Artificial intelligence to detect noise events in remote monitoring data.

Background: Remote monitoring (RM) of cardiac implantable electrical devices (CIEDs) can detect various events early. However, the diagnostic ability of CIEDs has not been sufficient, especially for lead failure. The first notification of lead failure was almost noise events, which were detected as arrhythmia by the CIED. A human must analyze the intracardiac electrogram to accurately detect lead failure. However, the number of arrhythmic events is too large for human analysis. Artificial intelligence (AI) seems to be helpful in the early and accurate detection of lead failure before human analysis. Objective: To test whether a neural network can be trained to precisely identify noise events in the intracardiac electrogram of RM data. Methods: We analyzed 21 918 RM data consisting of 12 925 and 1884 Medtronic and Boston Scientific data, respectively. Among these, 153 and 52 Medtronic and Boston Scientific data, respectively, were diagnosed as noise events by human analysis. In Medtronic, 306 events, including 153 noise events and randomly selected 153 out of 12 692 nonnoise events, were analyzed in a five-fold cross-validation with a convolutional neural network. The Boston Scientific data were analyzed similarly. Results: The precision rate, recall rate, F1 score, accuracy rate, and the area under the curve were 85.8 ± 4.0%, 91.6 ± 6.7%, 88.4 ± 2.0%, 88.0 ± 2.0%, and 0.958 ± 0.021 in Medtronic and 88.4 ± 12.8%, 81.0 ± 9.3%, 84.1 ± 8.3%, 84.2 ± 8.3% and 0.928 ± 0.041 in Boston Scientific. Five-fold cross-validation with a weighted loss function could increase the recall rate. Conclusions: AI can accurately detect noise events. AI analysis may be helpful for detecting lead failure events early and accurately.

Risk stratification for the occurrence of ventricular fibrillation in patients with early repolarization syndrome.

BACKGROUND: Several signs of malignant early repolarizations have been proposed in patients with early repolarization syndrome (ERS). However, reports have challenged the efficacy of these signs in predicting future ventricular fibrillation (VF) in patients with ERS. OBJECTIVE: This study aimed to assess the predictive value of various electrocardiogram (ECG) markers for future VF events in patients with ERS. METHODS: We retrospectively evaluated the clinical characteristics of 44 patients with ERS to identify risk factors for VF during follow-up. RESULTS: After the initial event, 16 patients experienced VF (VF group), whereas 28 did not (non-VF group). The VF group had a longer QRS interval, more fragmented QRS (fQRS), and a higher T/R voltage ratio than the non-VF group. Wide J waves were more prevalent in the VF group; however, other J-wave markers did not differ between the groups. Positive late potentials recorded on signal-averaged ECGs were more frequent in the VF group. Whereas none of the patients showed spontaneous Brugada syndrome on ECG, the VF group frequently exhibited pilsicainide-induced ST-segment elevation. These ECG markers were significantly associated with the occurrence of VF during follow-up. Patients with multiple ECG factors, including QRS abnormalities (wide QRS or fQRS), wide J waves, and a high T/R ratio, had a worse prognosis than patients without multiple factors, effectively stratifying patient risk. CONCLUSION: The occurrence of VF in patients with ERS may be associated with conduction abnormalities such as QRS widening, fQRS, high T/R ratio, positive late potentials, and pilsicainide test results. Therefore, ECG factors could be useful in identifying high-risk patients.

Clinical characteristics of electrical storm in patients with early repolarization syndrome.

BACKGROUND: Early repolarization syndrome (ERS) is an idiopathic ventricular fibrillation (VF) associated with inferolateral J waves. While electrical storm (ES) in ERS is not rare, their characteristics and risk factors are not fully understood. OBJECTIVE: This study aimed to clarify the significance of ES in ERS. METHODS: We evaluated 44 patients with ERS who experienced VF/sudden cardiac death or arrhythmic syncope. We assessed clinical characteristics to identify the risk factors for ES. RESULTS: In total, 13 patients (30%) experienced ES (ES group). Of these, 11 patients (85%) experienced ES during the acute phase of initial VF episodes and 2 patients (2%) experienced ES during follow-up. VF associated with ES occurred during therapeutic hypothermia in 6 of 13 patients (46%). The J-wave voltage during therapeutic hypothermia was higher in the ES group than that in the patients without ES. Isoproterenol was used in 5 patients (38%), which decreased J-wave voltage and relieved ES. Among the clinical markers, shorter QT and QTp intervals (the interval from QRS onset to the peak of T wave), pilsicainide-induced ST elevation, and high scores on the Shanghai Score System were associated with ES. Although pilsicainide induced ST elevation in 6 of 34 patients (18%), spontaneous Brugada electrocardiographic patterns did not appear to be associated with VF. Therapeutic hypothermia was also a risk factor for acute phase ES. CONCLUSION: Patients with ERS in the ES group frequently had short QT and QTp intervals, pilsicainide-induced ST elevations, and high Shanghai Score System scores. Therapeutic hypothermia was also associated with acute phase ES.

