AI diagnosis of heart sounds differentiated with super StethoScope.

In the aging global society, heart failure and valvular heart diseases, including aortic stenosis, are affecting millions of people and healthcare systems worldwide. Although the number of effective treatment options has increased in recent years, the lack of effective screening methods is provoking continued high mortality and rehospitalization rates. Appropriately, auscultation has been the primary option for screening such patients, however, challenges arise due to the variability in auscultation skills, the objectivity of the clinical method, and the presence of sounds inaudible to the human ear. To address challenges associated with the current approach towards auscultation, the hardware of Super StethoScope was developed. This paper is composed of (1) a background literature review of bioacoustic research regarding heart disease detection, (2) an introduction of our approach to heart sound research and development of Super StethoScope, (3) a discussion of the application of remote auscultation to telemedicine, and (4) results of a market needs survey on traditional and remote auscultation. Heart sounds and murmurs, if collected properly, have been shown to closely represent heart disease characteristics. Correspondingly, the main characteristics of Super StethoScope include: (1) simultaneous collection of electrocardiographic and heart sound for the detection of heart rate variability, (2) optimized signal-to-noise ratio in the audible frequency bands, and (3) acquisition of heart sounds including the inaudible frequency ranges. Due to the ability to visualize the data, the device is able to provide quantitative results without disturbance by sound quality alterations during remote auscultations. An online survey of 3648 doctors confirmed that auscultation is the common examination method used in today's clinical practice and revealed that artificial intelligence-based heart sound analysis systems are expected to be integrated into clinicians' practices. Super StethoScope would open new horizons for heart sound research and telemedicine.

Total atrial conduction time as a possible predictor of atrial fibrillation recurrence after catheter ablation for paroxysmal atrial fibrillation: relationship between electrical atrial remodeling and structural atrial remodeling time courses.

PURPOSE: Recently, the estimated total atrial conduction time measured using tissue Doppler imaging (PA-TDI duration) has been reported as a more accurate predictor of atrial fibrillation (AF) recurrence after catheter ablation than left atrial volume index (LAVI). The PA-TDI duration is considered to reflect electrical and structural remodeling in the right atrium (RA) and left atrium (LA). We sought to investigate the association between AF recurrence and PA-TDI duration after AF ablation. METHODS: We studied 209 patients who underwent radiofrequency ablation for paroxysmal AF and 75 patients who underwent second ablation for AF recurrence. We assessed the duration from the onset of the P wave on the surface electrocardiogram to the atrial electrogram in distal coronary sinus (CS) (PA-CSd duration) indicating electrical remodeling of the atrium, the PA-CS proximal duration (PA-CSp duration) representing electrical remodeling of RA, and the conduction time in CS (proximal to distal) (CSp-CSd duration) reflecting electrical remodeling of LA. We also measured LAVI as a marker of structural remodeling of LA. RESULTS: The PA-TDI duration had a positive correlation with PA-CSd duration. In the patients with AF recurrence, PA-TDI duration, PA-CSd duration, and CSp-CSd duration in the second ablation were significantly longer than those in the first (p < 0.01, respectively), whereas there was no significant difference in LAVI and PA-CSp duration between the first and second ablation sessions. CONCLUSION: A prolonged PA-TDI duration after AF ablation may indicate advanced electrical remodeling of LA, and may predict AF recurrence after ablation in patients with paroxysmal AF.

A randomized comparison of two direct oral anticoagulants for patients undergoing cardiac ablation with a contemporary warfarin control arm.

BACKGROUND: The safety and efficacy of periprocedural use of direct oral anticoagulants (DOACs) for atrial fibrillation (AF) remain unclear. We compared the incidence of asymptomatic cerebral micro-thromboembolism and hemopericardium following AF ablation among patients receiving edoxaban, rivaroxaban, and warfarin and between normal- and low-dose use of edoxaban and rivaroxaban. METHODS: This prospective randomized study included 170 consecutive AF patients. Patients taking DOACs upon admission to our hospital were randomly assigned to an edoxaban group or to a rivaroxaban group. Warfarin was continued in patients receiving warfarin at admission. All patients underwent AF ablation, and cerebral MRI was performed to evaluate asymptomatic cerebral micro-thromboembolism the day after the procedure. RESULTS: Sixty-one patients were assigned to edoxaban and 63 to rivaroxaban. Warfarin was continued in 46 patients. Although asymptomatic cerebral micro-thromboembolism was detected in 25 patients (16.3%), there were no significant differences among the groups. Hemopericardium occurred in 2 patients (one each in the rivaroxaban and warfarin groups). The incidence of asymptomatic cerebral micro-thromboembolism was higher in the low-dose group (9 patients, 25.7%) than in the normal-dose group (8 patients, 10.0%) for patients prescribed either edoxaban or rivaroxaban (p < 0.05). The proportion of males (88.0%, 69.5%, p < 0.05), history of prior AF ablation (64.0%, 42.2%, p < 0.05), and hypertension (68.0%, 46.1%, p < 0.05) were significantly higher in patients with cerebral thromboembolism. CONCLUSIONS: The incidence of asymptomatic cerebral micro-thromboembolism and hemopericardium in AF ablation was similar among patients using edoxaban, rivaroxaban, and warfarin. However, low doses of DOACs may increase the risk of asymptomatic stroke.

