[Muscle-Specific Receptor Tyrosine Kinase Antibody Positive Myasthenia Gravis].

Reportedly, patients with muscle-specific kinase (MuSK) antibody-positive myasthenia gravis (MG) account for approximately 3.0% of all patients with MG in Japan. Compared with patients who have acetylcholine receptor antibody-positive MG, those with MuSK antibody-positive MG show young-onset disease with female predominance, a low rate of ocular involvement (5.9%), and greater severity of dysphagia. The aforementioned types of MG are indistinguishable based on clinical symptoms and electrophysiological tests, and measurement of MuSK antibodies is essential for diagnosis. Thymectomy and complement inhibitors are not indicated for treatment, and acetylcholinesterase inhibitors, steroids, immunosuppressants, plasma exchange, intravenous immunoglobulin therapy, and neonatal Fc receptor inhibitors are used.

Pitfalls and tips for lumenless lead extraction inserted deep within the ventricular septum.

Key Clinical Message: This case highlights the pitfalls and provides tips for the extraction of deeply implanted lumenless leads, and encourages careful lead selection in the current era of widespread left bundle branch area pacing. Abstract: The extraction of cardiovascular implantable electronic device leads is sometimes complicated. We describe a case with difficult but successful extraction of SelectSecure, a lumenless permanent pacemaker lead, implanted deep in the ventricular septum, highlighting its pitfalls and tips in the current era of left bundle branch area pacing.

Impact of Sleep Apnea on Nocturnal Parasympathetic Activity in Atrial Fibrillation Patients After Catheter Ablation　- Implications for Heart Rate Variability Analysis.

BACKGROUND: The impact of sleep apnea (SA) on heart rate variability (HRV) in atrial fibrillation (AF) patients has not been investigated.Methods and Results: Of 94 patients who underwent AF ablation between January 2021 and September 2022, 76 patients who had a nocturnal Holter electrocardiography and polysomnography conducted simultaneously were included in the analysis. A 15-min duration of HRV, as determined by an electrocardiogram during apnea and non-apnea time, were compared between patients with and without AF recurrence at 12 months' postoperatively. Patients had a mean age of 63.4±11.6 years, 14 were female, and 20 had AF recurrence at 12 months' follow-up. The root mean square of the difference between consecutive normal-to-normal intervals (RMSSD, ms) an indicator of a parasympathetic nervous system, was more highly increased in patients with AF recurrence than those without, during both apnea and non-apnea time (apnea time: 16.7±4.5 vs. 13.5±3.3, P=0.03; non-apnea time: 20.9±9.5 vs. 15.5±5.9, P<0.01). However, RMSSD during an apneic state was decreased more than that in a non-apneic state in both groups of patients with and without AF recurrence (AF recurrence group: 16.7±4.5 vs. 20.9±9.5, P<0.01; non-AF recurrence group; 13.5±3.3 vs. 15.5±5.9, P=0.03). Consequently, the effect of AF recurrence on parasympathetic activity was offset by SA. Similar trends were observed for other parasympathetic activity indices; high frequency (HF), logarithm of HF (lnHF) and the percentage of normal-to-normal intervals >50 ms (pNN50). CONCLUSIONS: Without considering the influence of SA, the results of nocturnal HRV analysis might be misinterpreted. Caution should be taken when using nocturnal HRV as a predictor of AF recurrence.

[Diagnosis and Treatment of Lambert-Eaton Myasthenic Syndrome].

Approximately 90% of patients with Lambert-Eaton myasthenic syndrome (LEMS) show positive P/Q-type voltage-gated calcium channels antibodies, which can be broadly classified clinically as paraneoplastic, particularly with small cell lung carcinoma and non-paraneoplastic without cancer. The first Japanese guideline for LEMS was developed in May 2022 as MG/LEMS Practice Guideline 2022. This article describes the epidemiology, symptoms, diagnosis, examination, treatment, and prognosis of this condition, based on the LEMS guidelines.

Mitral regurgitation outcomes after transcatheter atrial septal defect closure.

