Late life-threatening arrhythmia in patients with Brugada syndrome: Results from long-term follow-up in a large Japanese cohort.

INTRODUCTION: Most patients with Brugada syndrome (BrS) are first diagnosed in their 40s, with sudden cardiac death (SCD) often occurring in their 50s. Ventricular fibrillation (VF) may occur in some patients with BrS despite having been asymptomatic for a long period. This study aimed to assess the incidence and risk factors for late life-threatening arrhythmias in patients with BrS. METHODS: Patients with BrS (n = 523; mean age, 51 ± 13 years; male, n = 497) were enrolled. The risk of late life-threatening arrhythmia was investigated in 225 patients who had experienced no cardiac events (CEs: SCD or ventricular tachyarrhythmia) for at least 10 years after study enrollment. The incidence of CEs during the follow-up period was examined. RESULTS: During the follow-up of the 523 patients, 59 (11%) experienced CEs. The annual incidences of CEs were 2.87%, 0.77%, and 0.09% from study enrollment to 3, 3-10, and after 10 years, respectively. Among 225 patients who had experienced no CEs for at least 10 years after enrollment, four patients (1.8%) subsequently experienced CEs. Kaplan-Meier analysis revealed significant differences in the incidence of late CEs between patients with and without a history of symptoms (p = .032). The positive and negative predictive values of late CEs for the programmed electrical stimulation (PES) test were 2.9% and 100%, respectively. CONCLUSION: Our results suggest that patients with BrS who are asymptomatic and have no ventricular tachycardia/VF inducibility by PES are at extremely low risk of experiencing late life-threatening arrhythmias.

Clinical Usefulness of the Active Fixation Quadripolar Left Ventricular Lead Compared With the Passive Fixation Quadripolar Lead in Cardiac Resynchronization Therapy.

BACKGROUND: This study compared the stability of the Medtronic Attain Stability Quad (ASQ), a novel quadripolar active fixation left ventricular (LV) lead with a side helix, to that of conventional quadripolar leads with passive fixation (non-ASQ) and evaluated their LV lead performance.Methods and Results: In all, 183 consecutive patients (69 ASQ, 114 non-ASQ) who underwent cardiac resynchronization therapy (CRT) between January 2018 and June 2021 were enrolled. Complications, including elevated pacing capture threshold (PCT) levels, phrenic nerve stimulation (PNS), and LV lead dislodgement, were analyzed during the postimplantation period until the first outpatient visit after discharge. The frequency of LV lead-related complications was significantly lower in the ASQ than non-ASQ group (14% vs. 30%, respectively; P=0.019). Specifically, LV lead dislodgement occurred only in the non-ASQ group, and elevated PCT levels were significantly lower in the ASQ group (7% vs. 23%; P=0.007). Kaplan-Meier analysis confirmed a significantly lower incidence of LV lead-related complications in the ASQ group (log-rank P=0.005). Cox multivariable regression analysis showed a significant reduction in lead-related complications associated with ASQ (hazard ratio 0.44; 95% confidence interval 0.23-0.83; P=0.011). CONCLUSIONS: The ASQ group exhibited fewer LV lead-related complications requiring reintervention and setting changes than the non-ASQ group. Thus, the ASQ may be a favorable choice for CRT device implantation.

Local dispersion of repolarization in the occurrence of ventricular fibrillation in Brugada syndrome: Possibility of phase 2 reentry?

To date, there have been no reports of recording epicardial electrograms at the onset of spontaneous ventricular fibrillation (VF) in patients with Brugada syndrome (BrS). In the case of BrS, unipolar and bipolar electrogram recording on the right ventricular epicardium revealed that dispersion of repolarization with delayed potential was associated with spontaneous occurrence of VF. Phase 2 reentry associated with shortening and dispersion of action potential could have been recorded for the first time in BrS. Epicardial unipolar mapping can guide accurate and appropriate ablation for the elimination of arrhythmia substrate in J wave syndrome.

Efficacy of intrinsic antitachycardia pacing for ventricular tachycardia refractory to conventional burst pacing: A case series.

