Deep Learning-Based Recurrence Prediction of Atrial Fibrillation After Catheter Ablation.

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.

Safety and feasibility of implanting a transvenous implantable cardioverter defibrillator (TV-ICD) in the left axilla.

BACKGROUND: Transvenous implantable cardioverter defibrillator (TV-ICD) systems are commonly implanted in the left anterior chest because of an easier implantation and better defibrillation threshold. This study aimed to evaluate the safety and feasibility of left axillary implantations of TV-ICD systems. METHODS: We performed left axillary TV-ICD implantations and compared that to the major complication rate and operation time of the conventional TV-ICD implantation site (left anterior chest). The electrical parameter trends were also assessed in the left axilla group. RESULTS: Seventy-six consecutive patients were evaluated for the analysis. Thirty-one patients had their system implanted in the left axilla and the reasons for the implantations included 29 patients for cosmetic reasons and two for post-infection conditions. The operation time and major complication rate were similar between the two groups (left anterior chest vs. left axilla: 134±62.4 min vs. 114±33.5 min, p = .11, 1/45 patient, 2.2% [pocket hematoma] vs. 1/31 patient, 3.2% [lead dislodgement], p = .77). During the follow up period (4.9±2.3years), no lead interruptions were observed in either group. The electrical lead parameters at the time of the implantation and follow up were similar in the study group (R wave sensing 20.8±33.4 vs. 11.2±7.42 mv, p = .34; lead impedance 464±64.7 vs. 418±135ohm, p = .22; pacing threshold [at 0.4 ms] 1.0±0.76 vs. 1.21±0.93V, p = .49). CONCLUSION: TV-ICD implantations in the left axilla were performed safely without increasing the operation time as compared to the conventional ICD implantation site. ICD implantations in the left axilla are an alternative in those not suitable for implanting TV-ICDs in the conventional implantation site.

Lesion size and adjacent tissue damage assessment with high power and short duration radiofrequency ablation: comparison to conventional radiofrequency ablation power setting.

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.

Impact of atrial mitral and tricuspid regurgitation on atrial fibrillation recurrence after ablation.

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.

Efficacy and Myocardial Injury With Subcutaneous Implantable Cardioverter Defibrillators　- Computer Simulation of Defibrillation Shock Conduction.

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.

Decreased Defibrillation Threshold and Minimized Myocardial Damage With Left Axilla Implantable Cardioverter Defibrillator Implantation.

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<0.001). CONCLUSIONS: Clinically and theoretically, the left axilla was shown to be an improved ICD implantation site that may reduce DFT and lessen myocardial damage due to shock. Lower DFT also facilitates less myocardial damage, as a result of the lower shock required.

Left axillary pacemaker generator implantation with a direct puncture of the left axillary vein.

BACKGROUND: Pacemaker generators are routinely implanted in the anterior chest. However, where to place the generator may need to be considered from the mental, functional, and cosmetic standpoints. METHODS: In this study, we performed the left axillary pacemaker generator implantation with a direct puncture of the left axillary vein in 40 consecutive patients, and evaluated the late safety and efficacy of this implantation. Complications, changes in the lead sensing, pacing threshold, and impedance were used as safety indexes for a mean follow-up of 3.4 years. In addition, the efficacy was also evaluated by comparing their questionnaire survey results to 119 patients in a control group of anterior chest implantation. RESULTS: Lead dislodgements were observed in two patients of the experiment group. There were no migrations of generators from the implantation site or abnormal variations in the pacing threshold, lead sensing, or impedance. In the left anterior chest and left axillary groups, 85% and 10% of the patients were worried about an external impact, 80% and 25% were worried about electromagnetic interference, and 68% and 0% answered that the pacemaker implantation site was noticeable, respectively. Apparently, more patients had a sense of security and cosmetic satisfaction with the left axillary implantation. CONCLUSION: The left axillary generator implantations may reduce the mental burden and cause no safety concerns, and may be performed if functional or cosmetic outcomes are required.

Impact of right atrial structural remodeling on recurrence after ablation for atrial fibrillation.

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 < .001), and the arrhythmia-free survival rates in these groups at 12 months were 68.0% and 91.4%, respectively. Additionally, there was a significant difference in recurrence-free survival after RA structural remodeling in each type of AF (log-rank, P < .001). CONCLUSIONS: RA structural remodeling is a useful predictor of clinical outcome after PVI regardless of the type of AF. Our results suggest that patients without RA structural remodeling may be good candidates for successful ablation with PVI.

The Association of Cardio-Ankle Vascular Index (CAVI) with Biatrial Remodeling in Atrial Fibrillation.

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.

The impact of sleep apnea on right atrial structural remodeling with atrial fibrillation.

