Validation of ablation site classification accuracy and trends in the prediction of potential reconnection sites for atrial fibrillation using the CARTONET® R12.1 model.

Background: CARTONET® enables automatic ablation site classification and reconnection site prediction using machine learning. However, the accuracy of the site classification model and trends of the site prediction model for potential reconnection sites are uncertain. Methods: We studied a total of 396 cases. About 313 patients underwent pulmonary vein isolation (PVI), including a cavotricuspid isthmus (CTI) ablation (PVI group) and 83 underwent PVI and additional ablation (i.e., box isolation) (PVI+ group). We investigated the sensitivity and positive predictive value (PPV) for automatic site classification in the total cohort and compared these metrics for PV lesions versus non-PV lesions. The distribution of potential reconnection sites and confidence level for each site was also investigated. Results: A total of 29,422 points were analyzed (PV lesions [n = 22 418], non-PV lesions [n = 7004]). The sensitivity and PPV of the total cohort were 71.4% and 84.6%, respectively. The sensitivity and PPV of PV lesions were significantly higher than those of non-PV lesions (PV lesions vs. non-PV lesions, %; sensitivity, 75.3 vs. 67.5, p < .05; PPV, 91.2 vs. 67.9, p < .05). CTI and superior vena cava could not be recognized or analyzed. In the potential reconnection prediction model, the incidence of potential reconnections was highest in the posterior, while the confidence was the highest in the roof. Conclusion: The automatic site classification of the CARTONET®R12.1 model demonstrates relatively high accuracy in pulmonary veins excluding the carina. The prediction of potential reconnection sites feature tends to anticipate areas with poor catheter stability as reconnection sites.

Global Results of Implantable Loop Recorder for Detection of Atrial Fibrillation After Stroke: Reveal LINQ Registry.

BACKGROUND: We aimed to quantify the incidence of atrial fibrillation (AF) in patients with cryptogenic stroke globally, as well as separately in patients in and outside of Japan, using an implantable loop recorder from a prospective, observational, Reveal LINQ Registry. METHODS AND RESULTS: Patients developing cryptogenic stroke and monitored by implantable loop recorder for searching AF were studied. The primary end point was incidence of AF within 36 months after insertion. Secondary end points were recurrent ischemic stroke/transient ischemic attack and AF-related treatment strategies. A total of 271 patients (61.6±14.3 years, 170 men, 60 from Japan) were enrolled from 12 countries. AF was detected in 28.2% at 36 months. The median time from enrollment to AF detection was 7.9 months. During the first 12 months, the AF detection rate slope was relatively steeper in the Japanese subgroup versus non-Japanese patients. However, by 3 years, the cumulative incidence of AF detection did not differ between groups. Age was the only variable associated with AF detection (hazard ratio, 1.05 [95% CI, 1.02-1.07] per year), trending higher in older age groups. Of the 271 patients, 11 (4.1%) developed recurrent ischemic stroke/transient ischemic attack; AF was detected by implantable loop recorder in only 1 of these patients. Patients with detected AF were more commonly taking oral anticoagulation than those without AF at the last follow-up (64.7% versus 25.3%, P<0.001). CONCLUSIONS: The rate of AF detection was similar to other studies in stroke populations monitored by implantable loop recorders, including CRYSTAL-AF (Cryptogenic Stroke and Underlying Atrial Fibrillation), STROKE-AF (Stroke of Unknown Cause and Underlying Atrial Fibrillation) and PER-DIEM (Post-Embolic Rhythm Detection With Implantable Versus External Monitoring). Patients with detected AF more commonly initiated anticoagulation than those without AF.

Multicenter prospective observational study to clarify the current status and clinical outcome in Japanese patients who have an indication for implantable cardioverter defibrillator (ICD) or wearable cardioverter defibrillator (WCD) (TRANSITION JAPAN-ICD/WCD study): Rationale and design of a prospective, multicenter, observational, comparative study.

