Significant Control of Gas Invasion to the Phase Behavior of Deep-Seated Hydrocarbon Fluids in Western Junggar Basin, NW China.

In the western Junggar Basin, various oil and gas phases, such as black oil, volatile oil, condensate, and gas, have been discovered and reported. However, the primary factors responsible for the variations in oil and gas phases in different regions of the basin are not yet clearly understood. This study uses geochemical analyses, numerical simulations, and geological analyses to determine the extent of gas invasion in different regions, simulate the mechanism of gas invasion altering phase behavior, and shed light on its significant impact on fluid phases in hydrocarbons across diverse regions. The results show that the phase states of deep-seated fluids vary regionally, which is characterized by a gradual change from black oil to volatile oil, condensate, and gas from the northwest to the southeast. Gas invasion varies across oil reservoirs in different regions: the northwest regions show no significant gas invasion, the middle regions have a slight to moderate gas invasion, and the southeast regions exhibit the strongest gas invasion from heavy to severe. Varied degrees of gas invasion and corresponding phase transition rates, dependent on the gas dryness coefficient, are the primary causes of hydrocarbon fluid phase variations.

RV1+RV3 Index to Differentiate Idiopathic Ventricular Arrhythmias Arising From Right Ventricular Outflow Tract and Aortic Sinus of Valsalva: A Multicenter Study.

BACKGROUND: This study aimed to investigate the predictive value of parameters of every precordial lead and their combinations in differentiating between idiopathic ventricular arrhythmias (IVAs) from the right ventricular outflow tract and aortic sinus of Valsalva (ASV). METHODS AND RESULTS: Between March 1, 2018, and December 1, 2021, consecutive patients receiving successful ablation of right ventricular outflow tract or ASV IVAs were enrolled. The amplitude and duration of the R wave and S wave were measured in every precordial lead during IVAs. These parameters were either summed, subtracted, multiplied, or divided to create different indexes. The index with the highest area under the curve to predict ASV IVAs was developed, compared with established indexes, and validated in an independent prospective multicenter cohort. A total of 150 patients (60 men; mean age, 45.3±16.4 years) were included in the derivation cohort. The RV1+RV3 index (summed R-wave amplitude in leads V1 and V3) had the highest area under the curve (0.942) among the established indexes. An RV1+RV3 index >1.3 mV could predict ASV IVAs with a sensitivity of 95% and a specificity of 83%. Its predictive performance was maintained in the validation cohort (N=109). In patients with V3 R/S transition, an RV1+RV3 index >1.3 mV could predict ASV IVAs, with an area under the curve of 0.892, 93% sensitivity, and 75% specificity. CONCLUSIONS: The RV1+RV3 index is a simple and novel criterion that accurately differentiates between right ventricular outflow tract and ASV IVAs. Its performance outperformed established indexes, making it a valuable tool in clinical practice.

Sex difference in atrial scar prevalence: What can we learn from the STABLE-SR-III trial?

BACKGROUND: Female sex has long been recognized to present a higher risk of stroke and atrial fibrillation (AF) recurrence after circumferential pulmonary vein isolation (CPVI) than in males. However, the underlying mechanisms and benefits of additional low-voltage area (LVA) modification in women remain unknown. OBJECTIVE: The purpose of this study was to investigate differences in atrial substrate and efficacy of additive LVA ablation between sex subgroups. METHODS: Patients with paroxysmal atrial fibrillation (PAF) aged 65-80 years were randomly assigned to either CPVI plus LVA modification (STABLE-SR) group or CPVI alone group. The primary outcome was freedom from atrial arrhythmias after a single ablation procedure. RESULTS: Of 414 patients included in STABLE-SR-III, 204 (49.3%) were women (mean age 70.5 ± 4.7 years). Women demonstrated significantly higher LVA prevalence (51.5% vs 32.9%; P <.001) and LVA burden (6.5% vs 2.9%; P <.001) than men. In the STABLE-SR group, additional LVA ablation was associated with a 63% reduction in recurrence for women compared with the CPVI alone group (10.8% vs 29.4%; adjusted hazard ratio 0.37; 95% confidence interval 0.18-0.75; P for interaction = .040). However, this finding was not observed in men (18.7% vs 18.5%). In the female subgroup, both group 1 (CPVI + LVA modification) and group 3 (CPVI alone in females without LVA) had similar clinical outcomes, which were much better than in Group 2 (CPVI alone in women with LVA) (90% vs 83.8% vs 63.6%; P = .003). CONCLUSION: In older patients with PAF, women demonstrated more advanced atrial substrate, including higher prevalence and burden of LVA compared with men. Women may receive greater benefit from additional LVA modification than men.

