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Abstract In the field of cardiac electrophysiology, there is a universal desire: the discovery of a flawless diagnostic maneuver for supraventricular tachycardias (SVTs). This is not merely a wish but a shared odyssey. To improve diagnostic accuracy and achieve sufficient sensitivity and specificity, numerous diagnostic maneuvers have been proposed. However, each has its limitations and prompts a search for new diagnostic techniques. This continuous cycle of discovery and refinement, which we titled “SVT Quest” is reviewed in chronological sequence. This adventure in diagnosing narrow QRS tachycardia unfolds in 3 steps: Step 1 involves differentiating atrial tachycardia from other SVTs based on the observations such as V‐A‐V or V‐A‐A‐V response, ΔAA interval, VA linking, the last entrainment sequence, and response to the atrial extrastimulus. Step 2 focuses on differentiating orthodromic reciprocating tachycardia from atrioventricular nodal reentrant tachycardia based on the observations such as tachycardia reset upon the premature ventricular contraction during His refractoriness, uncorrected/corrected postpacing interval, differential ventricular entrainment, orthodromic His capture, transition zone analysis, and total pacing prematurity. Step 3 characterizes the concealed nodoventricular/nodofascicular pathway and His‐ventricular pathway‐related tachycardia based on observations such as V‐V‐A response, ΔatrioHis interval, and paradoxical reset phenomenon. There is no single diagnostic maneuver that fits all scenarios. Therefore, the ability to apply multiple maneuvers in a case allows the operator to accumulate evidence to make a likely diagnosis. Let's embark on this adventure!

Abstract Background Despite the positive impact of implantable cardioverter defibrillators (ICDs) and wearable cardioverter defibrillators (WCDs) on prognosis, their implantation is often withheld especially in Japanese heart failure patients with reduced left ventricular ejection fraction (HFrEF) who have not experienced ventricular tachycardia (VT) or ventricular fibrillation (VF) for uncertain reasons. Recent advancements in heart failure (HF) medications have significantly improved the prognosis for HFrEF. Given this context, a critical reassessment of the treatment and prognosis of ICDs and WCDs is essential, as it has the potential to reshape awareness and treatment strategies for these patients. Methods We are initiating a prospective multicenter observational study for HFrEF patients eligible for ICD in primary and secondary prevention, and WCD, regardless of device use, including all consenting patients. Study subjects are to be enrolled from 31 participant hospitals located throughout Japan from April 1, 2023, to December 31, 2024, and each will be followed up for 1 year or more. The planned sample size is 651 cases. The primary endpoint is the rate of cardiac implantable electronic device implementation. Other endpoints include the incidence of VT/VF and sudden death, all‐cause mortality, and HF hospitalization, other events. We will collect clinical background information plus each patient's symptoms, Clinical Frailty Scale score, laboratory test results, echocardiographic and electrocardiographic parameters, and serial changes will also be secondary endpoints. Results Not applicable. Conclusion This study offers invaluable insights into understanding the role of ICD/WCD in Japanese HF patients in the new era of HF medication.

Abstract Background Atrioventricular nodal reentrant tachycardia (AVNRT) sometimes recurs even after anatomical slow pathway (SP) ablation targeting the rightward inferior extension (RIE). This multicenter study aimed to determine the reasons for AVNRT recurrence. Methods and Results Forty‐six patients were treated successfully for recurrent AVNRT. Initial treatment was for 38 slow‐fast AVNRTs, 3 fast‐slow AVNRTs, 2 slow‐slow AVNRTs, 2 slow‐fast and fast‐slow AVNRTs, and 1 noninducible AVNRT. All initial treatments were of RF application to the RIE; SP elimination was achieved in 11, dual AVN physiology was seen in 29, and AVNRT remained inducible in 5. The recurrent AVNRTs included 34 slow‐fast AVNRTs, 6 fast‐slow AVNRTs, 3 slow‐slow AVNRTs, 2 slow‐fast and fast‐slow AVNRTs, and 1 slow‐fast and slow‐slow AVNRTs. Successful ablation site was within the RIE in 39 and left inferior extension in 7. In 30 of 39, the successful RIE site was in the same area or higher than that of the initial procedure. Conclusion For a high majority (around 85%) of patients in whom AVNRT recurs after initial ablation success, the site of a second successful procedure will be within the RIE even though the RIE was originally targeted. Furthermore, a high majority (around 86%) of sites of successful ablation will be higher than those originally targeted.

Abstract Background Although pulmonary vein isolation (PVI) for atrial fibrillation (AF) utilizing radiofrequency (RF) applications with a very high‐power and short‐duration (vHPSD) has shortened the procedure time, the determinants of pulmonary vein (PV) gaps in the first‐pass PVI and acute PV reconnections are unclear. Methods An extensive encircling PVI was performed with the QDOT MICRO catheter with a vHPSD (90 W–4 s) in 30 patients with AF (19 men, 64 ± 10 years). The association of the PV gap sites (first‐pass PVI failure, acute PV reconnections [spontaneous reconnections or dormant conduction provoked by adenosine triphosphate] or both) with the left atrial (LA) wall thickness and LA bipolar voltage on the PVI line and ablation‐related parameters were assessed. Results PV gaps were observed in 29 (6%) of 480 segments (16 segments per patient) in 17 patients (56%). The PV gaps were associated with the LA wall thickness, bipolar voltage, and the number of RF points (LA wall thickness, 2.5 ± 0.5 vs. 1.9 ± 0.4 mm, p

