Enhancing Origin Prediction: Deep Learning Model for Diagnosing Premature Ventricular Contractions with Dual-Rhythm Analysis Focused on Cardiac Rotation.

BACKGROUND: Several algorithms can differentiate inferior axis premature ventricular contractions (PVCs) originating from the right side and left side on 12-lead electrocardiograms (ECGs). However, it is unclear whether distinguishing the origin should rely solely on PVC or incorporate sinus rhythm (SR). AIMS: We compared the Dual-Rhythm model (incorporating both SR and PVC) to the PVC model (using PVC alone), and quantified the contribution of each ECG lead in predicting the PVC origin for each cardiac rotation. METHODS: This multicenter study enrolled 593 patients from 11 centers-493 from Japan and Germany, and 100 from Belgium, which used as the external validation dataset. Using a hybrid approach combining a Resnet50-based convolutional neural network and a Transformer model, we developed two variants-the PVC and Dual-Rhythm models-to predict PVC origin. RESULTS: In the external validation dataset, the Dual-Rhythm model outperformed the PVC model in accuracy (0.84 vs. 0.74, respectively; p < 0.01), precision (0.73 vs. 0.55, respectively; p < 0.01), specificity (0.87 vs. 0.68, respectively; p < 0.01), area under the receiver operating characteristic curve (0.91 vs. 0.86, respectively; p = 0.03), and F1-Score (0.77 vs. 0.68, respectively; p = 0.03). The contributions to PVC origin prediction were 77.3% for PVC and 22.7% for the SR. However, in patients with counterclockwise rotation, SR had a greater contribution in predicting the origin of right-sided PVC. CONCLUSIONS: Our deep learning-based model, incorporating both PVC and SR morphologies, resulted in a higher prediction accuracy for PVC origin. Considering SR is particularly important for predicting right-sided origin in patients with counterclockwise rotation.

Efficacy of Complex Fractionated Atrial Electrogram-Guided Extensive Encircling Pulmonary Vein Isolation for Persistent Atrial Fibrillation.

Background: In persistent AF, the effect of adjunctive ablation in addition to PV isolation (PVI) is controversial. We considered a new modified PVI including complex fractionated atrial electrogram (CFAE) area. Methods and Results: In 57 patients with persistent AF undergoing first ablation, CFAE were mapped before ablation and CFAE-guided extensive encircling PVI (CFAE-guided EEPVI) was performed. The PVI line was designed to include the CFAE area near PV or to cross the minimum cycle length points of the CFAE area near PV (CFAE-guided EEPVI group). The outcome was compared with conventional PVI in 34 patients with persistent AF (conventional PVI group). During a mean follow-up of 365±230 days after the first procedure, AF in 13 and atrial tachycardia (AT) in 9 patients recurred in the CFAE-guided EEPVI group, while only AF in 17 patients recurred in the conventional PVI group. Eight of 9 AT in the CFAE-guided EEPVI group were successfully ablated at second procedure. After first and second procedures, the recurrence of atrial tachyarrhythmia in the CFAE-guided EEPVI group was significantly reduced compared with the conventional PVI group (8 patients, 14% vs. 11 patients, 32%, respectively; P<0.01, log-rank test). Conclusions: CFAE-guided EEPVI was more effective for persistent AF compared with conventional PVI after first and second procedures, because recurring AT as well as re-conduction of PV was successfully ablated.

Prophylactic catheter ablation of ventricular tachycardia before cardioverter-defibrillator implantation in patients with non-ischemic cardiomyopathy: Clinical outcomes after a single endocardial ablation.

BACKGROUND: Outcomes related to prophylactic catheter ablation (PCA) for ventricular tachycardia (VT) before implantable cardioverter-defibrillator (ICD) implantation in non-ischemic cardiomyopathy (NICM) are not well characterized. We assessed the efficacy of single endocardial PCA in NICM patients. METHODS: We retrospectively analyzed 101 consecutive NICM patients with sustained VT. We compared clinical outcomes of patients who underwent PCA (ABL group) with those who did not (No ABL group). Successful PCA was defined as no inducible clinical VT. We also compared the clinical outcomes of patients with successful PCA (PCA success group) with those of the No ABL group. Endpoints were appropriate ICD therapy (shock and anti-tachycardia pacing) and the occurrence of electrical storm (ES). RESULTS: PCA was performed in 42 patients, and it succeeded in 20. The time to ES occurrence was significantly longer in the ABL group than in the No ABL group (p=0.04). The time to first appropriate ICD therapy and ES occurrence were significantly longer in the PCA success group than in the No ABL group (p=0.02 and p<0.01, respectively). CONCLUSION: Single endocardial PCA can decrease ES occurrence in NICM patients. However, high rates of VT recurrence and low success rates are issues to be resolved; therefore, the efficacy of single endocardial PCA is currently limited.