A Simple Score to Predict New-Onset Atrial Fibrillation After Ablation of Typical Atrial Flutter.

BACKGROUND: New-onset atrial fibrillation (NeAF) is common after cavotricuspid isthmus-dependent counterclockwise atrial flutter (CCW-AFL) ablation. This study aimed to investigate a simple predictive model of NeAF after CCW-AFL ablation. METHODS: From January 2013, to December 2017, consecutive patients receiving CCW-AFL ablation were enrolled from 3 centres. Clinical, echocardiographic, and electrocardiographic data were collected and followed. Patients from 2 centres and another centre were assigned into the derivation and validation cohorts, respectively. In the derivation cohort, logistic regression was performed to evaluate the ability of parameters to discriminate those with and without NeAF. A score system was developed and then validated. RESULTS: Two hundred seventy-one patients (mean 59.7 ± 13.6 age; 205 male) were analyzed. During follow-up (73.0 ± 6.5 months), 107 patients (39.5%) had NeAF; 190 and 81 patients were detected in the derivation and validation cohorts, respectively. Hypertension, age ≥ 70 years, left atrial diameter ≥ 42 mm, P-wave duration ≥ 120 ms and the negative component of flutter wave in lead II ≥ 120 ms were selected as the final parameters. A weighted score was used to develop the HAD-AF score ranging from 0 to 9. In the derivation cohort, area under the receiver operating characteristic curve (AUC) was 0.938 (95% confidence interval [CI], 0.902-0.974), superior to those of currently used CHA2DS2-VASC (0.679, 95% CI, 0.600-0.757) and HATCH scores (0.651, 95% CI, 0.571-0.730) (P < 0.001). Performance maintained in the validation cohort. CONCLUSIONS: Six years after CCW-AFL ablation, 39.5% of patients developed NeAF. HAD-AF score can reliably identify patients likely to develop NeAF after CCW-AFL ablation.

General anesthesia enhances lesion quality and ablation efficiency of circumferential pulmonary vein isolation.

Background: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. General anesthesia (GA) resolves the problem of pain intolerability and provides regular respiratory mode which might improve the catheter maneuverability of AF ablation. This study aims to compare the procedural performance of PVI under GA versus conscious sedation (CS) from multiple perspectives. Methods: A total of 36 consecutive patients undergoing first AF ablation under GA were enrolled in GA group. Another 109 patients receiving AF ablation under CS in the same period were selected as the control group. After propensity score matching, 29 matched pairs with similar baseline characteristics were available for further analysis. The AIFV (using AI to analyze the raw data from CARTO3 system) system was used to evaluate six procedural parameters in each PVI procedure. Results: Compared with CS, PVI under GA had a significantly shorter total PVI time (51.4 min vs. 67.8 min; p = .003) and higher radiofrequency ratio (62.6% vs. 55.8%; p = .032). The number of gaps (1.0 vs. 3.0; p < .001) and the rate of break point were significantly lower in the GA group. GA was also associated with a higher effective ablation-index ratio (87.5% vs. 74.1%; p < .001) and effective force-over-time ratio (85.3% vs. 69.2%; p = .001). After a medium follow-up time of 24 months, 12/29 (41.4%) patients in the CS group and 6/29 (20.7%) patients in the GA group suffered from AF recurrence (p = .156). Conclusions: GA improves the lesion quality and procedural efficiency of PVI from multiple perspectives evaluated by the AIFV system.

