Automatic detection of end QRS notching or slurring

The purpose of this study was to define criteria suited to automated detection of end QRS notching and slurring and to evaluate their accuracy. One hundred resting 12 lead ECGs from young adult men, split randomly into equal training and test sets, were examined independently by two reviewers for the presence of such notching or slurring. Consensus was reached by re-examination. Logic was added to the Glasgow resting ECG program to automate the detection of the phenomenon. After training, the automated detection had a sensitivity (SE) of 92.1% and a specificity (SP) of 96.6%. For the test set, SE was 90.5%, SP 96.5%. Two populations of healthy subjects – one Caucasian, one Nigerian – were analysed using the automated method. The prevalence of notching/slurring with peak/onset amplitude respectively ≥ 0.1 mV in two contiguous inferolateral leads was 23% and 29% respectively. In conclusion, the detection of end QRS notching or slurring can be automated with a high degree of accuracy

Spatial QRS-T angle and cognitive decline in older subjects

Background:An abnormally wide spatial QRS-T angle on an ECG is a marker of heterogeneity in electrical activity of cardiac ventricles and is linked with cardiovascular events. Growing evidence suggests that cardiac dysfunction might signal future cognitive decline. Objective: In this study, we investigated whether spatial QRS-T angle associates with future cognitive decline in older subjects at high cardiovascular risk. Methods:We included 4,172 men and women (mean age 75.2±3.3 years) free of cardiac arrhythmias from the PROSPER cohort. Spatial QRS-T angle was calculated from baseline 12-lead ECGs using a matrix transformation method. Cognitive function was assessed using 4 neuropsychological tests including Stroop test, letter-digit coding test, immediate and delayed picture word learning tests. Cognitive function was assessed at baseline and repeatedly during a mean follow-up time of 3.2 years. Using linear mixed models, we calculated the annual changes of cognitive scores in sex-specific thirds of spatial QRS-T angle. Results:Participants with wider spatial QRS-T angle had a steeper decline in letter-digit coding test (β= –0.0106, p = 0.004), immediate picture-word learning test (β= –0.0049, p = 0.001), and delayed picture-word learning test (β= –0.0055, p = 0.013). All associations were independent of arrhythmias, cardiovascular risk factors, comorbidities, medication use, cardiovascular events, and other ECG abnormalities including QRS duration, QTc interval, T wave abnormalities, and left ventricular hypertrophy. Conclusion:Abnormal cardiac electrical activity characterized by wide spatial QRS-T angle associates with accelerated cognitive decline independent of conventional cardiovascular factors. These findings suggest a link between a non-traditional ECG measure of pre-clinical cardiac pathology and future cognitive decline

Sudden Cardiac Death in Dialysis: Arrhythmic Mechanisms and the Value of Non-invasive Electrophysiology

Sudden Cardiac Death (SCD) is the leading cause of cardiovascular death in dialysis patients. This review discusses potential underlying arrhythmic mechanisms of SCD in the dialysis population. It examines recent evidence from studies using implantable loop recorders and from electrophysiological studies in experimental animal models of chronic kidney disease. The review summarizes advances in the field of non-invasive electrophysiology for risk prediction in dialysis patients focusing on the predictive value of the QRS-T angle and of the assessments of autonomic imbalance by means of heart rate variability analysis. Future research directions in non-invasive electrophysiology are identified to advance the understanding of the arrhythmic mechanisms. A suggestion is made of incorporation of non-invasive electrophysiology procedures into clinical practice.Key Concepts:– Large prospective studies in dialysis patients with continuous ECG monitoring are required to clarify the underlying arrhythmic mechanisms of SCD in dialysis patients.– Obstructive sleep apnoea may be associated with brady-arrhythmias in dialysis patients. Studies are needed to elucidate the burden and impact of sleeping disorders on arrhythmic complications in dialysis patients.– The QRS-T angle has the potential to be used as a descriptor of uremic cardiomyopathy.– The QRS-T angle can be calculated from routine collected surface ECGs. Multicenter collaboration is required to establish best methodological approach and normal values.– Heart Rate Variability provides indirect assessment of cardiac modulation that may be relevant for cardiac risk prediction in dialysis patients. Short-term recordings with autonomic provocations are likely to overcome the limitations of out of hospital 24-h recordings and should be prospectively assessed

