Impact of frailty in patients with non-valvular atrial fibrillation undergoing catheter ablation.

Background: The relationships between frailty and clinical outcomes in elderly Japanese patients with non-valvular atrial fibrillation (NVAF) after catheter ablation (CA) have not been established. We evaluated the frailty rate of patients undergoing CA for NVAF, examined whether CA for NVAF improves frailty, and analyzed the CA outcomes of patients with and without frailty. Methods: Elderly Japanese patients (≥65 years; mean age: 72.8 years) who participated in the real-world ablation therapy with anti-coagulants in management of atrial fibrillation registry and who responded to the frailty screening index survey were included (n = 213). Frailty and AF recurrence were assessed preoperatively and at 3 and 6 months after CA. Results: Twenty-six patients (12.8%) were frail, 109 (53.7%) were pre-frail, and 68 (33.5%) were robust. Cardiovascular (frailty: 0.5%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year) and cardiac (frailty: 0.5%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year) events, as well as major bleeding (frailty: 0.3%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year), were numerically more frequent in the frailty group. No deaths from cardiovascular or stroke/systemic thromboembolic events occurred. A large proportion of patients did not experience 3-month (frailty: 96.2%; pre-frailty: 96.3%; robust: 88.2%) or 6-month (frailty: 88.5%; pre-frailty: 91.7%; robust: 86.8%) AF recurrence after CA. Weight loss, walking speed, and fatigue improved in the frailty and pre-frailty groups after CA. Conclusion: Japanese patients aged ≥65 years with frailty or pre-frailty had improved frailty screening index components, such as weight loss, walking speed and fatigue, after CA. Therefore, elderly patients with frailty or pre-frailty may benefit from CA for NVAF.

Real-World Investigation on Anticoagulation Management Before and After Catheter Ablation for Atrial Fibrillation in Japan　- Periprocedural and Long-Term Outcomes.

BACKGROUND: Optimal periprocedural oral anticoagulant (OAC) therapy before catheter ablation (CA) for atrial fibrillation (AF) and the safety profile of OAC discontinuation during the remote period (from 31 days and up to 1 year after CA) have not been well defined.Methods and Results: The RYOUMA registry is a prospective multicenter observational study of Japanese patients who underwent CA for AF in 2017-2018. Of the 3,072 patients, 82.3% received minimally interrupted direct-acting OACs (DOACs) and 10.2% received uninterrupted DOACs. Both uninterrupted and minimally interrupted DOACs were associated with an extremely low thromboembolic event rate. Female, long-standing persistent AF, low creatinine clearance, hepatic disorder, and high intraprocedural heparin dose were independent factors associated with periprocedural major bleeding. At 1 year after CA, DOAC was continued in 55.9% of patients and warfarin in 56.4%. The incidence of thromboembolic and major bleeding events for 1 year was 0.3% and 1.2%, respectively. Age ≥73 years, dementia, and AF recurrence were independently associated with major bleeding events. Univariate analyses revealed that warfarin continuation and off-label overdose of DOACs were risk factors for major bleeding after CA. CONCLUSIONS: High intraprocedural dose of heparin was associated with periprocedural major bleeding events. At 1 year after CA, over half of the patients had continued OAC therapy. Thromboembolic events were extremely low; however, major bleeding occurred in 1.2%. Age ≥73 years, dementia, and AF recurrence were independently associated with major bleeding after CA.

Study design of nationwide Japanese Catheter Ablation Registry: Protocol for a prospective, multicenter, open registry.

BACKGROUND: Catheter ablation has become a popular interventional treatment for cardiac tachyarrhythmias and the number has been on the rise year by year. However, little is known about its efficacy and safety in the real-world settings. METHOD: Japanese Catheter Ablation (J-AB) Registry is a nationwide, multicenter, observational registry, performed by Japanese Heart Rhythm Society (JHRS), collaborated with National Cerebral and Cardiovascular Center. This study is a voluntary nationwide registry and data are collected prospectively using a Research Electronic Data Capture (REDCap) system. Detailed data collection including antiarrhythmic medication is also performed every September. The acute success rate at discharge and the complications associated with ablation procedure will be collected in all cases. Major bleeding events are defined according to Bleeding Academic Research Consortium criteria. Based on the provided information, the annual incidence and predictive factors for outcome will be investigated by the Event Assessment Committee. This registry started in August 2017 and the number of participating medical instructions will be more than 250 hospitals and the target procedure number will be 70 000 per year. We will also compare the results with other registries in foreign countries. RESULT: The results of this study are currently under investigation. CONCLUSION: The J-AB registry will provide a real-world data regarding the acute success and complications in Japan, focusing on various types of catheter ablation for cardiac arrhythmias.