Background: Despite the positive impact of implantable cardioverter defibrillators (ICDs) and wearable cardioverter defibrillators (WCDs) on prognosis, their implantation is often withheld especially in Japanese heart failure patients with reduced left ventricular ejection fraction (HFrEF) who have not experienced ventricular tachycardia (VT) or ventricular fibrillation (VF) for uncertain reasons. Recent advancements in heart failure (HF) medications have significantly improved the prognosis for HFrEF. Given this context, a critical reassessment of the treatment and prognosis of ICDs and WCDs is essential, as it has the potential to reshape awareness and treatment strategies for these patients. Methods: We are initiating a prospective multicenter observational study for HFrEF patients eligible for ICD in primary and secondary prevention, and WCD, regardless of device use, including all consenting patients. Study subjects are to be enrolled from 31 participant hospitals located throughout Japan from April 1, 2023, to December 31, 2024, and each will be followed up for 1 year or more. The planned sample size is 651 cases. The primary endpoint is the rate of cardiac implantable electronic device implementation. Other endpoints include the incidence of VT/VF and sudden death, all-cause mortality, and HF hospitalization, other events. We will collect clinical background information plus each patient's symptoms, Clinical Frailty Scale score, laboratory test results, echocardiographic and electrocardiographic parameters, and serial changes will also be secondary endpoints. Results: Not applicable. Conclusion: This study offers invaluable insights into understanding the role of ICD/WCD in Japanese HF patients in the new era of HF medication.

Impact of frailty in patients with non-valvular atrial fibrillation undergoing catheter ablation.

Background: The relationships between frailty and clinical outcomes in elderly Japanese patients with non-valvular atrial fibrillation (NVAF) after catheter ablation (CA) have not been established. We evaluated the frailty rate of patients undergoing CA for NVAF, examined whether CA for NVAF improves frailty, and analyzed the CA outcomes of patients with and without frailty. Methods: Elderly Japanese patients (≥65 years; mean age: 72.8 years) who participated in the real-world ablation therapy with anti-coagulants in management of atrial fibrillation registry and who responded to the frailty screening index survey were included (n = 213). Frailty and AF recurrence were assessed preoperatively and at 3 and 6 months after CA. Results: Twenty-six patients (12.8%) were frail, 109 (53.7%) were pre-frail, and 68 (33.5%) were robust. Cardiovascular (frailty: 0.5%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year) and cardiac (frailty: 0.5%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year) events, as well as major bleeding (frailty: 0.3%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year), were numerically more frequent in the frailty group. No deaths from cardiovascular or stroke/systemic thromboembolic events occurred. A large proportion of patients did not experience 3-month (frailty: 96.2%; pre-frailty: 96.3%; robust: 88.2%) or 6-month (frailty: 88.5%; pre-frailty: 91.7%; robust: 86.8%) AF recurrence after CA. Weight loss, walking speed, and fatigue improved in the frailty and pre-frailty groups after CA. Conclusion: Japanese patients aged ≥65 years with frailty or pre-frailty had improved frailty screening index components, such as weight loss, walking speed and fatigue, after CA. Therefore, elderly patients with frailty or pre-frailty may benefit from CA for NVAF.

Four-Stage Rocket technique: A novel strategy for lead extractions using laser sheaths from the femoral vein.

INTRODUCTION: Transvenous lead extractions (TLEs) for cardiac implantable electronic device complications often encounter difficulties with strong adhesions to the myocardium or vessels. In this report, we introduce a novel "Four-Stage Rocket" technique for effective TLE in cases where conventional methods fail. METHODS AND RESULTS: Two challenging cases where conventional TLE methods failed were treated using a combination of four devices: Needle's Eye Snare, Agilis NxT Steerable Introducer, GlideLight Laser sheath, and GORE® DrySeal Flex Introducer sheath, employed via the inferior vena cava. The "Four-Stage Rocket" technique successfully detached firmly adhered leads near the tricuspid valve annulus, where the traditional superior vena cava approach was inadequate. CONCLUSION: The "Four-Stage Rocket" technique offers a potential alternative in complex TLE cases, aligning the laser direction with the adhesion detachment and reducing the tissue damage risk.

Postoperative intravenous patient-controlled analgesia improves pain management after subcutaneous implantable defibrillator implantation.

