Outflow Tract Ventricular Arrhythmias Research Articles

Mapping and Ablation of Arrhythmias from Uncommon Sites (Aortic Cusp, Pulmonary Artery, and Left Ventricular Summit).

Despite advances in our understanding of the relevant anatomy and mapping and catheter ablation techniques of idiopathic outflow tract ventricular arrhythmias, challenging sites for catheter ablation remain the aortic cusps, pulmonary artery, and notably the left ventricular summit. A systematic approach should be used to direct mapping efforts efficiently between endocardial, coronary venous, and epicardial sites. Foci at the left ventricular summit, particularly intraseptal and at the inaccessible epicardial region, remain difficult to reach and when percutaneous techniques fail, surgical ablation remains an option but with risk of late coronary artery stenosis.

Mapping and Ablation of Ventricular Outflow Tract Arrhythmias.

Arrhythmias arising from the ventricular outflow tracts are commonly encountered. Although largely benign, they can also present with heart failure and sudden cardiac death. Mapping and ablation of these arrhythmias is commonly performed in the electrophysiology laboratory with a high success rate, but occasionally can prove challenging to abolish. This article discusses the mapping and ablation of outflow tract arrhythmias and the challenges that can be overcome by a systematic approach.

Trends in Successful Ablation Sites and Outcomes of Ablation for Idiopathic Outflow Tract Ventricular Arrhythmias

This study sought to examine clinical characteristics of procedural and long-term outcomes in patients undergoing catheter ablation (CA) of outflow tract ventricular arrhythmias (OT-VAs) over 16 years. CA is an effective treatment strategy for OT-VAs. Patients undergoing CA for OT-VAs from 1999 to 2015 were divided into 3 periods: 1999 to 2004 (early), 2005 to 2010 (middle), and 2011 to 2015 (recent). Successful ablation site (right ventricular OT, aortic cusps/left ventricular OT, or coronary venous system/epicardium), VA morphology (right bundle branch block or left bundle branch block), and acute and clinical success rates were assessed. Six hundred eighty-two patients (336 female) were included (early: n=97; middle: n=204; recent: n=381). Over time there was increase in use of irrigated ablation catheters and electroanatomic mapping, and more VAs were ablated from the aortic cusp/left ventricular OT or coronary venous system/epicardium (14% vs. 45% vs. 56%; p<0.0001). Acute procedural success was achieved in 585 patients (86%) and was similar between groups (82% vs. 84% vs. 88%; p=0.27). Clinical success was also similar between groups (86% vs. 87% vs. 88%; p=0.94), but more patients in earlier periods required repeat ablation (18% vs. 17% vs. 9%; p=0.02). Overall complication rate was 2% (similar between groups). Over a 16-year period there was an increase in patients undergoing CA for OT-VTs, with more ablations performed at non-right ventricular outflow tract locations using electroanatomic mapping and irrigated-tip catheters. Over time, single procedure success has improved and complications have remained limited.

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

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

P3750Efficiency of electrocardiographic algorithms in management of idiopathic outflow tract ventricular arrhythmias in children