BACKGROUND: Worsening mitral regurgitation (MR) is a complication of intervention for atrial septal defect (ASD). Little is known about mitral valve (MV) characteristics associated with worsening MR. We aimed to elucidate MR outcomes and predictors of worsening MR after transcatheter ASD closure. METHODS: We analyzed changes in MR from prior to transcatheter ASD closure to 6 months after the procedure and predictors of worsening MR via baseline transthoracic echocardiography in 238 patients (64.7% females; mean age, 53 ± 22 years). RESULTS: Worsening MR was defined as worsening to moderate in patients with less than or equal to mild MR at baseline or vena contracta width increasing of ≥2 mm by 6-month follow-up in patients with moderate MR. Worsening MR was observed in 29 patients (12.2%). The associated echocardiographic findings were pseudoprolapse, hamstringing, stiffness, and anteroposterior and intercommissural mitral annulus diameter in the univariable logistic regression analysis (all P < 0.05). Multivariable analysis after adjusting for age; long-standing persistent atrial fibrillation; and ASD size showed that models combining MV leaflet findings such as pseudoprolapse or hamstringing, or anterior leaflet stiffness with the ratio of the sum of anterior and posterior leaflet lengths to intercommissural mitral annulus diameter were statistically significant for predicting worsening MR (R2 = 0.393, P < 0.001 and R2 = 0.385, P < 0.001, respectively). CONCLUSIONS: Worsening MR after transcatheter ASD closure might depend on MV leaflet findings and annulus size in patients with long-standing persistent atrial fibrillation.

Mitral valve leaflet stiffness predicts residual mitral regurgitation after transcatheter edge-to-edge mitral valve repair.

BACKGROUND: Residual regurgitation after transcatheter edge-to-edge mitral valve repair (TMVR) is a predictor of poor prognosis in patients with functional mitral regurgitation (FMR). This study sought to identify the mitral valve (MV) parameters measured by three-dimensional transesophageal echocardiography (3D-TEE) and MV leaflet features that predict residual mitral regurgitation (MR) after TMVR in patients with FMR. METHODS: Consecutive patients with FMR who underwent TMVR were classified into two groups based on the degree of residual MR just after TMVR: < 2+ in the optimal MR reduction group and ≥ 2+ in the suboptimal MR reduction group. The two groups were compared with respect to 3D-TEE parameters and the MV leaflet features, including the following parameters: stiffness, defined as a leaflet that remains at a fixed angle even during diastole, and thickness, measured in both clear and rough zones. RESULTS: Thirty-four of 46 patients (74%) were classified as the optimal MR reduction group. Multivariable analysis showed that anterior mitral leaflet + posterior mitral leaflet length/anteroposterior annulus diameter (p = .044) and MV leaflet stiffness (p = .007) were independent predictors of residual MR. CONCLUSION: MV leaflet stiffness and the ratio of MV leaflet lengths to the annulus diameter may be good predictors of residual MR after TMVR in patients with FMR.

Prediction model for the new onset of atrial fibrillation combining features of 24-hour Holter electrocardiogram with 12-lead electrocardiogram.

Background: Several factors that predict new-onset atrial fibrillation (AF) have been investigated using the 24-hour Holter electrocardiogram (ECG) and 12-lead ECG; however, these have been based on each test independently. The aim of this study was to combine findings from the two tests to create a comprehensive, easy-to-use score and to examine its validity. Methods and Results: A total of 502 patients underwent 24-hour Holter ECG and 12-lead ECG were followed up for 6.2 ± 3.5 years, and 66 patients developed new-onset AF. Multivariate Cox regression analyses revealed that total number of supraventricular extrasystoles (SVEs) ≥ 100 beats/day and SVE's longest run ≥ 3 beats on 24-hour Holter ECG and PR interval ≥ 185 ms, amplitude ratio of P wave (aVR/V1) < 1.0 and amplitude of RV5 + SV1 ≥ 2.2 mV on 12-lead ECG were significant independent predictors for developing AF (all p < 0.01). Using these cut-off points, the PAAFS (acronym for risk factors) score was constructed by adding one point for each parameter if the patient met each of the criteria. The area under the curve (AUC) of the PAAFS score was 0.80, compared to the AUCs of 24-hour Holter ECG-only factors (0.73) and 12-lead ECG-only factors (0.72), indicating an improvement in score. The annual incidence of AF for each PAAFS score were 0.0%, 0.2%, 0.7%, 1.9%, 5.6%, and 11.1%/year for scores 0 to 5, respectively. Conclusion: The PAAFS score, which combines findings from 24-hour Holter ECG and 12-lead ECG, was superior to 24-hour Holter ECG and 12-lead ECG alone in predictive accuracy for new-onset AF.