Significant delayed conduction and characteristic ventricular tachycardias in patients with cardiac sarcoidosis and electrical storm.

INTRODUCTION: Electrical storm (ES) of ventricular tachyarrhythmias (VTAs) is an important cause of sudden death in patients with cardiac sarcoidosis (CS). VTAs in CS are associated with myocardial scarring and inflammation. However, little is known about the risk factors of ES in patients with CS and VTAs. The objective of this study is to clarify the characteristics and risk factors for the development of ES in patients with CS. METHODS: The study population included consecutive 52 patients with CS and sustained VTA. Twenty-five out of 52 patients experienced ES. We evaluated clinical characteristics, imaging modalities, and electrocardiogram (ECG) parameters to determine the risk factors associated with ES. RESULTS: Half of the patients experienced VTAs as the initial symptom of sarcoidosis, and eight patients had ES as the initial VTA episode. There were no differences in cardiac imaging abnormalities between patients with and without ES. Among ECG markers, significant QRS fragmentation (odds ratio [OR]: 7.9, p = .01) and epsilon waves (OR: 12.24, p = .02) were associated with ES. Among the ventricular tachycardia (VT) characteristics, multiple morphologies of monomorphic VTs (OR: 10.9, p < .01), short VT cycle lengths (OR: 12.5, p < .01), and polymorphic VT (OR: 13.5, p < .01) were associated with ES. Bidirectional VTs were detected in 10 patients with ES and one patient without ES. Immunosuppressive therapy relieved ES in some patients. CONCLUSIONS: ES was common in patients with CS and VTAs. Significant depolarization abnormalities that appeared as QRS fragmentation, epsilon waves, and specific VT characteristics were associated with ES.

Syncope and loss of consciousness after implantation of a cardioverter-defibrillator in patients with Brugada syndrome: Prevalence and characteristics in long-term follow-up.

Background: Syncope is a significant prognostic factor in patients with Brugada syndrome (BrS). However, the risk of ventricular arrhythmia in patients with nonarrhythmic loss of consciousness (LOC) is similar to that in asymptomatic patients. LOC events after implantable cardioverter-defibrillator (ICD) implantation may provide insights into underlying causes of the initial LOC episode. Objective: The purpose of this study was to examine LOC characteristics following ICD implantation. Methods: We retrospectively analyzed 112 patients with BrS (mean age 47 years; 111 men) who were treated with an ICD. The patients were classified into 3 groups based on symptoms at implantation: asymptomatic (35 patients); LOC (46 patients); and ventricular tachyarrhythmia (VTA) (31 patients). We evaluated the incidence and cause of LOC during long-term follow-up after ICD implantation. Results: During mean follow-up of 12.2 years, 41 patients (37%) experienced LOC after ICD implantation. Arrhythmic LOC occurred in 5 asymptomatic patients, 14 LOC patients, and 16 patients with VTA. Nonarrhythmic LOC, similar to the initial episode, occurred after ICD implantation in 6 patients with prior LOC (2 with neurally mediated syncope and 4 with epilepsy). Most epileptic patients experienced LOC during rest or sleeping, and did not show an abnormal encephalogram during initial evaluation of the LOC episodes. Conclusion: After ICD implantation, 13% of patients had nonarrhythmic LOC similar to the initial episode. Accurate classification of LOC based on a detailed medical history is important for risk stratification, although distinguishing arrhythmic LOC from epilepsy-related LOC episodes can be challenging depending on the circumstances and characteristics of the LOC event.

Significance of left posterior extension of early repolarization in patients with J-wave syndrome.