Abstract Introduction Ablation of idiopathic ventricular arrhythmias (IVA) originating in left ventricle outflow tract (LVOT) are more challenging as compared to right ventricle outflow tract (RVOT). In recent years, several ECG algorithms predicting the site of origin (SOO) of arrhythmia for adult population have been published. There is a sparse information on their diagnostic performance in children. Purpose The aim of this study was to validate two algorithms: 1) Novel TZ index, 2) V2S/V3R and their combined application in children for predicting the appropriate SOO of IVA. Methods Two groups of children without structural heart disease, thorax anomalies and normal QRS complexes during sinus rhythm were included in the study: 1) patients with IVA with inferior axis who underwent successful RFCA using the 3D-electroanatomical system, 2) patients with paced or mechanically-induced QRS complexes from LVOT or RVOT during other procedures. ECGs were analyzed in a specially developed software for analyzing the amplitude of the QRS complex waves. Semi-automated measurements of amplitudes of QRS complexes and calculations were carried out for 2 published algorithms: 1) Novel TZ index, 2) V2S/V3R. The results of their separate and combined use were compared with SOO of acute successful RFCA and mapping or spot of pacing. Results 108 PVC morphologies (68 from the RVOT and 40 from LVOT) from 74 pediatric patients (age: 14.0±2.9, 39 female) were included into the study. The algorithm V2S/V3R predicted left-sided SOO with a sensitivity and specificity of 94%. Novel TZ-index showed sensitivity of 89% and specificity of 84%. Combined use of Novel TZ-index+V2S/V3R showed high sensitivity (92%) and very height specificity (97%) of the LVOT SOO prediction Conclusion Both algorithms allowed accurate, simple and precise identification of SOO of RVOT/LVOT IVA in children. The combined use of those algorithms may facilitate additional pharmacologic treatment, omitting RVOT mapping with direct mapping LVOT, performance of the procedure by experienced operator.

The V1-V3 transition index as a novel electrocardiographic criterion for differentiating left from right ventricular outflow tract ventricular arrhythmias.

The aim of this study was to develop a new electrocardiographic criterion for differentiating the origin of outflow tract ventricular arrhythmias (OT-VAs) with precordial transition in lead V3. A total of 147 consecutive patients with OT-VAs displaying precordial transition in lead V3 who underwent successful catheter ablation in the right ventricular outflow tract (RVOT) (n = 118) or left ventricular outflow tract (LVOT) (n = 29) were included in this study. The V1-V3 transition index was defined as the sum of S-wave amplitude in lead V1 and V2 during premature ventricular contractions (PVCs) divided by the S-wave amplitude during sinus rhythm (SR), respectively, minus the sum of R-wave amplitude in lead V1, V2, and V3 during PVCs divided by the R-wave amplitude during SR, respectively, i.e., [(SPVC/SSR)V1 + (SPVC/SSR)V2] - [(RPVC/RSR) V1 + (RPVC/RSR)V2 + (RPVC/RSR)V3]. The V1-V3 transition index was significantly higher for RVOT origins than for LVOT origins (1.25 ± 2.48 vs. - 3.94 ± 3.11; P < 0.001). Receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.931 for the V1-V3 transition index, and a cutoff value of > - 1.60 predicted a RVOT origin with a 93% sensitivity and 86% specificity. With respect to AUC and accuracy, the V1-V3 transition index was superior to any previously proposed ECG indices for differentiating left from right OT-VAs. In 37 prospective cases, the new index was able to predict the site of a RVOT origin with 95% accuracy (35 of 37 cases). The V1-V3 transition index is a useful novel ECG criterion for distinguishing left from right OT-VAs with precordial transition in lead V3.

Utility of local atrial electrogram pattern for predicting left main coronary artery anatomical distance during mapping in the left pulmonary sinus of valsalva.

Ablation of right ventricular outflow tract (RVOT) ventricular arrhythmia (VA) within the left pulmonary sinus of Valsalva (LPSV) may increase the risk of left main coronary artery (LMCA) injury. To delineate the anatomical characteristics between LMCA and LPSV and their association with atrial potential (AP) mapping in LPSV. A total of 104 consecutive patients with RVOT-VA undergoing cardiac-gated computed tomography coronary angiography (CTCA) after ablation were retrospectively analyzed. The LMCA-LPSV anatomic relationship was classified into three types based on the CTCA measurements. Types 1 and 2 had a shorter LMCA-LPSV distance than that of type 3 (P < .001). The left atrial appendage (LAA)-LMCA distance and LAA-LPSV distance were associated with the incidence of AP in LPSV (odds ratio [OR] = 3.43, 95% confidence interval [CI]: 1.86-6.34, P < .001; OR = 1.196, 95% CI: 1.09-1.31, P < .001, respectively). Furthermore, the LMCA-LPSV distance showed a linear correlation with the LAA-LPSV distance (r2 = 0.93, P < .001). According to receiver operating characteristic (ROC) analysis, a LMCA-LPSV distance <5.4 mm could predict the possibility of AP during LPSV mapping (sensitivity 83%, specificity 81%, and area under the ROC curve 0.86). The presence of AP in the LPSV may be useful to predict a short distance from the LPSV to the LMCA and to identify patients at higher risk of LMCA injury. This information may contribute to efficient and safe ablation in this area but should be confirmed in future studies.

