Left Ventricular Outflow Tract Origin Research Articles

The V6R/V5R index, a novel ECG criterion, can identify idiopathic ventricular arrhythmias arising from the aortic cusp

Abstract Background Idiopathic ventricular arrhythmias (VAs) with a left ventricular outflow tract (LVOT) origin often have dominant R waves (R wave amplitude>S wave amplitude) in the precordial leads (V1 through V6). Radiofrequency catheter ablation (RFCA) within the aortic cusp can eliminate LVOT-VAs. However, some require RFCA at the aorto-mitral continuity (AMC), the endocardium just below the LV summit, and/or mitral annulus for a cure. No ECG indices have been fully established to help differentiate between VAs that can be ablated from the aortic cusp and those that require ablation from other sites. Purpose The purpose of this study was to identify ECG indices useful in differentiating VAs with an aortic cusp origin from those from outside the cusp among the LVOT-VAs. Methods Among 200 patients in whom successful RFCA of idiopathic VAs was obtained at the OT, this study included 36 (totaling 37 premature ventricular complexes [PVCs]) who had dominant R waves in the precordial leads and an LVOT origin. According to the PVC origins, the PVCs were classified into 2 groups: 1) Cusp group (n=22); PVCs were successfully eliminated by RFCA within or just under the aortic cusp and 2) non-cusp group (n=15); PVCs were successfully ablated from the other LVOT sites described above or by a sequential unipolar ablation (combination of the cusp, AMC, and mitral annulus). The detailed PVC morphology was compared between the 2 groups. Results There was no significant difference in the ratio of the Q wave amplitude in aVL to aVR, V2 R/S amplitude ratio, V2 R/S duration index, V2 transition ratio, transition zone index, or V2S/V3R index between the 2 groups. However, the ratio of the R wave amplitude in V6 to V4 (V6R/V4R index) was significantly higher in the cusp group than in the non-cusp group (0.68±0.14 mV vs. 0.52±0.15 mV, p=0.002). The receiver operating characteristic curve demonstrated that a V6R/V4R index of >0.56 predicted the PVCs originated from the cusp with a sensitivity of 0.73 and specificity of 0.91 (area under the curve of 0.81). Conclusion The V6R/V4R index is a simple and useful ECG parameter and could distinguish PVCs with an aortic cusp origin from those originating from outside the cusp among the LVOT-VAs with a high accuracy.

Validation of a clinical model for predicting left versus right ventricular outflow tract origin of idiopathic ventricular arrhythmias.

Prediction of the chamber of origin in patients with outflow tract ventricular arrhythmias (OTVA) remains challenging. A clinical risk score based on age, sex and presence of hypertension was associated with a left ventricular outflow tract (LVOT) origin. We aimed to validate this clinical score to predict an LVOT origin in patients with OTVA. In a two-center observational cohort study, unselected patients undergoing catheter ablation (CA) for OTVA were enrolled. All procedures were performed using an electroanatomical mapping system. Successful ablation was defined as a ≥80% reduction of the initial overall PVC burden after 3 months of follow-up. Patients with unsuccessful ablation were excluded from this analysis. We included 187 consecutive patients with successful CA of idiopathic OTVA. Mean age was 52±15 years, 102 patients (55%) were female, and 74 (40%) suffered from hypertension. A LVOT origin was found in 64 patients (34%). A score incorporating age, sex and presence of hypertension reached 73% sensitivity and 67% specificity for a low (0-1) and high (2-3) score, to predict an LVOT origin. The combination of one ECG algorithm (V2 S/V3 R-index) with the clinical score resulted in a sensitivity and specificity of 81% and 70% for PVCs with R/S transition at V3 . The published clinical score yielded a lower sensitivity and specificity in our cohort. However, for PVCs with R/S transition at V3, the combination with an existing ECG algorithm can improve the predictability of LVOT origin.