Optimal strength and number of shocks at upper limit of vulnerability testing required to predict high defibrillation threshold without inducing ventricular fibrillation.

BACKGROUND: The upper limit of vulnerability (ULV) closely correlates with the defibrillation threshold (DFT). The aim of this study was to establish the optimal protocol for using the ULV test to predict high DFT (>20 J) without inducing ventricular fibrillation (VF). METHODS AND RESULTS: The 10-J and 15-J ULV test with 3 coupling intervals (-20, 0, and +20 ms to the peak of T-wave) and the DFT test were performed in 96 patients receiving implantable cardioverter defibrillator. ULV ≤ 10 J was confirmed in 47 (49%). ULV ≤ 15 J was confirmed in 70 (77%) of 91 patients (15-J ULV test could not be done in 5). The sensitivity and negative predictive value of both ULV >10 J and >15 J for predicting high DFT were 100%. The specificity and positive predictive value of ULV >15 J were higher than those for ULV >10 J (85% vs. 55%, 43% vs. 22%, respectively). The rate of VF inducibility for confirming ULV ≤ 15 J was lower than that for ULV ≤ 10 J (23% vs. 51%, P<0.0001). On analysis of single 15-J ULV test only at the peak of T-wave, VF was not induced in 79 of 91 patients, but 4 of these had high DFT. CONCLUSIONS: The 15-J ULV test with 3 coupling intervals could correctly identify high-DFT patients and reduce the necessity for VF induction at defibrillator implantation.

Dabigatran in the peri-procedural period for radiofrequency ablation of atrial fibrillation: efficacy, safety, and impact on duration of hospital stay.

PURPOSE: Dabigatran is effective for both the prevention of stroke and bleeding in patients with atrial fibrillation (AF). However, the safety and efficacy of the use of dabigatran in the peri-procedural period for radiofrequency catheter ablation (RFCA) of AF is unknown. Therefore, the purpose of this study was to evaluate the safety and efficacy of dabigatran in the peri-procedural period for RFCA of AF and the duration of hospital stay. METHODS: Consecutive patients (n = 227) who underwent RFCA for AF were prospectively analyzed. Peri-procedural anticoagulant therapy with dabigatran (n = 101, D group) was compared with warfarin and heparin bridging (n = 126, W group). Dabigatran was discontinued 12-24 h before and restarted 3 h after the procedure. Warfarin was stopped 3 days before the procedure and unfractionated heparin was administered. RESULTS: Ischemic stroke occurred in one patient of the D group (0.8 %). There was no significant difference between the two groups in the incidence of major bleeding (three cases of cardiac tamponade in each group and one case of intracranial bleeding in the W group, p = 0.93) or minor bleeding (five cases in the D group vs. five in the W group, p = 0.54). The duration of hospital stay was significantly shorter in the D group than in the W group (7.2 vs. 10.3 days, p = 0.0001). CONCLUSIONS: Peri-procedural anticoagulation therapy with dabigatran for RFCA of AF was equally safe and effective compared with warfarin and heparin bridging. The use of dabigatran for RFCA of AF shortened the duration of hospital stay.

Rate-dependent and site-specific conduction block at the posterior right atrium and drug effects evaluated using a noncontact mapping system in patients with typical atrial flutter.

INTRODUCTION: Conduction block in the posterior right atrium (RA) plays an important role in perpetuating atrial flutter (AFL). Although conduction blocks have functional properties, it is not clear how the block line changes with the pacing rate, pacing site, and administration of antiarrhythmic drugs. METHODS AND RESULTS: Forty patients with typical AFL were enrolled. Pacing (110, 170, 230 ppm) from the coronary sinus ostium (CSo) and low lateral RA was performed. After 1 mg/kg pilsicainide (pure sodium channel blockade) administration, the pacing protocol was repeated. Conduction block was assessed based on a color-coded isopotential map and 20 points of virtual unipolar electrograms in the posterior RA using noncontact mapping. Block line proportion was defined as the percentage of length of the block line between the superior and inferior vena cava. The pacing rate-dependent extension of the block proportion was significant during pacing from both sides (pacing from the CSo: 59 ± 17% at 110 ppm, 69 ± 16% at 230 ppm, P < 0.05; pacing from the low lateral RA: 43 ± 19% at 110 ppm, 55 ± 22% at 230 ppm, P < 0.05). The block line was significantly longer during CSo pacing than during low lateral RA pacing at each rate (all P < 0.05). After pilsicainide administration, the block line extended further. CONCLUSION: In addition to pacing rate-dependent and site-dependent changes in the block line, pilsicainide further extended the block line length. This phenomenon explains the clinical observation that counterclockwise AFL occurs more frequently than clockwise AFL, and the mechanism of class IC AFL.