Clinical efficacy of open-irrigated electrode cooled with half-normal saline for initially failed radiofrequency ablation of idiopathic outflow tract ventricular arrhythmias.

Acute failure of radiofrequency ablation (RFA) of ventricular arrhythmias (VAs) occur in 10%-20% of patients and is partly attributed to inadequate lesion depth acquired with standard ablation protocols. Half-normal saline (HNS)-irrigation is a promising strategy to improve the success rate of VA ablation. This study investigated the efficacy of HNS-irrigated ablation after a failed standard plain normal saline solution (PNSS)-irrigated ablation on idiopathic outflow tract ventricular arrhythmia (OT-VA). This is a prospective observational study of consecutive patients undergoing RFA of idiopathic OT-VA comparing the efficacy of additional HNS-irrigated ablation for failed standard PNSS-irrigated ablation. Acute failure was defined as persistence of spontaneous VA or persistent inducibility of the clinical VA. Out of 160 OT-VA cases (51 ± 15-year-old, 62 males), 31 underwent HNS irrigation after a failed standard PNSS-irrigated ablation. The HNS group had a significantly longer procedure time (60.06 ± 43.83 vs 37.51 ± 33.40 minutes; P = .013) and higher radiation exposure (31.45 ± 20.24 vs 17.22 ± 15.25 minutes; P = .001) than the PNSS group but provided an additional acute success in 21 of 31 (67.7%) patients. Over a follow-up duration of 7.8 ± 4.6 months, 24 recurrences were identified, including 8 (25.8%) in the HNS and 16 (12.4%) in the PNSS group, with lower freedom from recurrence in the HNS group (log rank P = .009). No major complication was observed. HNS-irrigated ablation after failed standard PNSS-irrigated ablation is safe and additionally improves acute ablation success by 67.7% for idiopathic OT-VA but with a higher rate of recurrence on follow-up. Whether the application of HNS as initial irrigant could result in better outcome requires further investigation.

Late fractionated potentials in catheter ablation for right ventricular outflow tract ventricular arrhythmias.

Endocardial late fractionated potentials during sinus rhythm mapping may reflect abnormal "subendocardial" substrates associated with right ventricular outflow tract (RVOT) ventricular arrhythmias (VAs). The aim of this study was to explore the clinical outcomes of catheter ablation guided by these late fractionated potentials for RVOT VAs in patients without structural heart disease. From January 2016 to March 2018, 28 patients underwent catheter ablation for RVOT premature ventricular contractions (PVCs) or ventricular tachycardia (VT), guided by the EnSite NavX or Velocity V5.0 three-dimensional mapping system (Abbott, St. Paul, MN, USA). Among them, 10 patients (35.7%) were found to have endocardial late fractionated potentials during sinus rhythm mapping (Group 1). Group 2 was composed of 18 patients in whom no endocardial late fractionated potentials were seen. The burden of VAs, acute procedural success, and 3-month clinical outcomes were analyzed. The average duration of late fractionated potentials after the end of QRS during sinus rhythm mapping in group 1 was 45.00±17.15 ms. Baseline demographics and morphology and burden of PVCs were similarly distributed between both groups. Group 1 had higher acute procedural success compared to group 2 (100%vs 66.7%; P=.039). Moreover, at 3-month follow-up, group 1 had lower total PVCs (49 (1-5986) versus 4316 (1-23231); P=.048), PVC burden (0% (0-5.9) vs 4.3% (0-18.9); P=.055), and higher clinical success (100%vs 55.6%; P=.025) compared to group 2. The identification and elimination of endocardial late fractionated potentials during sinus rhythm mapping could improve the acute success and short-term outcomes of ablation for RVOT VAs.