Similarly high success and low complication rates of catheter ablation for idiopathic premature ventricular contractions from the left and right ventricular outflow tract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation is the first line treatment for idiopathic premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT) but not from the left ventricular outflow tract (LVOT), due to presumed lower success and higher complication rates in the LVOT. In this observational single center study we analyzed success rates and complication rates in patients undergoing catheter ablation for idiopathic PVCs with an inferior axis. Methods Patients undergoing catheter ablation for idiopathic PVCs with an inferior axis at Hannover Heart Rhythm Center between 2012 and 2020 were included. Patients were excluded if no activation mapping could be performed because of low PVC activity. Ablation success was defined as complete suppression of the index PVC at the end of the procedure. Results 108 patients (53% male, age 53 ± 17 years) with predominantly symptomatic (94%) PVCs with one (72%), two (20%) or more (8%) morphologies and a PVC count of 22063 ± 14426 /24h were included. 47 PVCs (44%) were located in the RVOT (21 anterior RVOT and 26 septal RVOT) and 39 PVCs (36%) in the LVOT (11 lateral LVOT, 5 septal LVOT, 8 RCC, 2 ACC, 13 LCC). 14 PVCs (13%) had the origin close to the CS/LV summit and 8 PVCs (7%) in the parahisian region. Overall success rate was 82%. Success rates for RVOT and LVOT origin were 98% (46/47 cases) and 97% (38/39 cases) respectively. No significant differences in procedure time (145 ± 68 vs. 158 ± 72 min), ablation time (441 ± 328 vs. 462 ± 307 sec), fluoroscopy time (496 ± 521 vs. 519 ± 473 sec) or minor complications (5 vs. 8) were observed for outflow tract PVCs, and no major complications occurred in this group. However, 3 major complications and significantly lower success rates were observed for non-outflow tract PVCs (0/8 for parahisian origin, 4/14 (29%) for CS/LV summit origin). 2 patients with a parahisian focus experienced higher degree AV block and 1 patient with an LV summit focus had a pericardial tamponade. Conclusion Catheter ablation of PVCs with LVOT origin can be performed with similarly high success and low complication rates compared to PVCs with RVOT origin, and therefore could be considered as first-line therapy like RVOT PVCs. On the other hand, identification of PVCs with a parahisian or CS/LV summit focus should be aspired before an ablation procedure, as these localizations are associated with poorer ablation outcome and higher complication rates.

PO-04-061 A RARE CASE OF FOCAL LEFT VENTRICULAR OUTFLOW TRACT VENTRICULAR TACHYCARDIA LATE AFTER TRANSCATHETER AORTIC VALVE REPLACEMENT

Transcatheter aortic valve replacement (TAVR) is commonly used to treat severe aortic stenosis (AS). To date there is only one reported case of post-TAVR, new onset, left ventricular outflow tract (LVOT) ventricular tachycardia (VT) which was ablated above the TAVR valve. We report a case of late presenting symptomatic LVOT VT, which was successfully ablated via a trans-septal approach, without fluoroscopy, using intracardiac echocardiography (ICE) and electroanatomic mapping (EAM), thereby, avoiding catheter manipulation in the aorta above the valve. N/A A 68-year-old man underwent TAVR for severe AS with Sapien 3 valve (Edwards Lifescience). Nine months later, the patient developed worsening dyspnea. Echocardiogram showed well seated TAVR valve, and exercise nuclear stress revealed no ischemia. During the stress test, he had slow monomorphic VT at rest, during exercise, and recovery (100-120 bpm). A 24-hour Holter monitor revealed a ventricular arrhythmia burden of 55% with rates between 85 and 112 bpm. The 12-lead ECG of VT had an initial positive deflection in lead I, QS in V1 and V2, and an initial R wave in V3 taller than the sinus QRS, suggesting a septal right ventricular outflow tract (RVOT) vs. LVOT origin. There was no improvement with beta-blocker therapy. An electrophysiology study was performed using ICE and CARTO (Biosense Webster, Diamond Bar, CA). Activation mapping in the septal RVOT revealed a 20ms presystolic electrogram (far field) and an 80% pace map, despite the unipolar signal with QS complex. Radiofrequency ablation performed at this site only mildly suppressed the arrhythmia. The decision was made to map from the LVOT via transseptal access using EAM and real-time markers from Cartosound real time images to accurately visualize the ablation catheter below the TAVR. Earliest activation was beneath the left coronary cusp directly across the RVOT lesions with a sharp 22ms pre-systolic electrogram, unipolar QS, and 90% pace map match. Ablation performed here successfully eliminated the VT even after isoproterenol infusion and programmed stimulation. The patient’s symptoms have resolved, and he remains arrhythmia free. LVOT VA’s may rarely occur post TAVR, although a direct cause cannot be ascertained. This is the first report of successfully ablating the arrhythmia in a TAVR patient using a transeptal, subvalvular approach without fluoroscopy, and avoiding any risks associated with the aortic approach.