Anticoagulation Intensity during Appendage Occlusion:Lessons from Silent Cerebral Embolism.

INTRODUCTION: Endovascular left atrial appendage occlusion (LAAO) is associated with a high incidence of peri-procedure silent cerebral embolisms (SCE), while the recommended activated clotting time (ACT) level by the expert consensus is lower than that in atrial fibrillation (AF) ablation. The aim of our study is to investigate whether raising the targeted ACT level during LAAO to the same level as AF ablation could decrease the incidence of SCE. METHODS: It was a prospective observational cohort study. Consecutive AF patients receiving LAAO between January 2021 and December 2022 were included and categorized into two groups based on the time of enrollment. Patients enrolled in 2021 (group 250) maintained a target ACT level of ≥250 s during LAAO procedure, while patients enrolled in 2022 (group 300) maintained the peri-procedure ACT ≥300 s. All patients underwent cerebral magnetic resonance imaging (MRI) before and after the procedure. RESULTS: A total of 81 patients were included (38 in the group 250 and 43 in the group 300). After inverse probability of treatment weighting (IPTW), patients in the group 250 showed a significantly lower incidence of SCE than group 300 (IPTW p = 0.038). Only a stable high ACT pattern could decrease the risk of SCE. No significant differences were found between other ACT change patterns on the SCE incidence. CONCLUSION: Raising the peri-procedure ACT level to a stable 300 seconds could decrease the risk of the SCE without increasing the major bleeding events.

Value of q waves in lateral and left precordial leads in patients with left bundle branch block to predict the response to cardiac resynchronization therapy.

BACKGROUND: The cardiac resynchronization therapy (CRT) non-response rate can reach 30% in heart failure (HF) patients with left bundle branch block (LBBB). This study aimed to evaluate the value of baseline q waves in leads I, V5, or V6 in predicting response to CRT in patients with HF and LBBB. METHODS: Patients with HF (left ventricular ejection fraction ≤35%) and LBBB receiving CRT implantation were retrospectively enrolled. Baseline characteristics and electrocardiogram parameters, including lateral and left precordial q waves were evaluated. Non-response to CRT was defined as the improvement of left ventricular ejection fraction (LVEF) < 5% at a 6-month follow-up. RESULTS: A total of 132 patients (mean age 63.0 ± 10.4 years, 94 [71.2%] male) were included. Among them, 32 patients with q waves in leads I, V5, or V6 were classified into the qLBBB (+) group, and the rest without q waves in these leads were defined as the qLBBB (-) group. The CRT non-response rate in the qLBBB (+) group was markedly higher than that in the qLBBB (-) group (68.8% vs. 33.3%, p < .001). Multivariable logistic regression analysis revealed that the presence of baseline q waves in leads I, V5, or V6 remained significantly associated with a higher rate of CRT non-response in patients with HF and LBBB (odds ratio: 4.8, 95% confidence interval: 1.5-15.0, p = .007). CONCLUSION: Any q wave in leads I, V5, or V6 was an independent predictive factor for CRT non-response in patients with HF and LBBB.

Persistent left superior vena cava isolation in patients with atrial fibrillation: Selective or empirical?

BACKGROUND: Persistent left superior vena cava (PLSVC) is the most prevalent form of thoracic venous abnormality and can serve as a significant arrhythmogenic source in atrial fibrillation (AF). METHODS AND RESULTS: Among the 3950 patients who underwent radiofrequency ablation for AF between September 2014 to April 2020, 17 patients (mean age 59.4 ± 8.0 years, 64.7% male) with PLSVC were identified. Among them, nine patients (52.9%) had a prior history of pulmonary vein isolation (PVI) alone. Eight out of nine patients who experienced AF recurrence underwent PLSVC isolation with or without pulmonary vein (PV) reconnection. For the remaining eight patients (47.1%), PVI plus PLSVC isolation were performed during the index procedure. Ectopy originating from PLSVC was documented in 11 patients (64.7%) and successful PLSVC isolation was achieved in 16 patients (94.1%). After a median follow-up of 28.3 months, freedom from AF/ atrial tachycardia (AT) was observed in 13 patients (76.5%). CONCLUSION: Empirical PLSVC isolation beyond PVI appears to be a feasible and safe strategy to prevent AF recurrence in patients with concomitant PLSVC.