Correction to: Differentiating Right- and Left-Sided Outflow Tract Ventricular Arrhythmias: Classical ECG Signatures and Prediction Algorithms

Correction to: Differentiating Right- and Left-Sided Outflow Tract Ventricular Arrhythmias: Classical ECG Signatures and Prediction Algorithms

Long-term follow-up and comparison of techniques in radiofrequency ablation of ventricular arrhythmias originating from the aortic cusps (AVATAR Registry)

Radiofrequency ablation (RFA) of outflow tract ventricular arrhythmia (VA) that originates from the aortic cusps can be challenging. Data on long‑ term efficacy and safety as well as optimal technique after aortic cusp ablation have not previously been reported. This aim of the study was to determine the short- and long‑ term outcomes after RFA of aortic cusp VA, and to evaluate aortic valve injuries according to echocardiographic screening. This was a prospective multicenter registry (AVATAR, Aortic Cusp Ventricular Arrhythmias: Long Term Safety and Outcome from a Multicenter Prospective Ablation Registry) study. A total of 103 patients at a mean age of 56 years (34-64) from the "Electra" Registry (2005-2017) undergoing RFA of aortic cusps VA were enrolled. The following 3 ablation techniques were used: zero‑fluoroscopy (ZF; electroanatomical mapping [EAM] without fluoroscopy), EAM with fluoroscopy, and conventional fluoroscopy‑ based RFA. Data on clinical history, complications after RFA, echocardiography, and 24‑ hour Holter monitoring were collected. The follow up was 12 months or longer. There were no major acute cardiac complications after RFA. In one case, a vascular access complication required surgery. The median (interquartile range [IQR]) procedure time was 75 minutes (IQR, 58-95), median follow‑ up, 32 months (IQR, 12-70). Acute and long term procedural success rates were 93% and 86%, respectively. The long‑ term RFA outcomes were observed in ZF technique (88%), EAM with fluoroscopy (86%), and conventional RFA (82%), without differences. During long‑ term follow‑up, no abnormalities were found within the aortic root. Ablation of VA within the aortic cusps is safe and effective in long‑ term follow up. The ZF approach is feasible, although it requires greater expertise and more imaging modalities.

Prognostic Value of Time Dependent Voltage Abatement During Remote Magnetic Navigation Guided Ablation in Idiopathic Right Ventricular Outflow Tract Arrhythmias

scholarly articles on cardiology Journal of Cardiology & Cardiovascular Therapy is an Open Access, international peer reviewed journal launched from Juniper Publishers. Cardiology is a branch of medicine deals with the disorders of heart that keeps cardiologists up to date with advances in the diagnosis and treatment of cardiovascular diseases.

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.

Magnetic resonance imaging abnormalities in the basal interventricular septum of patients with left ventricular outflow tract arrhythmias.