A novel and effective ECG method to differentiate right from left ventricular outflow tract arrhythmias: Angle-corrected V2S.

Background and aimsStandard 12-lead electrocardiogram (ECG) patterns combined with the anatomical cardiac long-axis angle revealed by chest X-ray can prevent the influence of cardiac rotation, physical shape, and lead position, so it may be an ideal means to predict the origin of the outflow tract (OT) ventricular arrhythmias (OTVAs) for ablation procedures. The study explores the value of this strategy in identifying the origin of OTVA.MethodsThis study was conducted using a retrospective cohort and a prospective cohort of consecutive patients at two centers. The anatomical cardiac long-axis angle was calculated by measuring the angle between the cardiac long-axis (a line joining the apex to the midpoint of the mitral annulus) and the horizontal plane on a chest X-ray. The V2S angle was calculated as the V2S amplitude times the angle. We ultimately enrolled 147 patients with symptomatic OTVAs who underwent successful radiofrequency catheter ablation (RFCA) (98 women (66.7%); mean age 46.9 ± 14.7 years; 126 right ventricular OT (RVOT) origins, 21 left ventricular OT (LVOT) origins) as a development cohort. The new algorithm was validated in 48 prospective patients (12 men (25.0%); mean age 48.0 ± 15.8 years; 36 RVOT, 12 LVOT origins).ResultsPatients with RVOT VAs had greater V2S, long-axis angle, and V2S angle than patients with LVOT VA (all P < 0.001). The cut-off V2S angle obtained by receiver operating characteristic (ROC) curve analysis was 58.28 mV° for the prediction of RVOT origin (sensitivity: 85.7%; specificity: 95.2%; positive predictive value: 99.1%; negative predictive value: 52.6%). The AUC achieved using the V2S angle was 0.888 (P < 0.001), which was the highest among all indexes (V2S/V3R: 0.887 (P < 0.016); TZ index: 0.858 (P < 0.001); V1-2 SRd: 0.876 (P < 0.001); V3 transition: 0.651 (P < 0.001)). In the prospective cohort, the V2S angle had a high overall accuracy of 93.8% and decreased the procedure time (P = 0.002).ConclusionV2S angle can be a novel measure that can be used to accurately differentiate RVOT from LVOT origins. It could help decrease ablation duration and radiation exposure.

Interventricular septum angle obtained from cardiac computed tomography for origin differentiation of outflow tract ventricular arrhythmia between left and right.

Our objective was to explore whether the accuracy of the transitional zone index (TZI) for outflow tract ventricular arrhythmias (OT-VAs) origin is affected by cardiac rotation and the additive value of interventricular septum angle (IVSa) obtained from coronary computed tomography angiography (CCTA). Standard 12-lead ECGs of OT-VAs with inferior axis in consecutive patients undergoing both CCTA examination and successful ablation were retrospectively analyzed. The IVSa was defined as an angle between the long axis of IVS and sagittal axis of the body from CCTA. 64 patients (31 men; mean age 54.2±11.6 years) were enrolled. The OT-VAs exhibited right ventricular outflow tract origin in 46 (71.9%) patients and 36 (78.3%) were diagnosed correctly by TZI. The left ventricular outflow tract origin OT-VAs was observed in 18 (28.1%) patients and 16 (88.9%) were diagnosed correctly by TZI. The patients were then divided into TZI correct group (n=52) and TZI incorrect group (n=12). In the TZI incorrect group, 11/12 (91.7%) cases were R/S transition in lead V3 with the TZ score during premature ventricular contractions [2.8(2.5-3.4)], and the TZI between -1.5 and 0. The IVSa was significantly larger in the TZI incorrect group than correct group (52.0±6.9° vs. 39.0±6.1°; p &lt;.0001). The IVSa ≥46° predicted TZI incorrect with 92% sensitivity, 94% specificity, and 94% accuracy. The IVSa is a novel cardiac rotation index that reliably improves TZI to differentiate the OT-VAs origin, especially for the OT-VAs with lead V3 R/S transition.