Genotype-dependent differences in age of manifestation and arrhythmia complications in short QT syndrome.

BACKGROUND: Short QT syndrome (SQTS) is a rare inheritable arrhythmia, associated with atrial and ventricular fibrillations, caused by mutations in six cardiac ion channel genes with high penetrance. However, genotype-specific clinical differences between SQTS patients remain to be elucidated. METHODS AND RESULTS: We screened five unrelated Japanese SQTS families, and identified three mutations in KCNH2 and KCNQ1. A novel mutation KCNH2-I560T, when expressed in COS-7 cells, showed a 2.5-fold increase in peak current density, and a positive shift (+14 mV) of the inactivation curve compared with wild type. Computer simulations recapitulated the action potential shortening and created an arrhythmogenic substrate for ventricular fibrillation. In another family carrying the mutation KCNQ1-V141M, affected members showed earlier onset of manifestation and frequent complications of bradyarrhythmia. To determine genotype-specific phenotypes in SQT1 (KCNH2), SQT2 (KCNQ1), and other subtypes SQT3-6, we analyzed clinical variables in 65 mutation-positive patients among all the 132 SQTS cases previously reported. The age of manifestation was significantly later in SQT1 (SQT1: 35 ± 19 years, n = 30; SQT2: 17 ± 25 years, n = 8, SQT3-6: 19 ± 15 years, n = 15; p = 0.011). SQT2 exhibited a higher prevalence of bradyarrhythmia (SQT2: 6/8, 75%; non-SQT2: 5/57, 9%; p < 0.001) and atrial fibrillation (SQT2: 5/8, 63%; non-SQT2: 12/57, 21%; p = 0.012). Of 51 mutation-positive individuals from 16 SQTS families, nine did not manifest short QT, but exhibited other ECG abnormalities such as atrial fibrillation. The resulting penetrance, 82%, was lower than previously recognized. CONCLUSION: We propose that SQTS patients may exhibit different clinical manifestations depending upon their genotype.

Verapamil-Sensitive Upper Septal Idiopathic Left Ventricular Tachycardia: Prevalence, Mechanism, and Electrophysiological Characteristics.

OBJECTIVES: This study sought to demonstrate the prevalence, mechanism, and electrocardiographic and electrophysiological characteristics of upper septal idiopathic left fascicular ventricular tachycardia (US-ILVT). BACKGROUND: ILVT is classified into left anterior and posterior types with no clear data about US-ILVT. METHODS: Among 193 ILVT patients, we identified 12 patients (6.2%; age 41 ± 22 years, 7 men) with US-ILVT. RESULTS: Of 12 patients with US-ILVT, 6 patients (50%) had previous history of radiofrequency catheter ablation for common ILVT. Sustained VT (cycle length: 349 ± 53 ms) was seen in all patients with a QRS interval slightly wider (104 ± 18 ms) than that during sinus rhythm (90 ± 19 ms). The VT exhibited an identical QRS configuration as sinus rhythm in 6 (50%) and incomplete right bundle branch block configuration in another 6. His-ventricular interval during VT was always shorter than that during sinus rhythm (27 ± 5 ms vs. 47 ± 10 ms). Purkinje potentials were activated in a reverse direction to that of common ILVT; namely, the diastolic potential (P1) was activated retrogradely but the pre-systolic potential (P2) was activated antegradely. At the left upper-middle ventricular septum, P1 potential was recorded during VT, preceding the QRS by 54 ± 20 ms. Radiofrequency catheter ablation at that site eliminated the VT with no recurrence during a 58 ± 35 months of follow-up. CONCLUSIONS: US-ILVT is an identifiable VT that shares common criteria with ILVT and has a narrow QRS interval. Some US-ILVT cases appeared after common ILVT ablation. It is a reverse type of common ILVT (orthodromic form) with baseline morphological abnormalities that might provide a potential substrate for such VT.