Concealed structural abnormalities were detected by delayed enhancement - magnetic resonance imaging (DE-MRI) in patientswith apparently idiopathic tachycardia of left ventricular (LV) origin. Basal septal fibrosis was evaluated as a potential arrhythmia substrate in patients with left ventricular outflow tract (LVOT) arrhythmias. A total of 22 patients with LVOT arrhythmias, including frequent monomorphic premature ventricular complexes (PVCs) in 15 patients and ventricular tachycardia (VT) in 7 patients, underwent catheter ablation and DE-MRI. A total of 19 patients with frequent PVCs and 17 patients with idiopathic VT of other origin served as a control group. Basal septal intramural fibrosis as thin strip-shaped intramyocardial DE or as marked intramyocardial DE involving >25% of wall thickness was detected more frequently in patients with LVOT arrhythmias (41% and 32%) than in patients with non LVOT arrhythmias (14% and 3%). After successful ablation, 4/16 patients with basal septal intramural fibrosis and LVOT PVCs (n = 3) or LVOT VT (n = 1) compared with no patient without basal septal fibrosis experienced episodes of sustained VT with similar or different QRS morphology resulting in ICD therapy in three patients. Follow-up DE-MRI after PVC ablation (17 ± 7 months) revealed an increase in LV ejection fraction from 49 ± 5% to 56 ± 5% (n = 9) but the amount of septal DE remained unchanged. Basal septal intramural fibrosis may serve as the arrhythmia substrate in a substantial part of patients with premature ventricular complexes (PVCs) and VT originating from the LVOT and identifies patients with continued risk for VT recurrence after initially successful ablation of LVOT arrhythmias.

NON-INVASIVE ELECTROANATOMICAL MAPPING FOR PREDICTING SITE OF ORIGIN OF OUTFLOW TRACT VENTRICULAR TACHCYARDIAS

Prediction of site of origin of ventricular arrhythmias (VA) prior to ablation is important for procedural prognostication, risk assessment and preparation. We used noninvasive electrocardiographic mapping (ECM) to identify the origin of outflow tract VAs (OTVA). We included patients with OTVA

A rule-based method to model myocardial fiber orientation in cardiac biventricular geometries with outflow tracts.

Rule-based methods are often used for assigning fiber orientation to cardiac anatomical models. However, existing methods have been developed using data mostly from the left ventricle. As a consequence, fiber information obtained from rule-based methods often does not match histological data in other areas of the heart such as the right ventricle, having a negative impact in cardiac simulations beyond the left ventricle. In this work, we present a rule-based method where fiber orientation is separately modeled in each ventricle following observations from histology. This allows to create detailed fiber orientation in specific regions such as the endocardium of the right ventricle, the interventricular septum, and the outflow tracts. We also carried out electrophysiological simulations involving these structures and with different fiber configurations. In particular, we built a modeling pipeline for creating patient-specific volumetric meshes of biventricular geometries, including the outflow tracts, and subsequently simulate the electrical wavefront propagation in outflow tract ventricular arrhythmias with different origins for the ectopic focus. The resulting simulations with the proposed rule-based method showed a very good agreement with clinical parameters such as the 10ms isochrone ratio in a cohort of nine patients suffering from this type of arrhythmia. The developed modeling pipeline confirms its potential for an in silico identification of the site of origin in outflow tract ventricular arrhythmias before clinical intervention.

Electrophysiological characteristics of the earliest activation site in idiopathic right ventricular outflow tract arrhythmias under mini‐electrode mapping

Right ventricular outflow tract ventricular arrhythmias (RVOT VAs) often originate in the voltage-transitional zone. The target electrogram could be compromised by the architecture of the roving catheter. Mini-electrodes could improve the mapping resolution, especially in low-voltage areas. The aim was to assess the electrophysiological characteristics of the earliest activation site (EAS) of RVOT VAs during mapping using mini-electrodes. Twenty-seven patients with RVOT-type VAs were mapped using Orion mini-electrodes and the Rhythmia mapping system. Bipolar and unipolar electrograms were analyzed and compared with conventional ablation catheter recordings. Twenty-five patients (25 of 27) were successfully mapped and ablated at the RVOT. At the EAS, all 25 (100%) patients exhibited local sharp potentials (spiky potential) at the VAs, and 88% (22 of 25) individuals showed reverse late potentials in adjacent sinus beats on the bipolar mini-electrode recordings. Related unipolar electrograms manifested 20% "q-plateau-QS," 76% "gross QS," and 4% "late QS" patterns related to spiky potential voltages and advanced times. Compared with electrograms recorded by ablation catheter, bipolar mini-electrode recordings exhibited significantly shorter spiky potential durations (P = 0.001) and a significantly increased incidence of the reverse late potentials (P = 0.041). Unipolar mini-electrode recordings had a lower incidence ratio of "late QS" patterns (P = 0.039). Compared with ablation catheter mapping, mini-electrodes improved the mapping resolution of the EAS of RVOT VAs and exhibited shorter spiky potential durations and reduced incidence of "later QS" unipolar patterns.

