Deep Convolutional Bidirectional LSTM Model for identifying Ventricular Tachyarrhythmia using ECG Signal Variability

An electrocardiogram (ECG) signal is used widely to detect ventricular tachyarrhythmia (VTA) and to diagnose heart disease. Deep learning models and large ECG data have made the diagnosis of VTA an attractive task to demonstrate the power of artificial intelligence in clinical applications. One of the life-threatening complications of VTA is cardiac arrest (CA). The VTA is divided into two categories: ventricular fibrillation (VF) and ventricular tachycardia (VT). Abnormal electrical activity in the ventricle causes VT, which leads to CA, whereas the chaotic electrical activity in the ventricle leads to VF. To improve the clinical diagnostic system and to help cardiologists, it is essential to identify the risk of VTA at an early stage. The goal of this paper is to develop an end-to-end (E2E) deep learning model that uses a convolution neural network (CNN) and a bidirectional long-short term memory network (BiLSTM) to classify VT and VF arrhythmias from multiple ECG databases. The CNN extracts features from ECG signals, and BiLSTM learns information. The ECG signals are acquired from the MIT-BIH malignant ventricular arrhythmia database (VFDB) and the Creighton University VTA database (CUDB). These ECG signals indicate that heart rate variability is a fast and dynamic event. Before the method's implementation, ECG signals are windowed at a fixed size according to annotation information and then normalized within each window. In terms of accuracy and sensitivity, the proposed CNN-BiLSTM deep learning model outperforms existing state-of-the-art methods. These results made it possible to obtain a relatively higher average accuracy (AC) of 99.37%, precision (PE) of 97.12%, a sensitivity (SE) of 98.15%, and F-score (FS) of 98.43%, and an overall accuracy of 99.07%, respectively.

Predictive value of electrophysiological study for risk stratification of ventricular tachyarrhythmias in patients with non-ischemic cardiomyopathy and chronic systolic heart failure

A systematic review and meta-analysis of studies providing information on the use of intracardiac electrophysiological study (EPS) to stratify the risk of ventricular tachyarrhythmia (VT) in patients with non-ischemic chronic heart failure with low left ventricle ejection fraction (HFrEF). Relevant publications were searched until 20.01.2021 by two independent researchers in major search engines, electronic archives of clinical research, and open access preservatives repository. The end point considered was an episode of sudden cardiac death or sustained paroxysm of VT, or an appropriate electrotherapy of an implanted cardiac defibrillator. Ten clinical trials with 608 relevant patients (mean age: 51.5 ± 12 years; mean left ventricle EF: 26.8±8.5%, NYHA class: I - 17.7%; II - 33.7%; III - 35.9%, IV - 12.7%) were selected. The end point was registered in 92 patients (15.1%): in 47 patients (43.9%) with previously induced VT during EPS and in 45 patients (8.9%) without VT. The diagnostic odds ratio was 5.57 (2.27-13.63). The combined sensitivity and specificity of the EPS were 42% (26-61%) and 88% (83-92%) respectively. The results indicate the potential of EPS to stratify the arrhythmic risk in patients with non-ischemic HFrEF.

Physiology of magnesium metabolism and the use of magnesium in intensive care (literature review with the results of personal observations, part 3)

In this review, we presented the results of experimental and clinical studies that most convincingly demonstrate the role of magnesium metabolism disorders in the development of myocardial damage, fatal arrhythmias, and arterial hypertension. We also highlighted the diagnosis of latent magnesium deficiency in the body and the role of magnesium deficiency in the pathogenesis of cardiomyopathy, congestive heart failure, and mitral valve prolapse. Oral Mg supplementation helps to reduce mean arterial pressure, peripheral vascular resistance, and the frequency of isolated and burst ventricular extrasystoles and attacks of unstable ventricular tachyarrhythmia. The researchers found that many patients with severe mitral valve prolapse had low serum Mg levels, and Mg supplementation was associated with improved patient outcomes. Monitoring the status of magnesium metabolism in the body is ne-cessary not only in intensive care and in the hospital as a whole but is also relevant in outpatient practice. The cost of magnesia therapy is quite low, but at the same time, regular intake of magnesium preparations or dietary supplements, containing mainly magnesium, can significantly improve the results of treatment of many diseases and prevent the development of complications that are dangerous for the body.