Recognition of inferiorly dislocated fast pathways guided by three-dimensional electro-anatomical mapping.

PURPOSE: Slow pathway (SP) ablation of atrioventricular (AV) nodal reentrant tachycardia (AVNRT) can be complicated by unexpected AV block even at sites >10 mm inferior to the bundle of His (HB), and one cause is thought to be the inferior dislocation of an antegrade fast pathway (A-FP). We assessed locations of FPs guided by CARTO. METHODS: Sites of FPs were mapped guided by CARTO before SP ablation in 18 patients with slow-fast AVNRT. The A-FP was defined as the site with the minimum interval between the stimulus and HB potential when pace mapping in the right atrial septum. RESULTS: The A-FP was 7.9 ± 7.5 mm inferior and 2.9 ± 5.0 mm posterior to the HB. In 6 of 18 patients (33%), the A-FP was inferiorly dislocated >10 mm to the HB. SP ablation was successfully performed in all patients at sites >10 mm from both the HB and the A-FP without AV block. In the inferiorly dislocated A-FP group, A-FPs seemed to be positioned much more on atrial sites and sufficiently posterior to SP ablation sites. CONCLUSIONS: The A-FP inferiorly dislocated >10 mm to the HB in one third of patients with AVNRT and seemed to be positioned deep on atrial sites. It is again emphasized that SP ablation within the triangle of Koch should be performed at a very ventricular annulus site, particularly in the inferiorly dislocated A-FP group.

Utility of virtual unipolar electrogram morphologies to detect transverse conduction block and turnaround points of typical atrial flutter.

BACKGROUND: Noncontact mapping is useful for the diagnosis of various arrhythmias. Virtual unipolar electrogram morphologies (VUEM) of the conduction block and the turnaround points, however, are not well defined. We compared the VUEM characteristics of a transverse conduction block in the posterior right atrium (RA) with those of contact bipolar electrograms obtained during typical atrial flutter (AFL). METHODS: Contact bipolar electrograms were used to map the posterior RA during typical AFL in 16 patients. Twenty points of the VUEM recorded along the block line were analyzed and compared with contact bipolar electrograms. RESULTS: Seventeen AFLs were analyzed. Fifteen AFLs showed an incomplete transverse conduction block in the posterior RA by contact bipolar mapping. A double potential on the block line corresponded to the two components of the VUEM, in which the second component showed an Rs, RS, or rS pattern. At the turnaround point, a fused double potential of the contact bipolar electrograms corresponded to a change of the second component of the VUEM from an rS to a QS morphology. Two AFLs showed a complete block line in the posterior RA. The contact bipolar electrogram showed double potentials from the inferior vena cava to the superior vena cava, whereas the second component of the VUEM remained in an unchanged Rs, RS, or rS pattern. CONCLUSION: VUEM analysis was a reliable method for identifying the posterior block line during AFL. This method may also be applicable for detecting block lines and turnaround points of circuits in other unmappable arrhythmias.

Dilated phase of hypertrophic cardiomyopathy caused by Fabry disease with atrial flutter and ventricular tachycardia.

We describe a case of a 60-year-old male with dilated phase of hypertrophic cardiomyopathy caused by Fabry disease. He was diagnosed to have a cardiac variant of Fabry disease by an enzyme assay and a right ventricular endomyocardial biopsy which revealed specific features of this disease and cardiac involvement was the sole manifestation. He has developed dilated cardiomyopathy with sustained atrial flutter and frequent non-sustained ventricular tachycardia requiring isthmus ablation and cardiac resynchronization therapy with defibrillator.

Upper turnover portion of the reentry circuit for typical and reverse typical atrial flutter.