Abstract Background This study aimed to establish a systematic method for diagnosing atrioventricular nodal reentrant tachycardia (AVNRT) with a bystander concealed nodoventricular pathway (cNVP). Methods We analyzed 13 cases of AVNRT with a bystander cNVP, 11 connected to the slow pathway (cNVP‐SP) and two to the fast pathway (cNVP‐FP), along with two cases of cNVP‐related orthodromic reciprocating tachycardia (ORT). Results The diagnostic process was summarized in three steps. Step 1 was identification of the presence of an accessory pathway by resetting the tachycardia with delay (n = 9) and termination without atrial capture (n = 4) immediately after delivery of a His‐refractory premature ventricular contraction (PVC). Step 2 was exclusion of ORT by atrio‐His block during the tachycardia (n = 4), disappearance of the reset phenomenon after the early PVC (n = 7), or dissociation of His from the tachycardia during ventricular overdrive pacing (n = 1). Moreover, tachycardia reset/termination without the atrial capture (n = 2/2) 1 cycle after the His‐refractory PVC was specifically diagnostic. Exceptionally, the disappearance of the reset phenomenon was also observed in the two cNVP‐ORTs. Step 3 was verification of the AVN as the cNVP insertion site, evidenced by an atrial reset/block preceding the His reset/block in fast–slow AVNRT with a cNVP‐SP and slow–fast AVNRT with a cNVP‐FP or His reset preceding the atrial reset in slow–fast AVNRT with a cNVP‐SP. Conclusion AVNRT with a bystander cNVP can be diagnosed in the three steps with few exceptions. Notably, tachycardia reset/termination without atrial capture one cycle after delivery of a His‐refractory PVC is specifically diagnostic.

Abstract Background The effects of the patient's disease awareness on the management of postablation of atrial fibrillation (AF) are unknown. Methods One hundred thirty‐three AF patients undergoing an initial ablation were given a disease awareness questionnaire with a score of 16 points (8 points about AF in general and 8 points about oral anticoagulants) for the Jessa Atrial Fibrillation Knowledge Questionnaire (JAKQ) before and 1‐year‐after ablation. We divided them into the poor disease awareness group and good disease awareness group according to the median value (75%) of the total JAKQ score about AF in general, and compared the baseline patient characteristics and the 1‐year changes in the JAKQ score, medication adherence, blood pressure, laboratory data, echocardiographic parameters, and AF/atrial tachycardia (AT) recurrence rate between the two groups. Results Forty‐two (31.6%) patients were classified as having poor disease awareness (

The coexistence of 2 Mahaim pathways represents a diagnostic challenge. We present a case in which the SH/HA intervals were useful for identifying concealed nodoventricular or His-ventricular pathways.

Abstract Background Ablation strategies and modalities for atrial fibrillation (AF) have transitioned over the past decade, but their impact on post‐ablation medication and clinical outcomes remains to be fully investigated. Methods We divided 682 patients who had undergone AF ablation in 2014–2019 (420 paroxysmal AFs [PAF], 262 persistent AFs [PerAF]) into three groups according to the period, that is, the 2014–2015 (n = 139), 2016–2017 (n = 244), and 2018–2019 groups (n = 299), respectively. Results Persistent AF became more prevalent and the left atrial (LA) diameter larger over the 6 years. Extra‐pulmonary vein (PV)‐LA ablation was more frequently performed in the 2014–2015 group than in the 2016–2017 and 2018–2019 groups (41.1% vs. 9.1% and 8.1%; p

Abstract Background A subeustachian pouch (SEP) often hinders the completion of a cavotricuspid isthmus (CTI) ablation of typical atrial flutter (AFL) and sometimes causes steam‐pops during a power‐controlled ablation. We hypothesized that real‐time bull's‐eye monitoring of the catheter surface temperature might be useful to locate the SEP where the temperature can rise rapidly, and a temperature‐controlled ablation might avoid steam pops. This study aimed to demonstrate this hypothesis. Methods A temperature‐controlled CTI ablation with a QDOT MICRO™ catheter (n = 10) and a conventional power‐controlled CTI ablation (n = 10) were performed with an output power of 35 W. During the RF application, the bull's eye monitor for monitoring the catheter surface temperatures was assessed. A “red‐bull sign” was defined as an entire red‐colored bull's‐eye monitor, indicating that the catheter‐tip temperature of all 6 thermocouples rose rapidly over 47°C. Results In a total of 115 lesions (12 ± 3 per patient), a “red‐bull sign” was observed in 39 (33.9%) lesions where the RF output was reduced to 26 ± 8 W. All 39 “red‐bull sign” lesions corresponded to the location of the SEP as delineated by ICE before the ablation. The red‐bull sign accurately indicated the presence of a SEP with a sensitivity of 84.7% and specificity of 100%. Bidirectional block of the CTI was completed in all patients in either catheter group without any steam‐pops. Conclusion Real‐time surface temperature monitoring and a red‐bull sign might be useful to detect the SEP. A temperature‐controlled CTI ablation with the QDOT MICRO catheter might be safe for avoiding steam pops.