Association between P-wave terminal force in lead V1 and extent of left atrial low-voltage substrate in older patients with paroxysmal atrial fibrillation.

BACKGROUND: The P-wave terminal force in lead V1 (PTFV1) is a marker of cardiomyopathy and risk of atrial fibrillation (AF). Low-voltage area (LVA) in the left atrium (LA), which indicates underlying atrial fibrosis, could predict AF recurrence. This study aimed to investigate the correlation between PTFV1 and LVA in older patients with paroxysmal AF. METHODS: From May 1, 2020, to October 31, 2021, a total of 162 patients aged 65-80 years with paroxysmal AF who underwent index ablation procedures were enrolled. PTFV1 was measured in sinus rhythm (SR) using 12-lead electrocardiograms prior to the ablation. Abnormal PTFV1 was defined as a ≥ 4 mVms depression. Additional LVA ablation beyond circumferential pulmonary vein isolation (CPVI) was performed if LVAs were found. RESULTS: Among the 162 patients, 88 had a normal PTFV1 and 74 had an abnormal PTFV1 prior to ablation. There was a significant difference in LVA in patients with and without an abnormal PTFV1 (LVA, 11.0 vs. 5.1 cm2, P < 0.001; LVA burden, 8.9% vs. 4.5%, P < 0.001). PTFV1 and PTAV1 were highest in the upper tertile with extensive LVAs (P < 0.001). Multivariate analysis revealed that abnormal PTFV1 was an independent predictor of LVAs (ß = 4.961; 95% CI, 2.135-7.788; P < 0.001). After a median follow-up of 23 months, the AF-free survival rate was similar between the normal PTFV1 group and the abnormal PTFV1 group (13/88 vs. 12/74, hazard ratio [HR], 0.933 [95% CI, 0.425-2.047]; P = 0.861). CONCLUSIONS: Abnormal PTFV1 at baseline was independently associated with the extent of LVA in older patients with paroxysmal AF.

Hidden Fatal ECG Manifestations.

This case report presents the electrocardiogram findings of a patient in their 50s with syncope and palpitation and amaurosis followed by loss of consciousness for several minutes without preceding position change, cough, chest pain, or shortness of breath.

Arrhythmogenic Right Ventricular Cardiomyopathy With Extensive Abnormal Substrate: Is Isolation Possible?

BACKGROUND: In arrhythmogenic right ventricular cardiomyopathy (ARVC) patients with extensive right ventricular free wall (RVFW) abnormal substrate, large-area homogenization with combined epicardial and endocardial approach is time consuming and often inadequate for modification. OBJECTIVES: This study aimed to explore the feasibility and efficacy of RVFW abnormal substrate isolation in such patients to control ventricular tachycardia (VT). METHODS: Eight consecutive ARVC patients with VT who had extensive abnormal RVFW substrate were included. VT induction was performed before substrate mapping and modification. Detailed voltage mapping was done during sinus rhythm. A circumferential linear lesion was deployed along the border zone of low-voltage area on the RVFW to achieve electrical isolation. Other small areas with fractionated or late potentials were further homogenized. RESULTS: All 8 patients had RVFW endocardial low-voltage area. The entire RV low-voltage area was 113.8 ± 84.1 cm2 (49.6% ± 29.8%) and the dense scar was 59.6 ± 39.8 cm2 (25.0% ± 14.1%). Electrical isolation of abnormal substrate was achieved in 5 of 8 (62.5%) patients via endocardial approach alone and 3 of 8 (37.5%) patients via a combination of endocardial and epicardial approach. Electrical isolation was verified by slow automaticity (5 of 8, 62.5%) or RV noncapture (3 of 8, 37.5%) during high-output pacing inside the encircled area. VTs were induced in 6 patients before ablation, and all patients were rendered noninducible after ablation. During a median follow-up of 43 months (range: 24-53 months), 7 of 8 (87.5%) patients remained free of sustained VT. CONCLUSIONS: Electrical isolation of RVFW is feasible and can be the option in ARVC patients with extensive abnormal substrate.