BACKGROUND: The posteromedial right atrium (PMRA) forms a block line during typical atrial flutter (AFL). However, whether upper turnover portion exists at the anterior or posterior superior vena cava (SVC) has not been determined. METHODS: We performed right atrial mapping during AFL in 20 patients (typical AFL, n = 17; reverse typical AFL, n = 3) using an electroanatomical mapping system. RESULTS: Mean AFL cycle length was 224 +/- 20 ms and mean number of mapping points was 140 +/- 27. PMRA formed a block line during both typical and reverse AFL in all patients. However, in 16 of 17 patients mapped with typical AFL, PMRA did not extend superiorly to the orifice of the SVC and AFL wave propagated between the upper limit of the PMRA and the posterior SVC. In the remaining patient mapped with typical AFL, a double potential was recorded along the PMRA continuously between the orifices of the inferior vena cava (IVC) and SVC. In the three patients mapped with reverse typical AFL, a posterior barrier was detected from IVC to the upper limit of the PMRA and AFL wave propagated between the upper limit of the PMRA and the posterior SVC. Mean length from IVC to upper limit of the PMRA was 81 +/- 8% of the length from IVC to SVC. CONCLUSIONS: PMRA forms a functional block line during both typical and reverse typical AFL. The upper turnover portion of reentry circuit for AFL was observed between the upper limit of the PMRA and the posterior SVC in the majority of isthmus-dependent AFL patients.

Endocardial substrate mapping for monomorphic ventricular tachycardia ablation in ischemic and non-ischemic cardiomyopathy.

We investigated the differences in the endocardial substrates between ischemic cardiomyopathy (ICM) and non-ICM (NICM) by using electro-anatomical mapping and pace-mapping. We studied 18 patients (ICM and NICM, 9 each) with monomorphic ventricular tachycardia (VT) documented by 12-leads ECG. Low voltage area was defined by signal amplitude <1.5 mV. A pace-map QRS morphology that matched VT in >10 of the 12-leads ECG was regarded as a pace-map match. And conduction delay during pace-mapping was defined as the stimulus to QRS interval >or=40 ms. Low voltage area was 53.8 +/- 21.5 and 20.8 +/- 16.7 cm2 in ICM and NICM patients, respectively (P = 0.002). Pace-mapping was assessed in 6 ICM and 9 NICM. Pace-map match with conduction delay were obtained in all the 6 ICM patients. But in NICM patients, pace-map match with conduction delay was obtained in 3 patients. Pace-map match sites where conduction delay was not observed were obtained in 5 patients. Pace-map match could not be obtained in 1 patient. We attempted ablation in 6 ICM and 7 NICM patients. Subsequently, VT recurrence was not observed in ICM but it was observed in 6 of 7 NICM patients (log-rank P = 0.0016). In NICM patients, the arrhythmogenic substrate that represented the abnormal electrogram and conduction delay was observed less within the endocardial surface when compared with that observed in ICM. VT recurrence rate subsequent to endocardial ablation was higher in NICM than in ICM patients.

Identification of the right ventricular pacing site for cardiac resynchronization therapy (CRT) guided by electroanatomical mapping (CARTO).

BACKGROUND: The optimal left ventricle (LV) pacing site for cardiac resynchronization therapy (CRT) has been investigated, but less is known about the optimal site in the right ventricle (RV). The present study examined whether electrical resynchronization guided by electroanatomical mapping (CARTO) results in mechanical resynchronization. METHODS AND RESULTS: The study group included 13 patients indicated for CRT: 10 with nonischemic cardiomyopathy, 2 with ischemic cardiomyopathy and 1 with cardiac sarcoidosis, (mean LV ejection fraction: 32+/-10%). CARTO of the RV septum was performed to identify the site with the most delayed conduction time during LV pacing. Hemodynamic measurements were performed during conventional biventricular pacing with the RV apex and LV (C-BVP) and during biventricular pacing with the most delayed site of the RV (d-RV) and LV (D-BVP). Lead placement at 15 coronary sinus veins was examined in the 13 patients. During pacing from anterolateral veins (n=2), the d-RV was the RV apex (RVA) in 1 patient and the mid-septum in the other. During pacing from lateral veins (n=9), the d-RV comprised the RVA (n=3), the mid-septum (n=5), and the right ventricular outflow tract (RVOT) (n=1). During pacing from the posterolateral veins (n=3), the d-RV was the RVOT in all cases. In 11 of 15 sites, d-RV differed from conventional RVA. Compared with C-BVP, D-BVP produced a significant improvement in LV dp/dt. Furthermore, RV mid-septum and LV pacing markedly increased LV dp/dt and pulse pressure (PP), but RVOT and LV pacing did not. D-BVP vs C-BVP: %LV dp/dt 30+/-20 and 15+/-15%, p<0.05; RV mid-septum and LV pacing vs C-BVP: %LV dp/dt 35+/-20 and 10+/-15%, p<0.02, and vs PP 33+/-20 and 10+/-29 mmHg, p<0.02. CONCLUSIONS: For pacing from the LV lateral vein, potential improvement of cardiac performance compared with that by conventional RVA placement may be realized with concomitant pacing from the d-RV (mid-septum).