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

BackgroundSeveral 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.ObjectivesWe sought to evaluate a new ECG criterion differentiating the origin of outflow tract with precordial transition in lead V3.MethodsWe 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).ResultsWe 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.ConclusionThe 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.

The QRS-right ventricular apex interval as acut-off value to differentiate the origin of outflow tract premature ventricular complexes.

Many electrocardiography (ECG) criteria have been proposed for the localization of outflow tract premature ventricular contractions (PVCs); however, in some cases, it is difficult to accurately localize the origin of PVCs using the surface ECG. The authors aimed to study the QRS-right ventricular apex (RVA) interval measured during electrophysiological study and its role in the differentiation between different sites of origin of outflow tract PVCs. The study included 90patients (81females, mean age 37.20 ± 7.87) referred for outflow tract PVC ablation. The authors measured the interval from the onset of the earliest QRS complex of the PVCs to the distal RVA intracardiac signal (the QRS-RVA interval) during the electrophysiological study and correlated this interval with the origin of outflow tract PVCs as identified by successful ablation during the procedure. The QRS-RVA interval was significantly longer in PVCs originating from the left ventricular outflow tract (LVOT) compared to the right ventricular outflow tract (RVOT) (67.33 ± 7.56 for LVOT PVCs vs. 37.11 ± 4.34 for RVOT PVCs, p < 0.001). Receiver operating characteristic (ROC) analysis showed that aQRS-RVA interval ≥ 48 ms predicted an LVOT origin of PVCs. Ashorter interval was noted in PVCs originating from the RVOT free wall rather than the septal RVOT wall, and ashorter interval was also noted in LVOT PVCs originating from the right coronary cusp as compared to other LVOT PVCs, although these differences did not reach statistical significance. Measuring the QRS-RVA interval is asimple and accurate method for differentiating the origin of outflow tract PVCs during an electrophysiological study. AQRS-RVA interval ≥ 48 ms predicts an LVOT origin of PVCs rather than an RVOT origin.

A High-Precision Machine Learning Algorithm to Classify Left and Right Outflow Tract Ventricular Tachycardia

IntroductionMultiple algorithms based on 12-lead ECG measurements have been proposed to identify the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT) locations from which ventricular tachycardia (VT) and frequent premature ventricular complex (PVC) originate. However, a clinical-grade machine learning algorithm that automatically analyzes characteristics of 12-lead ECGs and predicts RVOT or LVOT origins of VT and PVC is not currently available. The effective ablation sites of RVOT and LVOT, confirmed by a successful ablation procedure, provide evidence to create RVOT and LVOT labels for the machine learning model.MethodsWe randomly sampled training, validation, and testing data sets from 420 patients who underwent successful catheter ablation (CA) to treat VT or PVC, containing 340 (81%), 38 (9%), and 42 (10%) patients, respectively. We iteratively trained a machine learning algorithm supplied with 1,600,800 features extracted via our proprietary algorithm from 12-lead ECGs of the patients in the training cohort. The area under the curve (AUC) of the receiver operating characteristic curve was calculated from the internal validation data set to choose an optimal discretization cutoff threshold.ResultsThe proposed approach attained the following performance: accuracy (ACC) of 97.62 (87.44–99.99), weighted F1-score of 98.46 (90–100), AUC of 98.99 (96.89–100), sensitivity (SE) of 96.97 (82.54–99.89), and specificity (SP) of 100 (62.97–100).ConclusionsThe proposed multistage diagnostic scheme attained clinical-grade precision of prediction for LVOT and RVOT locations of VT origin with fewer applicability restrictions than prior studies.

Lead I R-wave amplitude to distinguish ventricular arrhythmias with lead V3 transition originating from the left versus right ventricular outflow tract.