Objective: Postoperative pain is a major issue with subcutaneous implantable cardioverter defibrillators (S-ICD). In 2020, we introduced intravenous patient-controlled analgesia (IV-PCA) in addition to the conventional, request-based analgesia for postoperative pain control in S-ICD. To determine the effect and safety, we quantitatively assessed the effect of IV-PCA after S-ICD surgery over conventional methods. Methods: During the study period, a total of 113 consecutive patients (age, 50.1 ± 15.5 years: males, 101) underwent a de novo S-ICD implantation under general anesthesia. While the postoperative pain was addressed with either request-based analgesia (by nonsteroid anti-inflammatory drugs, N = 68, dubbed as "PCA absent") or fentanyl-based IV-PCA in addition to the standard care (N = 45, dubbed as "PCA present"). The degree of postoperative pain from immediately after surgery to 1 week were retrospectively investigated by the numerical rating scale (NRS) divided into four groups at rest and during activity (0: no pain, 1-3: mild pain, 4-6: moderate pain, 7-10: severe pain). Results: Although IV-PCA was removed on Day 1, it was associated with continued better pain control compared to PCA absent group. At rest, the proportion of patients expressing pain (mild or more) was significantly lower in the PCA present group from Day 0 to Day 4. In contrast to at rest, a better pain control continued through the entire study period of 7 days. No serious adverse events were observed. A few patients experienced nausea in both groups and the inter-group difference was not found significant. Conclusion: IV-PCA suppresses postoperative pain in S-ICD without major safety concerns.

Comparison of the electrophysiological properties of the pulmonary veins between paroxysmal and persistent atrial fibrillation.

Background: The role of the pulmonary veins (PVs) as triggers in atrial fibrillation (AF) is well-known; however, their detailed electrophysiological properties have not been thoroughly examined. Objective: This study aimed to investigate the electrophysiological properties of the PVs between paroxysmal AF (pAF) and persistent AF (perAF). Methods: Prior to catheter ablation in patients with pAF (n = 51) and perAF (n = 41), a voltage map of the left atrium and PVs was created under sinus rhythm, and the area of the myocardial sleeves in the PVs and their electrophysiological characteristics, including the pacing threshold and effective refractory period (ERP), were compared between the two groups. Results: Compared with perAF, the myocardial sleeves of PVs for pAF were significantly larger for all PVs. The ERP for perAF was significantly shorter than that for pAF for all PVs. The pacing threshold for perAF was significantly higher than that for pAF for the right and left superior PVs. Conclusion: In patients with perAF, a decrease in the normal myocardial sleeves and a shortening of the ERP were observed for all PVs. Those changes in the electrophysiological properties of the PVs might be related to the persistence of AF.

Does the same lesion index mean the same efficacy and safety profile: influence of the differential power, time, and contact force on the lesion size and steam pops under the same lesion index.

BACKGROUND: The lesion index (LSI) helps predict the lesion size and is widely used in ablation of various types of arrhythmias. However, the influence of the ablation settings on the lesion formation and incidence of steam pops under the same LSI value remains unclear. METHODS: Using a contact force (CF) sensing catheter (TactiCath™) in an ex vivo swine left ventricle model, RF lesions were created with a combination of various power steps (30 W, 40 W, 50 W) and CFs (10 g, 20 g, 30 g, 40 g, 50 g) under the same LSI values (5.2 and 7.0). The correlation between the lesion formation and ablation parameters was evaluated. RESULTS: Ninety RF lesions were created under a target LSI value of 5.2, and eighty-four were developed under a target LSI value of 7.0. In the LSI 5.2 group, the resultant lesion size widely varied according to the ablation power, and a multiple regression analysis indicated that the ablation energy delivered was the best predictor of the lesion formation. To create a lesion depth > 4 mm, an ablation energy of 393 J is the best cutoff value, suggesting a possibility that ablation energy may be used as a supplemental marker that better monitors the progress of the lesion formation in an LSI 5.2 ablation. In contrast, such inconsistency was not obvious in the LSI 7.0 group. Compared with 30 W, the 50-W ablation exhibited a higher incidence of steam pops in both the LSI 5.2 and 7.0 groups. CONCLUSIONS: The LSI-lesion size relationship was not necessarily consistent, especially for an LSI of 5.2. To avoid any unintentional, weak ablation, the ablation energy may be a useful supportive parameter (393 J as a cutoff value for a 4-mm depth) during ablation with an LSI around 5.2. Thanks to a prolonged ablation time, the LSI-lesion size relationship is consistent for an LSI of 7.0. However, it is accompanied by a high incidence of steam pops. Care should be given to the ablation settings even when the same LSI value is used.

Age-dependent contribution of intrinsic mechanisms to sinoatrial node function in humans.

