Feasibility of a novel atrial mechanical sensing method for leadless atrioventricular synchronous pacing.

INTRODUCTION: Few studies have demonstrated a high degree of atrioventricular (AV) synchrony with a new leadless pacemaker called Micra AV. Our group previously reported a new and unique sensing method. We believe that this novel sensing method, "Simplified A3 method," might facilitate better AV synchrony than a conventional sensing method in almost all cases with Micra AV implantation. METHODS: We conducted a non-randomized retrospective study comparing the two pacing methods at two centers. From December 1, 2021 to October 31, 2022, Micra AV was implanted for 32 patients at the two centers. Twenty of the 32 patients with sinus rhythm and complete AV block were included in this study. In Group 1, the conventional setting was programmed as follows: auto A3 threshold, auto A3 window-end (WE), and auto A4 threshold turned on during hospitalization. In Group 2, the "Simplified A3 method" was programmed as follows: auto A3 threshold and auto A3WE turned off. Instead, an intentionally prolonged A3WE (850-1000 ms) and low A3 threshold (A3 signal amplitude + 0.5-1.0 m/s2) were programmed. RESULTS: Twenty patients were analyzed. In Group 2, AV synchrony (%AMVp) was significantly higher at the first outpatient clinic (63.0 ± 5.7% vs 81.0 ± 4.2%, p = .03). A3 threshold was significantly lower in Group 2 (5.9 ± 0.7 m/s2, p < .05 vs 2.3 ± 0.5 m/s2, p < .05). CONCLUSION: Our novel sensing method might be a more feasible sensing method for obtaining higher AV synchrony than the conventional algorithm.

A case of cardiac sarcoidosis mimicking acute phase of takotsubo cardiomyopathy evaluated by multimodality cardiac imaging.

The patient was a 68-year-old woman who experienced loss of consciousness owing to a seizure while walking and bruised her face. Twelve­lead electrocardiography displayed a complete atrioventricular block. Transthoracic echocardiography displayed hypokinesis from the middle to apex of the myocardium. Emergency coronary angiography displayed no clear stenosis of the coronary arteries, and left ventriculography displayed takotsubo-like abnormal left ventricular wall motion. 99mTc-sestamibi/123I-beta-methyl iodophenyl pentadecanoic acid dual single-photon emission computed tomography displayed a perfusion/metabolism mismatch in the left apex, anterior segment, and inferior segment of the myocardium in the acute phase, which improved in the chronic phase. Similar mismatch findings were observed in the ventricular septum, which persisted in the chronic phase. Blood biomarkers of sarcoidosis were positive. Myocardial delayed enhancement was observed in the mid layer of the basal septum and inferior wall on cardiac magnetic resonance imaging. Fluorodeoxyglucose-positron emission tomography displayed signal accumulation in the basal septum. The clinical course of the patient suggested the possibility of cardiac sarcoidosis combined with takotsubo cardiomyopathy. This is a valuable case in which changes over time were detected by multimodality cardiac imaging. Learning objective: Cardiac manifestations of both takotsubo cardiomyopathy and sarcoidosis are similar, with both causing abnormal left ventricular wall motion. The co-occurrence of these conditions has been seldomly reported to date. The similarity of the characteristics of each condition poses a challenge in the diagnostic process. The utilization of multimodality cardiac imaging techniques, as demonstrated in the present case, is an effective means of establishing a diagnosis.

Nutritional Status and Sleep Quality Are Associated with Atrial Fibrillation in Patients with Obstructive Sleep Apnea: Results from Tokyo Sleep Heart Study.