Intrinsic antitachycardia pacing (iATP) is a novel automated ventricular ATP algorithm that designs ATP sequences based on the analysis of prior failed ATP. Real-world data on the efficacy and safety of iATP are lacking. Among 124 ventricular tachycardia (VT) episodes in 130 consecutive patients (mean age at implantation: 63.8 ± 14.9 years; sex, 95 male and 35 female) for whom implantable cardioverter defibrillator or cardiac resynchronization therapy defibrillator equipped with iATP algorithm was implanted, we investigated the efficacy and safety of iATP for VT refractory to conventional burst pacing. Eight patients had a total of 17 episodes of iATP therapy after failed conventional burst pacing within 11.2 ± 6.6 months of follow-up. Eleven VT episodes (64.7%) in seven patients (87.5%) were successfully terminated by iATP, and only one patient (12.5%) experienced VT acceleration. iATP might be useful for VTs refractory to conventional burst pacing with a low risk of VT acceleration.

Very late-onset atrial lead perforation leading to pneumopericardium.

BACKGROUND: Atrial lead perforation may lead to pneumopericardium or pneumothorax within a few days of device implantation. METHODS AND RESULTS: We report a case of atrial lead perforation 6 years after cardiac resynchronization therapy implantation, which resulted in pneumopericardium and pneumothorax. CONCLUSION: Although pneumopericardium caused by atrial lead perforation can spontaneously resolve with conservative treatment, as it did in this case, treatment should be decided based on the patient's general condition and lead performance.

Detailed analysis of tachycardia cycle length aids diagnosis of the mechanism and location of atrial tachycardias.

AIMS: Although the mechanism of an atrial tachycardia (AT) can usually be elucidated using modern high-resolution mapping systems, it would be helpful if the AT mechanism and circuit could be predicted before initiating mapping. OBJECTIVE: We examined if the information gathered from the cycle length (CL) of the tachycardia can help predict the AT-mechanism and its localization. METHODS: One hundred and thirty-eight activation maps of ATs including eight focal-ATs, 94 macroreentrant-ATs, and 36 localized-ATs in 95 patients were retrospectively reviewed. Maximal CL (MCL) and minimal CL (mCL) over a minute period were measured via a decapolar catheter in the coronary sinus. CL-variation and beat-by-beat CL-alternation were examined. Additionally, the CL-respiration correlation was analysed by the RhythmiaTM system. : Both MCL and mCL were significantly shorter in macroreentrant-ATs [MCL = 288 (253-348) ms, P = 0.0001; mCL = 283 (243-341) ms, P = 0.0012], and also shorter in localized-ATs [MCL = 314 (261-349) ms, P = 0.0016; mCL = 295 (248-340) ms, P = 0.0047] compared to focal-ATs [MCL = 506 (421-555) ms, mCL = 427 (347-508) ms]. An absolute CL-variation (MCL-mCL) < 24 ms significantly differentiated re-entrant ATs from focal-ATs with a sensitivity = 96.9%, specificity = 100%, positive predictive value (PPV) = 100%, and negative predictive value (NPV) = 66.7%. The beat-by-beat CL-alternation was observed in 10/138 (7.2%), all of which showed the re-entrant mechanism, meaning that beat-by-beat CL-alternation was the strong sign of re-entrant mechanism (PPV = 100%). Although the CL-respiration correlation was observed in 28/138 (20.3%) of ATs, this was predominantly in right-atrium (RA)-ATs (24/41, 85.7%), rather than left atrium (LA)-ATs (4/97, 4.1%). A positive CL-respiration correlation highly predicted RA-ATs (PPV = 85.7%), and negative CL-respiration correlation probably suggested LA-ATs (NPV = 84.5%). CONCLUSION: Detailed analysis of the tachycardia CL helps predict the AT-mechanism and the active AT chamber before an initial mapping.

Prevalence and risk factors of cardiac thrombus prior to ventricular tachycardia catheter ablation in structural heart disease.