BackgroundThe electrophysiology algorithm for localizing left or right origins of outflow tract ventricular arrhythmias (OT‐VAs) with lead V3 transition still needs further investigation in clinical practice.HypothesisLead I R‐wave amplitude is effective in distinguishing the left or right origin of OT‐VAs with lead V3 transition.MethodsWe measured lead I R‐wave amplitude in 82 OT‐VA patients with lead V3 transition and a positive complex in lead I who underwent successful catheter ablation from the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT). The optimal R‐wave threshold was identified, compared with the V2S/V3R index, transitional zone (TZ) index, and V2 transition ratio, and validated in a prospective cohort study.ResultsLead I R‐wave amplitude for LVOT origins was significantly higher than that for RVOT origins (0.55 ± 0.13 vs. 0.32 ± 0.15 mV; p < .001). The area under the curve (AUC) for lead I R‐wave amplitude as assessed by receiver operating characteristic (ROC) analysis was 0.926, with a cutoff value of ≥0.45 predicting LVOT origin with 92.9% sensitivity and 88.2% specificity, superior to the V2S/V3R index, TZ index, and V2 transition ratio. VAs in the LVOT group mainly originated from the right coronary cusp (RCC) and left and right coronary cusp junction (L‐RCC). In the prospective study, lead I R‐wave amplitude identified the LVOT origin with 92.3% accuracy.ConclusionLead I R‐wave amplitude provides a useful and simple criterion to identify RCC or L‐RCC origin in OT‐VAs with lead V3 transition.

A Simplified Two-Stepwise Electrocardiographic Algorithm to Distinguish Left from Right Ventricular Outflow Tract Tachycardia Origin

Background: There are several electrocardiographic algorithms to predict the origin of idiopathic outflow tract ventricular arrhythmias (OT-VAs). This study aimed to develop a more accurate and efficient stepwise electrocardiographic algorithm to discriminate left ventricular outflow tract (LVOT) from right ventricular outflow tract (RVOT) origin. Methods and Results: We analyzed 12-lead electrocardiographic characteristics of 173 consecutive OT-VAs patients who underwent successful radiofrequency catheter ablation in the RVOT (n = 124) or LVOT (n = 49). Based on the areas under the receiver operating characteristic curves, the combination of transitional zone (TZ) index <0 and V2S/V3R index ≤1.5 exhibited 93.5% sensitivity, 85.9% specificity, and 87.3% accuracy. A further analysis was performed in the 71 OT-VAs with a V3-lead precordial transition. The sensitivity, specificity, and accuracy of the integration of V2S/V3R index ≤1.5 and R-wave deflection interval in lead V3 >80 ms were 91.7, 83.1, and 85.9%, respectively. In the prospective evaluation, the combination of TZ index and V2S/V3R index could identify the correct origin sites with 91.2% accuracy in the overall analysis, and the integration of V2S/V3R index ≤1.5 and R-wave deflection interval in lead V3 >80 ms exhibited 94% accuracy in V3-lead precordial transition. Conclusions: The combination of TZ index <0 and V2S/V3R index ≤1.5 is a simple and efficient stepwise electrocardiographic algorithm for predicting LVOT origin. For the OT-VAs with a V3-lead precordial transition, the integration of V2S/V3R index ≤1.5 and R-wave deflection interval in lead V3 >80 ms would be a better choice.

Amplitude of QRS complex within initial 40 ms in V2 (V2QRSi40): Novel electrocardiographic criterion for predicting accurate localization of outflow tract ventricular arrhythmia origin

The initial depolarization vector of outflow tract (OT) ventricular arrhythmia (VA) varies in different origins, which may help to predict OT-VA origin more accurately. The purpose of this study was to develop a more accurate electrocardiographic (ECG) criterion for differentiating between left and right OT-VA origins. We studied 275 patients with successful ablation in the right ventricular outflow tract (RVOT) (n = 207) or left ventricular outflow tract (LVOT) (n = 68) in the development cohort. Amplitude of the QRS complex within initial 40 ms (QRSi40) in precordial leads was measured. A novel criterion for identifying OT-VA origin was developed based on the development cohort. Predictive performance of novel criterion was further validated by comparing with previous ECG criteria (V2S/V3R index, V2 transition ratio, and transition zone index) in the validation cohort with 107 patients (RVOT 75; LVOT 32). QRSi40 of identical precordial leads were significantly greater in the LVOT group than the RVOT group (P <.05). In the development cohort, QRSi40 of V2 (V2QRSi40) exhibited the greatest area under the curve of 0.950, with cutoff ≥0.52 mV predicting LVOT origin (sensitivity 86.0%; specificity 94.6%). In the validation cohort, V2QRSi40 ≥0.52 mV outperformed previous criteria in predictive performance (accuracy 90.7%; sensitivity 84.4%; specificity 93.3%). This advantage of V2QRSi40 over previous criteria also held true for subgroups of transition zone index = 0 and V3 R/S transition. V2QRSi40 is a novel and accurate ECG criterion to predict OT-VA origin that outperforms previous criteria.