Differentiating Right- and Left-Sided Outflow Tract Ventricular Arrhythmias – A Review of “Classical” ECG Signatures and Prediction Algorithms

Differentiating Right- and Left-Sided Outflow Tract Ventricular Arrhythmias – A Review of “Classical” ECG Signatures and Prediction Algorithms

Anatomical proximity dictates successful ablation from adjacent sites for outflow tract ventricular arrhythmias linked to the coronary venous system.

Catheter ablation of outflow tract ventricular arrhythmias (OTVAs) with the earliest activation within the coronary venous system (CVS) can be challenging. When ablation from the CVS is not feasible or ineffective, an approach from anatomically adjacent site(s) can be considered. We report the outcomes of an anatomical approach for OTVAs linked to the CVS. We retrospectively analysed 665 OTVA patients. Of these, 65 (9.8%) had the earliest activation within the CVS. In 53 (82%) cases, an anatomical approach was attempted. The targeted adjacent anatomical structure was the endocardial left ventricular outflow tract (LVOT) in 24 (45%), the left coronary cusp or the left/right cusp junction in 17 (32%) patients, and the right ventricular outflow tract (RVOT) in 12 (23%). The anatomical approach was successful in 26 (49%) patients (27% from the coronary cusps, 65% from the LVOT, and 8% from the RVOT). The difference in activation times between the earliest activation site within the CVS and the targeted site was not significantly different between the successful and unsuccessful groups (14.2 ± 11.2 ms vs. 13.2 ± 9.3 ms; P = 0.89). The anatomical distance from the earliest activation site to the targeted site was shorter for the successful group (9.7 ± 2.4 mm vs. 13.1 ± 6.5 mm; P < 0.05). In particular, when the anatomical distance was >12.8 mm, anatomical approach was successful in only 1/13 (8%). In patients with OTVAs linked to the CVS, an anatomical approach targeting an adjacent site can be effective, particularly when the distance between the sites is <12.8 mm.

Variant of ventricular outflow tract ventricular arrhythmias requiring ablation from multiple sites: Intramural origin

The optimal site of ablation of idiopathic left ventricular outflow tract (LVOT) ventricular arrhythmias (VAs) is challenging as activation mapping can reveal similar activation times in different anatomical sites, suggesting an intramural origin. We sought to assess whether in patients with intramural VAs and with multiple early activation sites (EASs), sequential ablation of all the early EASs could improve acute and long-term clinical outcomes. A total of 116 patients undergoing catheter ablation for symptomatic LVOT VAs were enrolled in this study. Thirty-nine patients (34%) were referred for a redo procedure, whereas the remaining presented for a first procedure. Mapping was performed manually in 86 cases (74%) and with a magnetic robotic system (Niobe, Stereotaxis, St. Louis, MO) in the remainder of the cases. Of the 116 patients, 15 (13%) were found to have multiple sites of equally early activation. In patients with multiple EASs, the mean pre-QRS activation time was significantly less than in patients with a single EASs (-26 ± 3 ms vs -38 ± 6 ms; P<.005). Sequential ablation of all the EASs was possible in 14 patients (93%), resulting in complete arrhythmia suppression. After a mean follow-up of 21 ± 5 months, all patients with successful ablation of all multiple early EASs remained free from clinical VAs. Intramural LVOT VAs manifesting with multiple EASs require ablation at all sites to achieve acute and long-term success, particularly if none of the EASs is > -30ms pre-QRS activation time.