AIMS: Assess prevalence, risk factors, and management of patients with intra-cardiac thrombus referred for scar-related ventricular tachycardia (VT) ablation. METHODS AND RESULTS: Consecutive VT ablation referrals between January 2015 and December 2019 were reviewed (n = 618). Patients referred for de novo, scar-related VT ablation who underwent pre-procedure cardiac computed tomography (cCT) were included. We included 401 patients [61 ± 14 years; 364 male; left ventricular ejection fraction (LVEF) 40 ± 13%]; 45 patients (11%) had cardiac thrombi on cCT at 49 sites [29 LV; eight left atrial appendage (LAA); eight right ventricle (RV); four right atrial appendage]. Nine patients had pulmonary emboli. Overall predictors of cardiac thrombus included LV aneurysm [odds ratio (OR): 6.6, 95%, confidence interval (CI): 3.1-14.3], LVEF < 40% (OR: 3.3, CI: 1.5-7.3), altered RV ejection fraction (OR: 2.3, CI: 1.1-4.6), and electrical storm (OR: 2.9, CI: 1.4-6.1). Thrombus location-specific analysis identified LV aneurysm (OR: 10.9, CI: 4.3-27.7) and LVEF < 40% (OR: 9.6, CI: 2.6-35.8) as predictors of LV thrombus and arrhythmogenic right ventricular cardiomyopathy (OR: 10.6, CI: 1.2-98.4) as a predictor for RV thrombus. Left atrial appendage thrombi exclusively occurred in patients with atrial fibrillation. Ventricular tachycardia ablation was finally performed in 363 including 7 (16%) patients with thrombus but refractory electrical storm. These seven patients had tailored ablation with no embolic complications. Only one (0.3%) ablation-related embolic event occurred in the entire cohort. CONCLUSION: Cardiac thrombus can be identified in 11% of patients referred for scar-related VT ablation. These findings underscore the importance of systematic thrombus screening to minimize embolic risk.

Clinical Significance of Atrial Tachyarrhythmia Duration for Ventricular Arrhythmia in Patients With Cardiac Resynchronization Therapy.

BACKGROUND: Atrial tachyarrhythmias (ATAs) are reportedly associated with ventricular arrhythmias (VAs). However, little is known about the association between ATA duration and the risk of VA. We investigated the relationship between ATA duration and subsequent VA in patients with a cardiac resynchronization therapy defibrillator (CRT-D).Methods and Results: We investigated associations between the longest ATA duration during the first year after cardiac resynchronization therapy (CRT) implantation and VA and VA relevant to ATA (VAATA) in 160 CRT-D patients. ATAs occurred in 63 patients in the first year. During a median follow-up of 925 days from 1 year after CRT implantation, 40 patients experienced 483 VAs. Kaplan-Meier analysis showed a significantly higher risk of VA in patients with than without ATA in the first year (log rank P=0.0057). Hazard ratios (HR) of VA (HR 2.36, 2.10, and 3.04 for ATA >30s, >6 min and >24 h, respectively) and only VAATA (HR 4.50, 5.59, and 11.79 for ATA >30s, >6 min and >24 h, respectively) increased according to the duration of ATA. In multivariate analysis, ATA >24 h was an independent predictor of subsequent VA (HR 2.42; P=0.02). CONCLUSIONS: Patients with ATA >24 h in the first year after CRT had a higher risk of subsequent VA and VAATA. The risk of VA, including VAATA, increased with the longest ATA duration.

Transvenous lead extraction versus surgical lead extraction or conservative treatment for cardiac implantable electronic device infections: Propensity score-weighted analyses of a nationwide claim-based database.

INTRODUCTION: Infection is one of the most important complications associated with cardiac implantable electronic device (CIED) therapy. The number of reports comparing the outcomes of transvenous lead extraction (TLE), surgical lead extraction, and conservative treatment for CIED infections using a real-world database is limited. This study investigated the association between the treatment strategies for CIED infections and their outcomes. METHODS: We performed a retrospective analysis of 3605 patients with CIED infections admitted to 681 hospitals using a nationwide claim-based database collected between April 2012 and March 2018. RESULTS: We divided the 3605 patients into TLE (n = 938 [26%]), surgical lead extraction (n = 182 [5.0%]), and conservative treatment (n = 2485 [69%]) groups. TLE was performed more frequently in younger patients and at larger hospitals (p for trend < .001 for both). The rate of TLE increased during the study period, whereas that of surgical lead extraction decreased (p for trend < .001 for both). TLE was associated with lower in-hospital mortality (vs. surgical lead extraction: odds ratio [OR], 0.20; 95% CI, 0.06-0.70; vs. conservative treatment: OR, 0.45; 95% CI: 0.22-0.94) and lower 30-day readmission rates (vs. surgical lead extraction: OR, 0.18; 95% CI: 0.06-0.56; vs. conservative treatment: OR, 0.06; 95% CI, 0.03-0.13) in propensity score-weighted analyses. CONCLUSIONS: Only 26% of patients hospitalized for CIED infections received TLE. TLE was associated with significantly lower in-hospital mortality and 30-day recurrence rates than surgical lead extraction and conservative treatment, suggesting that TLE should be more widely recommended as a first-line treatment for CIED infections.