Clinical Significance of Physical Examination for Hypertrophic Cardiomyopathy.

BACKGROUND: Patients with hypertrophic cardiomyopathy (HCM) show various physical findings, but their clinical significance has not been systematically evaluated.Methods and Results: This study evaluated 105 consecutive patients with HCM who had undergone phonocardiography and external pulse recording. Physical examinations included a visible jugular a-wave (Jug-a), audible 4th sound (S4), and double or sustained apex beat. The primary outcome was a composite of all-cause death and hospitalization for cardiovascular disease. A total of 104 non-HCM subjects served as controls. The prevalence of visible Jug-a in the seated or supine position, audible S4, and a sustained or double apex beat in patients with HCM were 10%, 71%, 70%, 42%, and 27%, respectively, all of which were significantly higher than in the controls (0%, 20%, 11%, 17%, and 2%; P<0.001 for all comparisons). The combination of visible Jug-a in the supine position and audible S4 yielded a specificity of 94% and sensitivity of 57%. During a follow-up period of 6.6 years, 6 patients died and 10 were hospitalized. The absence of audible S4 was a predictor of cardiovascular events (hazard ratio, 3.91; 95% confidence interval, 1.41 to 10.8; P=0.005). CONCLUSIONS: Detection of these findings has clinical importance in the diagnosis and risk stratification of HCM prior to the use of advanced imaging techniques.

Tako-Tsubo Syndrome Following Pulmonary Vein Isolation for Atrial Fibrillation in a Patient with Primary Aldosteronism.

Tako-tsubo syndrome (TTS) can be triggered by emotional or physical stress and is characterized by transient left ventricular dysfunction with apical ballooning. Some neurologic disorders and pheochromocytoma serve as triggers for TTS, however, its association with primary aldosteronism (PA) is not well known. Pulmonary vein isolation (PVI) with catheter ablation for atrial fibrillation (AF) has been performed worldwide, and TTS following PVI has been reported as a rare complication. Sympathetic stimulation can play an important role in TTS development, however, its mechanism and risk factors are not yet understood.We describe a 72-year-old woman with PA who developed TTS after PVI with radiofrequency catheter ablation (RFCA) for symptomatic paroxysmal AF. Complete isolation of the pulmonary vein was carried out without any complications, however, she complained of epigastric discomfort 7 hours after the procedure. An electrocardiogram showed recurrent AF with a new negative-T wave and prolonged QT interval. Transthoracic echocardiography revealed apical ballooning and basal hypercontraction, characteristic of TTS, and coronary angiography showed no significant stenosis. She was diagnosed with TTS following RFCA for AF and managed well with conservative therapy.The present case suggests that TTS should be recognized as a complication associated with AF ablation. Moreover, PA may be involved in TTS development by increasing sympathetic activity. Further studies on the mechanism and characteristics of TTS are required.

Cardiac Rehabilitation for Patients With Stable Ischemic Heart Disease Without Revascularization　- Rationale and Design of a Single-Arm Pilot Study.

Background: Clinical practice guidelines strongly recommend optimal medical therapy (OMT), including lifestyle modification, pharmacotherapy, and exercise-based cardiac rehabilitation (CR), in patients with stable ischemic heart disease (SIHD). However, the efficacy and safety of CR in patients with SIHD without revascularization remain unclear. Methods and Results: The Prospective Registry of STable Angina RehabiliTation (Pre-START) study is a multicenter, prospective, single-arm, open-label pilot study to evaluate the efficacy and safety of CR on health-related quality of life (HRQL), exercise capacity, and clinical outcomes in Japanese patients with SIHD without revascularization. In this study, all patients will undergo guideline-based OMT and are encouraged to have 36 outpatient CR sessions within 5 months after enrollment. The primary endpoint is the change in the Seattle Angina Questionnaire-7 summary score between baseline and the 6-month visit; an improvement of ≥5 points will be defined as a clinically important change. Secondary endpoints include changes in other HRQL scores and exercise capacity between baseline and the 6-month visit, as well as clinical outcomes between enrollment and the 6-month visit. Conclusions: The Pre-START study will provide valuable evidence to elucidate the efficacy and safety of CR in patients with SIHD and indispensable information for a subsequent randomized controlled trial. The study was registered with the University Hospital Medical Information Network (UMIN) Clinical Trials Registry (ID: UMIN000045415) on April 1, 2022.

