12-lead ECG Recordings Research Articles

A novel 12-lead standard ECG derived scoring system for risk stratification in the emergency department

Abstract Background/Aims The ECG represents a routinely used diagnostic tool in the assessment of patients in the emergency department. Beside specific alterations within the ECG indicative of underlying pathologies, such as ST-elevation in myocardial infarction, several other parameters have been developed over the past decades that proofed themselves as strong and independent predictors of worsened outcome independent of a specific underlying pathology. These include basic metrics such as heart rate and QRS duration, but also more advanced biomarkers such as QRS microfragmentation (QRSµf) [1] and total cosine R to T (TCRT) [2] . In this work, we aimed to summarize all these markers derived from 12-lead standard ECGs into one novel risk score and evaluate its performance as mortality predictor in the emergency department. Methods We retrospectively collected 10- second 12- lead ECG recordings unselected patients presenting to the emergency department of a large university hospital between September 2019 and June 2022. For each patient a risk score was calculated from the first retrieved ECG using the criteria displayed in Figure 1. Calculation of all parameters was done as previously published. Patients with a total score of 0-1 points, 2-3 points, 4-6 points and 7 points were considered as low, intermediate, high and very high risk, respectively. The performance of the risk score was evaluated using Cox regression analysis and Kaplan-Meier curves with all-cause mortality within one year as primary endpoint. Results In total, 10 781 patients were included in our analyses. Median age was 69 (IQR 54-80) years, 5 588 (52%) were male and 5 193 (48%) were female. 6 966 (65%) patients were considered as low risk, 2 656 (25%) patients as intermediate risk, 1 098 (10%) patients as high risk and 61 (1%) patients as very high risk according to the ECG risk score with one year mortality rates of 8%, 17%, 26% and 43%, respectively (p < 0.001 for difference). In cox regression analysis the novel ECG risk score was a strong and independent predictor of one-year all-cause mortality with a hazard ratio of 1.35 (95% CI 1.31-1.39, p < 0.001). Kaplan-Meier survival curves for different risk categories are displayed in Figure 2. Conclusion In an unselected population of patients presenting to the emergency department of a large university hospital a novel risk score calculated from standard 12-lead ECGs recorded during clinical routine was a strong and independent mortality predictor. Further studies are needed to evaluate how incorporation of the novel score into existing triage systems can improve patient care.Figure 1:Calculation of ECG risk scoreFigure 2:Kaplan-Meier survival curves

Comparison of vest-recorded electrocardiogram versus conventional electrocardiogram concerning ST-deviation in acute coronary syndrome

Abstract Background and Aim With the 12 lead ECG being the cornerstone in the diagnosis of ACS Development of a home-based, user-friendly recording of a 12 lead ECG will be a breakthrough in combating delay in diagnosing Acute Coronary Syndrome (ACS). This study evaluates the potential of a wearable vest 12-lead ECG (V-ECG) compared with the gold standard, conventional 12-lead ECGs (C-ECG) in diagnosing ACS. Methodology A prospective single-centre observational study conducted in a tertiary care centre. C-ECG and wearable V-ECG were recorded in hemodynamically stable adult patients and patients with normal ECG. The location of the electrodes in the vest included ten specific torso positions. Two independent physicians interpreted all the ECGs in a blinded fashion. Results Out of 241 patients, the vest fitted 236 patients (97.9%). Among 234 patients (72.5% males, 27.5% females; mean age 57.5 years), 154 had ACS. Three patients had an additional set of ECGs recorded, given their dynamic ECG changes during hospitalisation. The sensitivity and specificity of V-ECG, compared with the gold standard C-ECG for the diagnosis of ACS, were 98.7% ( CI 95.36-99.77) and 96.5% (CI 90.2-99.1), respectively. Among patients with STEMI, the sensitivity of V-ECG went up to 100% (CI 95.9-100). V-ECG has correctly identified anterior and inferior STEMI patients with 100% accuracy. Conclusion 12 lead ECG recording by a wearable garment using novel torso positions is feasible in the vast majority, including both genders, and reasonably accurate for diagnosing ACS. Highlights Commercial availability of this vest might enable an otherwise lay person to record an ECG in an out-of-hospital setting (even at home), thus leading to an expedited diagnosis of ACS and saving precious time and lives.

