A new composite indicator consisting of left ventricular extracellular volume, N-terminal fragment of B-type natriuretic peptide, and left ventricular end-diastolic volume is useful for predicting reverse remodeling after catheter ablation for atrial fibrillation.

Recently, myocardial extracellular volume (ECV) analysis has been measurable on computed tomography (CT) using new software. We evaluated the use of cardiac CT to estimate the myocardial ECV of left ventricular (LV) myocardium (LVM) to predict reverse remodeling (RR) in cases of atrial fibrillation (AF) after catheter ablation (CA). Four hundred and seven patients underwent CA for AF in our institution from April 2014 to Feb 2021. Of these, 33 patients (8%) with an LVEF ≤ 50% and who had undergone CT were included in our study. We estimated the LVM ECV using commercial software to analyze the CT data. RR was defined as an improvement in LVEF to > 50% after CA. LVEF increased to > 50% in 24 patients (73%) after CA. In all 24 patients, LVM ECV, LV end-diastolic and end-systolic volumes (LVEDV and LVESV), and the n-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) were significantly lower than in the other nine patients (P = 0.0037, 0.0273, 0.0443, and < 0.0001). On receiver operating characteristic curve analysis, the best cut-off of ECV, LVEDV, LVESV and NT-proBNP for the prediction of RR were 37.73%, 120 mL, 82 mL, and 1267 pg/mL, respectively. We newly defined the ENL (ECV, NT-proBNP, and LVEDV) score as the summed score for the presence or absence (1 or 0; maximum score = 3) of ECV, NT-proBNP, and LVEDV values less than or equal to each best cut-off value, and found that this score gave the highest area under the curve for the prediction of RR (0.9583, P < 0.0001). The ENL score may be useful for predicting RR in patients with AF undergoing CA.

Pathophysiological background and prognosis of common atrial flutter in non-elderly patients: Comparison to Atrial Fibrillation.

BACKGROUND: It is unclear whether there is any difference in the background and prognosis between non-elderly patients who undergo catheter ablation of atrial fibrillation (AF) and common atrial flutter (CAFL). PURPOSE: To investigate the difference between the patient background of both CAFL and AF in the non-elderly. METHODS: In 526 consecutive patients who underwent catheter ablation of clinical paroxysmal/persistent CAFL or AF in our hospital, we enrolled only patients under 60 years old. Cases harboring both AFL and AF were excluded. We analyzed the patient characteristics, echocardiographic findings, electrocardiographic (ECG) abnormalities during sinus rhythm, and clinical course after ablation. RESULTS: In total, 196 patients (Cohort 1: 142 males, 156 AF cases) were analyzed. AFL patients were younger than AF patients (47.4 ± 10.6 vs. 50.2 ± 6.4years, p = 0.031) and organic heart disease (OHD) was significantly more common in AFL patients than AF patients (42.5% vs. 11.5%, p<0.001). In 161 patients excluding OHD (Cohort 2), ECG abnormalities were more frequent in AFL than in AF patients (78.3% vs. 39.1%, p = 0.001). There were no significant differences in all-cause death, onset of heart failure, and cerebral strokes. On the other hand, the number of cases that required a pacemaker was significantly higher in the CAFL group than AF group (0.0% vs. 26.1%, p-value <0.001). These results suggested that CAFL may reflect occurrence of any atrial myocardial damage, even if it does not lead to heart failure. CONCLUSIONS: Our present study suggested that CAFL may be associated with a broader atrial myocardial disorder in non-elderly patients.

Peak deflection index as a predictor of a free-wall implantation of contemporary leadless pacemakers.