Abstract Extremely low alanine aminotransferase (ALT) may reflect aging, frailty, sarcopenia, and malnutrition in several cardiovascular diseases, but the association between low ALT and patient characteristics, cardiovascular and all-cause mortality is not well investigated in the population with atrial fibrillation. We conducted a post hoc analysis of a prospective, observational multicenter study. Patients with nonvalvular AF in the SAKURA AF Registry (n = 3156) were classified into 3 tertiles according to baseline ALT: first (ALT ≤ 15 U/L, n = 1098), second (15

Introduction Data are lacking on the extent to which patients with non-valvular atrial fibrillation (AF) who are aged ≥80 years benefit from ablation treatment. The question pertains especially to patients’ postablation quality of life (QoL) and long-term clinical outcomes.Methods and analysis We are initiating a prospective, registry-based, multicentre observational study that will include patients aged ≥80 years with non-valvular AF who choose to undergo treatment by catheter ablation and, for comparison, such patients who do not choose to undergo ablation (either according to their physician’s advice or their own preference). Study subjects are to be enrolled from 52 participant hospitals and three clinics located throughout Japan from 1 June 2022 to 31 December 2023, and each will be followed up for 1 year. The planned sample size is 660, comprising 220 ablation group patients and 440 non-ablation group patients. The primary endpoint will be the composite incidence of stroke/transient ischaemic attack (TIA) or systemic embolism (SE), another cardiovascular event, major bleeding and/or death from any cause. Other clinical events such as postablation AF recurrence, a fall or bone fracture will be recorded. We will collect standard clinical background information plus each patient’s Clinical Frailty Scale score, AF-related symptoms, QoL (Five-Level Version of EQ-5D) scores, Mini-Mental State Examination (optional) score and laboratory test results, including measures of nutritional status, on entry into the study and 1 year later, and serial changes in symptoms and QoL will also be secondary endpoints. Propensity score matching will be performed to account for covariates that could affect study results.Ethics and dissemination The study conforms to the Declaration of Helsinki and the Ethical Guidelines for Clinical Studies issued by the Ministry of Health, Labour and Welfare, Japan. Results of the study will be published in one or more peer-reviewed journals.Trial registration number UMIN000047023.

Abstract Aims Multi‐organ dysfunction was recently reported to be a common condition in patients with heart failure (HF). The Model for End‐stage Liver Disease eXcluding International normalized ratio (MELD‐XI) score reflects liver and kidney function. The prognostic relevance of this score has been reported in patients with a variety of cardiovascular diseases who are undergoing interventional therapies. However, the relationship between the severity of hepatorenal dysfunction assessed by the MELD‐XI score and the long‐term clinical outcomes of HF patients receiving cardiac resynchronization therapy (CRT) has not been evaluated. Methods and results Clinical records of 283 patients who underwent CRT implantation between March 2003 and October 2020 were retrospectively evaluated (mean age 67 ± 12, 22.6% female). Blood samples were collected before CRT implantation. Patients were divided into three groups based on tertiles of the MELD‐XI score: first tertile (MELD‐XI = 9.44, n = 95), second tertile (9.44

Abstract Atrial fibrillation (AF) is a progressive disease that starts with structural or functional changes in the left atrium and left ventricle, and evolves from paroxysmal toward sustained forms. Early detection of structural or functional changes in the left atrium and left ventricle in the paroxysmal stage could be useful for identifying a higher risk of progression to persistent AF and future cardio-cerebrovascular events. The aim of this study was to test the hypothesis that the feature tracking (FT) left atrial (LA) strain and left ventricular (LV) extracellular volume fraction (ECV) derived from cardiovascular magnetic resonance (CMR) could detect early changes in remodeling of the left atrium and ventricle in the paroxysmal AF (PAF) stage. The participants were comprised of 106 PAF patients (age, 66.1 ± 10.7 years; 66% male) who underwent clinical CMR before pulmonary vein isolation and 20 control subjects (age, 68.3 ± 8.6 years; 55% male). The CMR-FT LA strain/phasic function and LV-ECV were compared between the PAF and control groups. The total and passive LA empty fraction (LAEF) and LA strain (corresponding to LA reservoir and conduit function) were decreased in the PAF group as compared to the control group. However, active LAEF (corresponding to the LA booster pump function) did not differ significantly between the PAF group (33.9 ± 10.9%) and control group (37.9 ± 13.3%, p = 0.15), while the active LA strain (corresponding to the LA booster pump function) was significantly decreased in the PAF group (11.4 ± 4.3 vs. 15.2 ± 5.6%, p = 0.002). The LV-ECV was significantly greater in the PAF group (28.7 ± 2.8%) than control group (26.6 ± 2.0%, p = 0.002). In the PAF group, the LV-ECV correlated significantly with the E/e′ and LA volume index. Regarding the LA strain, correlations were seen between the LV-ECV and both the reservoir function and conduit function. CMR-FT LA strain in combination with the LV-ECV in a single clinical study offers a potential imaging marker that identifies LA/LV remodeling including subtle LA booster pump dysfunction undetectable by the conventional booster pump LAEF in the PAF stage.

Abstract Desmin‐related myopathy (DRM) is a rare heritable cardiac and skeletal muscle disease caused by mutations in the desmin gene (DES). DRM is generally characterized by skeletal muscle weakness, conduction disturbance, and dilated cardiomyopathy. However, the clinical cardiac phenotypes of DRM are not yet fully understood. Herein, we report the first case of DRM with the de novo missense DES mutation, R454W, that is characterized by left ventricular non‐compaction cardiomyopathy, progressive cardiac conduction defect, spontaneous coronary artery dissection, and no skeletal muscle weakness. Our case findings suggest that clinicians should genetically test patients who have cardiomyopathy, progressive cardiac conduction defect, and coronary artery dissection, even if the patient has neither family history of DRM nor skeletal muscle symptoms.

