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Annals of Noninvasive Electrocardiology... Jan 2014In acute coronary syndromes, the electrocardiogram (ECG) provides important information about the presence, extent, and severity of myocardial ischemia. At times, the... (Review)
Review
In acute coronary syndromes, the electrocardiogram (ECG) provides important information about the presence, extent, and severity of myocardial ischemia. At times, the changes are typical and clear. In other instances, changes are subtle and might be recognized only when ECG recording is repeated after changes in the severity of symptoms. ECG interpretation is an essential part of the initial evaluation of patients with symptoms suspected to be related to myocardial ischemia, along with focused history and physical examination. Patients with ST-segment elevation on their electrocardiogram and symptoms compatible with acute myocardial ischemia/infarction should be referred for emergent reperfusion therapy. However, it should be emphasized that a large number of patients may have ST-elevation without having acute ST-elevation acute coronary syndrome, while acute ongoing transmural ischemia due to an abrupt occlusion of an epicardial coronary artery may occur in patients with ST-elevation less than the thresholds defined by the guidelines. Up-sloping ST-segment depression with positive T waves is increasingly recognized as a sign of regional subendocardial ischemia associated with severe obstruction of the left anterior descending coronary artery. Widespread ST-segment depression, often associated with inverted T waves and ST-segment elevation in lead aVR during episodes of chest pain, may represent diffuse subendocardial ischemia caused by severe coronary artery disease. In case of hemodynamic compromise, urgent coronary angiography has been increasingly recommended for these patients.
Topics: Acute Coronary Syndrome; Electrocardiography; Humans
PubMed: 24382164
DOI: 10.1111/anec.12130 -
Swiss Medical Weekly 2016The 12-lead electrocardiogram (ECG) is the most frequently used technology in clinical cardiology. It is critical for evidence-based management of patients with most... (Review)
Review
The 12-lead electrocardiogram (ECG) is the most frequently used technology in clinical cardiology. It is critical for evidence-based management of patients with most cardiovascular conditions, including patients with acute myocardial infarction, suspected chronic cardiac ischaemia, cardiac arrhythmias, heart failure and implantable cardiac devices. In contrast to many other techniques in cardiology, the ECG is simple, small, mobile, universally available and cheap, and therefore particularly attractive. Standard ECG interpretation mainly relies on direct visual assessment. The progress in biomedical computing and signal processing, and the available computational power offer fascinating new options for ECG analysis relevant to all fields of cardiology. Several digital ECG markers and advanced ECG technologies have shown promise in preliminary studies. This article reviews promising novel surface ECG technologies in three different fields. (1) For the detection of myocardial ischaemia and infarction, QRS morphology feature analysis, the analysis of high frequency QRS components (HF-QRS) and methods using vectorcardiography as well as ECG imaging are discussed. (2) For the identification and management of patients with cardiac arrhythmias, methods of advanced P-wave analysis are discussed and the concept of ECG imaging for noninvasive localisation of cardiac arrhythmias is presented. (3) For risk stratification of sudden cardiac death and the selection of patients for medical device therapy, several novel markers including an automated QRS-score for scar quantification, the QRS-T angle or the T-wave peak-to-end-interval are discussed. Despite the existing preliminary data, none of the advanced ECG markers and technologies has yet accomplished the transition into clinical practice. Further refinement of these technologies and broader validation in large unselected patient cohorts are the critical next step needed to facilitate translation of advanced ECG technologies into clinical cardiology.
Topics: Arrhythmias, Cardiac; Electrocardiography; Heart Failure; Humans; Myocardial Ischemia; Signal Processing, Computer-Assisted; Vectorcardiography
PubMed: 27124801
DOI: 10.4414/smw.2016.14303 -
Annals of Noninvasive Electrocardiology... May 2020Acute myocarditis represents a challenging diagnosis as there is no pathognomonic clinical presentation. In patients with myocarditis, electrocardiogram (ECG) can... (Review)
Review
BACKGROUND
Acute myocarditis represents a challenging diagnosis as there is no pathognomonic clinical presentation. In patients with myocarditis, electrocardiogram (ECG) can display a variety of non-specific abnormalities. Nevertheless, ECG is widely used as an initial screening tool for myocarditis.