Combined simultaneous FDG-PET/MRI with T1 and T2 mapping as an imaging biomarker for the diagnosis and prognosis of suspected cardiac sarcoidosis

Purpose To evaluate the diagnostic and prognostic significance of combined cardiac 18F-fluorodeoxyglucose (FDG) PET/MRI with T1/T2 mapping in the evaluation of suspected cardiac sarcoidosis. Methods Patients with suspected cardiac sarcoidosis were prospectively enrolled for cardiac 18F-FDG PET/MRI, including late gadolinium enhancement (LGE) and T1/T2 mapping with calculation of extracellular volume (ECV). The final diagnosis of cardiac sarcoidosis was established using modified JMHW guidelines. Major adverse cardiac events (MACE) were assessed as a composite of cardiovascular death, ventricular tachyarrhythmia, bradyarrhythmia, cardiac transplantation or heart failure. Statistical analysis included Cox proportional hazard models. Results Forty-two patients (53 ± 13 years, 67% male) were evaluated, 13 (31%) with a final diagnosis of cardiac sarcoidosis. Among patients with cardiac sarcoidosis, 100% of patients had at least one abnormality on PET/MRI: FDG uptake in 69%, LGE in 100%, elevated T1 and ECV in 100%, and elevated T2 in 46%. FDG uptake co-localized with LGE in 69% of patients with cardiac sarcoidosis compared to 24% of those without, p = 0.014. Diagnostic specificity for cardiac sarcoidosis was highest for FDG uptake (69%), elevated T2 (79%), and FDG uptake co-localizing with LGE (76%). Diagnostic sensitivity was highest for LGE, elevated T1 and ECV (100%). After median follow-up duration of 634 days, 13 patients experienced MACE. All patients who experienced MACE had LGE, elevated T1 and elevated ECV. FDG uptake (HR 14.7, p = 0.002), elevated T2 (HR 9.0, p = 0.002) and native T1 (HR 1.1 per 10 ms increase, p = 0.044) were significant predictors of MACE even after adjusting for left ventricular ejection fraction and immune suppression treatment. The presence of FDG uptake co-localizing with LGE had the highest diagnostic performance overall (AUC 0.73) and was the best predictor of MACE based on model goodness of fit (HR 14.9, p = 0.001). Conclusions Combined cardiac FDG-PET/MRI with T1/T2 mapping provides complementary diagnostic information and predicts MACE in patients with suspected cardiac sarcoidosis.

Cardiac and non-cardiac characteristics of Jervell-Lange-Nielsen syndrome

We aimed to analyze the management of children with Jervell-Lange-Nielsen syndrome based on their clinical and genetic characteristics and to assess the effectiveness of their therapy.Methods. We analyzed medical data from 12 Jervell and Lange-Nielsen syndrome patients. Mean follow-up was 8.3±5.1 years. Comprehensive cardiological examination include the standard 12-lead electrocardiography (ECG), echocardiography, stress-test, 24-hour Holter recordings, blood tests, thyroid ultrasound, and assessment of thyroid hormone levels, and if necessary, consultation with a neurologist.Results. At the first visit, the mean age was 3.0±2 years old, girls prevailed (67%). All patients are alive now. The mean QTc was 578.9±57.3 ms. Cardiac events had 10 patients (83%), mean age at the first event was 1.9±1.6 years. In 67% of children, syncope was initially regarded as epileptic. All patients received beta-blockers, which were prescribed at mean age 3.0±2.3 years (from 1 month to 7 years). In 8 patients cardiac events recurred despite regular and adequate beta-blocker therapy, all of them were implanted with implanted cardioverter-defibrillator. It was found that patients with the first syncope under the age of 1.5 and delayed initiation of therapy (at the mean age 4.3±1.7 years) had multiple recurrences of syncope despite therapy. Non-cardiac symptoms include sensorineural hearing loss in 100% of cases and hypochromic anemia in 75% of cases.Conclusion. In Jervell-Lange-Nielsen patients who are characterized by resistant ventricular tachyarrhythmia aggressive antiarrhythmic therapy at a very early age is essential for increasing the risk of life-threatening cardiac events. Consequently, diagnosis of the disease in the first days of life is extremely relevant. ECG screening is crucial in solving the problem of early diagnosis of the disease. Extracardiac pathology in patients with Jervell-Lange-Nielsen syndrome necessitates the interaction of doctors of different specialties together when managing a patient.