Abstract Background Metabolic syndrome/epicardial adipose tissue (EAT) plays an important role in atrial fibrillation (AF). Although reverse atrial remodeling (RAR) often occurs after AF ablation, the effects of EAT on RAR remain unknown. Methods Study subjects were 104 patients in whom transthoracic echocardiography (TTE) was performed before AF ablation and 3, 6, and 12 months afterward. EAT was assessed in terms of its thickness adjacent to the right ventricular anterior wall in the TTE parasternal view. RAR was defined as >10% reduction in the left atrial volume (LAV) index by the 3‐month follow‐up examination. Results Postablation RAR occurred in 57/104 (55%) patients. RAR absence was associated with a relatively thick EAT (4.92 ± 1.65 vs. 3.92 ± 1.17 mm, P = 0.0005), small LAV index (24.6 ± 7.5 vs. 28.8 ± 10.6 mL/m2, P = 0.0233), and metabolic syndrome (62% vs. 28%, P = 0.0006). Metabolic syndrome and EAT were shown to be independent predictors of RAR absence. Thick EAT was significantly associated with AF recurrence after ablation (5.05 ± 2.19 mm vs. 4.17 ± 1.16 mm for no AF recurrence group, P = 0.0116), but metabolic syndrome was not (48% vs. 42%, P = 0.6189). Despite no change in body weight, EAT thickness decreased significantly by 12 months in patients without AF recurrence (4.17 ± 1.16 vs. 3.65 ± 1.16 mm, P

Aims. In the guidelines for cardiac resynchronization therapy (CRT), there is a gap between the Japanese Circulation Society (JCS) criteria, which specify a QRS duration of ≥120 ms, and other countries, with a QRS ≥ 130 ms. The efficacy of CRT remains controversial in patients with a narrow QRS

Abstract Background Limited data exist on indicators of durable pulmonary vein isolation (PVI) undergoing cryoballoon ablation (CBA) for atrial fibrillation (AF). We investigated whether balloon temperature and time to PVI can be used to predict early PV reconduction (EPVR), including residual PV conduction and adenosine triphosphate‐induced dormant conduction and the relation between touch‐up ablation of EPVR sites and mid‐term recurrence of AF. Methods We obtained procedural and outcome data from the records of 130 consecutive patients who underwent CBA and followed up for 13.4 months. Results EPVR was identified in 86 (17%) PVs of 61 (47%) patients. Balloon temperatures during 30 seconds (−27 ± 5.7°C vs −31 ± 5.5°C), 60 seconds (−36 ± 5.6°C vs −41 ± 5.4°C), and at the nadir point (−41 ± 7.4°C vs −49 ± 7.0°C) were significantly higher, and the time to PVI was longer (90 ± 50 seconds vs 52 ± 29 seconds) in PVs with EPVR than in those without (P

Background: The association between circulating adiponectin levels and atrial fibrillation (AF) is uncertain. We, therefore, investigated whether an increased serum adiponectin level is implicated in the long-term recurrence of AF after ablation therapy. Methods: Our study included 100 consecutive patients (88 men; median age, 57.9±10.9 years) who underwent catheter ablation for AF at our hospital between 2011 and 2013. The adiponectin and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured before ablation and compared between those in whom AF recurred and those in whom AF did not recur. Results: Elevation in adiponectin levels was significantly associated with female sex, non-paroxysmal AF, heart failure, higher NT-proBNP and matrix metallo-proteinase-2 levels, and lower body mass index. After a stepwise adjustment for any potential confounding variables, the adiponectin levels remained significantly associated with female sex (beta=0.2601, P=0.0041), non-paroxysmal AF (beta=0.2708, P=0.0080), and higher NT-proBNP levels (beta=0.2536, P= 0.0138). During the median follow-up period of 26.2 months, AF recurred in 48 of the 100 patients. Stepwise multivariate adjustment showed that an increased log-transformed NT-proBNP (Hazard ratio [HR], 2.18; 95% confidence interval [CI] 1.25â4.00; P=0.0055), longer duration of AF (HR, 1.87; 95%CI 1.01â3.76; P=0.0465), and decreased left ventricular ejection fraction (HR, 0.96; 95%CI 0.93â0.99; P=0.0391) were independent predictors of recurrent AF after catheter ablation, but adiponectin was not. Conclusions: Our data indicated that adiponectin was partially responsible for progression of AF, but the correlation between adiponectin levels and AF recurrence was not significant. Keywords: Atrial fibrillation, Adiponectin, NT-proBNP, Ablation

Background: The relationship between cardiac contrast-enhanced magnetic resonance imaging (CE-MRI)-derived scar characteristics and substrate for ventricular tachycardia (VT) in patients with structural heart disease (SHD) has not been fully investigated. Methods: This study included 51 patients (mean age, 63.3±15.1 years) who underwent CE-MRI with SHD and VT induction testing before ablation. Late gadolinium-enhanced (LGE) regions on MRI slices were quantified by thresholding techniques. Signal intensities (SIs) 2–6 SDs above the mean SI of the remote left ventricular (LV) myocardium were considered as scar border zones, and SI>6 SDs, as scar zone, and the scar characteristics related to VT inducibility and successful ablation via endocardial approaches were evaluated. Results: The proportion of the total CE-MRI-derived scar border zone in the inducible VT group was significantly greater than that in the non-inducible VT group (26.3±9.9% vs. 19.2±7.8%, respectively, P=0.0323). The LV endocardial scar zone to total LV myocardial scar zone ratio in patients whose ablation was successful was significantly greater than that in those whose ablation was unsuccessful (0.61±0.11 vs. 0.48±0.12, respectively, P=0.0042). Most successful ablation sites were located adjacent to CE-MRI-derived scar border zones. Conclusions: By CE-MRI, we were able to characterize not only the scar, but also its location and heterogeneity, and those features seemed to be related to VT inducibility and successful ablation from an endocardial site.