Exploring novel algorithms for atrial fibrillation detection by driving graduate level education in medical machine learning

During the lockdown of universities and the COVID-Pandemic most students were restricted to their homes. Novel and instigating teaching methods were required to improve the learning experience and so recent implementations of the annual PhysioNet/Computing in Cardiology (CinC) Challenges posed as a reference. For over 20 years, the challenges have proven repeatedly to be of immense educational value, besides leading to technological advances for specific problems. In this paper, we report results from the class ‘Artificial Intelligence in Medicine Challenge’, which was implemented as an online project seminar at Technical University Darmstadt, Germany, and which was heavily inspired by the PhysioNet/CinC Challenge 2017 ‘AF Classification from a Short Single Lead ECG Recording’. Atrial fibrillation is a common cardiac disease and often remains undetected. Therefore, we selected the two most promising models of the course and give an insight into the Transformer-based DualNet architecture as well as into the CNN-LSTM-based model and finally a detailed analysis for both. In particular, we show the model performance results of our internal scoring process for all submitted models and the near state-of-the-art model performance for the two named models on the official 2017 challenge test set. Several teams were able to achieve F1 scores above/close to 90% on a hidden test-set of Holter recordings. We highlight themes commonly observed among participants, and report the results from the self-assessed student evaluation. Finally, the self-assessment of the students reported a notable increase in machine learning knowledge.

Arrhythmia detection based on multi-scale fusion of hybrid deep models from single lead ECG recordings: A multicenter dataset study

BackgroundElectrocardiogram automated arrhythmia detection plays a crucial role in the early prevention and diagnosis of cardiovascular diseases. However, previous research relies on noise removal algorithms and extracting solid features from raw ECGs. Besides, existing heartbeat classifiers ignore underlying complementary information of various scales, and intra-patient paradigms often lead to biased results. MethodsWe constructed a novel end-to-end Multi-Scale Convolutional Neural Network-Sequence to Sequence architecture for heartbeat classification to address these issues. We have verified this approach on the clinical data collected by wearable devices and two heterogeneous datasets. ResultsThe proposed model can effectively capture multi-granularity frequency and longitudinal temporal information by fusion representation and sequence learning. The overall F1 score of our approach was achieved at 99.57%, which exceeded the reference pure cascade model by 4.36%.

The Effect of High-Altitude Acclimatisation on Ultra-Short Heart Rate Variability.

IntroductionHigh-altitude (HA) exposure affects heart rate variability (HRV) and has been inconsistently linked to acute mountain sickness (AMS). The influence of increasing HA exposure on ultra-short HRV and its relationship to gold standard HRV measures at HA has not been examined.MethodsThis was a prospective observational study of adults aged ≥ 18 years undertaking a HA trek in the Dhaulagiri region of the Himalayas. Cardiac inter-beat-intervals were obtained from a 10-s recording of supra-systolic blood pressure (Uscom BP+ device) immediately followed by 300 s single lead ECG recording (CheckMyHeart device). HRV was measured using the RMSSD (root mean square of successive differences of NN intervals) at sea level (SL) in the United Kingdom and at 3,619, 4,600, and 5,140 m at HA. Oxygen saturations (SpO2) were measured using finger-based pulse oximetry. The level of agreement between the 10 and 300 s RMSSD values were examined using a modified Bland–Altman relative-difference analysis.ResultsOverall, 89 participants aged 32.2 ± 8.8 years (range 18–56) were included of which 70.8% were men. HA exposure (SL vs. 3,619 m) was associated with an initial increase in both 10 s (45.0 [31.0–82.0]) vs. 58.0 [33.0–119.0] ms) and 300 s (45.67 [33.24–70.32] vs. 56.48 [36.98–102.0] ms) in RMSSD. Thereafter at 4,600 and 5,140 m both 10 and 300 s RMSSD values were significantly lower than SL. From a total of 317 paired HRV measures the 10 and 300 s RMSSD measures were moderately correlated (Spearman r = 0.66; 95% CI: 0.59–0.72; p < 0.0001). The median difference (bias) in RMSSD values (300 s − 10 s) was −2.3 ms with a lower and upper limit of agreement of −107.5 and 88.61 ms, respectively with no differences with altitude. Overall, 293/317 (92.4%) of all paired HRV values fell within the 95% CI limits of agreement. Neither HRV method was predictive of AMS.ConclusionIncreasing HA affects ultra-short HRV in a similar manner to gold-standard 300 s. Ultra-short HRV has a moderate agreement with 300 s measurements. HRV did not predict AMS.