Dynamics of Soluble Thrombomodulin and Circulating miRNAs in Patients with Atrial Fibrillation Undergoing Radiofrequency Catheter Ablation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the world and has a high risk of thromboembolism. The most effective approach, catheter ablation, requires evaluation by electrocardiography. The aim of our study was to investigate novel clinical markers that predict restoration of sinus rhythm (SR) after catheter ablation. Seventy-eight consecutive patients with AF underwent catheter ablation and were separated into 2 groups: restored SR and recurrent AF. The levels of 4 blood proteins (serum or plasma) and 3 mature microRNAs (miRNAs) and their primary miRNAs (pri-miRNAs) in serum were measured before and after ablation, and the associations between each parameter were analyzed statistically. Soluble thrombomodulin (s-TM) and plasminogen activator inhibitor-1 (PAI-1) levels increased above baseline after ablation in both the restored SR (s-TM 11.55 [2.92] vs 13.75 [3.38], P < .001; PAI-1 25.74 [15.25] vs 37.79 [19.56], P < .001) and recurrent AF (s-TM 10.28 [2.78] vs 11.67 [3.37], P < .001; PAI-1 26.16 [15.70] vs 40.74 [22.55], P < .001) groups. Levels of C-reactive protein and asymmetric dimethylarginine were not significantly changed. Pri-miR-126 levels significantly decreased after ablation in the recurrent AF group, but the other miRNAs and pri-miRNAs did not. The measurement of s-TM and pri-miR-126 in blood was a useful tool to reflect the condition of AF patients with catheter ablation.

Evaluation of safety and efficacy of periprocedural use of rivaroxaban and apixaban in catheter ablation for atrial fibrillation.

BACKGROUND: We previously reported that dabigatran increased the risk of microthromboembolism and hemopericardium compared with warfarin. The safety of non-vitamin-K-antagonist oral anticoagulants (NOACs) in the periprocedural use of atrial fibrillation (AF) ablation is controversial. This study aimed to compare the incidence of asymptomatic cerebral microthromboembolism and hemopericardium in AF ablation among periprocedural use of rivaroxaban, apixaban, and warfarin. METHODS AND RESULTS: This study was a prospective, randomized registry. Patients taking NOACs upon visiting our hospital were randomly assigned into 2 groups; rivaroxaban and apixaban. Warfarin was continued in patients taking warfarin. Asymptomatic cerebral microthromboembolism was evaluated by magnetic resonance imaging on the day after the ablation procedure. In 176 consecutive patients (101 paroxysmal, and 75 persistent AF), rivaroxaban was used in 55, apixaban in 51, and warfarin in 70. There were no symptomatic cerebral infarctions in this study. Asymptomatic cerebral microthromboembolism was detected in 32 (18.4%) patients; nine (16.4%) with rivaroxaban, 10 (20%, p=0.80; vs. rivaroxaban) with apixaban, and 13 (18.8%, p=0.81; vs. rivaroxaban) with warfarin. Hemopericardium occurred in 5 (2.8%) patients; 2 with rivaroxaban, 1 with apixaban (p=1.0; vs. rivaroxaban), and 2 with warfarin (p=1.0; vs. rivaroxaban). In multivariate analysis, concomitant coronary angiography (p<0.05, odds ratio 5.73) was a predictor of cerebral thromboembolism. CONCLUSIONS: The incidence of asymptomatic cerebral microthromboembolism and hemopericardium in AF ablation is similar among the periprocedural use of rivaroxaban, apixaban, and warfarin.

The optimal setting of complex fractionated atrial electrogram software in substrate ablation for atrial fibrillation.