Scar-related atrial macroreentries: Different arrhymogenic basis generates different reentry type.

BACKGROUND: Catheter ablation is an established therapeutic strategy to treat scar-related macroreentry atrial tachycardia (MAT). However, the scar properties and arrhythmogenicity and the reentry type have not been clearly defined. METHODS AND RESULTS: A total of 122 patients with scar-related MAT were enrolled in this study. The atrial scars were classified into two categories: spontaneous scars (Group A: n = 28) and iatrogenic scars (Group B: n = 94). According to the relationship between scar location and the reentry circuit, MAT was described as scar pro-flutter MAT, scar-dependent MAT, and scar-mediated MAT. The reentry type of MAT was significantly different between Groups A and B: pro-flutter (40.5% vs. 62.0%, p = 0.02), scar-dependent AT (40.5% vs. 13.0%, p < 0.001), and scar-mediated AT (19.0% vs. 25.0%, p = 0.42). After a median follow-up of 25 months, 21 patients with AT recurrence were observed. Compared with the spontaneous group, there was a lower recurrence rate of MAT in the iatrogenic group (28.6% vs. 10.6%, p = 0.03). CONCLUSION: Scar-related MAT has three reentry types, and the proportion of each type varies with the scar properties and its arrhythmogenic basis. Optimization of the ablation strategy based on the scar properties to improve the long-term outcome of catheter ablation of MAT is necessary.

Plasma 8-Hydroxy-2'-Deoxyguanosine, a Potential Valuable Biomarker for Atrial Fibrosis Is Influenced by Polymorphism of DNA Methylation Gene.

BACKGROUND: Previous studies revealed a relationship between 8-hydroxy-2'-deoxyguanosine (8-OHdG) and the occurrence/recurrence of atrial fibrillation (AF). This 2-part study aimed to validate whether DNA damage related to 8-OHdG is associated with left atrial (LA) fibrosis in AF patients quantified by voltage mapping (Part I), and to identify the underlying genetic components regulating the 8-OHdG level (Part II).Methods and Results: Plasma 8-OHdG determination, DNA extraction, and genotyping were conducted before catheter ablation. LA voltage mapping was performed under sinus rhythm. According to the percentage of low voltage area (LVA), patients were categorized as stage I (<5%), stage II (5-10%), stage III (10-20%), and stage IV (>20%). Part I included 209 AF patients. The 8-OHdG level showed an upward trend together with advanced LVA stage (stage I 8.1 [6.1, 10.5] ng/mL, stage II 8.5 [5.7, 14.1] ng/mL, stage III 14.3 [12.1, 16.5] ng/mL, stage IV 13.9 [10.5, 16.0] ng/mL, P<0.000). Part II included 175 of the 209 patients from Part I. Gene-set analysis based on genome-wide association study summary data identified that the gene set named 'DNA methylation on cytosine' was the only genetic component significantly associated with 8-OHdG concentration. CONCLUSIONS: Higher 8-OHdG levels may predict more advanced LVA of the LA in AF patients. DNA methylation is the putative genetic component underlying oxidative DNA damage in AF patients.

Predictors of pacemaker implantation within three months after catheter ablation of atrial fibrillation.