Purkinje network and myocardial substrate at the onset of human ventricular fibrillation: implications for catheter ablation.

AIMS: Mapping data of human ventricular fibrillation (VF) are limited. We performed detailed mapping of the activities underlying the onset of VF and targeted ablation in patients with structural cardiac abnormalities. METHODS AND RESULTS: We evaluated 54 patients (50 ± 16 years) with VF in the setting of ischaemic (n = 15), hypertrophic (n = 8) or dilated cardiomyopathy (n = 12), or Brugada syndrome (n = 19). Ventricular fibrillation was mapped using body-surface mapping to identify driver (reentrant and focal) areas and invasive Purkinje mapping. Purkinje drivers were defined as Purkinje activities faster than the local ventricular rate. Structural substrate was delineated by electrogram criteria and by imaging. Catheter ablation was performed in 41 patients with recurrent VF. Sixty-one episodes of spontaneous (n = 10) or induced (n = 51) VF were mapped. Ventricular fibrillation was organized for the initial 5.0 ± 3.4 s, exhibiting large wavefronts with similar cycle lengths (CLs) across both ventricles (197 ± 23 vs. 196 ± 22 ms, P = 0.9). Most drivers (81%) originated from areas associated with the structural substrate. The Purkinje system was implicated as a trigger or driver in 43% of patients with cardiomyopathy. The transition to disorganized VF was associated with the acceleration of initial reentrant activities (CL shortening from 187 ± 17 to 175 ± 20 ms, P < 0.001), then spatial dissemination of drivers. Purkinje and substrate ablation resulted in the reduction of VF recurrences from a pre-procedural median of seven episodes [interquartile range (IQR) 4-16] to 0 episode (IQR 0-2) (P < 0.001) at 56 ± 30 months. CONCLUSIONS: The onset of human VF is sustained by activities originating from Purkinje and structural substrate, before spreading throughout the ventricles to establish disorganized VF. Targeted ablation results in effective reduction of VF burden. KEY QUESTION: The initial phase of human ventricular fibrillation (VF) is critical as it involves the primary activities leading to sustained VF and arrhythmic sudden death. The origin of such activities is unknown. KEY FINDING: Body-surface mapping shows that most drivers (≈80%) during the initial VF phase originate from electrophysiologically defined structural substrates. Repetitive Purkinje activities can be elicited by programmed stimulation and are implicated as drivers in 37% of cardiomyopathy patients. TAKE-HOME MESSAGE: The onset of human VF is mostly associated with activities from the Purkinje network and structural substrate, before spreading throughout the ventricles to establish sustained VF. Targeted ablation reduces or eliminates VF recurrence.

Zero-fluoroscopy ablation in patients with cardiac electronic implantable devices.

