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In this paper, we propose a novel method of voltage-map reconstruction using the Advisor™ HD Grid (Abbott Laboratories, Abbott Park, IL) to elucidate the 3-dimensional anatomical and electrophysiological substrates. High-density mapping makes it possible to clarify the activation pattern during ventricular tachycardia and a substrate during sinus rhythm on the endocardial surface. To enhance the mapping resolution, the use of catheters with smaller electrodes and closer interelectrode spacing can be used.1 In contrast, the unipolar or bipolar with wider interelectrode can be a clue for estimating the substrate in 3 dimensions because of far-field potential sensing.2,3 In this case report, we describe the successful identification of a heterogeneous scar within a dense scar with the use of a reconstructed voltage map with wider interelectrode spacing and suggest the involvement of the heterogeneous scar in the mechanism of functional block.

Background Recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) is associated with left atrial (LA) remodeling; however, its association with right atrial (RA) remodeling remains unclear. Objective This study aimed to identify whether RA structural remodeling could predict recurrence of AF after PVI. Methods This study prospectively analyzed 245 patients with AF who had undergone PVI. RA and LA volumes were determined by contrast‐enhanced computed tomography. Atrial structural remodeling was defined as an atrial volume of ≥110 mL according to previous reports and receiver operating characteristic curve analysis. Results After excluding 32 patients, 213 patients were analyzed. During a follow‐up period of 12 months, 41 patients (19%) demonstrated atrial arrhythmia recurrence after PVI. With the Cox proportional‐hazards model, RA structural remodeling was the only predictor of arrhythmia recurrence (hazard ratio, 1.012; 95% confidence interval 1.003‐1.021; P = .009). Kaplan–Meier analysis showed that arrhythmia recurrence was more frequent in the RA structural remodeling group compared with the group without RA remodeling (log‐rank, P, A greater incidence of recurrence was observed in the presence of RA structural remodeling regardless of the AF type. RA structural remodeling was a useful predictor of clinical outcomes after PVI.

Aim: Arterial stiffness results in elevated left ventricular filling pressure and can promote atrial remodeling due to chronic pressure overload. However, the impact of arterial stiffness on the process of atrial remodeling in association with atrial fibrillation (AF) has not been fully evaluated. Methods: We enrolled 237 consecutive patients diagnosed with AF who had undergone ablation; data from 213 patients were analyzed. Cardio-ankle vascular index (CAVI) was used as a marker of arterial stiffness. The left atrial (LA) and right atrial (RA) volumes were determined by computed tomography imaging; atrial conduction and voltage amplitude were evaluated using a three-dimensional electromapping system used to guide the ablation procedure. Result: In univariate analysis, CAVI significantly correlated with atrial structural and electrical remodeling (LA volume index, r =0.297, P =0.001; RA volume index, r =0.252, P =0.004; LA conduction velocity, r =0.254, P = 0.003; LA mean voltage, r =−0.343, P =0.001, RA mean voltage; r =−0.245, P =0.015). Multivariate regression analysis revealed that CAVI and plasma levels of N-terminal B-type natriuretic peptide were independent determinants of LA and RA remodeling, respectively. On the other hand, age and LA conduction velocity were independent variables with respect to CAVI. Age-adjusted CAVI was highest in long-standing persistent AF when compared with measures of persistent or paroxysmal AF. Conclusion: CAVI was closely associated with biatrial remodeling in patients diagnosed with AF. These results suggest that arterial stiffness may play a significant role with respect to disease progression.

Background Radiofrequency catheter ablation (RFCA) is an effective therapy for atrial fibrillation (AF). However, it the problem of AF recurrence remains. This study investigates whether a deep convolutional neural network (CNN) can accurately predict AF recurrence in patients with AF who underwent RFCA, and compares CNN with conventional statistical analysis.Methods and Results:Three-hundred and ten patients with AF after RFCA treatment, including 94 patients with AF recurrence, were enrolled. Nine variables are identified as candidate predictors by univariate Cox proportional hazards regression (CPH). A CNNSurv model for AF recurrence prediction was proposed. The model's discrimination ability is validated by a 10-fold cross validation method and measured by C-index. After back elimination, 4 predictors are used for model development, they are N-terminal pro-BNP (NT-proBNP), paroxysmal AF (PAF), left atrial appendage volume (LAAV) and left atrial volume (LAV). The average testing C-index is 0.76 (0.72-0.79). The corresponding calibration plot appears to fit well to a diagonal, and the P value of the Hosmer-Lemeshow test also indicates the proposed model has good calibration ability. The proposed model has superior performance compared with the DeepSurv and multivariate CPH. The result of risk stratification indicates that patients with non-PAF, higher NT-proBNP, larger LAAV and LAV would have higher risks of AF recurrence. Conclusions The proposed CNNSurv model has better performance than conventional statistical analysis, which may provide valuable guidance for clinical practice.