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BACKGROUND:Schizophrenia is a major mental disorder with a never-ending search for etiology. Ion channel dysfunction is one among the etiologies proposed and various studies have been done on the same (1)(2)(3). Patients with Schizophrenia have a high incidence of Sudden cardiac death, almost three times the risk of general population.Brugada syndrome(4) and QTc prolongation (5) are a few among the cardiac disorders characterized by ion channel dysfunction (6) and can also lead to Sudden cardiac death (7). Identifying these two abnormalities in ECG can help prevent Sudden cardiac deaths especially in schizophrenia patients. This study aims to identify the prevalence of these abnormalities in ECG of patients with Schizophrenia and the socio demographic, clinical profile and drug treatment were correlated with the prevalence of these abnormalities. The importance of routine ECG screening in patients with Schizophrenia should be understood as well.AIMS:To estimate the prevalence of Brugada pattern ECG and QTc prolongation in Patients with Schizophrenia and their correlation with demographic factors, clinical and co-morbid factors and use of antipsychotics.MATERIALS AND METHODS:Convenience sampling of 160 cases with Schizophrenia fulfilling the study inclusion and exclusion criteria were recruited after obtaining IRB approval and informed consent. The sociodemographic factors, clinical and comorbid profile, treatment profile were recorded and analysed. A 12 lead ECG recording was taken for these patients. Screening of ECG for Brugada pattern and QTc prolongation were done. Prevalence was calculated in percentage. Bivariate and multivariate analysis were done to assess the association between variables.

B-PO04-193 BUT FOR THE BLIND SPOT: ACCURACY AND DIAGNOSTIC PERFORMANCE OF THE APPLE WATCH™ CARDIAC FEATURES IN PEDIATRIC PATIENTS

New wearable technologies have features of ambulatory ECG monitors. The Apple Watch™ (AW) offers heart rate (HR) tracking by photoplethysmography (PPG) and single lead ECG recordings. The accuracy of HR measurements by AW and diagnostic performance of AW ECGs among children have not been explored. The primary objective was to assess the accuracy of AW HR measurements compared to gold-standard modalities (GSM) in children. Secondary objectives included differentiation of sinus from non-sinus rhythm using AW ECGs. Patients ≤18 years were prospectively enrolled to wear an AW during 1) telemetry admission, 2) electrophysiology study (EPS), or 3) exercise stress test (EST). AW HR measurements were compared to those of a GSM by intra-class correlation coefficients (ICC). AW ECGs were recorded with concurrent 12 lead ECGs and reviewed by two blinded pediatric electrophysiologists for rhythm determination. 53 patients (median age 10 years, IQR 1.2-15.0) wore AW during telemetry (48%, n=26), EPS (20%, n=11), or EST (32%, n=16). Peak HR measured by AW had high ICC to GSM, but AW were unable to record HR > 210 bpm by PPG (Table 1). 56 AW ECGs were reviewed. Excellent agreement was seen among raters (agreement 92.5%, Kappa 0.85 +/- 0 .13). Identification of non-sinus rhythm by AW ECG showed a sensitivity of 90.3-93.5% and a specificity of 95.5-96.0%. AW HR values by PPG tightly correlated with GSM measurements with the notable limitation of inability to record HR > 210 bpm. This represents a blind-spot in the application of AW for tachycardia evaluation in pediatric patients. AW ECGs had good sensitivity and specificity in identification of non-sinus rhythm.