METHODS
We researched all possible ECG alterations during acute myocarditis evaluating prevalence, physiopathology, correlation with clinical presentation patterns, role in differential diagnosis, and prognostic yield.
RESULTS
The most common ECG abnormality in myocarditis is sinus tachycardia associated with nonspecific ST/T-wave changes. The presence of PR segment depression both in precordial and limb leads, a PR segment depression in leads with ST segment elevation, a PR segment elevation in aVR lead or a ST elevation with pericarditis pattern favor generally diagnosis of perimyocarditis rather than myocardial infarction. In patients with acute myocarditis, features associated with a poorer prognosis are: pathological Q wave, wide QRS complex, QRS/T angle ≥ 100°, prolonged QT interval, high-degree atrioventricular block and malignant ventricular tachyarrhythmia. On the contrary, ST elevation with a typical early repolarization pattern is associated with a better prognosis.
CONCLUSIONS
ECG alterations in acute myocarditis could be very useful in clinical practice for a patient-tailored approach in order to decide appropriate therapy, length of hospitalization, and frequency of followup.
Topics: Acute Disease; Electrocardiography; Humans; Myocarditis; Prognosis
PubMed: 31778001
DOI: 10.1111/anec.12726 -
JACC. Clinical Electrophysiology Aug 2018This study evaluated a new algorithm relying on maximal pre-excitation.
OBJECTIVES
This study evaluated a new algorithm relying on maximal pre-excitation.
BACKGROUND
Prior knowledge of accessory pathway (AP) location facilitates an individual ablation strategy. Delta-wave analysis on a 12-lead electrocardiogram is recognized as crucial for predicting ablation site, but can be ambiguous at basal state.
METHODS
An algorithm based on maximal pre-excitation, as induced by atrial pacing during an electrophysiological study, was initially developed in 132 patients with a single manifest AP. The maximally pre-excited QRS features included the global polarity in lead V (step 1), inferior leads (step 2), and leads V or I (step 3), as well as the morphology in lead II (step 4). Three investigators prospectively tested the new algorithm in 207 consecutive patients by comparing its efficacy to a control algorithm relying on basal pre-excitation.
RESULTS
The accuracy, defined as the percent of patients with an exact prediction of AP location, was significantly greater with the new algorithm (90% vs. 63%; p < 0.001). The reproducibility, defined as the level of agreement between investigators in determining AP location, was excellent (κ > 0.75; p < 0.05) with the new algorithm and fair (0.40 < κ < 0.75; p < 0.05) with the control algorithm.
CONCLUSIONS
An algorithm based on maximal pre-excitation allows accurate and reproducible localization of manifest APs. When ablation is indicated, the analysis of maximal pre-excitation is a sensible approach for giving a head start in endocardial mapping.
Topics: Accessory Atrioventricular Bundle; Adult; Algorithms; Catheter Ablation; Cohort Studies; Electrocardiography; Humans; Signal Processing, Computer-Assisted
PubMed: 30139487
DOI: 10.1016/j.jacep.2018.03.018 -
BMC Medical Informatics and Decision... Nov 2022The standard configuration's set of twelve electrocardiogram (ECG) leads is optimal for the medical diagnosis of diverse cardiac conditions. However, it requires ten... (Review)
Review
BACKGROUND
The standard configuration's set of twelve electrocardiogram (ECG) leads is optimal for the medical diagnosis of diverse cardiac conditions. However, it requires ten electrodes on the patient's limbs and chest, which is uncomfortable and cumbersome. Interlead conversion methods can reconstruct missing leads and enable more comfortable acquisitions, including in wearable devices, while still allowing for adequate diagnoses. Currently, methodologies for interlead ECG conversion either require multiple reference (input) leads and/or require input signals to be temporally aligned considering the ECG landmarks.