BACKGROUND: Leadless pacemakers are an effective treatment for bradycardia. However, some cases exhibit pericardial effusions, presumably associated with device implantations on the right ventricular free-wall. The present study was carried out to find the ECG features during ventricular pacing with a Micra, which enabled distinguishing free-wall implantations from septal implantations without using imaging modalities. METHODS: Thirty-one consecutive patients who received Micra implantations in our facility were enrolled. The location of the device in the right ventricle was evaluated using echocardiography or computed tomography in order to determine whether the device was implanted on the septum (Sep group), apex (Apex group), or free-wall (FW group). The differences in the 12-lead ECG during ventricular pacing by the Micra were analyzed between the Sep and FW groups. RESULTS: The body of the Micra was clearly identifiable in 22 patients. The location of the device was classified into Sep in 12 patients, Apex in 4, and FW in 6. The mean age was highest in the FW and lowest in the Sep group (82.7 ± 6.6 vs. 72.8 ± 8.7 years, p = 0.027). The peak deflection index (PDI) was significantly larger in the FW group than Sep/Apex group in lead V1 (Sep: 0.505 ± 0.010, Apex: 0.402 ± 0.052, FW: 0.617 ± 0.043, p = 0.004) and lead V2 (Sep: 0.450 ± 0.066, Apex: 0.409 ± 0.037, FW: 0.521 ± 0.030, p = 0.011), whereas there was no difference in the QRS duration, transitional zone, and QRS notching. CONCLUSION: The PDI in V1 could be useful for predicting implantations of Micra devices on the free-wall and may potentially stratify the risk of postprocedural pericardial effusions.

Predicting therapies in Japanese hypertrophic cardiomyopathy patients with an implantable cardioverter-defibrillator using the 2014 European Society of Cardiology guidelines.

Previous studies have shown that the sudden cardiac death (SCD) prediction model proposed by the 2014 European Society of Cardiology (ESC) guideline (5-Year Risk-SCD) was validated in European patients with hypertrophic cardiomyopathy (HCM). However, there are limited data on Asian patients with HCM. We assessed the validity of the estimated 5-Year Risk-SCD in Japanese HCM patients with an implantable cardioverter-defibrillator (ICD) using the2014 ESC guidelines. We retrospectively examined data of 492 consecutive Japanese patients with an ICD. Sixty-two Japanese HCM patients with an ICD were enrolled in this study, and 50 patients (81%) were followed up for ≥ 5 years. We analyzed the characteristics and outcomes of these 50 patients. We investigated the incidence of appropriate ICD therapy as categorized by the ESC guideline and compared the 5-Year Risk-SCD with the 5-year rate of appropriate shock therapies. Based on the 2012 Japanese Circulation Society guideline and the 2011guidelines of the American Heart Association and American College of Cardiology Foundation, 10 and 40 patients met classes I and IIa of the ICD recommendation, respectively. However, only 18 (36%) patients were classified into class I or IIa of the ESC guideline. Among 50 patients followed up for ≥ 5 years after ICD implantation, the incidences of appropriate ICD therapies for classes I, IIa, IIb, and III indications based on the 2014 ESC guideline were 50%, 38%, 17%, and 0%, respectively. Risk stratification for SCD using 5-Year Risk-SCD is valid in Japanese HCM patients with an ICD, and the 2014 ESC guideline might be useful for the indication of ICD implantation in Japan.

Successful cryoablation of ventricular extrasystoles originating from the vicinity of the left anterior fascicle.

A 32-year-old male received catheter ablation of frequent ventricular extrasystoles (VEs). His electrocardiogram showed monomorphic VEs with an inferior axis and early precordial transitional zone. During electrophysiological testing, a 10-pole catheter positioned in the left ventricular outflow tract recorded sharp pre-potentials just before the ventricular activation during VEs as well as sinus beats. Three-dimensional mapping was performed by annotating the sharp pre-potentials to reveal that the earliest activation site was deemed to be close to the left anterior fascicle. A cryoablation catheter was introduced into the left ventricle and freezing for 240 seconds successfully eliminated the clinical VEs without any complications.

Estimation of the accessory pathway location of the manifest Wolf-Parkinson-White syndrome using synthesized right-sided chest leads.

PURPOSE: The classification using QRS morphology of V1 lead is a useful simple predictor of accessory pathway location (type A, R or Rs pattern; type B, rS pattern; type C, QS or Qr pattern), but often leads to misdiagnosis of accessory pathway location, especially in types B and C. The synthesized 18-lead electrocardiography (ECG) derived from standard 12-lead ECG can provide virtual waveforms of right-sided chest leads. This study aimed to evaluate the usefulness of the right-sided chest lead ECG for prediction of accessory pathway location. METHODS: This retrospective study included 44 patients in whom successful ablation of manifest Wolff-Parkinson-White (WPW) syndrome was performed. Synthesized ECG waveforms were automatically generated, and ECG data obtained before the procedure. RESULTS: There were 26, 4, and 14 patients with left, right, and septal accessory pathways, respectively. All left accessory pathway cases have type A in V1 and syn-V4R leads. Of the 4 right accessory pathway cases, 2 have type B in V1 and syn-V4R leads. Other 2 of 4 cases have type C. In V1 lead, 5 of 14 septal accessory pathway cases have type C, 7 of 14 cases have type B, and 2 of 14cases have type A. In syn-V4R lead, all 14 septal accessory pathway cases have type C. The QRS morphology of V1 and syn-V4 leads could predict the site of accessory pathway with overall accuracy of 79% and 95%, respectively. CONCLUSIONS: QRS morphology of syn-V4R lead may be useful for predicting accessory pathway location of manifest WPW syndrome.