The prognostic value of dispersion of repolarization in stress cardiomyopathy

IntroductionAlthough abnormalities of ventricular repolarization are a hallmark of SC, their clinical impact on management remains to be determined. This study sought to evaluate the prognostic value of dispersion of repolarization in stress cardiomyopathy (SC) with regards to major cardiac events (MCE), recovery time, and recurrence. MethodsThis study analyzed data from258 patients with SC, from January 2009 to January 2018. Standard 12 lead ECG recordings during the acute, subacute, and recovery phases were collected for each eligible patient. Logistic regression was used to identify independent predictors of MCE, a composite of 30 day all-cause mortality, cardiogenic shock, life-threatening ventricular arrhythmias, and stroke. ResultsAmong the 101 eligible patients (80.2% females, mean age 45.8 ± 11.5 years) in the study cohort, MCE occurred in 16 patients (15.8%). Cox regression analysis identified two independent predictors of MCE: increased ΔQT dispersion ≥ 40 ms (HR 1.31, 95% CI 1.05–9.77, p = 0.029) and increased Δnegative T wave amplitude dispersion ≤ −2.0 mV (HR 1.25, 95% CI 1.11–11.93, p = 0.018) during the subacute phase. The final regression model had good accuracy (sensitivity 81.3%, specificity 96.5%) and discriminative power (AUC 0.89, 95% CI 0.83–0.95). Kaplan-Meier analysis revealed that there was increasing MCE in patients with zero, one, or two predictors (log rank p < 0.001). In addition, patients with increased dispersion also had a significantly longer time to achieve complete recovery (21.4 ± 6.8 vs. 8.5 ± 4.3 days, p = 0.012) and a higher incidence of recurrence (31.3% vs. 2.4%, p = 0.011) of SC. ConclusionEvaluation of dynamic changes of dispersion of repolarization is a simple bed-side tool with high predictive accuracy for prognostication of short term adverse outcomes, delayed recovery, and recurrence in patients with SC.

P580Performance evaluation of dual vs. single lead automatic, real-world arrhythmic ECG recordings

Abstract Background Detection of treatment-demanding paroxysmal arrhythmias can be difficult. Use of single lead ECG recordings for detection of Atrial Fibrillation (AF) has shown to lead to high false positive discovery rates, and requirements of additional manual clinical interpretation or 12-lead ECG to reach satisfactory diagnostic precision. Use of sequential, dual-lead ECG recordings for detection of AF has indicated significant clinical improvement in detection yield of AF and reduction of false positive discovery rates as compared to single lead-ECG. Methods The Coala Heart Monitor (Coala Life AB, Stockholm Sweden) system was evaluated by manual interpretation of 1,000 consecutive anonymous printouts of chest- and thumb-ECG waveforms, without any exclusion. The anonymized printouts contained three 10 s. strips of ECG at 25 mm/s, including mean heart rate, RR median and any user-provided annotation but with personal identification and algorithm analysis results blinded. The recordings were derived from actual Coala users with no training, control or influence, under a defined time period. The prevalence of cardiac conditions in the user population was unknown. The blinded recordings were manually interpreted by a trained cardiologist. The interpretation was compared with the automatic analysis performed by an enhanced algorithm in the Coala Cloud to evaluate ECG signal performance and to calculate performance metrics of a combination of sequential dual chest- and thumb-ECG measurements as compared to the clinical performance metrics of singe lead ECG measurements only. Results Metric Result using dual chest- and thumb-ECG and P-wave detection algorithm Result based on single lead thumb-ECG only Prevalence of AF in the recordings 14.4% (143 of 990 recordings) 14.4% (143 of 990 recordings) Percentage of recordings with ECG quality good enough to permit manual interpretation. 99,2% (8 of 998 non-readable) 98,7% (13 of 998 non-readable) Negative predictive value (NPV) for detecting AF 0.992 0.995 Positive predictive value (PPV) for detecting AF 0.872 0.647 False positive discovery rate 12.8% 35,3% Sensitivity for detecting AF 0.951 0.972 Specificity for detecting AF 0.976 0.909 Accuracy 0.973 0.919 Conclusion Based on 1,000 real-world recordings the combination of dual chest- and thumb-ECG with P-wave detection yielded significantly higher Positive Predictive Values as compared to single lead ECG measurements. Dual chest- and thumb-ECG reduced false positive AF indications from 35,3% for single lead-ECG to 12,8% using combined chest- and thumb-ECG with P-wave detection.