Study Protocol of Cardiac Rehabilitation for Acute Myocardial Infarction From the JROAD/JROAD-DPC Database　- JROAD-CR.

Background: Although cardiac rehabilitation (CR) has been reported to be effective for improving the prognosis of acute myocardial infarction (AMI), more patients must participate in CR during admission and as outpatients. Factors contributing to, and countermeasures against, the low CR participation rate need to be identified. Here we describe the protocol for a study designed to evaluate the effectiveness and problems of CR for AMI from the Japanese Registry of All Cardiac and Vascular Diseases (JROAD) and the JROAD-Japanese Diagnosis Procedure Combination system (JROAD-DPC) database. Methods and Results: This is a multicenter retrospective cohort study that will use the JROAD/JROAD-DPC database to evaluate the effectiveness of CR for AMI (JROAD-CR). Five thousand patients with AMI who were admitted to hospitals registered in the JROAD database in 2014 will be investigated with regard to their baseline characteristics, AMI severity and treatment, examination results, history of CR, and prognosis up to 5 years. We will also investigate the presence, quantity, and quality of CR, and evaluate the effectiveness of CR with respect to cost, exercise tolerance, and prognosis during admission and follow-up. Conclusions: The JROAD-CR study will seek to reveal the effectiveness of CR for AMI in the era of early reperfusion therapy and shortened hospitalization.

The impact of home electrocardiograph measurement rate on the detection of atrial fibrillation recurrence after ablation: A prospective multicenter observational study.

Background: This multicenter prospective observational study examined the impact of additionally using a home electrocardiograph (ECG) to detect atrial fibrillation (AF) recurrence after ablation. Methods: Between May 2019 and December 2020, 128 patients undergoing ablation were enrolled in the study. After performing ablation, they were instructed to measure their ECGs at home using Complete (ECG paired with a blood pressure monitor; Omron Healthcare, Japan) every day and to visit the hospital every 3 months until after 12 months for 24-hour Holter ECG and 12-lead ECG as usual care (UC). Results: After ablation, 94 patients were followed up, and AF recurrence at 12 months was detected more commonly in adjudicators-interpreted Complete (31 [33 %]) than in UC (18 [9 %]) (hazard ratio 1.95, 95 % confidence interval [95 %CI] 1.35-2.81, P < 0.001). In patients with recurrent AF found via both modalities (n = 16), the time to first AF detection by Complete was 40.9 ± 73.9 days faster than that in UC (P = 0.04). Notably, when the adherence to Complete measurement was divided by 80 %, the add-on effect of Complete on the detection of recurrent AF in UC indicated the hazard ratio (HR) of 1.71 (95 %CI 0.92-3.18, P = 0.09) for the low adherence (<80 %) group, but it was significant for the high adherence (≥80 %) group, with HR of 2.19 (95 %CI 1.43-3.36, P < 0.001). Conclusions: Despite a shorter measurement time, Complete detected recurrent AF more frequently and faster compared with UC after AF ablation. A significant adherence-dependent difference of Complete was found in detecting AF recurrence.

Comparison of maximum-sized visually guided laser balloon and cryoballoon ablation.

