9 ± 8.6 ms, p = 0.005) or those with focal VT (−30.6 ± 11.5 ms, p = 0.001). Patients were followed up for 112 ± 19 months. Those with clinical VT events had lower Global-RVI than both ARVC and BrS patients without VT (−54.5 ± 13.5 ms vs −36.2 ± 8.8 ms, p = 0.007) and focal VT patients (−30.6 ± 11.5 ms, p = 0.002). ConclusionsRVI reliably identifies the earliest RV endocardial activation site of VT in BrS and ARVC but not focal ventricular arrhythmias and predicts the incidence of haemodynamically significant arrhythmias. Therefore, RVI may be of value in predicting VT exit sites and hence targeting of re-entrant arrhythmias.

Late cure of focal ventricular arrhythmias post-catheter ablation: electrophysiological characteristics and long-term outcome.

Late cure after a previously failed ablation of ventricular arrhythmias (VAs) is a relatively common phenomenon. The present study sought to delineate the incidence and electrophysiological characteristics of late cure in idiopathic VA patients. Totally, 45 idiopathic VA cases (mean age 44 ± 18years, 27 males) either failed acutely or recurred within 12h were enrolled in this study. Based on intensive clinical observations in the acute period, 19 (42%) patients demonstrated late cure in the first week after the procedure. The late cure patients had significantly better acute and cumulative ablation effects during the procedure than did those without a late cure. Additionally, they had a prediction that originated from the right ventricular outflow tract, aortic-mitral continuum, and left summit area relative to other sites (13/18 vs 6/27, p < 0.01). In a median follow-up of 24 [14, 46] months, 7/19 (37%) patients had their VAs recurred. The late cure group had significantly more patients cured at long-term follow-up than those without (12/19 vs 0/26, p < 0.01). A cutoff value of the "time to eliminate VAs" > 7.0s was able to predict a long-term recurrence of the VAs with 62.5% sensitivity and 85.7% specificity. The late cure of VAs occurs in more than one third of patients who have a seemingly unsuccessful ablation session, which is clustered in the first week after the procedure. However, long-term recurrence of VAs occurred in 37% of the late cure patients, emphasizing the importance of long-term follow-up.

Ventricular Ectopy in the Context of Left Ventricular Systolic Dysfunction: Risk Factors and Outcomes Following Catheter Ablation

Ectopy-mediated cardiomyopathy (EMC) is a potentially reversible form of left ventricular systolic dysfunction. Various risk factors for the development of EMC have been proposed in the literature. We aim to assess medium term outcomes of focal ventricular arrhythmia (VA) ablation in the setting of cardiomyopathy (CMP) and to validate published risk factors for EMC. Medium term recovery of left ventricular (LV) function and freedom from VA recurrence was assessed and compared between patients undergoing focal VA ablation in the setting of CMP and a control group with normal LV function. Univariate and multivariate analyses for CMP risk factors were performed and compared against prior published risk factors. Of 152 patients who underwent 170 focal VA ablation procedures, 54 (36%) had CMP and the remaining 98 patients had normal LV systolic function. At medium term follow-up, 85% of patients with CMP were free of VA recurrence and median left ventricular ejection fraction (LVEF) had improved from 40 to 52%. Age, male gender, premature ventricular complex (PVC) burden, non- right ventricular outflow tract (RVOT) sites of origin, PVC QRS duration and PVC minimum coupling interval were predictive of CMP on univariate analysis, but only gender persisted on multivariate analysis. Medium term outcome in patients undergoing focal VA in the setting of CMP are satisfactory with improvement in LV function achievable in most patients. Prior risk factors described in the literature are variable and inconsistent, likely reflecting heterogeneous study populations.

Three-Dimensional Noninvasive Imaging of Ventricular Arrhythmias in Patients With Premature Ventricular Contractions.

Noninvasive imaging of cardiac electrical activity promises to provide important information regarding the underlying arrhythmic substrates for successful ablation intervention and further understanding of the mechanism of such lethal disease. The aim of this study is to evaluate the performance of a novel 3-D cardiac activation imaging technique to noninvasively localize and image origins of focal ventricular arrhythmias in patients undergoing radio frequency ablation. Preprocedural ECG gated contrast enhanced cardiac CT images and body surface potential maps were collected from 13 patients within a week prior to the ablation. The electrical activation images were estimated over the 3-D myocardium using a cardiac electric sparse imaging technique, and compared with CARTO activation maps and the ablation sites in the same patients. Noninvasively-imaged activation sequences were consistent with the CARTO mapping results with an average correlation coefficient of 0.79, average relative error of 0.19, and average relative resolution error of 0.017. The imaged initiation sites of premature ventricular contractions (PVCs) were, on average, within 8 mm of the last successful ablation site and within 3 mm of the nearest ablation site. The present results demonstrate the excellent performance of the 3-D cardiac activation imaging technique in imaging the activation sequence associated with PVC, and localizing the initial sites of focal ventricular arrhythmias in patients. These promising results suggest that the 3-D cardiac activation imaging technique may become a useful tool for aiding clinical diagnosis and management of ventricular arrhythmias.