Complex anatomy surrounding the left atrial posterior wall: analysis with 3D computed tomography.

Few studies have explored the topographic anatomy of the esophagus, posterior wall of the left atrium (LA), or fat pads using multidetector computed tomography (MDCT) to prevent the risk of esophageal injury during atrial fibrillation (AF) ablation. MDCT was performed in 110 consecutive patients with paroxysmal or persistent AF before the ablation procedure to understand the anatomic relationship of the esophagus. Two major types of esophagus routes were demonstrated. Leftward (type A) and rightward (type B) routes were found in 90 and 10% of the patients, respectively. A type A route had a larger mean size of the LA than type B. The fat pad was identifiable at the level of the inferior pulmonary vein in 91% of the patients without any predominance of either type. The thickness of the fat pad was thinner in the patients with a dilated LA (>42 mm) than in those with a normal LA size (≤42 mm) (p = 0.01). The results demonstrated that the majority of cases had a leftward route of the esophagus. There was a close association between the LA dilatation and fat pad thinning. With a dilated LA, the esophagus may become easily susceptible to direct thermal injury during AF ablation. Visualization of the anatomic relationship may contribute to the prevention of the potential risk of an esophageal injury.

Ablation of epicardial right ventricular tachycardia provoked by proarrhythmic RV pacing in a patient with dilated cardiomyopathy.

Ventricular arrhythmias are common in the setting of nonischemic dilated cardiomyopathy (NIDCM). However, the characterization of the substrate and mechanism of epicardial ventricular tachycardia (VT) associated with NIDCM is limited, and to the best of our knowledge VT due to myocardial reentry within the right ventricular (RV) epicardium associated with NIDCM has not been reported. We report a case of RV epicardial VT provoked by RV pacing that was successfully ablated.

Atrial defibrillation threshold as a novel predictor of clinical outcome of catheter ablation for persistent atrial fibrillation.

AIMS: Catheter ablation for persistent atrial fibrillation (AF) is currently performed with different procedural endpoints. When AF did not terminate during ablation procedure, electrical cardioversion was performed at different defibrillation threshold (DFT) according to AF characteristics and atrial electrophysiologic substrates. We sought to evaluate the impact of atrial DFT after catheter ablation for persistent AF on clinical outcome. METHODS AND RESULTS: We studied 128 patients with persistent AF (age 63±9 years, 106 men). After completion of circumferential pulmonary vein isolation, the left atrial substrate ablation was performed until AF terminated or all identified complex fractionated electrograms were eliminated. If AF did not terminate during ablation, an internal cardioversion protocol was started at 5J and was increased incrementally in 5 J steps until successful cardioversion was accomplished. Procedural AF termination was achieved in 50 patients (Group A). Atrial fibrillation was terminated by cardioversion with DFT≤10 J in 47 patients (Group B) and with DFT>10 J in 31 patients (Group C). At 14±7 follow-up months after 1.3±0.5 sessions, 47 (94%) Group A patients, 42 (89%) Group B patients, and 14 (45%) Group C patients remained in sinus rhythm. In multivariate analysis of Group B and Group C, DFT (hazard ratio 5.54, P<0.001) and AF duration (hazard ratio 3.74, P=0.011) were independent predictors of recurrent arrhythmia. CONCLUSION: When AF does not terminate after the completion of predetermined stepwise ablation, further extensive ablation to terminate AF might be unnecessary if the AF can be successfully terminated by electrical cardioversion at low DFT.

No severe pulmonary vein stenosis after extensive encircling pulmonary vein isolation: 12-month follow-up with 3D computed tomography.