Recording of Bipolar Multichannel ECGs by a Smartwatch: Modern ECG Diagnostic 100 Years after Einthoven.

Aims: Feasibility study of accurate three lead ECG recording (Einthoven I, II and III) using an Apple Watch Series 4. Methods: In 50 healthy subjects (18 male; age: 40 ± 12 years) without known cardiac disorders, a 12-lead ECG and three bipolar ECGs, corresponding to Einthoven leads I, II and III were recorded using an Apple Watch Series 4. Einthoven I was recorded with the watch on the left wrist and the right index finger on the crown, Einthoven II with the watch on the left lower abdomen and the right index finger on the crown, Einthoven III with the watch on the left lower abdomen and the left index finger on the crown. Four experienced cardiologists were independently asked to assign the watch ECGs to Einthoven leads from 12-lead ECG for each subject. Results: All watch ECGs showed an adequate signal quality with 134 ECGs of good (89%) and 16 of moderate signal quality (11%). Ninety-one percent of all watch ECGs were assigned correctly to corresponding leads from 12-lead ECG. Thirty-nine subjects (78%) were assigned correctly by all cardiologists. All assignment errors occurred in patients with similar morphologies and amplitudes in at least two of the three recorded leads. Erroneous assignment of all watch ECGs to leads from standard ECG occurred in no patient. Conclusion: Recording of Einthoven leads I-III by a smartwatch is accurate and highly comparable to standard ECG. This might contribute to an earlier detection of cardiac disorders, which are associated with repolarization abnormalities or arrhythmias.

Evaluation of the diagnostic accuracy of smartphone electrocardiogram recorder compared to standard 12 lead electrocardiography in hospital settings

Objectives: To evaluate Smartphone-based Electrocardiogram Recorders (S-ECG-R) diagnostic accuracy compared to standard 12 lead ECG. Methods: A cross-sectional comparative study was conducted in a tertiary cardiac center in Riyadh, Kingdom of Saudi Arabia from December 2017 to February 2018. A total of 403 patients underwent both standard 12 leads ECG and S-ECG-R recordings in the same time. All recordings were checked initially by an electrophysiologist to confirm the accurate diagnosis. Then, the 806 recordings were randomly distributed among 6 certified cardiologists to interpret the rhythms and to evaluate rhythms quality. Results: In this study 211 (52%) males and 192 (48%) females were included, with a mean age of 52±18 years. Of the included rhythms,149 (37%) were abnormal. The majority of which were atrial fibrillation 46 (11%), sinus tachycardia 35 (9%) and premature ventricular contractions 33 (8%). Analysis revealed an overall similar diagnostic sensitivity and specificity of S-ECG-R to the standard 12 lead ECG recording, sensitivity (97.3% versus (vs) 98%) and specificity (99.6% vs. 99.6%). However, cardiologists were more confident during interpreting standard ECG recordings in 91% of the recordings while in 71% of S-ECG-R recordings. Conclusion: The ECG rhythms produced by smartphone accessory have a good diagnostic accuracy in diagnosing arrhythmias. The utility of using S-ECG-R for out-patient is to be determined. Saudi Med J 2019; Vol. 40 (6): 575-581 doi: 10.15537/smj.2019.6.24206 How to cite this article: Towhari J, Masud N, Alanazi H. Evaluation of the diagnostic accuracy of smartphone electrocardiogram recorder compared to standard 12 lead electrocardiography in hospital settings . Saudi Med J 2019; 40 (6): 575-581. doi: 10.15537/smj.2019.6.24206.