INTRODUCTION: Utilizing a three-dimensional (3-D) mapping system and intracardiac echocardiography (ICE) has allowed ablation procedures with less or without fluoroscopy; however, there is limited data for patients with cardiac electronic implantable device (CIED) leads regarding the suspected risk of lead injury. Therefore, we sought to explore technics to perform safe trans-septal approach and catheter manipulation technique in patients with CIED leads. METHODS AND RESULTS: This study comprised 49 consecutive patients (59% males, median 73 years old) with CIED who underwent catheter ablation for supraventricular tachycardia requiring the trans-septal approach, 15 without fluoroscopy (zero-fluoro group), and 34 with fluoroscopy (conventional-fluoro group), between July 2019 and April 2021. All procedures were performed under a 3-D mapping system and ICE guidance. We compared the differences in treatment and development of complications between the two groups. The procedures were for atrial fibrillation (82%) and atrial tachycardia (76%). Coronary sinus catheter insertion and the trans-septal procedure were successfully performed in all patients. The median time from venipuncture to trans-septal procedure (zero-fluoro vs. conventional-fluoro group: 28 [18-37] min vs. 24 [21-31] min, p = .70), total procedure time (231 [142-274] min vs. 175 [163-225] min, p = .63), and the acute procedural success rate (100% vs. 97%, p = 1.00) did not differ between both groups. No patient showed lead-related complications in both groups. CONCLUSION: This is the first study to show zero-fluoro ablation for supraventricular arrhythmia using 3-D mapping and ICE in patients with CIED leads was feasible under careful catheter manipulation.

Distribution of atrial low voltage induced by vein of Marshall ethanol infusion.

INTRODUCTION: Systematic and quantitative descriptions of vein of Marshall (VOM)-induced tissue ablation are lacking. We sought to characterize the distribution of low voltage observed in the left atrium (LA) after VOM ethanol infusion. METHODS AND RESULTS: The distribution of ethanol-induced low voltage was evaluated by comparing high-density maps performed before and after VOM ethanol infusion in 114 patients referred for atrial fibrillation ablation. The two most frequently impacted segments were the inferior portion of the ridge (82.5%) and the first half of the mitral isthmus (pulmonary vein side) (92.1%). Low-voltage absence in these typical areas resulted from inadvertent ethanol infusion in the left atrial appendage vein (n = 3), initial VOM dissection (n = 3), or a "no branches" VOM morphology (n = 1). Visible anastomosis of the VOM with roof or posterior veins more frequently resulted in low-voltage extension beyond typical areas, toward the entire left antrum (19.0% vs. 1.9%, p = .0045) or the posterior LA (39.7% vs. 3.8%, p < .001) but with a limited positive predictive value ranging from 29.4% to 43.5%. Ethanol-induced low voltage covered a median LA surface of 3.6% (1.9%-5.0%) and did not exceed 8% of the LA surface in 90% of patients. CONCLUSION: VOM ethanol infusion typically locates at the inferior ridge and the adjacent half of the mitral isthmus. Low-voltage extensions can be anticipated but not guaranteed by the presence of visible anastomosis of the VOM with roof or posterior veins.

Preoperative personalization of atrial fibrillation ablation strategy to prevent esophageal injury: Impact of changes in esophageal position.

INTRODUCTION: Due to changes in esophageal position, preoperative assessment of the esophageal location may not mitigate the risk of esophageal injury in catheter ablation for atrial fibrillation (AF). This study aimed to assess esophageal motion and its impact on AF ablation strategies. METHODS AND RESULTS: Ninety-seven AF patients underwent two computed tomography (CT) scans. The area at risk of esophageal injury (AAR) was defined as the left atrial surface ≤3 mm from the esophagus. On CT1, ablation lines were drawn blinded to the esophageal location to create three ablation sets: individual pulmonary vein isolation (PVI), wide antral circumferential ablation (WACA), and WACA with linear ablation (WACA + L). Thereafter, ablation lines for WACA and WACA + L were personalized to avoid the AAR. Rigid registration was performed to align CT1 onto CT2, and the relationship between ablation lines and the AAR on CT2 was analyzed. The esophagus moved by 3.6 [2.7 to 5.5] mm. The AAR on CT2 was 8.6 ± 3.3 cm2 , with 77% overlapping that on CT1. High body mass index was associated with the AAR mismatch (standardized ß 0.382, p < .001). Without personalization, AARs on ablation lines for individual PVI, WACA, and WACA + L were 0 [0-0.4], 0.8 [0.5-1.2], and 1.7 [1.2-2.0] cm2 . Despite the esophageal position change, the personalization of ablation lines for WACA and WACA + L reduced the AAR on lines to 0 [0-0.5] and 0.7 [0.3-1.0] cm2 (p < .001 for both). CONCLUSION: The personalization of ablation lines based on a preoperative CT reduced ablation to the AAR despite changes in esophageal position.