Few studies have explored the utility of local electrogram-guided extensive encircling pulmonary vein isolation (EEPVI) by analyzing the pulmonary vein (PV) anatomy and occurrence of stenosis using multidetector computed tomography (MDCT). One hundred seventy-six paroxysmal atrial fibrillation (AF) patients underwent EEPVI with a double lasso technique. MDCT was performed in all patients before and at 3, 6 and 12 months after the ablation procedures to screen for PV stenosis. PV stenosis was defined as a >30% reduction in its diameter. A total of 700 PVs were analyzed. PV stenosis was observed in 15 of 700 PVs (2.1%). All stenoses were mild (mean 34.5 ± 3.3%). They were all asymptomatic, and none required treatment. After 12 months of follow-up, the PV narrowing regressed significantly compared with that at 3 months in the patients with PV stenosis (34.5 ± 3 to 30.4 ± 5%, P < 0.05). The remaining PVs exhibited a stable anatomy, and there was no significant progression of the PV narrowing. The results of this study demonstrated that detectable PV stenosis occurred in 2.1% of the PVs, and all stenoses were mild. Moreover, a significant regression of the PV narrowing was observed after 12-months of follow-up. This indicates that the local electrocardiogram-guided EEPVI was relatively safe regarding severe PV stenosis.

Local unipolar and bipolar electrogram criteria for evaluating the transmurality of atrial ablation lesions at different catheter orientations relative to the endocardial surface.

BACKGROUND: Recognition of the creation of transmural lesions (TLs) during atrial ablation procedures is important. OBJECTIVE: The purpose of this study was to characterize local unipolar electrograms (UEs) and bipolar electrograms (BEs) recorded from a TL at different catheter orientations. METHODS: In 13 porcines, 125 point-by-point ablations were performed in the smooth myocardial areas of the atria during recording of UE and BE. Catheter orientation was adjusted to be perpendicular or oblique (nonparallel; 80 sites) or parallel (75 sites) to the endocardial surface based on left atriograms. RESULTS: Microscopic examination revealed TLs in 54 sites and non-TLs in 71 sites. Irrespective of catheter orientation, the distal UE recorded from TLs consistently exhibited elimination of a negative deflection, whereas that from non-TLs did not. BE recorded from TLs with nonparallel catheter orientation consistently exhibited elimination of a positive deflection, whereas that with parallel catheter orientation exhibited one of two different patterns: (1) predominant attenuation (> or =75%) of the R wave at sites exhibiting QRS pattern preablation or (2) complete elimination of the R' wave at sites exhibiting RSR' pattern preablation. The heterogeneity of the patterns of morphologic change in BE at the different catheter orientations was due to the different degree of contribution of the proximal UE to BE. CONCLUSION: UE and BE criteria successfully differentiated TLs from non-TLs. Different BE criteria should be applied for recognizing TL formation in different catheter orientations.

Superior type of atypical AV nodal reentrant tachycardia: incidence, characteristics, and effect of slow pathway ablation.

BACKGROUND: Atypical atrioventricular (AV) nodal reentrant tachycardias (AVNRT) usually exhibit the earliest retrograde atrial activation (ERAA) at the right inferoseptum (Rt-IS) or proximal coronary sinus (PCS). The purpose of this study was to characterize atypical AVNRT with the ERAA at the right superoseptum (Rt-SS). METHODS: Seventy-three atypical AVNRTs induced in 63 cases were classified into the superior type with the ERAA at the Rt-SS and inferior type with the ERAA at the Rt-IS or PCS. RESULTS: There were nine superior (12%) and 64 inferior types of atypical AVNRT (88%) in seven and 56 cases, respectively. The superior type exhibited a short atrial-His interval during the tachycardia (166 +/- 41 ms), long His-atrial interval during the tachycardia (H-At:156 +/- 38 ms), and ventricular pacing at the tachycardia cycle length (TCL) (H-Ap:201 +/- 36 ms), and evidence for a lower common pathway, including second-degree AV block (four tachycardias) and an H-Ap being longer than the H-At (nine tachycardias). The TCL was shorter in the superior type than in the inferior type (322 +/- 35 vs 404 +/- 110 ms; P < 0.02). In the inferior type, all tachycardias were eliminated after the ablation at the Rt-IS (44 tachycardias) or PCS (20 tachycardias) where an ERAA was recorded. In the superior type, ablation at the Rt-IS was ineffective; however, ablation at the right midseptum eliminated seven (78%) of the nine tachycardias. CONCLUSIONS: The tachycardia circuit of the superior type might have deviated to a more superior part of Koch's triangle than that of the inferior type.