METHODS
Unlike the methods in the literature, this paper studies the possibility of converting ECG signals into all twelve standard configuration leads using signal segments from only one reference lead, without temporal alignment (blindly-segmented). The proposed methodology is based on a deep learning encoder-decoder U-Net architecture, which is compared with adaptations based on convolutional autoencoders and label refinement networks. Moreover, the method is explored for conversion with one single shared encoder or multiple individual encoders for each lead.
RESULTS
Despite the more challenging settings, the proposed methodology was able to attain state-of-the-art level performance in multiple target leads, and both lead I and lead II seem especially suitable to convert certain sets of leads. In cross-database tests, the methodology offered promising results despite acquisition setup differences. Furthermore, results show that the presence of medical conditions does not have a considerable effect on the method's performance.
CONCLUSIONS
This study shows the feasibility of converting ECG signals using single-lead blindly-segmented inputs. Although the results are promising, further efforts should be devoted towards the improvement of the methodologies, especially the robustness to diverse acquisition setups, in order to be applicable to cardiac health monitoring in wearable devices and less obtrusive clinical scenarios.
Topics: Humans; Electrocardiography; Wearable Electronic Devices; Electrodes; Heart Diseases; Databases, Factual
PubMed: 36447207
DOI: 10.1186/s12911-022-02063-6 -
JACC. Clinical Electrophysiology Feb 2023Multiple smart devices capable to detect atrial fibrillation (AF) are presently available. Sensitivity and specificity for the detection of AF may differ between...
BACKGROUND
Multiple smart devices capable to detect atrial fibrillation (AF) are presently available. Sensitivity and specificity for the detection of AF may differ between available smart devices, and this has not yet been adequately investigated.
OBJECTIVES
The aim was to assess the accuracy of 5 smart devices in identifying AF compared with a physician-interpreted 12-lead electrocardiogram as the reference standard in a real-world cohort of patients.
METHODS
We consecutively enrolled patients presenting to a cardiology service at a tertiary referral center in a prospective, diagnostic study.
RESULTS
We prospectively analyzed 201 patients (31% women, median age 66.7 years). AF was present in 62 (31%) patients. Sensitivity and specificity for the detection of AF were comparable between devices: 85% and 75% for the Apple Watch 6, 85% and 75% for the Samsung Galaxy Watch 3, 58% and 75% for the Withings Scanwatch, 66% and 79% for the Fitbit Sense, and 79% and 69% for the AliveCor KardiaMobile, respectively. The rate of inconclusive tracings (the algorithm was unable to determine the heart rhythm) was 18%, 17%, 24%, 21%, and 26% for the Apple Watch 6, Samsung Galaxy Watch 3, Withings Scan Watch, Fitbit Sense, and AliveCor KardiaMobile (P < 0.01 for pairwise comparison), respectively. By manual review of inconclusive tracings, the rhythm could be determined in 955 (99%) of 969 single-lead electrocardiograms. Regarding patient acceptance, the Apple Watch was ranked first (39% of participants).
CONCLUSIONS
In this clinical validation of 5 direct-to-consumer smart devices, we found differences in the amount of inconclusive tracings diminishing sensitivity and specificity of the smart devices. In a clinical setting, manual review of tracings is required in about one-fourth of cases.
Topics: Humans; Female; Aged; Male; Atrial Fibrillation; Prospective Studies; Wearable Electronic Devices; Algorithms; Electrocardiography
PubMed: 36858690
DOI: 10.1016/j.jacep.2022.09.011 -
Critical Care Nursing Clinics of North... Sep 2016Patients present to the emergency department (ED) with a wide range of complaints and ED clinicians are responsible for identifying which conditions are life... (Review)
Review
Patients present to the emergency department (ED) with a wide range of complaints and ED clinicians are responsible for identifying which conditions are life threatening. Cardiac monitoring strategies in the ED include, but are not limited to, 12-lead electrocardiography and bedside cardiac monitoring for arrhythmia and ischemia detection as well as QT-interval monitoring. ED nurses are in a unique position to incorporate cardiac monitoring into the early triage and risk stratification of patients with cardiovascular emergencies to optimize patient management and outcomes.