Strategy for repeat procedures in patients with persistent atrial fibrillation: Systematic linear ablation with adjunctive ethanol infusion into the vein of Marshall versus electrophysiology-guided ablation.

INTRODUCTION: The optimal strategy after a failed ablation for persistent atrial fibrillation (perAF) is unknown. This study evaluated the value of an anatomically guided strategy using a systematic set of linear lesions with adjunctive ethanol infusion into the vein of Marshall (Et-VOM) in patients referred for second perAF ablation procedures. METHODS AND RESULTS: Patients with perAF who underwent a second procedure were grouped according to the two strategies. The first strategy was an anatomically guided approach using systematic linear ablation with adjunctive Et-VOM, with bidirectional blocks at the posterior mitral isthmus (MI), roof, and cavotricuspid isthmus (CTI) as the procedural endpoint (Group I). The second one was an electrophysiology-guided strategy, with atrial tachyarrhythmia termination as the procedural endpoint (Group II). Arrhythmia behavior during the procedure guided the ablation strategy. Groups I and II consisted of 96 patients (65 ± 9 years; 71 men) and 102 patients (63 ± 10 years; 83 men), respectively. Baseline characteristics were comparable. In Group I, Et-VOM was successfully performed in 91/96 (95%), and procedural endpoint (bidirectional block across all three anatomical lines) was achieved in 89/96 (93%). In Group II, procedural endpoint (atrial tachyarrhythmia termination) was achieved in 80/102 (78%). One-year follow-up demonstrated Group I (21/96 [22%]) experienced less recurrence compared to Group II (38/102 [37%], Log-rank p = .01). This was driven by lower AT recurrence in Group I (Group I: 10/96 [10%] vs. Group II: 29/102 [28%]; p = .002). CONCLUSION: Anatomically guided strategy with adjunctive Et-VOM is superior to an electrophysiology-guided strategy for second procedures in patients with perAF at 1-year follow-up.

Sex differences in ventricular arrhythmia: epidemiology, pathophysiology and catheter ablation.

Evidence on sex differences in the pathophysiology and interventional treatment of ventricular arrhythmia in ischemic (ICM) or non-ischemic cardiomyopathies (NICM) is limited. However, women have different etiologies and types of structural heart disease due to sex differences in genetics, proteomics and sex hormones. These differences may influence ventricular electrophysiological parameters and may require different treatment strategies. Considering that women were consistently under-represented in all randomized-controlled trials on VT ablation, the applicability of the study results to female patients is not known. In this article, we review the current knowledge and gaps in evidence about sex differences in the epidemiology, pathophysiology and catheter ablation in patients with ventricular arrhythmias.

Impact of nocturnal hypoxemia on the recurrence of atrial tachyarrhythmia after catheter ablation of atrial fibrillation.

Factors causing atrial tachyarrhythmia recurrence after catheter ablation (CA) of atrial fibrillation (AF) remain undetermined. This study aimed to investigate the effect of nocturnal hypoxemia on the recurrence of atrial tachyarrhythmia after CA of AF. Among 594 patients with AF who underwent an ambulatory sleep study at the National Cerebral and Cardiovascular Center, Suita, Osaka, Japan (2014-2019), 365 underwent CA of AF; 290 patients who underwent CA were followed up for > 3 months. Multivariate Cox regression analysis was used to calculate hazard ratios (HRs) using clinical variables, to identify the independent predictors of atrial tachyarrhythmia recurrence after the final CA. Atrial tachyarrhythmia recurred in 45 of 290 (15.5%) patients during the median follow-up period of 479 days (interquartile range 225-1002). On the performing multivariate analysis of the data of patients who did not receive continuous positive airway pressure (CPAP), severe nocturnal hypoxemia [defined as the percentage of sleep time spent with SaO2 of < 90% (T90) over 20%] [HR 8.53, 95% confidence interval (CI) 1.872-38.814; P < 0.01] and an 1 mL/m2 increase in the left atrial volume index (HR 1.02, 95% CI 1.004-1.044; P = 0.02) were found to be independently associated with the recurrence of atrial tachyarrhythmia. In addition, the rates of freedom from atrial tachyarrhythmia after the final AF ablation with CPAP were significantly lower in the group with more severe nocturnal hypoxemia (Log-rank P = 0.03). In conclusion, it is necessary to consider both, AHI and nocturnal hypoxia while performing an ambulatory sleep apnea study. CA may be less effective in patients with more severe nocturnal hypoxia, despite the administration of CPAP.