The prevalence of obstructive sleep apnea (OSA) in patients with atrial fibrillation (AF) has been observed to be much higher than in control participants without AF. Limited data exist regarding the prevalence of AF in patients with OSA. The clinical characteristics, nutritional status, and sleep parameters associated with AF in patients with OSA remain unclear. In this study, we aimed to determine the prevalence and factors associated with AF in patients with OSA from a large Japanese sleep cohort (Tokyo Sleep Heart Study). This was a single-center explorative cross-sectional study. Between November 2004 and June 2018, we consecutively recruited 2569 patients with OSA who underwent an overnight full polysomnography at our hospital. They were assessed using a 12-lead ECG and echocardiography. The clinical characteristics, sleep parameters, and medical history were also determined. Of the OSA patients, 169 (6.6%) had AF. Compared with the non-AF patients, OSA patients with AF were older and male, and they had higher prevalence of a history of alcohol consumption, hypertension, chronic kidney disease, and undernutrition, as well as a reduced ejection fraction. With regard to the sleep study parameters, OSA patients with AF had reduced slow-wave sleep and sleep efficiency, as well as higher periodic limb movements. There were no significant differences in the apnea-hypopnea index or hypoxia index between the two groups. The logistic regression analysis demonstrated that age (OR = 4.020; 95% CI: 1.895-8.527; p < 0.001), a history of alcohol consumption (OR = 2.718; 95% CI: 1.461-5.057; p = 0.002), a high CONUT score (OR = 2.129; 95% CI: 1.077-4.209; p = 0.030), and reduced slow-wave sleep (OR = 5.361; 95% CI: 1.505-19.104; p = 0.010) were factors significantly related to AF. The prevalence of AF in patients with OSA was 6.6%. Age, a history of alcohol consumption, undernutrition, and reduced sleep quality were independent risk factors for the presence of AF in patients with OSA, regardless of the severity of OSA.

A case of short-coupled variant of Torsade de Pointes with bystander early repolarization in inferior leads.

The presence of J waves in cases of ventricular fibrillation (VF) is known to be a risk for sudden cardiac death. Recently, the effectiveness of radiofrequency catheter ablation (RFCA) for early repolarization syndrome (ERS) has been reported.The patient is a 30-year-old male with elevated J waves of 0.1 mV in the inferior leads, who had previously developed VF and undergone implantable cardioverter defibrillator (ICD) implantation. Because the VF from short coupled premature ventricular contraction (PVC) was presented, the RFCA of the triggered PVC was attempted. But it was unsuccessful due to no inducibility of the triggered PVC. After that, despite anti-arrythmia drug treatment, appropriate ICD shock for VF was observed. Although we decided to do a second ablation and evaluated epicardial arrhythmia substrate, no specific findings of early repolarization syndrome were found in the electrophysiological study. Finally, we considered that the cause of VF was short-coupled variant of Torsade de Pointes, and PVC ablation was performed. VF has not occurred since. We consider that this is a rare case to evaluate the epicardial arrhythmogenic substrate of J wave. Learning objective: Ablation of the epicardial arrhythmogenic substrate in patients with early repolarization syndrome (ERS) has been shown to be effective, but the relationship between abnormal epicardial potentials and the pathophysiology is unclear. In this case, J-wave and epicardial delayed potentials were not considered to represent obvious arrhythmogenic substrates. Ablation of the triggered premature ventricular contraction may be effective in ERS without apparent abnormal potentials.

Ventricular fibrillation immediately after the treatment of Graves' disease coexisting with atypical angina and long QT syndrome: a case report.

BACKGROUND: Palpitations due to Graves' disease are often caused by supraventricular arrhythmia. However, in rare cases, the background of coronary artery disease, genetic abnormalities, or channel abnormalities can cause ventricular fibrillation, which is a lethal arrhythmia. Here, we report a case of ventricular fibrillation after administration of beta-blockers early in the course of treatment for Graves' disease coexisting with atypical angina and long QT syndrome. CASE PRESENTATION: A 48-year-old man consulted a local general physician for chest discomfort and palpitations for approximately 2 weeks. He was diagnosed with Graves' disease and treated with thiamazole 15 mg, bisoprolol 1.25 mg, and nitroglycerin 0.3 mg. The patient continued to experience chest discomfort the next day and visited our hospital. The patient was treated with landiolol 0.125 mg/kg/min for heart rate control, and 20 min later, electrocardiography showed a change from the R-on-T phenomenon to ventricular fibrillation. After cardiopulmonary resumption and improvement of thyroid function, a stress test was performed, which revealed coronary angina and long QT syndrome. An implantable cardioverter defibrillator (ICD) was implanted in the patient for secondary prevention. Since then, no fatal arrhythmia has been observed to date. CONCLUSIONS: When beta-blockers are administered to patients with Graves' disease who have severe chest symptoms, fatal arrhythmias are possible. ICD implantation should be considered for the secondary prevention of fatal arrhythmias.