Surface Electrocardiogram Characteristics Research Articles

Machine learning for distinguishing right from left premature ventricular contraction origin using surface electrocardiogram features.

Precise localization of the site of origin of premature ventricular contractions (PVCs) before ablation can facilitate the planning and execution of the electrophysiological procedure. The purpose of this study was to develop a predictive model that can be used to differentiate PVCs between the left ventricular outflow tract and right ventricular outflow tract (RVOT) using surface electrocardiogram characteristics. A total of 851 patients undergoing radiofrequency ablation of premature ventricular beats from January 2015 to March 2022 were enrolled. Ninety-two patients were excluded. The other 759 patients were enrolled into the development (n = 605), external validation (n = 104), or prospective cohort (n = 50). The development cohort consisted of the training group (n = 423) and the internal validation group (n = 182). Machine learning algorithms were used to construct predictive models for the origin of PVCs using body surface electrocardiogram features. In the development cohort, the Random Forest model showed a maximum receiver operating characteristic curve area of 0.96. In the external validation cohort, the Random Forest model surpasses 4 reported algorithms in predicting performance (accuracy 94.23%; sensitivity 97.10%; specificity 88.57%). In the prospective cohort, the Random Forest model showed good performance (accuracy 94.00%; sensitivity 85.71%; specificity 97.22%). Random Forest algorithm has improved the accuracy of distinguishing the origin of PVCs, which surpasses 4 previous standards, and would be used to identify the origin of PVCs before the interventional procedure.

Differentiation of fasciculoventricular fibers from anteroseptal accessory pathways using the surface electrocardiogram

Fasciculoventricular fibers (FVFs) are responsible for 1%-5% of cases of asymptomatic preexcitation on the surface electrocardiogram (ECG). Unlike ventricular preexcitation seen in Wolff-Parkinson-White (WPW) syndrome, FVFs are not associated with sudden cardiac death from preexcited atrial fibrillation. The purpose of this study was to identify surface ECG variables that differentiate FVFs from true WPW syndrome. This is a retrospective case-control study comparing surface ECG characteristics of patients diagnosed with FVFs (cases) with those of patients with WPW syndrome and anteroseptal accessory pathways (controls) via intracardiac electrophysiology testing at a single institution from 2005 to2017. Twenty-four cases of FVFs confirmed by intracardiac electrophysiology testing were identified and compared with 48 consecutive controls with WPW syndrome and anteroseptal accessory pathways. Patients with WPW syndrome were found to have significantly higher delta wave amplitudes (4.8 ± 2.0 mm vs 1.9 ± 1.3 mm; P < .001), shorter PR intervals (94.6 ± 12.5 ms vs 106.8 ± 13.2 ms; P < .001), and longer QRS intervals (133.6 ± 19.0 ms vs 118.7 ± 24.7 ms; P = .006) than did those with FVFs. Multivariable logistic regression analysis identified the delta wave amplitude as the only independent predictor of WPW syndrome (odds ratio 3.1 per 1-mm increase; bootstrapped 95% confidence interval 1.5-6.4; c statistic 0.90; P = .002). The etiology of preexcitation in patients with an anteroseptal preexcitation pattern, whether because of a benign FVF or because of potentially serious WPW syndrome, can be noninvasively deduced using the surface ECG. A higher delta wave amplitude is an independent risk factor for the presence of WPW syndrome and can accurately distinguish WPW syndrome from a FVF with good test accuracy characteristics.

ID: 1081 Development and validation of surface electrocardiogram in the septal accessory pathway localization in typical Wolff-Parkinson-White syndrome

Objectives: This study was designed characteristics of surface electrocardiogram (ECG) for the localization of septal accessory pathway (AP) in the typical Wolff-Parkinson-White (WPW) syndrome to develop a new algorithm ECG for the septal AP localization, and to test the accuracy of the algorithm prospectively.&#x0D; Subject and Methods: We studied 106 patients, in 65 patients with typical WPW syndrome have a single anterograde with the localization of Aps identified by successful radiofrequency catheter ablation (RCFA) to develop a new ECG algorithm for the septal AP localization. Then this algorithm was tested propectively in 41 patients were compared with the location of AP’s successful ablation by RCFA (gold standard).&#x0D; Results: We found that the 12 lead ECG parameters in 65 patients with typical WPW syndrome such as the transition of the QRS complex, delta wave polarity in V1 lead, delta wave polarity in at least 2/3 inferior leads and morphology QRS was “QRS pattern’’ in inferior leads in diagnosis for the localization of septal APs with hight accuracy predicted from 83.3% to 100%, and for development of a new ECG algorithm. Then the following 41 patients were prospectively evaluated by the new derived algorithm for the septal pathways with high sensitivity and specificity from 84.6% to 100%.&#x0D; Conclusion: 12-lead ECG parameters in typical WPW syndrome closely related to the septal AP localization, in order to develop the new ECG algorithm by parameters as above; and can be used to a new septal ECG algorithm in predicted the location APs with high accuracy predicted

Pulmonary artery: A pivotal site for catheter ablation in idiopathic RVOT ventricular arrhythmias.