Background: The mechanisms underlying self-perpetuation of persistent atrial fibrillation (AF) are not well understood. To gain insight into these mechanisms, we conducted a study comparing left atrial (LA) electroanatomic maps obtained during sinus rhythm between patients with paroxysmal AF (PAF) and patients with persistent AF (PerAF). Methods: The study included 23 men with PAF (age, 56.3±12.1 years) and 13 men with PerAF (age, 54.3±13.4 years). LA voltage mapping was performed during sinus rhythm. The clinical and electroanatomic characteristics of the two groups were evaluated and analyzed statistically. Results: The bipolar voltages at the LA septum, roof, and posterior wall, right superior pulmonary vein (PV) and its antrum, right superior PV carina, and right inferior PV antrum were significantly lower in patients with PerAF than in those with PAF. The bipolar voltages in other parts of the LA did not differ statistically between the two groups. Conclusion: PAF and PerAF seem to be characterized by differences in the regional voltage in the LA and PVs. The LA structural remodeling of PerAF may initiate from the right PVs and their antra and LA septum, roof, and posterior wall.

Background: The relationship between atrial electrogram (EGM) characteristics in atrial fibrillation (AF) and those in sinus rhythm (SR) are generally unknown. The activation rate and direction may affect EGM characteristics. We examined characteristics of left atrial (LA) EGMs obtained during pacing from different sites. Methods: The study included 10 patients undergoing pulmonary vein isolation for AF. Atrial EGMs were recorded from a 64-pole basket catheter placed in the LA, and bipolar EGM amplitudes from the distal electrode pair (1–2) and proximal electrode pair (6–7) from 8 splines were averaged. The high right atrium (HRA), proximal coronary sinus (CSp), and distal coronary sinus (CSd) were paced at 600 ms and 300 ms. Results: When the LA voltage at SR was ≥1.5 mV, bipolar voltages of the HRA were greater than those of the CSp, which were greater than those of the CSd, regardless of the pacing cycle length. The shorter pacing cycle length resulted in a reduction of the LA EGM voltage at sites of SR voltage ≥1.5 mV, but no significant difference was seen at sites where the SR EGM amplitude was between >0.5 and

Background: Ablation targeting complex fractionated atrial electrograms (CFAEs) or high dominant frequency (DF) sites is generally effective for persistent atrial fibrillation (AF). CFAEs and/or high DF sites may exist in low-voltage regions, which theoretically represent abnormal substrates. However, whether CFAEs or high DF sites reflect low voltage substrates during sinus rhythm (SR) is unknown. Methods: Sixteen patients with AF (8 with paroxysmal AF; 8, persistent AF) underwent high-density mapping of the left atrium (LA) with a 3-dimensional electroanatomic mapping system before ablation. The LA was divided into 7 segments and the mean bipolar voltage recorded during AF and SR, CFAEs (cycle lengths of 50–120 ms), and DF sites were assessed in each segment with either a duo-decapolar ring catheter (n=10) or a 64-pole basket catheter (n=6). Low-voltage areas were defined as those of 8 Hz) did not correlate with % low-voltage sites during SR; however, CFAEs sites were located in high-voltage regions during AF and high DF sites were located in low voltage regions during AF. Conclusions: CFAEs and high DF areas during AF do not reflect damaged atrial myocardium as shown by the SR voltage. However, CFAEs and high DF sites may demonstrate different electrophysiologic properties because of different voltage amplitude during AF.

Abstract Background Cardiac myxoma is known to cause repeated events of cerebral embolism. Soft and irregularly shaped myxomas with high mobility are associated with a higher occurrence of cerebral embolism. In contrast, nonmobile cardiac myxomas with a round regular shape are rarely considered to be a cause of cerebral embolism. In this case, we present a patient with recurrent cerebral embolism associated with a small and nonmobile cardiac myxoma of round regular shape. Case presentation A 76-year-old Japanese man presented to our hospital with weakness in his right upper extremity. He had a history of right frontal lobe infarction in the previous month. T2-weighted magnetic resonance imaging revealed an area of hyperintensity in the left precentral gyrus, indicating acute cerebral infarction. Transthoracic echocardiography revealed normal left ventricular function and no abnormalities. However, transesophageal echocardiography showed a small and nonmobile left atrial tumor with round regular shape attached to the ostium secundum of the atrial septum. Based on these findings, we diagnosed recurrent cerebral infarction due to embolization caused by left atrial myxoma, and cardiac tumor extraction was performed on hospitalization day 36. The excised tumor measured 0.6 × 0.6 × 0.5 cm and was diagnosed as cardiac myxoma by histologic examination. Conclusions Even small and nonmobile cardiac myxomas with a round regular shape may cause recurrent cerebral infarction. The diagnosis of this type of atrial myxoma is elusive and transesophageal echocardiography was an effective method of detection. In a clinical situation, this type of cardiac myxoma may be overlooked as a cause of cerebral infarction.