Comparison of the performance of implantable cardioverter-defibrillator leads among manufacturers.

BACKGROUND: Leads are often considered the weakest link in implantable cardioverter-defibrillator (ICD) systems, and lead dysfunction is a major concern for ICD recipients. The aim of this study was to compare the lead performance from three different manufacturers. METHODS: We retrospectively reviewed consecutive patients who underwent ICD system implantation at Chiba University Hospital, Japan, between March 2008 and September 2017. The following leads were implanted in our center: Durata (St. Jude Medical, St. Paul, MN, USA, now Abbott) (n = 105), Linox and LinoxSmart (Biotronik, Berlin, Germany) (n = 66), and Sprint Quattro (Medtronic, Minneapolis, MN, USA) (n = 126). RESULTS: A total of 297 ICD leads were analyzed. Failure rates for Durata, Linox/LinoxSmart, and Sprint Quattro were 0.20%/patient year, 0.95%/patient year, and 1.84%/patient year, respectively, during a mean follow-up of 4.8, 6.4, and 3.0 years, respectively. The cumulative ICD lead survival probability was 98.9%, 100%, and 87.5%, after 5 years, respectively. The survival probability over the entire follow-up time as measured by the log-rank test was lower for Sprint Quattro leads than for either Durata (p = 0.011) or Linox/LinoxSmart (p = 0.028). The difference between Durata and Linox/LinoxSmart was not significant (p = 0.393). CONCLUSIONS: In this single-center retrospective study, the performance of Sprint Quattro was lower than the performance of Linox/LinoxSmart and Durata leads. Large-scale, multi-center studies or manufacturer-independent registries may be necessary to confirm or reject self-reported survival probabilities from manufacturers' product performance reports.

Impact of atrial high-rate episodes on the risk of future stroke.

BACKGROUND: Atrial fibrillation (AF) is the most common type of arrhythmia. The definition of AF in patients with cardiac implantable electronic devices (CIEDs) is not clear, and the appropriate treatment guideline for patients with episodes of AF has not been established yet. Additionally, little is known about the incidence of AF and embolic stroke events in Japanese patients with CIEDs. The purposes of this study were to identify the incidence of embolic stroke events in Japanese patients with and without AF events detected by CIEDs and to examine the risk factors of embolic stroke events. METHODS: We retrospectively analyzed the database of our CIED clinic. Every 6 months, episodes of AF were checked by CIEDs. Using univariate (Student's t-test and Fisher's exact test) and multivariate analyses, we examined the characteristics and incidence of embolic stroke events and investigated the relationship between episodes of AF and the incidence of embolic stroke events. RESULTS: In this study, we enrolled 348 consecutive patients who had no prior history of AF and were not administering anticoagulants (follow-up period, 65±58 months; age, 70±16 years; male sex, 64%; implantable cardioverter defibrillator, 55%). The mean CHADS2 and CHA2DS2-VASc scores were 1.7±1.1 and 2.8±1.5 points, respectively. Fifty-five patients (16%) had AF events detected by CIEDs that lasted for ≥30s, and 23 patients (6.6%) had embolic stroke during the follow-up period. Multivariate analysis demonstrated that independent predictors for embolic stroke were a left atrial diameter ≥40mm [odds ratio (OR) 3.1, 95% confidence interval (CI) 1.2-7.9, p=0.016] and episodes of AF (OR 5.3, 95% CI 2.2-13, p=0.0003). CONCLUSIONS: Embolic stroke events are common in Japanese patients with CIEDs. AF events lasting ≥30s and an enlarged left atrium are the risk factors of embolic stroke in this population.