Topics: Arrhythmias, Cardiac; Electrocardiography; Emergency Nursing; Emergency Service, Hospital; Humans; Ischemia; Monitoring, Physiologic; Triage
PubMed: 27484661
DOI: 10.1016/j.cnc.2016.04.009 -
Journal of Electrocardiology 2021Single‑lead electrocardiograms (1 L-ECGs) are increasingly used in (pre)clinical settings for the detection and monitoring of a range of rhythm and conduction... (Review)
Review
Single‑lead electrocardiograms (1 L-ECGs) are increasingly used in (pre)clinical settings for the detection and monitoring of a range of rhythm and conduction disorders. In this short communication paper, we aim to provide an overview of the usefulness and potential pitfalls when implementing 1 L-ECGs into everyday clinical practice. Moreover, we provide recommendations for improving signal quality, as well as a systematic approach to the interpretation of 1 L-ECGs, which is somewhat different from standard 12‑lead ECGs. Clinicians can use our illustrations and checklist as guidance when recording and interpreting 1 L-ECGs.
Topics: Electrocardiography; Humans
PubMed: 33725506
DOI: 10.1016/j.jelectrocard.2021.02.011 -
Europace : European Pacing,... Oct 2015More than 100 years after it was first invented, the 12-lead electrocardiogram (ECG) continues to occupy an important place in the diagnostic armamentarium of the... (Review)
Review
More than 100 years after it was first invented, the 12-lead electrocardiogram (ECG) continues to occupy an important place in the diagnostic armamentarium of the practicing clinician. With the recognition of relatively rare but important clinical entities such as Wolff-Parkinson-White and the long QT syndrome, this clinical tool was firmly established as a test for assessing risk of sudden cardiac death (SCD). However, over the past two decades the role of the ECG in risk prediction for common forms of SCD, for example in patients with coronary artery disease, has been the focus of considerable investigation. Especially in light of the limitations of current risk stratification approaches, there is a renewed focus on this broadly available and relatively inexpensive test. Various abnormalities of depolarization and repolarization on the ECG have been linked to SCD risk; however, more focused work is needed before they can be deployed in the clinical arena. The present review summarizes the current knowledge on various ECG risk markers for prediction of SCD and discusses some future directions in this field.
Topics: Arrhythmias, Cardiac; Coronary Artery Disease; Death, Sudden, Cardiac; Diagnosis, Computer-Assisted; Electrocardiography; Forecasting; Humans; Reproducibility of Results; Sensitivity and Specificity
PubMed: 26842119
DOI: 10.1093/europace/euv121 -
Sensors (Basel, Switzerland) Feb 2022The Apple Watch is capable of recording single-lead electrocardiograms (ECGs). To incorporate such devices in routine medical care, the reliability of such devices to...
The Apple Watch is capable of recording single-lead electrocardiograms (ECGs). To incorporate such devices in routine medical care, the reliability of such devices to obtain precordial leads needs to be validated. The purpose of this study was to assess the feasibility and reliability of a smartwatch (SW) to obtain precordial leads compared to standard ECGs. We included 100 participants (62 male, aged 62.8 ± 13.1 years) with sinus rhythm and recorded a standard 12-lead ECG and the precordial leads with the Apple Watch. The ECGs were quantitively compared. A total of 98 patients were able to record precordial leads without assistance. A strong correlation was observed between the amplitude of the standard and SW-ECGs' waves, in terms of P waves, QRS-complexes, and T waves (all -values < 0.01). A significant correlation was observed between the two methods regarding the duration of the ECG waves (all -values < 0.01). Assessment of polarity showed a significant and a strong concordance between the ECGs' waves in all six leads (91-100%, all -values < 0.001). In conclusion, 98% of patients were able to record precordial leads using a SW without assistance. The SW is feasible and reliable for obtaining valid precordial-lead ECG recordings as a validated alternative to a standard ECG.
Topics: Aged; Arrhythmias, Cardiac; Electrocardiography; Feasibility Studies; Humans; Male; Middle Aged; Reproducibility of Results
PubMed: 35161960
DOI: 10.3390/s22031217