Background: The definition of response to cardiac resynchronization therapy (CRT) varies across clinical trials. There are two main definitions, i.e., echocardiographic response and functional response. We assessed which definition was more reasonable. Methods: In this study of 260 patients who had undergone CRT, an echocardiographic response was defined as a reduction in a left ventricular end-systolic volume of greater than or equal to 15% or an improvement in left ventricular ejection fraction of greater than or equal to 5%. A functional response was defined as an improvement of at least one class category in the New York Heart Association functional classification. We assessed the response to CRT at 6 months after device implantation, based on each definition, and investigated the relationship between response and clinical outcomes. Results: The echocardiographic response rate was 74.2%. The functional response rate was 86.9%. Non-responder status, based on both definitions, was associated with higher all-cause mortality. Cardiac death was only associated with functional non-responder status (hazard ratio (HR) 2.65, 95% confidence interval (CI) 1.19–5.46, p = 0.0186) and heart failure hospitalization (HR 2.78, 95% CI, 1.29–5.26, p = 0.0111). Conclusion: After CRT implantation, the functional response definition of CRT response is associated with a higher response rate and better clinical outcomes than that of the echocardiographic response definition, and therefore it is reasonable to use the functional definition to assess CRT response.

Background: Consistent detection of rotor(s) and/or focal impulse(s) of atrial fibrillation can using a 64-pole basket catheter remain unclear. Methods and results: Intracardiac left atrial electrograms were recorded, prior to ablation, in 20 patients with atrial fibrillation. Unipolar electrograms, filtered at 0.1–300 Hz, were recorded and exported for an offline phase analysis. From the cohort, 8 of the 20 patients had analyzable data. Localized rotors were identified in 3 of these patients, with focal impulses detected in 4 patients. Conclusion: Localized rotors and focal impulses can be identified on phase maps of atrial fibrillation in a small number of patients.

Background: Although alteration of the amplitude and morphology of bipolar electrograms is used widely as a guide of the ablation effect, there is little information concerning unipolar electrograms. The amplitude and morphology of filtered bipolar (BP) and filtered unipolar (UP) electrograms were compared during pulmonary vein isolation in patients with atrial fibrillation. Methods: BP (30–250 Hz) and UP (30–100 Hz) signals from the ablation catheter were recorded before and after each ablation point at the pulmonary vein antrum in 6 patients with atrial fibrillation. Results: In the electrogram group with low-voltage amplitude in BP electrograms before ablation (

Background: Complex fractionated atrial electrograms (CFAEs) and high dominant frequency (DF) are targets for atrial fibrillation (AF) ablation. Although adenosine triphosphate (ATP) is known to promote AF by shortening the atrial refractory period, its role in the pathogenesis of CFAEs and DF during AF is not fully understood. Methods: We recorded electrical activity from a 64-electrode basket catheter placed in the left atrium (LA) of patients with paroxysmal AF (PAF, n=18) or persistent AF (PerAF, n=19) before ablation. Atrial electrogram fractionation intervals (FIs) and DFs were measured from bipolar electrograms of each adjacent electrode pair. Offline mean atrial FIs and DFs were obtained before bolus injection of 30 mg ATP. Peak effect was defined as an R–R interval >3 s. Results: With ATP, the mean FI decreased (from 110.4±29.1 ms to 90.5±24.7 ms, P

Background: Because obesity is an important risk factor for atrial fibrillation (AF), we conducted an animal study to examine the effect of a high-fat diet (HFD) on atrial properties and AF inducibility. Methods: Ten 8-week-old pigs (weight, 18–23 kg) were divided into two groups. For 18 weeks, five pigs were fed a HFD (HFD group) and five were fed a normal diet (control group). Maps of atrial activation and voltages during sinus rhythm were created for all pigs using the EnSite NavX system. Effective refractory period (ERP) and AF inducibility were also determined. When AF was induced, complex fractionated atrial electrogram (CFAE) mapping was performed. At 18 weeks, hearts were removed for comparing the results of histological analysis between the two groups. Body weight, lipid levels, hemodynamics, cardiac structures, and electrophysiological properties were also compared. Results: Total cholesterol levels were significantly higher (347 [191–434] vs. 81 [67–88] mg/dL, P=0.0088), and left atrium pressure was higher (34.5 [25.6–39.5] vs. 24.5 [21.3–27.8] mmHg, P=0.0833) in the HFD group than in the control group, although body weight only increased marginally (89 [78–101] vs. 70 [66–91] kg, P=0.3472). ERPs of the pulmonary vein (PV) were shorter (P