BACKGROUND: It is inevitable for patients to have a temporary or permanent pacemaker implanted during or after radiofrequency catheter ablation (RFCA) for treatment of atrial fibrillation (AF) in some cases. The aim of our study was to evaluate the incidence of pacemaker implantation (PMI) during or within 3 months of RFCA for AF and to identify the risk factors that were associated with PMI. METHODS: We performed a retrospective analysis of consecutive AF patients who underwent RFCA between August 2018 and October 2020 at our center. The incidence of PMI within 3 months during or after RFCA were assessed. A multivariate logistic regression model was performed to identify predictors of PMI. RESULTS: One thousand and five patients (mean age, 60.2 ± 10.3 years; 37.6% women) were included in this analysis. PVI was performed in all patients. A total of 23 (2.3%) patients had a pacemaker implanted within 3 months during or after ablation. Multivariable logistic regression analysis revealed that older age (OR: 1.08 [95% CI 1.03-1.13], p = .003), female sex (OR: 3.08 [95% CI 1.28-7.45], p = .012), paroxysmal AF (OR: 4.71 [95% CI 1.09-20.45], p = .038) and repeated ablation (OR: 2.78 [95% CI 1.04-7.40], p = .041) were the independent predictors for PMI. CONCLUSIONS: Older age, female sex, paroxysmal AF and repeated ablation were identified as predictive risk factors for PMI after RFCA in patients with AF. A "watch and wait" strategy could be taken for patients with temporary PMI after ablation, especially for those with prolonged sinus pause after AF termination.

Characteristics, Thrombus Resolution, and Long-Term Outcomes in Patients with Nonvalvular Atrial Fibrillation and Atrial Thrombus.

To assess the prevalence and management of atrial thrombus in patients with nonvalvular atrial fibrillation (NVAF) and identify the risk factors of the nonresolution of atrial thrombus. This single-center retrospective observational study consecutively enrolled patients with NVAF and atrial thrombus detected using transesophageal echocardiography (TEE) or cardiac computed tomography angiography (CTA) from January 2012 to December 2020. Patients with prior left atrial appendage (LAA) intervention were excluded. The primary endpoint was the presence of atrial thrombus, while the secondary endpoint was the complete resolution of atrial thrombus. The prevalence of atrial thrombus in patients with NVAF was 1.4%. Ninety patients with atrial thrombus (mean age 62.8 ± 11.9 years and 61.1% men) were finally analyzed. Atrial thrombus was in the LAA in 82 (91.1%) patients. During follow up, 60% of the patients showed complete resolution of atrial thrombus. Congestive heart failure (odds ratio [OR]: 8.94; 95% confidence interval [CI]: 1.67-47.80) and a history of ischemic stroke (OR: 8.28; 95% CI: 1.48-46.42) were independently associated with the risk of the nonresolution of atrial thrombus. The presence of atrial thrombus in patients with NVAF who received anticoagulation therapy is non-negligible. Even in anticoagulated patients, TEE or cardiac CTA might still be needed. Congestive heart failure and a history of ischemic stroke are risk factors of the nonresolution of atrial thrombus.

Progressive outcomes of bundle branch reentrant ventricular tachycardia in patients without structural heart disease.

BACKGROUND: Ablation strategies to treat bundle branch reentrant ventricular tachycardia (BBRT) are well described. However, reports of long-term follow-up outcomes in BBRT patients without structural heart disease (SHD) are limited. OBJECTIVE: The purpose of this study was to investigate the long-term follow-up prognosis of BBRT patients without SHD. METHODS: Changes in electrocardiographic and echocardiographic parameters were used to evaluate progression during follow-up. Potential pathogenic candidate variants were screened using a specific gene panel. RESULTS: Eleven consecutive BBRT patients without obvious SHD based on echocardiographic and cardiovascular magnetic resonance imaging results were enrolled. Median age was 20 (11-48) years, and median follow-up time was 72 months. During follow-up, PR interval [206 (158-360) ms vs 188 (158-300) ms; P = .018] and QRS duration [187 (155-240) ms vs 164 (130-178) ms; P = .008] each increased significantly compared with postablation. Right- and left-sided chamber dilation and reduced left ventricular ejection fraction (LVEF) also were observed. Clinical deterioration or events occurred in 8 patients: 1 sudden death; 3 both complete heart block and reduced LVEF; 2 significantly reduced LVEF; and 2 prolonged PR interval. Genetic testing results showed that 6 of 10 patients (excluding the patient with sudden death) had ≥1 potential pathogenic candidate variants. CONCLUSION: Further deterioration of His-Purkinje system conduction was observed in young BBRT patients without SHD after ablation. The His-Purkinje system may be the first target of genetic predisposition.