BACKGROUND: Complex fractionated atrial electrogram (CFAE)-targeted catheter ablation (CFAE ablation) requires a high rate of atrial fibrillation (AF) termination to provide good outcomes. We determined the optimal settings of CFAE software. METHODS: In our 430 consecutive patients, AF was terminated in 97 (234/242) and 79% (149/188) of patients with paroxysmal and persistent AF, respectively, by CFAE ablation combined with (31%) or without (69%) pulmonary vein isolation, occasionally with nifekalant infusion. We analyzed 109 consecutive patients who underwent CFAE ablation to determine the optimal settings for comparing subjective versus objective decisions by the CFAE software on CARTO3. We compared three settings: the default setting (0.05-0.15 mV, 50-120 ms) and two modified settings (#1: 0.05-0.30 mV, 40-70 ms, #2: 0.05-0.13 mV, 10-20 ms). We retrospectively analyzed 11,425 points during left atrial mapping before ablation and 10,306 points that were subjectively detected and ablated as CFAE points. An interval confidence level ≥6 denoted a site with CFAE. RESULTS: With the default setting, the accuracy, sensitivity, specificity, positive productive value, and negative productive values were 67, 42, 77, 48, and 73%, respectively. With modified setting #1, the values were 78, 55, 87, 74, and 77%, respectively, versus 64, 82, 60, 53, and 91%, respectively, for modified setting #2. CONCLUSION: These data suggest that setting #1 was generally superior to the default setting, whereas setting #2 was optimal for excluding areas not requiring ablation. The optimal CFAE software setting was a voltage of 0.05-0.30 mV and an interval parameter of 40-70 ms.

The incidence of asymptomatic cerebral microthromboembolism after atrial fibrillation ablation: comparison of warfarin and dabigatran.

BACKGROUND: Cerebral microthromboembolism after atrial fibrillation (AF) ablation has been reported in 4-20% with perioperative warfarin. Dabigatran is a new anticoagulant in patients with nonvalvular AF. We investigated the incidence of asymptomatic cerebral microthromboembolism after AF ablation with perioperative warfarin or dabigatran using diffusion-weighted and T2-weighted magnetic resonance imaging (MRI). METHODS AND RESULTS: Our study included 210 consecutive patients with AF (111 paroxysmal and 99 persistent) who underwent complex fractionated atrial electrogram-guided ablation (combined with pulmonary vein isolation, n = 110). Catheter irrigation was performed in all cases. Uninterrupted warfarin therapy was used in 180 patients (warfarin group) and interrupted only on the morning of the procedure with dabigatran in 30 (dabigatran group). All patients underwent cerebral MRI the day after ablation. New microthromboemboli were detected in 10.0% of the warfarin group and 26.7% of the dabigatran group (P < 0.05). The incidence of hemopericardium treated with pericardiocentesis was lower in the warfarin group than in the dabigatran group (2.5% vs 11.1%, P < 0.05). In multivariate analysis, the use of cardioversion was a predictor of new microthromboembolism development after AF ablation. CONCLUSIONS: The incidence of asymptomatic cerebral microthromboembolism and hemopericardium after AF ablation was significantly lower with perioperative warfarin therapy than with dabigatran therapy. Dabigatran may not be an effective alternative to warfarin for AF ablation, especially in patients who undergo cardioversion.

Effectiveness of esophagus detection by three-dimensional electroanatomical mapping to avoid esophageal injury during ablation of atrial fibrillation.

AIMS: Esophageal-left atrial (LA) fistula during atrial fibrillation (AF) ablation is a fatal event. We explored the relation of the esophagus-to-ablated point distance and esophageal temperature rise. METHODS: Consecutive patients (n=106) underwent complex fractionated atrial electrogram-guided AF ablation using CartoMerge; the pulmonary veins were isolated in 23 patients. Maximum radiofrequency (RF) power near the esophagus was 15 W. Ablated points with esophageal temperature rise (monitored with a probe) to ≥38.0°C were tagged; if ≥39.0°C, RF was discontinued. RESULTS: Of 1647 ablated points near the esophagus, 274 were associated with a temperature rise to 38.0-38.9°C and 241 points to ≥39.0°C. Distances (mm) from points to esophagus were 5.1 ± 0.6 (no rise), 4.2±3.1 (38.0-38.9°C), 2.9 ± 2.5 (≥39.0°C). Altogether, 15.5% of points in the upper LA posterior wall, 41.5% in the middle, and 30.2% in the lower caused rises to ≥38.0°C; 8.7%, 24.6%, and 11.0% caused rises to ≥39.0°C. The middle wall was most affected (p<0.01), as shown by multiple logistic regression analysis (both temperatures). Points causing a rise increased significantly as distance decreased (p<0.001). The odds ratio for rise to ≥38.0°C compared with <4.0 to >5.0 mm distance was 2.28 (p=0.004). The longest distance for ≥38.0°C rise was 18.5 mm. CONCLUSION: Distance is an important predictor of esophageal temperature rise. The middle LA posterior wall is most vulnerable. A dose of 15 W is too high for ablation, especially <4.0 mm from the esophagus. Points >20.0 mm away are relatively safe.