Shift in the earliest retrograde atrial activation site during the fast-slow form of atrioventricular nodal reentrant tachycardia after the radiofrequency modification of the atrioventricular node: is the atrium a necessary link?

Whether or not the perinodal atrium forms an upper link in the tachycardia circuit of the atypical form of AV nodal reentrant tachycardia (AVNRT) is controversial. We report a case with the fast-slow form of AVNRT in whom the earliest retrograde atrial activation site during the tachycardia changed from the right inferoseptum to the right superoseptum close to the His bundle without a change in the tachycardia cycle length following the radiofrequency energy applications to the earliest retrograde atrial activation site. It was speculated that a sub-atrial reentry with multiple atrial breakthroughs was the possible tachycardia mechanism in the present case.

"Left-variant" adenosine-sensitive atrial reentrant tachycardia ablated from the left coronary aortic sinus.

Adenosine-sensitive reentrant atrial tachycardia (AT) is usually amenable to ablation at the right superoseptum near the His bundle. We report a case with "left-variant" adenosine-sensitive reentrant AT. The AT was reproducibly induced by atrial extrastimulation with negative correlation between the coupling interval and return cycle, and was terminated by atrial extrastimulation and bolus of 2 mg of adenosine 5'-triphosphate. Ablations at the right superoseptum were unsuccessful; however, the AT was successfully ablated from the left coronary aortic sinus (LCAS) where the earliest atrial activation was recorded. Ablation at the LCAS might be effective in this entity resistant to right-sided ablation.

Predicting the need for an implantable cardioverter defibrillator using cardiac metaiodobenzylguanidine activity together with plasma natriuretic peptide concentration or left ventricular function.

UNLABELLED: Despite widespread use of implantable cardioverter defibrillators (ICDs), their cost and the fact that only a certain group of patients fully benefits from the devices require appropriate risk stratification of patients. This study investigated whether altered cardiac autonomic function is associated with the occurrence of ICD discharge or lethal cardiac events. METHODS: Fifty-four ICD-treated patients were prospectively followed after assessment of cardiac metaiodobenzylguanidine (MIBG) activity, quantified as the heart-to-mediastinum ratio (HMR), plasma concentration of brain natriuretic peptide (BNP), and left ventricular ejection fraction (LVEF). Patients were divided into 2 groups based on the presence (group A, n = 21) or absence (group B, n = 33) of appropriate ICD discharge during a 15-mo period. RESULTS: Group A had a significantly lower level of MIBG activity and a higher plasma BNP level than did group B. Univariate analysis revealed BNP level, any medication, and late HMR to be significant predictors, and multivariate analysis showed late HMR to be an independent predictor. An HMR of less than 1.95 with a plasma BNP level of more than 187 pg/mL or an LVEF of less than 50% had significantly increased power to predict ICD shock: positive predictive values, 82% (HMR + BNP) and 58% (HMR + LVEF); negative predictive values, 73% (HMR + BNP) and 77% (HMR + LVEF); sensitivities, 45% (HMR + BNP) and 67% (HMR + LVEF); and specificities, 94% (HMR + BNP) and 70% (HMR + LVEF). CONCLUSION: When combined with plasma BNP concentration or cardiac function, cardiac MIBG activity is closely related to lethal cardiac events and can be used to identify patients who would benefit most from an ICD.

Catheter ablation therapy for atrial fibrillation: current advancements in strategies.

Curing atrial fibrillation (AF) by catheter ablation has significantly improved patient morbidity and mortality. The circumferential pulmonary vein isolation technique is established as the principal procedure, with a high cure rate and acceptable safety, for paroxysmal AF, but new adjunctive ablation strategies targeting the AF substrates and sources for long-standing persistent/chronic AF have been developed. These new techniques include linear ablation, complex fractionated atrial electrogram guided ablation, dominant frequency map-guided ablation, ganglionated plexi ablation and disconnection of the coronary sinus and superior vena cava to ablate the AF substrates and sources. The long-term usefulness of the established technique and these innovative adjunctive approaches for the treatment of AF remains to be investigated.