In patients without associated myocardial diseases, characterized by left bundle branch block and inferior axis morphologies, repetitive idiopathic right ventricular tachycardias and ventricular premature contractions typically arise from right ventricular outflow tract (RVOT). Accumulated evidences have shown that radiofrequency catheter ablation is a useful treatment for patients with RVOT ventricular arrhythmias (VAs). Interestingly, several medical centers have shown that pulmonary artery (PA) is a potential novel site for catheter ablation in RVOT-like VAs, particularly in patients where termination of RVOT VAs at the usual site fails. In this review, we comprehensively demonstrated that RVOT VAs were successfully terminated at the site of PA, analyzed the characteristics of surface electrocardiogram and endocardial potentials, and explored the underlying mechanisms for these cases.

ASSA14-02-06 Radiofrequency Catheter Ablation of Ventricular Tachycardia After Repair of Congenital Heart Disease

Objective This study was designed to discuss the mechanism, critical isthmus, the characteristics of surface electrocardiogram (ECG) and the strategy of ablation of ventricular tachycardia (VT) after repair of congenital heart disease in order to increase the success rate and safety of radiofrequency catheter ablation (RFCA). Methods Eleven consecutive patients (9 men and 2 women, aged 6∼41 years) with recurrent and symptomatic VT after repair of congenital heart disease were investigated. Nine patients had undergone surgical repair of tetralogy of Fallot (TOF), 1 patient had an operation for severe congenital pulmonary stenosis and patch closure of ventricular septal defect (VSD) and suture of atrial septal defect (ASD), and the remaining patient had repair of trilogy of Fallot combined with right ventricular cardiomyopathy. The ECG showed sustained VTs in 10 patients and unsustained VTs in 1 patient, and 4 patients had the histories of syncope. Substrate mapping of the right ventricle during sinus rhythm was performed in all 11 patients. Unexcitable tissue identified from bipolar voltage ( Results In 9 patients after surgical repair of TOF, 19 different monomorphic VTs (cycle length, 170∼350 ms) could be induced; 15 were documented as clinical VTs, 2 VTs were hemodynamically unstable. In 1 patient of having an operation for severe congenital pulmonary stenosis and patch closure of VSD and suture of ASD, 1 nonsustained VT could be induced, the clinical 2 VTs could not be induced. Five morphologies of nonsustained VT could be induced in the remaining patient who had repair of trilogy of Fallot combined with right ventricular cardiomyopathy. In 10 patients who had surgical repair of TOF or severe congenital pulmonary stenosis and patch closure of VSD and suture of ASD, mapping and ablation was performed during VTs in 4 patients. In the other 6 patients, mapping and ablation was performed during sinus rhythm. The sites of surgical correction of the right ventricle were associated with the origins of VTs in these 10 patients. Combined with QRS morphology during VT and the results of mapping and ablation, anatomic isthmus 2 were ablated in 8 patients, isthmus 3 ablated in 8 patients, isthmus 5 ablated in 4 patients, and isthmus 4 ablated in 1 patient. Isthmus 2 and 3 as the reentry circuit critical isthmuses were more common. In the patient of having repair of trilogy of Fallot combined with right ventricular cardiomyopathy, 5 morphologies of nonsustained VTs (cycle length, 250∼310 ms, left bundle-branch block) could be induced, 2 were clinical VTs. Combined with the information of surgical operation method and the result of electroanatomic mapping, these VTs were considered being relevant with right ventricular cardiomyopathy, but not the surgical operation of congenital heart disease. Radiofrequency energy was delivered around the scar of the right ventricle apex and at the sites with late potential within the scar. All the 25 VTs induced in the 11 patients were caused by scar related reentry. Catheter ablation achieved acute success in 10 patients, including elimination of all VTs in 9 patients, and elimination of the clinical VTs in 1 patient. Ablation of VTs failed in the remaining patient with TOF because of lacking of inferior vena cava. During 3 months to 9 years of follow up, VTs recurred in 3 patients. Two of them had a successful ablation of VTs in the second procedure, and 1 patient had success in the third procedure. Conclusions Reentry circuit isthmuses in VTs late after repair of congenital heart disease are located within anatomically defined isthmuses bordered by unexcitable tissue of scar, patch or valve annulus. The isthmuses between the pulmonary annulus and right ventricular free wall scar/patch (isthmus 2), and between the pulmonary annulus and septal scar/patch (isthmus 3) were more common. In addition, the boundary between the scar/patch in the anterior right ventricular outflow and septal scar/patch (isthmus 5) could also be the critical isthmus of VT. RFCA of these 3 isthmuses could increase the success rate of VT after repair of congenital heart disease. The information of surgical operation prior to ablation and ventricular angiogram during the procedure were very important to predict critical isthmuses and direct electroanatomic mapping. Based on the electroanatomic mapping, RFCA of critical isthmuses of VTs in patients after repair of congenital heart disease might have a high success rate and a low recurrence, especially for unmappable VTs.