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.

V3R/V7 Index: A Novel Electrocardiographic Criterion for Differentiating Left From Right Ventricular Outflow Tract Arrhythmias Origins.

Several algorithms have been proposed to predict the origin of outflow tract (OT) ventricular arrhythmias (VAs) using standard 12-lead ECG. However, the additive value of right precordial and posterior leads is unknown. Standard 12-lead ECG, right precordial leads ECG (V3R, V4R, V5R) and posterior leads ECG (V7, V8, V9) were recorded and analyzed in a development cohort of consecutive patients undergoing OT-VAs ablation at a single center. These findings informed the development of a novel algorithm incorporating right precordial and posterior leads to discriminate between left ventricular OT (LVOT) and right ventricular OT (RVOT) foci. The performance of this novel algorithm which includes the V3R/V7 index was prospectively tested in a validation cohort of consecutive patients undergoing OT-VA ablation at 4 centers and compared with published algorithms. The location of the foci was determined by the successful ablation site. One hundred ninety-one patients were recruited, of which 94 formed the validation cohort (mean age of 45.7±15.6, 39% male, 79% RVOT foci). During OT-VAs, a QS pattern in lead V3R and an S wave in lead V7 were exclusively recorded in RVOT and LVOT foci, respectively. The V3R/V7 index of LVOT origin was significantly greater than that of RVOT (1.05±0.83 versus 0.28±0.23, P<0.001). The V3R/V7 index ≥0.85 predicted an LVOT origin with 87% sensitivity and 96% specificity. In the prospective evaluation, when the V3R/V7 index ≥0.85, an RVOT origin could be excluded with 98.6% accuracy. The area under the curve of V3R/V7 index (0.954) was larger than that of previously reported ECG criteria, including V2S/V3R (0.896), V2 transition ratio (0.792), and transition zone index (0.666). This novel index was also accurate in both patients without obvious LVOT or RVOT origins and subgroups with cardiac rotation or lead V3 R/S transition. The V3R/V7 index is a novel and accurate ECG criterion that predicts OT-VAs origin.

Prediction of premature ventricular complex origin in left vs. right ventricular outflow tract: a novel anatomical imaging approach.

Left ventricular (LV) outflow tract ventricular arrhythmias (OTVA) are associated with hypertension (HT), older age, and LV dysfunction, suggesting that LV overload plays a role in the aetiopathogenesis. We hypothesized that anatomical modifications of the LV outflow tract (LVOT) could predict left vs. right OTVA site of origin (SOO). Fifty-six (32 men, 53 ± 18 years old) consecutive patients referred for OTVA ablation were included. Cardiac multidetector computed tomography was performed before ablation and then imported to the CARTO system to aid the mapping and ablation procedure. Anatomical characteristics of the aortic root as well as aortopulmonary valvular planar angulation (APVPA) were analysed. The LV was the OTVA SOO (LVOT-VA) in 32 (57%) patients. These patients were more frequently male (78% vs. 22%, P = 0.001), older (57 ± 18 vs. 47 ± 18 years, P = 0.055), and more likely to have HT (59% vs. 21%, P = 0.004), compared to right OTVA patients. Aortopulmonary valvular planar angulation was higher in LVOT-VA patients (68 ± 5° vs. 55 ± 6°, respectively; P < 0.001). Absolute size of all aortic root diameters was associated with LVOT origin. However, after indexing by body surface area, only sinotubular junction diameter maintained a significant association (P = 0.049). Multivariable analysis showed that APVPA was an independent predictor of LVOT origin. Aortopulmonary valvular planar angulation ≥62° reached 94% sensitivity and 83% specificity (area under the curve 0.95) for predicting LVOT origin. The measurement of APVPA as a marker of chronic LV overload is useful for the prediction of left vs. right ventricular OTVA origin.