Background: Liver diseases drive the development and progression of atrial fibrillation (AF). The Fibrosis-4 (FIB4) index is a non-invasive scoring method for detecting liver fibrosis, but the prognostic impact of using it for AF patients is still unknown. Herein, we evaluated using the FIB4 index as a risk assessment tool for cardiovascular events and mortality in patients with AF. Methods: We performed a post-hoc analysis of a prospective, observational multicenter study. A total of 3067 patients enrolled in a multicenter Japanese registry were grouped as first tertile (FIB4 index < 1.75, n = 1022), second tertile (1.75 ≤ FIB4 index < 2.51, n = 1022), and third tertile (FIB4 index ≥ 2.51, n = 1023). Results: The third tertile had statistically significant results: older age, lower body mass index, increased heart failure prevalence, and lower clearances of hemoglobin and creatinine (all p < 0.05). During the follow-up period, incidences of major bleeding, cardiovascular events, and all-cause mortality were significantly higher for the third tertile (all p < 0.05). After multivariate adjustment, the third tertile associated independently with cardiovascular events (HR 1.72; 95% CI 1.31−2.25) and all-cause mortality (HR 1.43; 95% CI 1.06−1.95). Adding the FIB4 index to a baseline model with CHA2DS2-VASc score improved the prediction of cardiovascular events and all-cause mortality, as shown by the significant increase in the C-statistic (all p < 0.05), net reclassification improvement (all p < 0.001), and integrated discrimination improvement (all p < 0.001). A FIB4 index ≥ 2.51 most strongly associated with cardiovascular events and all-cause mortality in AF patients with high CHADS2 scores (all p < 0.001). Conclusions: The FIB4 index is independently associated with risks of cardiovascular events and all-cause mortality in AF patients.

Background: The presence of complex fractionated atrial electrograms (CFAEs) and high dominant frequencies (DFs) during atrial fibrillation (AF) have been demonstrated to be related to AF maintenance. Therefore, sequential mapping of CFAEs and DFs have been used for target sites of AF ablation. However, such mapping strategies are valid only if the CFAEs and DFs are spatiotemporally stable during the mapping procedure. We obtained spatially stable multi-electrode recordings to assess the spatiotemporal stability of CFAEs and DFs. Methods: We recorded electrical activity during AF for 10 min with a 64-electrode basket catheter (48 bipole electrode pairs) placed in the left atrium in 36 patients with AF (paroxysmal AF [PAF], n=16; persistent AF [PerAF], n=20). The spatial and temporal distribution of the CFAEs (fractionation interval 8 Hz) at 1-min intervals for 10 min were compared for each of the 48 bipoles. Results: The baseline CFAEs were located at 68.5±14.0% (32.9±6.7) of the 48 bipoles; however, the high DF sites were fewer (9.6±8.6% [4.6±4.1 bipoles]). The CFAEs sites did not change significantly during the 10-min recording period (kappa statistic: 0.71±0.24); however, the high DF sites changed significantly (kappa statistic: 0.07±0.19). These spatiotemporal changes in the CFAEs and high DFs did not differ between patients with PAF and PerAF. Conclusions: Regardless of the AF type, CFAEs sites, but not high DF sites, showed a high degree of spatial and temporal stability.

Introduction: Acute and mid-term effects of ablation for atrial fibrillation (AF) on left atrial (LA) and left ventricular (LV) function and the atrial electromechanical interval are controversial. Methods: Echocardiographic variables and the PA-TDI interval (time from ECG lead II P-wave onset to lateral a′ wave on tissue Doppler tracings, indicating the total atrial conduction time [TACT]) were evaluated in 33 paroxysmal AF patients before, 1 day, and 3, 6, and 12 months after ablation. Results: During a 12-month follow-up, 10 (30.3%) patients had recurrent AF, associated with a greater baseline LA volume (LAV) (48.4±19.3 mm3 vs. 38.7±11.4 mm3, P=0.0811) and PA-TDI interval (163.9±11.0 ms vs. 151.1±14.6 ms, P=0.0189) than in patients without AF recurrence. By 6 months after ablation, LAV had decreased progressively in the non-recurrence group (27.9±8.1 mm3, P

Background: Vector-projected 187-channel electrocardiograms (ECGs) were recorded in 45 patients with a Brugada-type ECG to evaluate spatial and transmural repolarization and dispersion of action potential duration in Brugada syndrome (BS). Methods: Corrected recovery time (RT-c, R wave peak to the first positive maximum derivative of the T wave with Bazett correction) and RT-c dispersion were calculated. The corrected T peak-end interval (T(p-e)-c, T wave peak to the end of the T wave with Bazett correction) and T(p-e)-c dispersion were calculated. Results: RT-c dispersion and T(p-e)-c interval were longer in patients with a type 1 ECG, but there was no significant difference in Tp-e dispersion between patients with a type 1 and those with a type 2/3 ECG. No significant correlation was noted between RT-c dispersion, T(p-e)-c dispersion, and symptoms. Late potentials (P=0.023) and a family history of sudden cardiac death (P=0.0017) were correlated with symptoms. Conclusions: Spatial dispersion of repolarization may constitute the electrocardiographic pattern of the Brugada type ECG and conduction disturbance in addition to repolarization abnormality may contribute to the development of malignant ventricular tachyarrhythmias.

The assessment of risk in the asymptomatic patient with long QT syndrome can often be a challenging task, particularly when the available evidence is limited to relatively small retrospective registries, not to mention the need to consider the effect of individual patient factors which are often difficult to quantitate. We describe the relatively uncommon case of a man with a long-standing diagnosis of Long QT 2 syndrome who suffered his first cardiac event in his late 60's, likely precipitated by the development of paroxysmal atrial tachycardia. A brief review of the available literature on risk assessment in adults with genetically confirmed long QT syndrome who have remained asymptomatic late into adulthood will follow the case.