Average beat interval (BI) and beat interval variability (BIV) are primarily determined by mutual entrainment between the autonomic-nervous system (ANS) and intrinsic mechanisms that govern sinoatrial node (SAN) cell function. While basal heart rate is not affected by age in humans, age-dependent reductions in intrinsic heart rate have been documented even in so-called healthy individuals. The relative contributions of the ANS and intrinsic mechanisms to age-dependent deterioration of SAN function in humans are not clear. We recorded ECG on patients (n = 16 < 21 years and n = 23 41-78 years) in the basal state and after ANS blockade (propranolol and atropine) in the presence of propofol and dexmedetomidine anesthesia. Average BI and BIV were analyzed. A set of BIV features were tested to designated the "signatures" of the ANS and intrinsic mechanisms and also the anesthesia "signature". In young patients, the intrinsic mechanisms and ANS mainly contributed to long- and short-term BIV, respectively. In adults, both ANS and intrinsic mechanisms contributed to short-term BIV, while the latter also contributed to long-term BIV. Furthermore, anesthesia affected ANS function in young patients and both mechanisms in adult. The work also showed that intrinsic mechanism features can be calculated from BIs, without intervention.

Fast-slow atrioventricular nodal re-entrant tachycardia incorporating superior and inferolateral left atrial slow pathways.

BACKGROUND: A 70-year-old man revealed a rare type of atrioventricular nodal re-entrant tachycardia (AVNRT) involving distinct retrograde pathways, superior slow pathway, and inferolateral left atrial slow pathway. RESULT: Radiofrequency ablation was successfully performed on the noncoronary cusp and in the left atrium, respectively, to eliminate the tachycardias. DISCUSSION AND CONCLUSION: Due to the anomalous electrical conduction patterns, careful diagnosis and ablation strategies were necessary to avoid the risk of atrioventricular block. These findings underscore the diversity and complexity of AVNRT and highlight the importance of tailored therapeutic approaches.

Impact of raising the upper extremity siding cardiac implantable electrical devices on postoperative safety.

Background: The upper extremity siding cardiac implantable electrical device tends to have a limited range of motion during the perioperative period; however, the underlying reason lacks scientific evidence. This study aimed to investigate the safety of the two methods (stepwise or early) of postoperative early upper extremity rehabilitation. Methods: We retrospectively investigated 650 consecutive patients with a new implantable pacemaker (PM), implantable cardioverter-defibrillator (ICD), cardiac resynchronization therapy (CRT), or generator exchange between March 2017 and December 2020.The limitation program was conducted from March 2017 to March 2018. The intervention program started as a stepwise protocol in April 2018 and was switched to an early protocol in December 2019. Results: This study analyzed 591 patients, excluding 59 who met the exclusion criteria. The mean age was 76.0 (69.0-82.0) years; 412 (69.7%) patients had a PM, 79 (13.4%) had an ICD, and 100 (16.9%) utilized CRT. There were 155 patients in the limitation protocol, 251 in the stepwise protocol, and 185 patients in the early protocol groups. Postoperative complications occurred in 53 (9.0%) patients. There was no significant difference in the incidence of all complications between the three groups (16 patients [10.3%] vs. 26 patients [10.4%] vs. 11 patients [5.9%]). Shoulder exercise-related complications were defined as hematoma (p = .94), lead dislodgement (p = .16), and increased pacing threshold (p = .23). General complications included wound infection (p = .51), pneumothorax (p = .27), tamponade (p = .07), and deep venous thrombosis (p = .26). Conclusion: Raising of the upper extremity siding cardiac implantable electrical devices above the head did not compromise postoperative safety.

Venous thoracic outlet syndrome, as a pitfall for cardiac implantable electronic device implantations.

The subclavian vein is typically used in cardiovascular implantable electronic device (CIED) implantations. External stress on the subclavian vein can lead to lead-related complications. There are several causes of this stress, such as frequent upper extremity movements or external injury. Venous thoracic outlet syndrome (TOS) can also become the cause of external lead stress. However, the diagnosis of venous TOS can be challenging because subclavian venography can appear normal at first glance. We present a unique case of a device infection in a patient with venous TOS. A careful observation of the imaging studies is vital for diagnosing venous TOS and a leadless pacemaker implantation could be an alternative therapeutic option.

Detailed investigation of the lesion formation with a novel contact force sensing catheter with a mesh-shaped irrigation tip.