ASSA14-02-11 Catheter ablation of anteroseptal accessory pathway: Implication for the strategies of mapping and ablation

<h3>Objective</h3> Catheter ablation of anteroseptal atrioventricular (AV) accessory pathway (AP) is still challenging because of their proximity to the normal AV conduction system that may be damaged with ablation. Traditionally, catheter ablation of anteroseptal APs via the inferior vena cava approach. In a few cases, anteroseptal AP ablation may fail because of conservative energy delivery at these sites or anatomical factor. In the recent years, a few cases of successful anteroseptal AP ablation in the noncoronary cusp (NCC) or sub tricuspid annulus have been reported. However, when need to map and ablate from the NCC or sub tricuspid annulus in patients with anteroseptal APs and what will be the mapping results at the NCC in patients with anteroseptal APs successful ablated in the, right anteroseptal region (RAS) have not been well evaluated. The purpose of this study was to discuss the characteristics of surface ECG, anatomic consideration, electrophysiology, and the strategy of ablation of anteroseptal APs in order to increase the success rate and safety of radiofrequency catheter ablation. <h3>Methods</h3> There were 55 consecutive patients (age 53 ± 11 years, 36 male) out of 2200 patients presenting with anteroseptal APs who underwent RF ablation at our centre between July 2006 and March 2013. On the basis of successful ablation location, these patients were divided into right anteroseptal region group (RAS group, through inferior vena cava approach), noncoronary cusp group (NCC group, through retrograde aorta approach) and sub tricuspid annulus group (Sub-TA group, throngh superior vena cava approach). The clinical characteristics, surface electrocardiogram (ECG), intracardiac electrogram findings, and response to ablation in these patients between three groups were analysed. The strategies for mapping and ablation of anteroseptal APs were discussed. <h3>Results</h3> Successful ablation were achieved in all the 55 patients with anteroseptal APs. The sites with successful ablation were located in the RAS, adjacent to the His bundle region, in 48 patients including in 9 patients whose initial ablation were unsuccessful in the NCC. In the 4 cases with successful ablation in the NCC, the initial attempt ablation in the NCC without trying in the RAS was performed in 1 cases in whom the decision to target the NCC was based on previous experience of V-A fusion pattern adjacent to the His bundle region suggestive of an NCC AP site. In 1 of the 4 patients, irrigated energy (30–40 W and infusion rate of 17–30 ml/min) was used to eliminated the AP in the NCC after failed ablation with non-irrigated energy. There were 3 cases underwent successful ablation at Sub-TA region by a superior approach from the right internal jugular vein. There were no important complications during perioperative period. All the patients underwent a period of 8 months to 7 years of follow-up by telephone or outpatient department. Four patents ablated in RAS region recurred. No recurrence in patients underwent successful ablation in NCC or Sub-TA region. <h3>Conclusions</h3> The results of catheter ablation of anteroseptal APs in a large case series indicate that anteroseptal APs in most patients can be successful ablated in RAS region, but in a few patients, anteroseptal APs need to be ablated from the NCC or Sub-TA region. The pre-excitation characteristics have no meaningful differences among the RAS, NCC and Sub-TA group. The incidence of anteroseptal AP which had to be ablated from NCC is relatively low, so ablation from NCC was not a preferential approach. The VA fusion pattern in RAS during retrograde AP conduction may be helpful to differentiate or predict successful ablation from RAS, NCC or Sub-TA in most patients with anteroseptal AP.

Electrophysiological characteristic and ablation of epicardial idiopathic ventricular arrhythmias arising around left fibrous triangle