BACKGROUND: J waves in the inferior or lateral leads are characteristic electrocardiographic (ECG) changes in patients with early repolarization syndrome (ERS). However, the presence of J waves in the left posterior region has not yet been evaluated. OBJECTIVE: The purpose of this study was to clarify the significance of J waves in the posterior left ventricle using leads V7-V9 and a body surface mapping (BSM) system. METHODS: Forty patients diagnosed with ERS were included. All patients exhibited J waves in either the contiguous inferior, lateral, or posterior leads. We evaluated the incidence of J waves in the inferolateral and posterior leads using a 15-lead ECG with synthesized V7-V9 and an 87-lead BSM. Additionally, we assessed the arrhythmogenicity of the posterior regions based on the morphology of the premature ventricular complexes (PVCs) associated with ventricular fibrillation (VF). RESULTS: J waves were observed in the lateral, inferior, and posterior leads of 26 (65%), 31 (78%), and 39 (97%) patients, respectively. J waves were found only in the posterior leads of 5 patients. BSM was evaluated in 9 patients, all of whom exhibited a positive area on the posterior region. PVCs associated with VF were recorded in 5 patients. Among patients with inferolateral and posterior J waves, all except 1 patient who displayed left bundle branch block morphology showed PVCs originating from the posterior left ventricular region. CONCLUSION: Posterior J waves are common in ERS patients. This abnormality can be detected using leads V7-V9 and the BSM system and may be associated with arrhythmogenesis.

Significant Delayed Activation on the Right Ventricular Outflow Tract Represents Complete Right Bundle-Branch Block Pattern in Brugada Syndrome.

Background The appearance of complete right bundle-branch block (CRBBB) in Brugada syndrome (BrS) is associated with an increased risk of ventricular fibrillation. The pathophysiological mechanism of CRBBB in patients with BrS has not been well established. We aimed to clarify the significance of a conduction delay zone associated with arrhythmias on CRBBB using body surface mapping in patients with BrS. Methods and Results Body surface mapping was recorded in 11 patients with BrS and 8 control patients both with CRBBB. CRBBB in control patients was transiently exhibited by unintentional catheter manipulation (proximal RBBB). Ventricular activation time maps were constructed for both of the groups. We divided the anterior chest into 4 areas (inferolateral right ventricle [RV], RV outflow tract [RVOT], intraventricular septum, and left ventricle) and compared activation patterns between the 2 groups. Excitation propagated to the RV from the left ventricle through the intraventricular septum with activation delay in the entire RV in the control group (proximal RBBB pattern). In 7 patients with BrS, excitation propagated from the inferolateral RV to the RVOT with significant regional activation delay. The remaining 4 patients with BrS showed a proximal RBBB pattern with the RVOT activation delay. The ventricular activation time in the inferolateral RV was significantly shorter in patients with BrS without a proximal RBBB pattern than in control patients. Conclusions The CRBBB morphology in patients with BrS consisted of 2 mechanisms: (1) significantly delayed conduction in the RVOT and (2) proximal RBBB with RVOT conduction delay. Significant RVOT conduction delay without proximal RBBB resulted in CRBBB morphology in patients with BrS.

Preventative effects of bisoprolol transdermal patches on postoperative atrial fibrillation in high-risk patients undergoing non-cardiac surgery: A subanalysis of the MAMACARI study.

BACKGROUND: Perioperative atrial fibrillation (POAF) after non-cardiac surgery is a risk factor for cardiovascular events including stroke and death. The aim of this subanalysis of the MAMACARI study, a multicenter randomized control study on the effectiveness of a bisoprolol transdermal patch for prevention of perioperative myocardial injury in high-risk patients undergoing non-cardiac surgery, was to identify the predictors of POAF after non-cardiac surgery in high-risk patients and to determine changes in blood pressure and heart rate during bisoprolol patch administration in the perioperative period. METHODS AND RESULTS: Patients aged over 60 years with hypertension and a high revised cardiac risk index (≥2) who were scheduled to undergo non-cardiac surgery were randomly assigned to a bisoprolol patch group (n = 120) or a control group (n = 120). We divided the patients into two groups: patients with POAF (POAF group; n = 16) and patients without POAF (non-POAF group; n = 206). Multivariate analysis showed that bisoprolol patch therapy (OR: 0.30, 95% CI: 0.092-0.978) and surgery time of 250 min or more (OR: 4.99, 95% CI: 1.37-18.2) were independently associated with POAF. Although systolic blood pressure did not differ significantly between the two groups throughout the perioperative period, treatment with a bisoprolol patch significantly reduced heart rate throughout the perioperative period compared with that in the control group. CONCLUSIONS: Low dose of a bisoprolol patch in the perioperative period was effective for prevention of POAF after non-cardiac surgery in high-risk patients, while long surgery time was an independent risk factor for POAF. It is expected that low dose of a bisoprolol patch can prevent POAF without causing hypotension.