AF Classification from a Short Single Lead ECG Recording: the PhysioNet/Computing in Cardiology Challenge 2017.

The PhysioNet/Computing in Cardiology (CinC) Challenge 2017 focused on differentiating AF from noise, normal or other rhythms in short term (from 9-61 s) ECG recordings performed by patients. A total of 12,186 ECGs were used: 8,528 in the public training set and 3,658 in the private hidden test set. Due to the high degree of inter-expert disagreement between a significant fraction of the expert labels we implemented a mid-competition bootstrap approach to expert relabeling of the data, levering the best performing Challenge entrants' algorithms to identify contentious labels. A total of 75 independent teams entered the Challenge using a variety of traditional and novel methods, ranging from random forests to a deep learning approach applied to the raw data in the spectral domain. Four teams won the Challenge with an equal high F1 score (averaged across all classes) of 0.83, although the top 11 algorithms scored within 2% of this. A combination of 45 algorithms identified using LASSO achieved an F1 of 0.87, indicating that a voting approach can boost performance.

Comparison of standard and Lewis ECG in detection of atrioventricular dissociation in patients with wide QRS tachycardia

BackgroundThe atrioventricular (AV) dissociation, which is frequently used in differential diagnosis of wide QRS complex tachycardia (WQCT), is the most specific finding of ventricular tachycardia (VT) with lower sensitivity. Herein, we aimed to show the importance of Lewis lead ECG records to detect ‘visible p waves’ during WQCT. MethodA total of 21 consecutive patients who underwent electrophysiologic study (EPS) were included in the study. During EPS, by using a quadripolar diagnostic catheter directed to the right ventricular apex, a fixed stimulus was given and the ventriculoatrial (VA) Wenkebach point was found, and a VT was simulated by a RV apical stimulus at 300ms. The standard and Lewis lead ECG records were taken during this procedure. ResultWe detected ‘visible p waves’ in 7 (33.3%) and 14 (66.7%) patients in the standard and Lewis lead ECG groups, respectively. In terms of the ‘visible p waves’, there was a statistically significant difference between groups (p=0.022). The sensitivity of standard and Lewis lead ECG in determination of the visible p waves was 33.3% and 66.7%, respectively. ConclusionThe Lewis lead ECG can be more informative about AV dissociation than the standard 12 lead ECG. As a result, we could suggest the assessment of the Lewis lead ECG recording in addition to the standard 12 lead ECG in differential diagnosis of VT in patients with WQCT.