Background: The success rate of radiofrequency catheter ablation of ventricular arrhythmias originating from Left Fibrous Triangle (LFT) is not high. This article was to discuss the characteristics of surface electrocardiogram and the strategy of ablation of ventricular arrhythmias originating from LFT. Methods: From February 2002 to March 2012, total 323 patients with outflow ventricular arrhythmias were ablated in our hospital, including 46 patients whose ventricular arrhythmias originated from the LFT. The mean age of the 46 patients was 44±13 years (16-87 years), and 24 of them (52.2%) were male. Thirty patients had frequent premature ventricular contractions (PVCs) and 16 patients had both PVCs and nonsustained or sustained ventricular tachycardia (VT). All the patients were examined with ECG, electrophysiology, active mapping and pace mapping. The computer tomography angiogram (CTA) 3D reconstruction of coronary artery, venous was completed in 20 patients. Results: Successful ablation was achieved in 41 of the 46 patients (89.1%, 41/46) targeting left coronary cusp (LCC, 30 patients), infra aortic valve (infra AV, 6 patients) and great cardiac vein (GCV, 5 patients). The surface ECG in all the three groups presented with inferior axis and R/S-transition in lead V1 and V2. There were no differences in the total QRS duration in the three groups. Most of the patients presented with right bundle branch block (RBBB) morphology in infra AV group and GCV group compared with LCC group (67%,80% vs 15%, P=0.002). Regarding to the classification of the LFT according to CTA, the patterns of distribution were as follows: closed in 10 (50%, 10/20) hearts; completely opened in 2 (10%, 2/20); inferiorly opened in 5 (25%, 5/20) hearts and superiorly opened in 1 (5%, 1/20) hearts. In the remaining 2 (10%, 2/20), there were not any distances between GCV and left coronary artery. The closest distance between the corner of the GCV and LCC is 17.6±4.2 mm (9.1mm∼26.3mm). Conclusions: Ventricular arrhythmias originating from the LFT can be ablated in the nadir of the LCC, infra AV and the GCV. The success rate may be impacted by the distance from the GCV and the LCC.

Characteristics of Surface Electrocardiogram during RV Mid Septal Pacing Compared with RV Outflow Pacing

Aims: To reduce a risk of perforation, the RV mid septum (RVMS) may be more appropriate pacing site compared with RV outflow tract (RVOT). Our aim was to investigate whether the paced QRS complex can be useful to confirm RVMS pacing. Methods: 20 patients (77±10 years) with an implanted a permanent pacemaker were classified into 3 groups, high RVOT (N=5), low RVOT (N=7) and RVMS (N=8), using by the computed tomography. The surface 12 leads electrocardiograms were analyzed and compared among 3 groups. Results: In RVMS pacing, the QRS duration (144±12 ms) and QRS transition (5.3±0.7) had no significant difference compared with those of high RVOT (154±14 ms, 5.4±0.5) and low RVOT (146±9 ms, 5.6±0.5). The voltage of lead of I in RVMS (0.61±0.2 mV), were significantly higher than that in high RVOT (−0.21±0.27 mV; P<0.001) and tended to be higher than that in low RVOT (0.23±0.19 mV). The presence of a q-wave in lead of I in RVMS (0/8) was infrequent compared with those in high RVOT (4/5) and low RVOT (2/5). A RS pattern/R pattern in lead II was infrequent in RVMS (6/2) than in high RVOT (0/5) and low RVOT (3/4). Conclusion: A QRS complex in lead I and/or II may be useful to confirm a RVMS pacing.

Surface electrocardiogram characteristics of atrial tachycardias occurring after pulmonary vein isolation

The purpose of this study was to describe the surface electrocardiogram (ECG) morphology of common atrial tachycardias (ATs) that occur after pulmonary vein (PV) isolation. Focal ATs from reconnected PVs and macroreentrant mitral annular (MA) flutter are the most common form of ATs occurring after PV isolation. Patients with persistent AT after PV isolation underwent mapping and ablation. Tachycardia origin and mechanism were determined using electroanatomic mapping and entrainment techniques. Patients with typical right atrial flutter occurring after PV isolation were also included for comparison. Thirty-nine tachycardias were identified in 36 patients, either focal left AT (n = 24) or MA flutter (n = 15). Focal ATs originated from reconnected segments of the right PVs (n = 14) and left PVs (n = 10). MA flutters were counterclockwise (CCL; n = 9) or clockwise (CL; n = 6). Patients with MA flutter had a shorter tachycardia cycle length (239 +/- 7 vs. 259 +/- 34 s; P <.05) than those with focal ATs. CCL MA flutter was positive in the inferior and precordial leads and had a significant negative component in leads I and aVL. CL MA flutter demonstrated the converse limb lead morphology with a significant negative F wave in the inferior leads and positive F wave in leads I and aVL. A negative component in lead I, when present, was best at differentiating CCL MA flutter from left PV ATs, while a positive F wave in lead I was best at differentiating CL MA flutter from CCL right atrial flutter. There are unique surface ECG characteristics for CL and CCL MA flutter and AT due to reconnected PVs; knowledge of these characteristics may help when planning an ablation strategy.

Abrupt changes in surface electrocardiogram characteristics predict spontaneous termination of paroxysmal atrial fibrillation

Abrupt changes in surface electrocardiogram characteristics predict spontaneous termination of paroxysmal atrial fibrillation