Prognosis of patients with severe left ventricular dysfunction after transvenous lead extraction and the need for additional hemodynamic support in the perioperative period.

BACKGROUND: Transvenous lead extraction (TLE) is necessary because of system infection, lead malfunction, or system upgrade. Patients with severe left ventricular dysfunction (SLVD) undergoing TLE may be at a higher risk because hemodynamic parameters may change unfavorably during or after TLE; however, this has not yet been clarified. OBJECTIVE: The purpose of this study was to examine whether patients with SLVD undergoing TLE have higher mortality. METHODS: All patients who underwent TLE were stratified as follows: patients with ejection fraction ≤ 35% (SLVD group) and those with ejection fraction > 35% (non-SLVD group). RESULTS: We assessed the data of 200 patients [SLVD group, 36 (18%); non-SLVD group, 164 (82%)]). Brain natriuretic peptide level and cardiac resynchronization therapy rate were higher in the SLVD group than in the non-SLVD group. There were no significant between-group differences in major complications and clinical success rates. Patients with SLVD were more likely to require additional hemodynamic support, such as catecholamine infusion, temporary atrium-ventricle sequential pacing, and temporary cardiac resynchronization therapy pacing (27.8% vs 1.2%; P < .001). The survival rate was not significantly different between the groups at 30 days and 1 year after TLE (SLVD vs non-SLVD: 30 days: 97.2% vs 99.4%; P = .215; 1 year: 80.6% vs 91.5%; P = .053). Multivariate Cox regression analysis revealed log brain natriuretic peptide and serum hemoglobin levels as predictors for 1-year mortality. CONCLUSION: The prognosis after TLE was comparable between patients with and without SLVD. However, additional hemodynamic support was often necessary for patients with SLVD.

[Cirrhotic cardiomyopathy-associated acute cardiac failure in a patient with decompensated alcoholic cirrhosis with massive hepatic hydrothorax].

Cirrhotic cardiomyopathy (CCM) is a chronic cardiac dysfunction in patients with cirrhosis and is characterized by altered diastolic relaxation, blunted contractile response to stress, and electrophysiological abnormalities;however, causes of CCM are unknown. Moreover, reduced cardiac afterload due to cirrhosis-related vasodilatation often masks cardiac insufficiency, whereas rapid hemodynamic overload reveals the presence of cirrhotic cardiomyopathy. Herein, we present the case of previously unrecognized cirrhotic cardiomyopathy that became overt with the development of severe acute cardiac failure. The rapidly worsening hepatic hydrothorax increased cardiac preload and intrathoracic pressure, which impaired cardiac filling. Furthermore, cardiac contractile function might have been worsened by hypoxia due to passive atelectasis and concomitant anemia.

MALDI-TOF/MS-based label-free binding assay for angiotensin II type 1 receptor: application for novel angiotensin peptides.

Angiotensin (Ang) II is critically involved in multiple cardiovascular diseases mainly through the Ang II type 1 (AT1) receptor. Thus, AT1 receptor antagonists have been widely used for the treatment of hypertension and other cardiovascular conditions. However, most binding assays for AT1 receptor are based on radioactivity or fluorescent labeling, which present disadvantages such as radioactive waste production and/or changes to the binding characteristics of the labeled receptor or ligand. This article describes the first matrix-assisted laser desorption ionization-time of flight/mass spectrometry (MS)-based label-free binding assay for AT1 receptor that can be performed in a high-throughput format. The affinity of competitors can be directly compared to that of Ang II by quantifying Ang II dissociated from the receptor-ligand complex using 50% methanol in water. The sensitivity and selectivity of MS analysis was improved by employing a stable-isotope ((13)C, (15)N)-labeled internal standard. This assay provided binding results equivalent to those obtained using other methods and revealed a significant decrease in the binding affinity of Ang II when the N-terminus underwent oxidative modification. The current setup of the assay can be easily adapted for other Ang receptors and would facilitate drug discovery studies targeting Ang receptors.

Overexpression of CLN1, CLN2, or ERG13 increases resistance to adriamycin in Saccharomyces cerevisiae.

To elucidate the mechanisms underlying adriamycin resistance, adriamycin resistance-related genes were explored using the budding yeast Saccharomyces cerevisiae as a useful eukaryotic model. The CLN1 and CLN2 genes, encoding G1 cyclin, and the ERG13 gene, encoding 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) synthase, were identified.