Background: Recently, a novel contact force (CF) sensing catheter with mesh-shaped irrigation tip (TactiFlex SE, Abbott) was invented and is expected to be useful for safe and effective radiofrequency ablation. However, this catheter's detailed characteristics of the lesion formation are unknown. Methods: With an in vitro model, TactiFlex SE and its predecessor, FlexAbility SE, were used. A cross-sectional analysis of 60 s lesions (combination of various energy power settings [30, 40, and 50 W], and CFs [10, 30, and 50 g]) and longitudinal analysis (combination of various powers [40 or 50 W], CFs [10, 30, and 50 g] and ablation times [10, 20, 30, 40, 50, and 60 s]) of both catheters were analyzed and compared. Results: One hundred eighty RF lesions were created in protocol 1 and 300 in protocol 2. The lesion formation, impedance changes, and steam pops characteristics were similar between the two catheters. Higher CFs were related to higher incidences of steam pops. A nonlinear, time-dependent increase in the lesion depth and diameter was observed for all power and CF settings, and linear, positive correlations between the RF delivery time and lesion volume were observed for all power settings. Compared with 40 W, a 50 W ablation created greater lesions. Longer durations with higher CF settings had a higher steam pop incidence. Conclusions: The lesion formation and incidence of steam pops with TactiFlex SE and FlexAbility SE were similar. A 40 or 50 W ablation with careful CF control not to exceed 30 g in addition to monitoring impedance drops was required to safely create transmural lesions.

Detailed analysis of the lesion formation using a diamond tip catheter in an ex vivo experimental model.

BACKGROUND: A novel Diamond Temp™ (DT; Medtronic, Minneapolis, MN, USA) catheter has enabled performing a surface temperature-controlled ablation. The chemical vapor deposition diamond of the ablation catheter acts as a thermal radiator and is useful for effective cooling of the ablation catheter tip. However, a detailed analysis of the lesion formation with this catheter remains unknown. METHODS: DT catheters were used in an excised swine heart experimental model. A cross-sectional analysis of 60-s lesions [a combination of various energy power settings (30, 40, and 50 W), and various contact forces (CF) (10, 30, and 50 g)] and a longitudinal analysis [a combination of various powers (40 W or 50 W), various CFs (10, 30, and 50 g), and various ablation times (5 s, 10 s, 15 s, 20 s, 25 s, 30 s, and 60 s)] of the DT catheter were analyzed. RESULTS: The maximum lesion depth, maximum diameter, and lesion volume with a 10 g ablation were significantly lower than those with a 30 g or 50 g ablation. There were no significant differences in the lesion formation between the 30 g ablation and 50 g ablation under each radiofrequency (RF) power setting. The impedance drops with steam pops were significantly greater than those without steam pops (pop (+) vs. pop (-), 26.2 ±â€¯6.6 Ohm vs. 18.4 ±â€¯7.1 Ohm, p = 0.0001). A non-linear, time-dependent increase in the lesion depth and diameter was observed for all power and CF settings. Comparing the lesion depth and diameter between 40 W and 50 W under the same CF setting and same ablation time, most of the settings had no significant difference. CONCLUSION: Ablation lesions created with the DT catheter were similar to other catheters. Similar ablation lesions were created with the 40 W or 50 W ablation under the same CF setting and same ablation time. Regardless of the ablation power, monitoring the general impedance during the RF application was indispensable for a safe procedure.

Initial multicenter clinical experience with the first-generation endoscopic guided laser balloon in Japan.

BACKGROUND: Isolation of the pulmonary veins (PVs) is the golden standard for atrial fibrillation (AF) ablation. To achieve a permanent PV isolation, the endoscopic guided HeartLight laser balloon system was invented. We analyzed the safety and efficacy of this laser balloon system. METHODS AND RESULTS: Three hundred four patients from 21 investigational sites inside Japan were enrolled in this study. One thousand sixty-two out of 1175 PVs (90.4%) were isolated using the HeartLight laser balloon. The isolation rate of the left superior, left inferior, right superior, and right inferior PVs was 87.8%, 91.3%, 91.6%, and 92.1%, respectively. The procedure time, defined as the time from the venous access to taking out the balloon, was 155 ± 39 min. The fluoroscopic time was 44 ± 25 min. The mean follow-up period was 309 ± 125 days. The freedom from AF recurrence at 3 months was 89.0% and at 12 months 82.1%. Adverse events occurred in 22 patients (7.2%) including phrenic nerve injury lasting more than 3 months in 1.6% and strokes in 1.0% of the patients. CONCLUSIONS: This initial experience demonstrated that the laser balloon ablation was feasible for PV isolation in Japanese AF patients.