Coronary Artery Occlusion Detection Using 3-Lead ECG System Suitable for Credit Card-Size Personal Device Integration

Background Early coronary occlusion detection by portable personal device with limited number of electrocardiographic (ECG) leads might shorten symptom-to-balloon time in acute coronary syndromes. Objectives The purpose of this study was to compare the accuracy of coronary occlusion detection using vectorcardgiographic analysis of a near-orthogonal 3-lead ECG configuration suitable for credit card-size personal device integration with automated and human 12 lead ECG interpretation. Methods The 12-lead ECGs with 3 additional leads (“abc”) using 2 arm and 2 left parasternal electrodes were recorded in 66 patients undergoing percutaneous coronary intervention prior to (“baseline”, n = 66), immediately before (“preinflation”, n = 66), and after 90-second balloon coronary occlusion (“inflation”, n = 120). Performance of computer-measured ST-segment shift on vectorcardgiographic loops constructed from “abc” and 12 leads, standard 12-lead ECG, and consensus human interpretation in coronary occlusion detection were compared in “comparative” and “spot” modes (with/without reference to “baseline”) using areas under ROC curves (AUC), reliability, and sensitivity/specificity analysis. Results Comparative “abc”-derived ST-segment shift was similar to two 12-lead methods (vector/traditional) in detecting balloon coronary occlusion (AUC = 0.95, 0.96, and 0.97, respectively, P = NS). Spot “abc” and 12-lead measurements (AUC = 0.72, 0.77, 0.68, respectively, P = NS) demonstrated poorer performance (P < 0.01 vs comparative measurements). Reliability analysis demonstrated comparative automated measurements in “good” agreement with reference (preinflation/inflation), while comparative human interpretation was in “moderate” range. Spot automated and human reading showed “poor” agreement. Conclusions Vectorcardiographic ST-segment analysis using baseline comparison of 3-lead ECG system suitable for credit card-size personal device integration is similar to established 12-lead ECG methods in detecting balloon coronary occlusion

Photoplethysmogram as a source of biomarkers for AI-based diagnosis of heart failure

We present our progress on the “Multi-SENSor SysteM and ARTificial intelligence in service of heart failure diagnosis (SensSmart)” project, which was introduced at the last year’s edition of the Workshop [1]. The goal of the SensSmart project is to enable early diagnosis of heart failure, through the development of: 1) a multi-sensor polycardiograph apparatus (PCG) that produces simultaneous acquisition of the subject’s electrocardiogram (ECG), photoplethysmogram (PPG), heart sounds, and heart movements, and 2) AI-assisted analysis of the acquired signals. This presentation is going to focus on the acquisition and processing of PPG signals. PPG is obtained by using a pulse oximeter which illuminates the skin and measures the changes in light absorption, thereby enabling the detection of blood volume changes in the vessels. Our PCG apparatus measures the blood flow through the brachial, radial, and carotid arteries. During each heartbeat, the generated waveform typically exhibits several characteristic points [2]. The magnitudes and time distances between these points are useful indicators of many cardiac conditions, including heart failure [3]. However, the inter-patient variability of the PPG waveform makes it challenging to derive simple rule-based diagnostic procedures. This has led many researchers to turn to statistical or machine learning methods for processing of PPG signals [4]. In this presentation, we give an overview of AI-based signal processing methods for PPG, and present some preliminary results and challenges in extracting features from real-world signals obtained using our PCG.XVI Photonics Workshop : Book of abstracts; March 12-15, 2023; Kopaonik, Serbi

Predicting defibrillation success in out-of-hospital cardiac arrested patients: Moving beyond feature design

Optimizing timing of defibrillation by evaluating the likelihood of a successful outcome could significantly enhance resuscitation. Previous studies employed conventional machine learning approaches and hand-crafted features to address this issue, but none have achieved superior performance to be widely accepted. This study proposes a novel approach in which predictive features are automatically learned.MethodsA raw 4s VF episode immediately prior to first defibrillation shock was feed to a 3-stage CNN feature extractor. Each stage was composed of 4 components: convolution, rectified linear unit activation, dropout and max-pooling. At the end of feature extractor, the feature map was flattened and connected to a fully connected multi-layer perceptron for classification. For model evaluation, a 10 fold cross-validation was employed. To balance classes, SMOTE oversampling method has been applied to minority class.ResultsThe obtained results show that the proposed model is highly accurate in predicting defibrillation outcome (Acc = 93.6 %). Since recommendations on classifiers suggest at least 50 % specificity and 95 % sensitivity as safe and useful predictors for defibrillation decision, the reported sensitivity of 98.8 % and specificity of 88.2 %, with the analysis speed of 3 ms/input signal, indicate that the proposed model possesses a good prospective to be implemented in automated external defibrillators.ConclusionsThe learned features demonstrate superiority over hand-crafted ones when performed on the same dataset. This approach benefits from being fully automatic by fusing feature extraction, selection and classification into a single learning model. It provides a superior strategy that can be used as a tool to guide treatment of OHCA patients in bringing optimal decision of precedence treatment. Furthermore, for encouraging replicability, the dataset has been made publicly available to the research community