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

Although several electrocardiographic (ECG) algorithms have been proposed for differentiating the origins of outflow tract ventricular arrhythmias, the most optimal one has not been agreed on. The purpose of this study was to establish an ECG diagnostic model based on the previous ECG algorithms. The following ECG diagnostic model, Y=-1.15×( TZ )-0.494×(V2S/V3R), was developed by standard 12-lead ECG algorithms in 488 patients with idiopathic premature ventricular contractions or ventricular tachycardia with a left bundle branch block pattern and inferior axis QRS morphology. Binary logistic regression analysis was performed to establish the ECG diagnostic model. The ECG diagnostic model consisted of two ECG algorithms-the transition zone (TZ) index and V2S/V3R index. The area under the curve by receiver operating characteristic curve analysis for the ECG diagnostic model was 0.88, with a cut-off value of ≥ -0.76 predicting a left ventricular outflow tract (LVOT) origin with a sensitivity of 82% and a specificity of 86%, which was higher than other ECG algorithms in this study. The predictive accuracy of the ECG diagnostic model was also the best among all ECG algorithms in patients with a lead V3 precordial transition. This model was tested prospectively in 207 patients with a sensitivity of 90%, a specificity of 87%, and Youden index of 0.77. A highly accurate ECG diagnostic model for correctly differentiating LVOT origin from right ventricular outflow tract origin was developed.

Origins location of the outflow tract ventricular arrhythmias exhibiting qrS pattern or QS pattern with a notch on the descending limb in lead V1

BackgroundVentricular outflow tract(VOT) ventricular arrhythmias(VAs) presenting qrS pattern or QS pattern with a notch on the descending limb in lead V1 were consistently thought of arising from the commissure between left and right coronary cusp (L-RCC) by previous studies. However, we found they could originate from other anatomic structures in VOT. This study aimed to investigate the exact origin of this kind VAs.MethodsForty-nine patients of VOT premature ventricular contrations/ventricular tachycardia(PVCs/VT) with lead V1 presenting qrS pattern or QS pattern with a notch on the descending limb undergoing successful radiofrequency catheter ablation(RFCA) in our center were analyzed.Results12-lead electrocardiogram(ECG) of these PVCs/VT were summarized. Among these PVCs/VT, 37 cases exhibited qrS morphology in lead V1, 12 cases presented QS pattern with a notch on the descending limb in the same lead. Based on the successful ablation sites, these PVCs/VT were divided into 2 groups: (1)Right ventricular outflow tract(RVOT) group (26 cases), and (2) Left ventricular outflow tract (LVOT) group(23 cases, 4 cases originating from the left coronary cusp(LCC), 2 from the right coronary cusp(RCC), 16 from the L-RCC, 1 from the area inferior to LCC(ILCC)). The ECG characteristics of each PVCs/VT were analyzed. Among these PVCs/VT, applying the precordial transitional zone index(TZ index) < 0 to predict LVOT origin was demonstrated with sensitivity of 95.65%, specificity of 96.15%, positive predicting value(PPV) of 95.65% and negative predicting value(NPV) of 96.15%. In LVOT group, further applying the r, R, m,or Rs morphology in lead I to predict L-RCC and RCC origin was demonstrated with sensitivity of 94.44%, specificity of 60.00%, PPV of 89.47% and NPV of 75.00%.ConclusionsVentricular outflow tract PVCs/VT with lead V1 presenting qrS pattern or QS pattern with a notch on descending limb not only arising from L-RCC, but also RVOT, LCC, RCC and ILCC. Combining TZ index and QRS morphology in lead I to predict origin site of these kind VAs is a convenient, simple and reliable method and facilitates the RFCA procedure.

Differentiating the origin of outflow tract ventricular arrhythmia using a simple, novel approach.