Myocardial tissue tagging with cardiovascular magnetic resonance

Cardiovascular magnetic resonance (CMR) is currently the gold standard for assessing both global and regional myocardial function. New tools for quantifying regional function have been recently developed to characterize early myocardial dysfunction in order to improve the identification and management of individuals at risk for heart failure. Of particular interest is CMR myocardial tagging, a non-invasive technique for assessing regional function that provides a detailed and comprehensive examination of intra-myocardial motion and deformation. Given the current advances in gradient technology, image reconstruction techniques, and data analysis algorithms, CMR myocardial tagging has become the reference modality for evaluating multidimensional strain evolution in the human heart. This review presents an in depth discussion on the current clinical applications of CMR myocardial tagging and the increasingly important role of this technique for assessing subclinical myocardial dysfunction in the setting of a wide variety of myocardial disease processes

Role of cardiac biomarkers in cognitive impairment and functional decline

This thesis aimed to investigate the link between cardiac biomarkers, cognitive impairment and functional decline in older subjects with a focus on non-invasive markers that are routinely available in clinical practice. The findings of this thesis show that markers of subclinical cardiac dysfunction are linked with accelerated cognitive decline and a higher risk of functional decline. In addition, we provide preliminary findings on the potential role of centrally acting natriuretic peptides in relation to cognitive impairment. Collectively, these findings highlight a complex pathophysiological heart-brain coupling that might extend beyond vascular and hemodynamic factors. Future studies are needed to investigate whether such link warrants mutual screening of the heart and the brain functions, and whether such practice could improve early diagnosis of dementia. Financial support for printing of this thesis was provided by Leiden University Medical Centre, Alzheimer Nederland and Dutch Heart Foundation.LUMC / Geneeskund

Morphological and electrophysiological differences between the Caucasian and South Asian Atrium

Introduction: South Asians (SAs) have a low prevalence of atrial fibrillation (AF) compared with Caucasians despite a higher prevalence of hypertension, diabetes mellitus and coronary artery disease. The aim of this thesis was to determine whether this was related to an under-detection of the arrhythmia and if not, whether differences in left atrial (LA) size, electrophysiological properties or autonomic function in SAs might help to explain this disparity. Methods: Retrospective and prospective cohort studies were performed on SA and Caucasian participants using data from implantable cardiac devices, cardiac magnetic resonance imaging scans, invasive electrophysiology studies and a range of non-invasive cardiac investigations. Results: The cumulative incidence of subclinical AF was significantly lower in SAs compared with Caucasians (log rank p=0.002) with an annual event rate of 6.9% versus 13.9%. In comparison with Caucasians, SAs were of a smaller height with lower lean body mass and higher waist:hip ratio; had lower minimum (27.7±11.1 ml vs 34.9±12.3 ml, p=0.002) and maximum LA volumes (64.7±21.1 ml vs 80.9±22.5 ml, p<0.001) even after matching for body surface area; lower P wave dispersion (males 28.0(12)ms vs 25.0(12)ms, p=0.039; females 24.0(12)ms vs 22.0(12)ms, p=0.004) and P wave terminal force in lead V1 (males 0.031(0.04)mm•s vs 0.021(0.03) mm•s, p=0.023; females 0.036(0.04)mm•s vs 0.034(0.04)mm•s, p=0.030), electrophysiological variations related to the inhomogeneity of LA conduction and LA size respectively; increased heart rate (82.5(18)bpm vs 78.0(18)bpm, p=0.024), lower atrioventricular (280(50)ms vs 300(60)ms, p=0.001) and ventriculoatrial (300(60)ms vs 320(93)ms, p=0.013) effective refractory periods and lower heart rate variability (in SA males), suggestive of sympathetic predominance. Conclusions: SAs have reduced LA size and evidence of increased sympathetic tone and reduced inhomogeneity in LA conduction. The morphological, electrophysiological and autonomic differences identified in SAs may help to explain why this ethnic group has a lower prevalence of AF

Measurement and Comparison of Selected Physical Fitness Components and Anthropometrical Characteristics of American, Middle Eastern, and East and Southeast Asian Male Students at Oklahoma State University

Higher Educatio

The Application of Computer Techniques to ECG Interpretation

This book presents some of the latest available information on automated ECG analysis written by many of the leading researchers in the field. It contains a historical introduction, an outline of the latest international standards for signal processing and communications and then an exciting variety of studies on electrophysiological modelling, ECG Imaging, artificial intelligence applied to resting and ambulatory ECGs, body surface mapping, big data in ECG based prediction, enhanced reliability of patient monitoring, and atrial abnormalities on the ECG. It provides an extremely valuable contribution to the field