Prognostic value of early post-infarction angina in elderly patients

Although numerous studies have shown that early post-infarction angina was a predictor of poor prognosis in patients with acute myocardial infarction, not a single study has considered this issue in the elderly. The goal of this study, based on a five-year follow-up of elderly patients with acute myocardial infarction, was to determine whether early post-infarction angina in the elderly had any influence on mortality and the incidence of additional coronary events. The study population consisted of 51 patients, aged 60 years or more, with acute myocardial infarction. Early post-infarction angina occurred in 31 subjects (Group 1), while it did not in 20 subjects (Group 2). Patients were monitored for five years and the incidences of death and new coronary events were recorded. A survival analysis was carried out using the Kaplan-Meier method. The survival analysis showed no difference between the observed groups concerning the following probabilities: death (p=0.9459), cardiac death (p=0.8253), myocardial reinfarction (p=0.7405), new coronary events (p=0.1708), unstable angina (p=0.1788), myocardial revascularisation (p=0.0691), and heart failure (p=0.7047j. In contrast to the younger population, where numerous studies have confirmed the link between early post-infarction angina and poor long-term prognosis, such findings could not be replicated in this study of the elderly population

The degree of coronary atherosclerosis as a marker of insulin resistance in non-diabetics

Introduction. The metabolic syndrome and its influence on coronary artery disease development and progression remains in focus of international research debates, while insulin resistance, which represents its core, is the key component of hypertension, dyslipidaemias, glucose intolerance and obesity. Objective. The aim of this study was to establish relationship between basal glucose and insulin levels, insulin sensitivity and lipid panel and the degree of coronary atherosclerosis in nondiabetic patients. Methods. The coronary angiograms were evaluated for the presence of significant stenosis, insulin sensitivity was assessed using the intravenous glucose tolerance test with a minimal model according to Bergman, while baseline glucose (G0), insulin (I0) and lipid panel measurements (TC, HDL, LDL, TG) were taken after a 12-hour fasting. Results. The protocol encompassed 40 patients (19 men and 21 women) treated at the Institute for Cardiovascular Diseases of the Clinical Centre of Serbia, Belgrade. All were non-diabetics who were divided into 3 groups based on their angios: Group A (6 patients, 15%, with no significant stenosis), Group B (18 patients, 45%, with a single-vessel disease) and Group C (16 patients, 40%, with multi-vessel disease). Presence of lower insulin sensitivity, higher I0 and TC in the group of patients with a more severe degree of coronary atherosclerosis (insulin sensitivity: F=4.279, p=0.023, A vs. C p=0.012, B vs. C p=0.038; I0: F=3.461 p=0.042, A vs. B p=0.045, A vs. C p=0.013; TC: F=2.572, p=0.09), while no significant difference was found for G0, LDL, HDL and TG. Conclusion. Baseline insulinaemia, more precisely, fasting hyperinsulinaemia could be a good predictor of significant coronary atherosclerosis in non-diabetic patients, which enables a more elegant cardiometabolic risk assessment in the setting of everyday clinical practice

Percutaneous implantation of self-expandable aortic valve in high risk patients with severe aortic stenosis: The first experiences in Serbia

Background/Aim. Aortic stenosis (AS) is the most common valvular heart disease in elderly people, with rather poor prognosis in symptomatic patients. Surgical valve replacement is the therapy of choice, but a significant number of patients cannot undergo surgical procedure. We presented initial experience of transcatheter aortic valve implantation (TAVI) performed in Catheterization Laboratory of the Clinic for Cardiology, Clinical Center of Serbia. Methods. The procedures were performed in 5 patients (mean age 76 ± 6 years, 2 males, 3 female) with severe and symptomatic AS with contraindication to surgery or high surgical risk. The decision to perform TAVI was made by the heart team. Pre-procedure screening included detailed clinical and echocardiographic evaluation, coronary angiography and computed tomography scan. In all the patients we implanted a self-expandable aortic valve (Core Valve, Medtronic, USA). Six months follow-up was available for all the patients. Results. All interventions were successfully performed without significant periprocedural complications. Immediate hemodynamic improvement was obtained in all the patients (peak gradient 94.2 ± 27.6 to 17.6 ± 5.2 mmHg, p < 0.001, mean pressure gradient 52.8 ± 14.5 to 8.0 ± 2.1 mmHg, p < 0.001). None of the patients developed heart block, stroke, vascular complication or significant aortic regurgitation. After 6 months, the survival was 100% with New York Heart Association (NYHA) functional improvement in all the patients. Conclusion. This successful initial experience provides a solid basis to treat larger number of patients with symptomatic AS and high surgical risk who are left untreated. [Projekat Ministarstva nauke Republike Srbije, br. ON 175 020

Left atrial appendage closure with Watchman device in prevention of thromboembolic complications in patients with atrial fibrillation: First experience in Serbia

Introduction. Atrial fibrillation (AF) is the major cause ofstroke, particularly in older patients over 75 years of age. EuropeanSociety of Cardiology guidelines recommend chronic anticoagulationtherapy in patients with atrial fibrillation ifCHA2DS2-VASc score is ≥ 1 (CHA2DS2-VASc score for estimatingthe risk of stroke in patients with non-rheumatic AFconsisting of the first letters of patients condition: C – congestiveheart failure; H – hypertension; A2 – age ≥ 75 years; D –diabetes mellitus; S2 – prior stroke, transitory ischaemic attack(TIA) or thrombolism; V – vascular disease; A – age 65–74years; Sc – sex category). However, a significant number of patientshave a high bleeding risk, or are contraindicated forchronic oral anticoagulation, and present a group of patients inwhom alternative treatment options for thromboembolic preventionare required. Transcatheter percutaneous left atrial appendageclosure (LAAC) devices have been recommended inpatients with contraindications for chronic anticoagulanttherapy. Case report. We present our first three patients withnonvalvular AF and contraindications for chronic anticoagulanttherapy who were successfully treated with implantation ofLAAC Watchman device in Catheterization Laboratory of theClinic for Cardiology, Clinical Center of Serbia in BelgradeConclusion. Our initial results with Watchman LAAC deviceare promising and encouraging, providing real alternative in patientswith non-valvular AF and contraindication for chronicanticoagulant therapy and high bleeding risk