CD11c.DTR mice develop a fatal fulminant myocarditis after local or systemic treatment with diphtheria toxin

To assess the role of alveolar macrophages (AMs) during a pulmonary Aspergillus fumigatus infection AMs were depleted by intratracheal application of diphtheria toxin (DTX) to transgenic CD11c.DTR mice prior to fungal infection. Unexpectedly, all CD11c.DTR mice treated with DTX died within 4-5 days, whether being infected with A. fumigatus or not. Despite measurable impact of DTX on lung functional parameters, these constrictions could not explain the high mortality rate. Instead, DTX-treated CD11c.DTR animals developed fulminant myocarditis (FM) characterized by massive leukocyte infiltration and myocardial cell destruction, including central parts of the heart's stimulus transmission system. In fact, standard limb lead ECG recordings of diseased but not healthy mice showed a "Brugada"-like pattern with an abnormally high ST segment pointing to enhanced susceptibility for potential lethal arrhythmias. While CD11c.DTR mice are extensively used for the characterization of CD11c(+) cells, including dendritic cells, several studies have already mentioned adverse side effects following DTX treatment. Our results demonstrate that this limitation is based on severe myocarditis but not on the expected lung constrictions, and has to be taken into consideration if this animal model is used. Based on these properties, however, the CD11c.DTR mouse might serve as useful animal model for FM.

The Effects of Ascent and Descent on Heart Rate and Rhythm at High Altitude

Introduction: Previous studies have reported a variable burden of cardiac arrhythmias, particularly supraventricular (SVE) and ventricular extrasystoles (VES), during hypoxic exposure. The majority of studies have either used simulated altitude and/or subjects at rest with passive ascent (eg cable car). In this study the burden and type of cardiac arrhythmias were recorded during exercise on ascent and descent to Kala Patthar (5643 m) in the Himalayas. Methods: Ten healthy British Military servicemen aged 18-50 years were included. Health status was confirmed following a baseline history, clinical examination, electrocardiogram and transthoracic echocardiogram. Continuous ambulatory 3 lead ECG recordings (Spacelabs LifeCardTM) were made during trekking ascent to 5643 m at 2610-3840 m, 3450-3880 m, 4240-4940 m and during descent at 5140-4371 m and at 4371-3710 m. Results: The average age of subjects was 36.1 ± 10.3 years (50% women). All subjects completed the three ascent and two descent treks that were recorded. There was a decrease in the maximal heart rates (p<0.0001) and oxygen saturations (p=0.004) with increasing HA. VEs were observed in 9/10 subjects at 2610- 3440 m, 7/10 at 3440-3710 m, 6/10 at 4270-4910 m, 9/10 at 5150-4270 m and in 6/10 at 4270-3710 m (p=0.30). Overall VE burden was non-significantly higher over ascent (95.0 ± 258.6/hour) versus descent (58.5 ± 171.5/hour; p=0.58). There was no significant change in SVEs (4/10 subjects overall) across the 5 treks (p=0.24). VEs (80.4 ± 226.5/hour) were more common than SVEs (0.11 ± 0.4/hour; p<0.001). There were no sustained pathological tachyarrhythmias. Conclusion: In this study moderate intensity exercise to 5643 m did not lead to significant cardiac arrhythmia development in healthy subjects. VEs are common and much more prevalent than SVEs and consistently observed during both ascent and descent.

An evaluation of eye tracking technology in the assessment of 12 lead electrocardiography interpretation

IntroductionThis study investigated eye tracking technology for 12 lead electrocardiography interpretation to Healthcare Scientist students. MethodsParticipants (n=33) interpreted ten 12 lead ECG recordings and randomized to receive objective individual appraisal on their efforts either by traditional didactic format or by eye tracker software. ResultsOne hundred percent of participants reported the experience positively at improving their ECG interpretation competency. ECG analysis time ranged between 13.2 and 59.5s. The rhythm strip was the most common lead studied and fixated on for the longest duration (mean 9.9s). Lead I was studied for the shortest duration (mean 0.25s). Feedback using eye tracking data during ECG interpretation did not produce any significant variation between the assessment marks of the study and the control groups (p=0.32). ConclusionsAlthough the hypothesis of this study was rejected active teaching and early feedback practices are recommended within this discipline.