BACKGROUND: Atrial remodeling associated with atrial fibrillation (AF) and sleep apnea is well known. Although sleep apnea is known to be associated with left atrial (LA) remodeling, its association with right atrial (RA) remodeling remains unclear. The study aimed to investigate the effect of sleep apnea on RA remodeling. METHODS: We enrolled 141 AF patients who had undergone ablation. Sleep study results were evaluated using a portable sleep apnea test device. RA and LA volumes were determined by computed tomography (CT), and atrial structural remodeling was defined as atrial volume on CT≥110mL according to previous reports. The atrial substrate was evaluated by three-dimensional electroanatomical mapping. RESULTS: After excluding 30 patients who received more than one catheter ablation or who could not receive enhanced CT, 111 patients were finally analyzed. The patients were classified into four groups according to the presence of RA and/or LA enlargement. Significant differences in AF type, N-terminal pro B-type natriuretic peptide (NT-proBNP) levels, and apnea-hypopnea index (AHI) were observed among the four groups. In univariate analysis, AHI values correlated with NT-proBNP levels (r=0.293, p=0.002), left ventricular ejection fraction (r=-0.198, p=0.044), LA volume (r=0.370, p<0.001), and RA volume (r=0.465, p<0.001). Multiple regression analysis showed that AHI was an independent predictor of increased RA volume, and LA was excluded as a multiple risk factor in AHI. AF type-adjusted AHI levels correlated with RA volume, and RA remodeling correlated with the percentage of LA low-voltage area. CONCLUSIONS: Sleep apnea was strongly associated with RA structural remodeling regardless of paroxysmal and non-paroxysmal AF, and this relationship was more prominent than the effect of LA. Our results suggest that the association between sleep apnea and RA dilatation should be given attention.

Analysis of Financial Factors Which Driving the Operating Margins of 880 Public Hospitals in Japan Using a Business Intelligence System.

Management improvement was strongly required at public hospital and Local Incorporated Administrative Agency hospitals in Japan. We analysed financial statements of 880 public hospitals using Business Intelligence System. In order to raise the efficiency of management, it is important to have patients with a high profitability (seriously ill patients) at municipal hospitals; whereas, in Local Incorporated Administrative Agency hospitals, avoiding producing ordinary losses and not incurring excessive expenses will be important for management improvement.

A case of transient apical hypertrophy associated with coronary vasospasm.

A 49-year-old woman was admitted to our hospital because of repeated loss of consciousness. On arrival, she was in cardiopulmonary arrest associated with arrhythmia of Torsades de pointes, and recovered from it after cardiopulmonary resuscitation and defibrillation. The administration of a ß-blocker and amiodarone was initiated to prevent ventricular tachycardia. On day 2, coronary angiography revealed non-obstructive coronary artery, and left ventriculography (LVG) exhibited hypokinesis in the anterior and apical wall. On day 20, an acetylcholine provocation test revealed a multivessel vasospasm, and LVG showed "spade-shaped left ventricle" in end-diastole because of apical hypertrophy. Transthoracic echocardiography (TTE) also showed apical wall thickness. Subsequent apical wall thickness gradually decreased and returned to normal on day 51 as observed on the TTE. Thus, we report a case of transient apical hypertrophy associated with coronary vasospasm, which was demonstrated by both the TTE and LVG. .

Paget-Schroetter Syndrome Resulting from Thoracic Outlet Syndrome and KAATSU Training.

A 29-year-old woman who worked as a KAATSU (a type of body exercise that involves blood flow restriction) instructor visited our emergency room with a chief complaint of swelling and left upper limb pain. Chest computed tomography (CT) showed non-uniform contrast images corresponding to the site from the left axillary vein to the left subclavian vein; vascular ultrasonography of the upper limb revealed a thrombotic obstruction at the same site, leading to a diagnosis of Paget-Schroetter syndrome (PSS). We herein report our experience with a case of PSS derived from thoracic outlet syndrome (TOS), in a patient who was a KAATSU instructor.

Evaluation of defibrillation safety and shock reduction in implantable cardioverter-defibrillator patients with increased time to detection: A randomized SANKS study.

BACKGROUND: The need for ways to minimize the number of implantable cardioverter-defibrillator (ICD) shocks is increasing owing to the risk of its adverse effects on life expectancy. Studies have shown that a longer detection time for ventricular tachyarrhythmia reduces the safety of therapies, in terms of syncope and mortality, but not substantially in terms of the success rate. We aimed to evaluate the effects of increased number of intervals to detect (NID) VF on the safety of ICD shock therapy and on the reduction of inappropriate shocks. METHODS: The present study was a prospective, multicenter, randomized, crossover study. Randomized VF induction testing with NID 18/24 or 30/40 was performed to compare the success rate of defibrillation with a 25-J shock and the time to detection. Inappropriate shock episodes were simulated retrospectively to evaluate a possibility of episodes avoidable at NID 24/32 and 30/40. RESULTS: Thirty-one consecutive patients implanted with an ICD or cardiac resynchronization therapy-defibrillator (CRT-D) were enrolled in this study. The success rate of defibrillation was 100% in both NID groups at the first shock. The time from VF induction to detection showed a significant increase in the NID 30/40 group (6.16±1.29 s vs. 9.00±1.31 s, p<0.001). Among the 120 patients implanted with an ICD or CRT-D, 10 experienced 32 inappropriate shock episodes. The inappropriate shock reduction rate was 53.1% and 62.5% with NID 24/32 and 30/40, respectively. CONCLUSIONS: The findings of this SANKS study suggest that VF NID 30/40 does not compromise the safety of ICD shock therapy, while decreasing the number of inappropriate shocks.