Numerous electrocardiographic (ECG) criteria have been proposed to identify localization of outflow tract ventricular arrhythmias (OT-VAs); however, in some cases, it is difficult to accurately localize the origin of OT-VA using the surface ECG. The purpose of this study was to assess a simple criterion for localization of OT-VAs during electrophysiology study. We measured the interval from the onset of the earliest QRS complex of premature ventricular contractions (PVCs) to the distal right ventricular apical signal (the QRS-RVA interval) in 66 patients (31 men aged 53.3 ± 14.0 years; right ventricular outflow tract [RVOT] origin in 37) referred for ablation of symptomatic outflow tract PVCs. We prospectively validated this criterion in 39 patients (22 men aged 52 ± 15 years; RVOT origin in 19). Compared with patients with RVOT PVCs, the QRS-RVA interval was significantly longer in patients with left ventricular outflow tract (LVOT) PVCs (70 ± 14 vs 33.4±10 ms, P < .001). Receiver operating characteristic analysis showed that a QRS-RVA interval ≥49 ms had sensitivity, specificity, and positive and negative predictive values of 100%, 94.6%, 93.5%, and 100%, respectively, for prediction of an LVOT origin. The same analysis in the validation cohort showed sensitivity, specificity, and positive and negative predictive values of 94.7%, 95%, 95%, and 94.7%, respectively. When these data were combined, a QRS-RVA interval ≥49 ms had sensitivity, specificity, and positive and negative predictive values of 98%, 94.6%, 94.1%, and 98.1%, respectively, for prediction of an LVOT origin. A QRS-RVA interval ≥49 ms suggests an LVOT origin. The QRS-RVA interval is a simple and accurate criterion for differentiating the origin of outflow tract arrhythmia during electrophysiology study; however, the accuracy of this criterion in identifying OT-VA from the right coronary cusp is limited.

An easy-to-use, operator-independent, clinical model to predict the left vs. right ventricular outflow tract origin of ventricular arrhythmias.

To identify clinical characteristics able to predict a left ventricular outflow tract (LVOT) origin in outflow tract ventricular arrhythmias (OTVAs). We included 117 consecutive patients (training sample) with successful radiofrequency ablation of OTVA in one centre. A predictive model for LVOT origin was obtained using clinical data. The model was prospectively validated in a second population (testing sample) of 143 patients from two additional centres. In training sample, mean age was 54 ± 17 years, 72 patients (61%) were male, and 63 (54%) had cardiovascular risk factors. Sixty (51%) patients had LVOT origin. Independent predictors for LVOT origin were the presence of hypertension [odds ratio (OR) 2.17, confidence interval (CI) 0.91-6.20, P = 0.09], male gender (OR 4.83, 95% CI 1.89-12.33, P < 0.001), and age >50 years (OR 4.46, 95% CI 1.57-12.7, P = 0.005). A simple score was constructed with these three variables to predict LVOT origin (mean predicted probability of 15% for score 0, 26% for score 1, 60% for score 2, and 87% for score 3, P < 0.001) and reached 80% sensitivity and 75% specificity. The score was validated in the testing sample and was not inferior to previously described electrocardiogram algorithms. Patients currently referred for OTVA ablation are older, more frequently men, and with a higher probability for LVOT origin than previously described. A LVOT origin is associated with the presence of hypertension, male gender, and older age, and can be anticipated by using a simple clinical score.

Estimation of the origin of ventricular outflow tract arrhythmia using synthesized right-sided chest leads

For successful ablation of ventricular outflow tract arrhythmia, estimation of its origin prior to the procedure can be useful. Morphology and lead placement in the right thoracic area may be useful for this purpose. Electrocardiography using synthesized right-sided chest leads (Syn-V3R, Syn-V4R, and Syn-V5R) is performed using standard leads without any additional leads. This study evaluated the usefulness of synthesized right-sided chest leads in estimating the origin of ventricular outflow tract arrhythmia. This retrospective study included 63 patients in whom successful ablation of ventricular outflow tract arrhythmia was performed. Numbers of arrhythmias originating from the left ventricle, the septum of the right ventricle, and the free wall of the right ventricle were 11, 40, and 13, respectively. In one patient, two different left ventricular outflow tract origins were found. Electrocardiographic recordings from right-sided chest leads were divided into three types as follows: those in which an R > S concordance, a transitional zone, or an R < S concordance were detected. In all left arrhythmia cases, R > S concordance was observed. A transitional zone was evident in 34 of 40 cases of right ventricular outflow tract arrhythmia originating in the ventricular septum, and an R < S concordance was observed in 6 of the 40 cases. However, an R < S concordance was found in all cases of right ventricular outflow tract arrhythmia originating in the free wall. Synthesized right-sided chest lead electrocardiography may be useful for estimating the origin of ventricular outflow tract arrhythmia.