Background Atrial fibrillation (AF) induces functional mitral regurgitation (FMR) and tricuspid regurgitation (FTR) during atrial remodeling. FMR and FTR are associated with AF prognosis, but the effects for AF recurrence after ablation have not been determined conclusively. Methods Two hundred thirty nine patients who underwent AF ablation were enrolled. Forty five patients were excluded. In total, 194 patients were analyzed. FMR and FTR were assessed by echocardiography. The left atrial volume index (LAVI) was evaluated by contrast-enhanced computed tomography. Results Significant FMR and moderate FTR were observed in 15 (7.7%) and in 25 (12.9%) patients, respectively. The severity of tricuspid regurgitation (TR) significant correlated with age, NT-proBNP, and LAVI. During a 13.4 month follow-up period of, 39 patients (20.1%) demonstrated AF recurrence. In the Cox proportional-hazards model, E/e’, FTR, and LAVI, were termed as predictor factors of AF recurrence (E/e’. hazard ratio [HR] = 1.117; P = 0.019, significant FTR. HR = 4.679; P = 0.041, LAVI. HR = 1.057; P = 0.003). Kaplan–Meier analysis showed that AF recurrence was more frequent in FTR compared with the nonsignificant FTR cases (log-rank, P = 0.001). Although survival analysis showed no difference with or without FMR, the presence of FMR and FTR was strongly associated with high-AF recurrence (log-rank, P = 0.004). Conclusions AF recurrence was associated with E/e’, LAVI, and extensive FTR. Specifically, the combination of FTR and FMR markedly worsens the AF prognosis.

There is increased interest in creating high-power short duration (HPSD) ablation lesions in the field of atrial fibrillation (AF) radiofrequency ablation (RFA). We evaluated the lesion characteristics and collateral damage using two separate RFA protocols setting (HPSD: 50 W and 7 s vs control: 25 W and 30 s) in vitro model. Sixteen freshly killed porcine hearts were obtained, and the atrium and ventricle slabs were harvested for ablation. The each slabs were placed in a tissue bath with circulating 0.9% NaCl at maintained temperature 37 °C. RFA was performed with 4 mm tip irrigated force sensing catheter. All lesions were ablated under recording the electrical parameters using with Ensite Navx system (St. Jude Medical, St. Paul, Minnesota). After RFA, lesion characteristics were assessed for each lesion. Thirty-five lesions were made for each ablation protocol (total 70 lesions for analysis). Ablation parameters were similar between two groups (HPSD vs control; impedance drop (Ω): 34.2 ± 13.1 vs 36.1 ± 8.65 P = 0.49, contact force (g): 13.9 ± 4.37 vs 14.6 ± 5.09, P = 0.51, lesion size index: 4.8 ± 0.52 vs 4.73 ± 0.59, P = 0.62). Although the lesion volume was similar, the HPSD ablation creates wider but more shallower lesions compared to control group (HPSD vs control; lesion volume: 29.6 ± 18.1 mm3 vs 35.5 ± 17.1 mm3 P = 0.16, lesion diameter: 4.98 ± 0.91 mm vs 4.45 ± 0.74 mm P = 0.0095, lesion depth: 2.2 ± 0.76 mm vs 2.8 ± 1.56 mm P = 0.046). Of these, 38 lesions were assessed for adjacent tissue damage and adjacent tissue damages were more frequent seen in control group (HPSD vs control; 1/19 (5.26%) vs 6/19 (31.5%), P = 0.036). Effective lesions were made with HPSD, thereby reducing RFA procedure time. Although the lesion volume was similar between two groups, collateral damage was less seen in HPSD group attributed by lesion characteristics.

BACKGROUND To reduce myocardial damage caused by implantable cardioverter defibrillator (ICD) shock, the left axilla was studied as an alternative pulse generator implantation site, and compared with the traditional implantation site, the left anterior chest. METHODS AND RESULTS Computer simulation was used to study the defibrillation conduction pattern and estimate the simulated defibrillation threshold (DFT) and myocardial damage when pulse generators were placed in the left axilla and left anterior chest, respectively; pulse generators were also newly implanted in the left axilla (n=30) and anterior chest (n=40) to compare the corresponding DFT. On simulation, when ICD generators were implanted in the left axilla, compared with the left anterior chest, the whole heart may be defibrillated with a lower defibrillation energy (left axilla 6.4 J vs. left anterior chest 12.0 J) and thus the proportion of cardiac myocardial damage may be reduced (2.1 vs. 4.2%). Clinically, ventricular fibrillation was successfully terminated with a defibrillation output ≤5 J in 86.7% (26/30) of the left axillary group, and in 27.5% (11/40) of the left anterior group (P

Background Subcutaneous implantable cardiac defibrillator (S-ICD) systems have a lower invasiveness than traditional ICD systems, and expand the indications of ICD implantations. The S-ICD standard defibrillation shock output energy, however, is approximately 4 times that of the traditional ICD system. This raises concern about the efficacy of the defibrillation and myocardial injury. In this study, we investigated the defibrillation efficacy and myocardial injury with S-ICD systems based on computer simulations. Methods and results First, computer simulations were performed based on the S-ICD system configurations proposed in a previous study. Furthermore, simulations were performed by placing the lead at the left or right parasternal margin and the pulse generator in the superior and inferior positions (0-10 cm) of the recommended site. The simulated defibrillation threshold (DFT) for the 4 S-ICD system configurations were 30.1, 41.6, 40.6, and 32.8 J, which were generally similar to the corresponding clinical results of 33.5, 40.4, 40.1, and 34.3 J. Conclusions The simulated DFT were generally similar to their clinical counterparts. In the simulation, the S-ICD system had a higher DFT but relatively less severe myocardial injury compared with the traditional ICD system. Further, the lead at the right parasternal margin may correspond to a lower DFT and cause less myocardial injury.