Right atrial tachycardia after atrial fibrillation ablation: prevalence, clinical characteristics, electrophysiological mechanisms, and long-term outcomes.

BACKGROUND: This study aims to evaluate the prevalence, clinical characteristics, electrophysiological mechanisms, and long-term outcomes of right atrial tachycardia (AT) in patients who underwent ablation for atrial fibrillation (AF). METHODS: From March 2010 to December 2020, 220 consecutive patients undergoing index AF ablation were referred for post-ablation AT recurrence. Thirty-five patients (35/220, 15.9%) with right AT recurrence (25 men; mean age 59.3 ± 10.2 years) were enrolled. These patients were divided into groups with right ATs exclusively (group 1) and right combined with left ATs (group 2). RESULTS: Fifty-three ATs were mapped in all patients, with thirty-nine ATs originating from the right atrium. The detailed distribution of all right ATs was 22 in the cavo-tricuspid isthmus (CTI), 6 in the ostium of superior vein cava (SVC), 4 in the right free wall, 4 in the right anterior atrial septum, 2 in coronary sinus ostium, and 1 in crista terminalis. Group 2 had a significantly higher incidence of typical atrial flutter (AFL) than group 1 (11/12, 90.9% vs. 12/24, 50.0%, P = 0.03). During the mean follow-up of 43.6 ± 25.2 months after the index AT ablation, the recurrence rate of AT/AF was 22.9% (8/35), and it was lower in group 1 than in group 2 (8.3% vs. 54.5%, P = 0.01). CONCLUSION: Right AT is relatively less common post-AF ablation. The CTI-dependent AFL and the ostium of SVC-derived focal AT constituted the major components of right ATs, suggesting the importance of ablation- and anatomy-related arrhythmogenic effects in the right atrium.

Epicardial catheter ablation of idiopathic ventricular arrhythmias originating from uncommon epicardial sites.

PURPOSE: Idiopathic epicardial ventricular arrhythmias (VAs) are clustered in the areas of the summit and crux. This study was to report a group of idiopathic epicardial VAs remote from the summit and crux areas. METHODS: In total, 9 patients (6 males, mean age 32 ± 13 years) were enrolled. The locations were identified by epicardial mapping and ablation. The electrocardiographic and electrophysiological characteristics were compared to those of 9 patients who had VAs ablated at the opposite endocardial site. RESULTS: VAs were identified at the epicardium, with 4 patients had VAs located at the inferior wall, one at the anterior wall, one at the apex and 3 patients had VAs at the lateral wall. A "QS" type at the location-related leads was the only identified surface electrocardiogram indication suggesting epicardial origin (compared to that of the controls, 100% vs 0%, p<0.001). Endocardial and epicardial mapping revealed pre-maturities of -11 ± 4 ms and -25 ± 8 ms, respectively (VS. -28 ± 8 ms revealed by endocardial mapping in control patients, p<0.001 and p=0.389, respectively). All of the study cases demonstrated an "rS" pattern in the endocardial unipolar electrogram. Acute and long-term successful ablation (a median of 11 months of follow-up) was achieved in all patients without complications. CONCLUSIONS: A distinct group of idiopathic VAs remote from the summit and crux areas warranting ablation by a subxiphoid approach were identified. Morphological ECG features of a "QS" type among the location-related grouped leads combined with the mapping findings helped in the identification of the epicardial site of origin.