Evaluation of ventricular tachyarrhythmias in patients with myocardial infarction after streptokinase therapy

Objectives: The occurrence of arrhythmias after myocardial infarction is associated with an increased risk of mortality. The purpose of this study was to investigate tachyarrhythmias after streptokinase therapy in myocardial infarction patients. Methods: This study was a case-control study. Among 262 patients with myocardial infarction who received streptokinase, 168 patients with ventricular tachyarrhythmia, ventricular fibrillation, or both (case group), and 94 patients without arrhythmia (control group) were selected. Their clinical information were collected by questionnaire. Data were analyzed using SPSS 20 software through chi-square test and Wilcoxon rank-sum. Results: There was no relationship between demographic variables or electrocardiogram changes and the type of arrhythmia in 168 participants in the group 1 (p > 0.05). However, there was a significant relationship between age (p = 0.04), sex (p = 0.049), diabetes (p = 0.039), hypertension (p = 0.037), history of beta-blocker use (p = 0.028), history of aspirin use (p = 0.023), number of the leads involved (p = 0.023) and occurrence of arrhythmia among the participants in the group 2. Conclusions: According to the findings of this study, patients with myocardial infarction who need to receive thrombolysis and who have any of the following conditions should be monitored by the health care staff to prevent development of ventricular tachyarrhythmias: old age, male gender, history of diabetes mellitus, hypertension or more lead involvement in their electrocardiogram.

Prediction of biological age and all-cause mortality by 12-lead electrocardiogram in patients without structural heart disease

Background There is a well-established relationship between 12-lead electrocardiogram (ECG) and age and mortality. Furthermore, there is increasing evidence that ECG can be used to predict biological age. However, the utility of biological age from ECG for predicting mortality remains unclear. Methods This was a single-center cohort study from a cardiology specialized hospital. A total of 19,170 patients registered in this study from February 2010 to March 2018. ECG was analyzed in a final 12,837 patients after excluding those with structural heart disease or with pacing beats, atrial or ventricular tachyarrhythmia, or an indeterminate axis (R axis > 180°) on index ECG. The models for biological age were developed by principal component analysis (BA) and the Klemera and Doubal’s method (not adjusted for age [BAE] and adjusted for age [BAEC]) using 438 ECG parameters. The predictive capability for all-cause death and cardiovascular death by chronological age (CA) and biological age using the three algorithms were evaluated by receiver operating characteristic analysis. Results During the mean follow-up period of 320.4 days, there were 55 all-cause deaths and 23 cardiovascular deaths. The predictive capabilities for all-cause death by BA, BAE, and BAEC using area under the curves were 0.731, 0.657, and 0.685, respectively, which were comparable to 0.725 for CA (p = 0.760, 0.141, and 0.308, respectively). The predictive capabilities for cardiovascular death by BA, BAE, and BAEC were 0.682, 0.685, and 0.692, respectively, which were also comparable to 0.674 for CA (p = 0.775, 0.839, and 0.706, respectively). In patients aged 60–74 years old, the area under the curves for all-cause death by BA, BAE, and BAEC were 0.619, 0.702, and 0.697, respectively, which tended to be or were significantly higher than 0.482 for CA (p = 0.064, 0.006, and 0.005, respectively). Conclusion Biological age by 12-lead ECG showed a similar predictive capability for mortality compared to CA among total patients, but partially showed a significant increase in predictive capability among patients aged 60–74 years old.

Beyond ejection fraction: Novel clinical approaches towards sudden cardiac death risk stratification in patients with dilated cardiomyopathy

: Implantable cardioverter-defibrillator (ICD) therapy is indicated for patients at risk for sudden cardiac death due to ventricular tachyarrhythmia. The most commonly used risk stratification algorithms use left ventricular ejection fraction (LVEF) to determine which patients qualify for ICD therapy, even though LVEF is a better marker of total mortality than ventricular tachyarrhythmias mortality. This review evaluates imaging tools and novel biomarkers proposed for better risk stratifying arrhythmic substrate, thereby identifying optimal ICD therapy candidates.