Background: Brugada syndrome is a distinct form of idiopathic ventricular fibrillation. We retrospectively investigated the incidence and clinical implications of supraventricular tachyarrhythmia in patients with Brugada syndrome. Methods: We reviewed 69 consecutive cases of Brugada syndrome, 11 of which had a history of syncope. Results: Seven patients (10.1%) had clinically documented supraventricular tachyarrhythmia: 3 patients with atrioventricular reentrant tachycardia, 2 with atrioventricular nodal reentrant tachycardia, and 2 with paroxysmal atrial fibrillation. The prevalence of a spontaneous type 1 Brugada electrocardiogram and symptoms (history of syncope, presyncope, documented ventricular tachyarrhythmia, or aborted sudden cardiac death) were significantly higher, and QRS duration was significantly longer in patients without than in those with supraventricular tachyarrhythmia. The PR and AH intervals were also longer in patients without than in those with supraventricular tachyarrhythmia, but the differences were not statistically significant. Conclusion: The arrhythmogenic substrate in Brugada syndrome may not be restricted to the ventricles. Palpitations in patients with this syndrome should raise the question of supraventricular tachyarrhythmia. Conversely, in patients with supraventricular tachyarrhythmia and aborted sudden cardiac death or syncope not related to supraventricular tachyarrhythmia, Brugada syndrome should be considered a possible additional electrophysiologic abnormality.

We describe a 49-year-old woman with atrial tachycardia (AT) and arrhythmogenic right ventricular cardiomyopathy/dysplasia. Cardiac magnetic resonance images showed a markedly dilated right atrium and right ventricle. Electroanatomical mapping showed that the AT originated from the right atrial appendage.

Background: Brugada-type ECG changes have been described in association with various cardiac disease states including electrolyte abnormalities, myocardial pathologies, and mechanical cardiac abnormalities as well as drug therapies with particular medications. Such potential confounding factors make it difficult to diagnose Brugada syndrome on the basis of standard guidelines. Methods: To investigate the incidence of significant coronary artery disease in patients with Brugada-type ECG, coronary angiography was performed in 55 patients with Brugada-type ECGs. Results: Five of the 55 patients (9%) had significant coronary artery stenosis, and 3 out of these 5 were asymptomatic. Patients with coronary artery disease were older than in those without coronary artery disease (59.4±7.2 years vs. 49.0±13.8 years, P=0.03). An electrophysiological study was performed in 4 of the 5 patients, and ventricular fibrillation was induced in all 4. Conclusions: We conclude that patients with Brugada-type ECGs should be evaluated for coronary artery disease, and this is especially important for patients in whom age could be a risk factor for the disease.

In this study, the prevalence and prognostic significance of the early repolarization (ER) pattern in the inferolateral leads in patients with Brugada syndrome were investigated. Clinical, genetic, and electrophysiological data were collected and analyzed from 69 individuals with either a spontaneous or drug-induced Brugada type 1 electrocardiogram (ECG) pattern. An ER pattern was defined as J-point elevation at least 0.1 mV from the baseline in at least 2 inferior or lateral leads. The presence of late potentials and inducibility of ventricular fibrillation (VF) by programmed stimulation were compared between patients with and without a J wave. Follow-up data, including outcome events, were obtained for all patients. An ER pattern was observed in the inferolateral leads in 6 patients with a spontaneous Brugada type 1 ECG pattern and in 1 patient with a drug-induced Brugada type 1 ECG pattern. There was no significant intergroup difference in symptoms, family history of sudden cardiac death, prevalence of late potentials, or inducibility of VF. No patient with the ER pattern developed a cardiac event during the mean follow-up period of 73.6±38.1 months. The ER pattern in the inferolateral leads is not uncommon in Brugada syndrome; however, the presence of a J wave does not appear to be associated with subsequent arrhythmic events in patients with Brugada syndrome.

A 73-year-old man with hypertrophic cardiomyopathy was referred for an electrophysiologic study and catheter ablation of premature ventricular contractions (PVCs)/nonsustained ventricular tachycardia (NSVT). The QRS morphology of the PVCs was right bundle branch block with an inferior axis. Transthoracic echocardiography showed left ventricular hypertrophy and a normal left ventricular ejection fraction without any obstruction in the left ventricle (LV). Intracardiac mapping showed that the earliest activation site of the PVCs was within the anterior portion of the basal LV, where a Purkinje potential preceded the QRS onset by 32 ms. Radiofrequency application at that site terminated the PVCs. The PVCs/NSVT did not recur during 10 months of follow-up.

Although the most feared cardiac manifestation in cardiac sarcoidosis is the onset of ventricular arrhythmia, some patients may present with supraventricular arrhythmias. We present a rare case of cardiac sarcoidosis associated with double tachycardia manifesting as atrial flutter and ventricular tachycardia.

We report an interesting case in which atrial fibrillation (AF) was terminated during ablation of high-dominant frequency (DF) sites covered with epicardial adipose tissue (EAT). High-DF sites are known to be related to the center of focal-firing rotors or local reentry circuits. Therefore, this phenomenon suggests that EAT may be related to the development of dominant rotors maintaining AF.

Here, we report a case of a 69-year-old patient with paroxysmal atrial fibrillation and inducible typical atrial flutter who required catheter ablation. After pulmonary vein isolation, cavotricuspid isthmus ablation was performed. During ablation at a lateral site of the cavotricuspid isthmus, a spiky potential appeared at the distal electrode of the ablation catheter, and subsequently, a 2:1 atrioventricular (AV) block occurred. Radiofrequency (RF) delivery at the same site caused a similar phenomenon, implying that the spiky potential may reflect a slow pathway potential as an anatomical variant of the rightward extension of the AV node.