Impact of Pre-Ablation Direct Current Cardioversion for Persistent Atrial Fibrillation to Predict Recurrence of Atrial Fibrillation after Catheter Ablation.

The efficacy of direct current (DC) cardioversion before catheter ablation (CA) for persistent atrial fibrillation (PerAF) patients remains controversial. We hypothesized that maintenance of sinus rhythm (SR) by pre-ablation DC cardioversion may predict the outcome of CA in patients with PerAF. A total of 383 PerAF patients with no or mild symptoms (EHRA I/II) who had undergone DC cardioversion before CA (301 males, 65 ± 10 years old, mean atrial fibrillation (AF) duration: 25 ± 47 months) were retrospectively enrolled. Whether or not SR was maintained at least 24 hour after DC cardioversion, patients were divided into two groups, namely, the DC-SR group and DC-AF group, and then all were followed until AF recurrence after CA. After DC cardioversion, 281 (73%) patients were categorized into the DC-SR group, and 102 (27%) were categorized into the DC-AF group. A total of 195 patients underwent CA at an average of 83 (54-145) days after DC cardioversion, including 161 (83%) in the DC-SR group and 34 (17%) in the DC-AF group. During follow-up (median: 15 [10-25] months), the number of patients who were free from AF was significantly higher in the DC-SR group compared with the DC-AF group (61.5% versus 38.3%, P < 0.0001). Multivariate analysis revealed that the DC-SR group (hazard ratio [HR]: 0.45, 95% confidence interval [CI]: 0.21-0.99, P = 0.047) and age at first AF diagnosis (HR: 0.95, 95% CI: 0.91-1.00, P = 0.039) were the independent predictors for being AF-free after CA. In conclusion, the 24-hour rhythm outcome of pre-ablation DC cardioversion and age at first AF diagnosis may predict the recurrence of AF after CA in patients with PerAF.

A case of anomalous aortic origin of coronary artery associated with a coved-type electrocardiogram.

Brugada syndrome (BrS) is a sudden cardiac death syndrome characterized by a coved-type electrocardiogram (ECG). Different disorders, such as ischemia, can emulate a Brugada-pattern ECG (Brugada phenocopy). We report herein, the first case of surgical epicardial electrophysiological mapping in a successfully resuscitated patient with an anomalous aortic origin of the coronary artery (AAOCA) associated with a coved-type ECG. It was debatable whether the coved-type ECG and the abnormal arrhythmogenic substrate in the epicardial right ventricular outflow tract were derived from BrS or from repetitive ischemia due to AAOCA; however, the epicardial electrophysiological mapping helped in deciding the treatment strategy.

Dormant conduction in the right ventricular outflow tract unmasked by adenosine in a patient with Brugada syndrome.

Recent data of electrophysiological mapping in patients with Brugada syndrome (BrS) suggest that the presence of an abnormal arrhythmogenic substrate in the epicardial right ventricular outflow tract is responsible for ST-segment elevation and ventricular fibrillation (VF). Complete elimination of the epicardial abnormal potentials normalizes Brugada-pattern electrocardiogram and suppresses VF recurrence. We herein report the first case of BrS in which an injection of adenosine unmasked dormant conduction in the epicardial RVOT after the disappearance of the epicardial potentials.

Pause-dependent mitral isthmus conduction block during ablation of the mitral isthmus: What is the mechanism?

Mitral isthmus (MI) ablation is commonly performed as an adjunct therapy to pulmonary isolation during the treatment for persistent atrial fibrillation. Confirmation of complete MI block is essential because an incomplete MI block may result in iatrogenic atrial tachycardia. However, there are several pitfalls in the diagnosis of an MI line block. We herein report a case of transient pause-dependent MI block during MI ablation.