Balloon ablation therapy has recently been used for atrial fibrillation (AF) ablation. Laser balloons possess the property in which the balloon size can be changed. Standard laser balloon ablation (Standard LBA) was followed by additional ablation using a maximally extended balloon (Extended LBA) and its lesion characteristics were compared to cryoballoon ablation (CBA), another balloon technology. From June 2020 to July 2021, patients with paroxysmal AF who underwent an initial pulmonary vein (PV) isolation were enrolled. Sixty-five patients with paroxysmal AF were included, 32 in the LBA and 33 in the CBA group. To measure the isolated surface area after the ablation procedures, left atrial voltage mapping was performed after Standard LBA, Extended LBA, and CBA. The baseline patient characteristics did not differ between LBA and CBA. Extended LBA could successfully increase the isolated area more than Standard LBA for all four PVs. Compared to CBA, the isolated area of both superior PVs was significantly greater with Extended LBA (left superior PV: 8.5 ± 2.1 vs 7.3 ± 2.4, p = 0.04, right superior PV: 11.4 ± 3.7 vs 8.7 ± 2.7, p < 0.01), and thus the non-isolated posterior wall (PW) was smaller (8.5 ± 3.4 vs 12.4 ± 3.3, p < 0.01). Nevertheless, changes in the cardiac injury markers were significantly lower with LBA than CBA. There was no significant correlation between the cardiac injury level and isolated area in both groups. In conclusion, Extended LBA exhibited a significantly greater isolation of both superior PVs and resulted in a smaller non-isolated PW, but the cardiac injury markers were significantly suppressed as compared to CBA.

Efficacy of Early Cardiac Rehabilitation After Cardiac Surgery　- Verification Using Japanese Diagnosis Procedure Combination Data.

Background: The current status of cardiac rehabilitation (CR) after cardiac surgery and the introduction of early CR (E-CR) in Japan are not fully understood. In this study, the current status of E-CR and its efficacy were investigated by the Academic Committee of the Japanese Association of Cardiac Rehabilitation. Methods and Results: We examined the rate of introduction of E-CR and its effects among 220,122 patients who underwent major cardiac and thoracic vascular surgery, as registered in the Diagnosis Procedure Combination (DPC) classification system, between April 2012 and March 2018. In this study, E-CR was defined as CR starting within 1 day after surgery. Patients with and without E-CR were propensity score matched and analyzed for clinical outcomes. Of all patients participating in CR after surgery, E-CR was initiated in 52.1%, 56.9%, 47.4%, and 54.1% of patients undergoing coronary artery bypass grafting, valve surgery, aortic surgery, and other cardiovascular surgery, respectively. After propensity score matching, outcomes for E-CR were significantly superior to non-E-CR in terms of in-hospital deaths, Barthel Index score at discharge, length of hospital stay, and hospitalization costs. Conclusions: E-CR after cardiac surgery was effective in terms of prognosis, hospital stay, and medical costs. This study is the first report using big data in Japan. The results indicate that further introduction of E-CR needs to be recommended in the future.

Motor end-plate analysis to diagnose immune-mediated myasthenia gravis in seronegative patients.

This study aimed to evaluate the diagnostic usefulness of motor end-plate (MEP) analysis along with clustered acetylcholine receptor (AChR) antibody (Ab) assays in patients with myasthenia-like symptoms but negative routine AChR and muscle-specific kinase (MuSK) Ab tests. MEP analysis of muscle biopsies of the biceps brachii was performed in 20 patients to try to differentiate between those with or without immune-mediated myasthenia gravis (MG). Using a quantitative method, complement C3 deposition and AChR densities in MEPs were examined. Independently, cell-based assays were used to detect serum clustered-AChR Abs. Only five of 20 patients had complement deposition at MEPs; four of these patients had reduced AChR densities similar to those in patients with typical AChR Ab positive MG, and distinct from those in the remaining 15 patients. Two of the four serum samples from these patients had clustered-AChR Abs. All complement-positive patients were considered as having immune-mediated MG and improved with appropriate treatments; although one patient presented with MG 3 years later, the remaining patients had other diagnoses during over 10 years of follow-up. These results suggest the usefulness of MEP analysis of muscle biopsies in diagnosing immune-mediated MG in seronegative patients with myasthenia-like symptoms but, due to the invasiveness of the muscle biopsy procedure, clustered AChR Abs should, if possible, be tested first.

Cardiogenic Shock Due to Unsuspected Tachycardia in a Child.

A 10-year-old girl experienced cardiac failure due to atrial tachycardia originating from a left atrial appendage. Surgical appendectomy was done after a recurrence of the atrial tachycardia just after the first attempt at catheter ablation. A second ablation attempt was avoided because of the risk of cardiac perforation. (Level of Difficulty: Intermediate.).