A Smart and Wearable Cardiac Healthcare System with Monitoring of Sudden Fall for Elderly and Post-Operative Patients

The dominance of chronic diseases, driven by an increasingly aging population with a new health paradigm that emphasizes early finding, early diagnosis and early treatment, is highly recommended. Especially, Cardiac disorders and sudden falls are the prominent reasons behind hospitalization of the elderly and post-operative patients. In the present work, we have designed and developed a GSM (Global System for Mobile) based wearable smart system with 3-axis accelerometer and three lead ECG recording system. The whole system is wearable for all and can be used as a real-time monitoring, self-diagnosis, and remote- diagnosis tool as it will detect whenever there is an abnormal heart condition and a sudden fall situation. The entire data flow program and evaluation for the system has been done under NI LabVIEW platform. After detecting the health abnormalities the system sends alert notifications to the care giver and health professionals to take compulsory actions. This paper also deals with estimation of ECG parameters as they have significant clinical values in order to detect cardiac disorders. With this developed system, elderly or ill individuals especially senior citizens who live alone or have a disability could stay independently at their home.

ASSA13-07-1 Comparison of the ECG Recordings Using a Novel Mobile ECG Recorder (EPI Mini) with a Clinically Validated Mobile Phone with ECG Recording Function (EPI Life)

Objective The Objective of the study is to compare the ECG recordings using a novel mobile ECG recorder (EPI Mini) with a clinically validated mobile phone with ECG recording function (EPI Life). Methods The EPI Mini and EPI Life are ECG recorders that use the same type of ECG chip modules, same surface electrodes and are able to record ECG following direct contact of the inbuilt contact electrodes with skin surfaces. The ECG recordings from EPI Life have been clinically validated with standard 12 lead ECG recordings. While the EPI Life is a mobile phone which allows the recording of ECGs and its transmission to a 24 hour centre, the EPI Mini is a mobile device that is a scaled down version of the EPI Life which records the ECG and transmits it wirelessly through smartphones. 30 consecutive healthy individuals aged 18 to 48 years consented to this prospective study. ECG recording using the EPI Mini device was performed, followed immediately by the recording of ECG using the EPI Life device in 3 different lead positions. ECG recordings were performed using modified limb leads I and II (mL I and mL II) and modified V5 precordial lead (mV5), and the optimal ECG recordings were compared. ECG parameters that were compared include ECG morphology (pattern and orientation of p wave, QRS complex, ST segment and T wave), QRS amplitude (R wave, S wave and R + S waves) and ECG parameters (PR interval and QT interval). The data were statistically assessed using linear regression analysis, as the Objective was to assess the correlation between the two modalities of ECG recording. Analysis was made between two variables, with X representing data from EPI Life ECG recordings and Y representing data from EPI Mini ECG recordings. From the data, the best fit value for the slope and P values were calculated. Results A total of 180 ECG recordings were obtained for comparison; 90 ECG recordings using EPI Life and 90 recordings using EPI Mini. The linear regression graphs show that there was good correlation, as demonstrated by the linearity of the units, X and Y plotted on the graph for QRS amplitude (R wave, S wave and R + S waves) and ECG parameters (PR interval and QT interval) for all 3 leads. The R wave, S wave, R + S waves, PR interval and QT interval had best fit value for the slope of 1.0623, 1.392, 1.120, 0.855 and 1.141 respectively for mL I. The R wave, S wave, R + S waves, PR interval and QT interval had best fit value for the slope of 1.021, 1.031, 1.025, 0.991 and 1.011 respectively for mL II. The R wave, S wave, R + S waves, PR interval and QT interval had best fit value for the slope of 0.951, 1.148, 1.034, 0.856 and 1.073 respectively for mV5. The P values were found to be less than 0.0001 for all the quantitative parameters that were analysed. There was 100% correlation of the ECG morphology for ECG recordings from both devices for all the subjects when comparing the mL I, mL II and mV5 leads. Conclusions There was statistically significant correlation between the quantitative ECG parameters recorded using the novel EPI Mini and the clinically validated EPI Life. In addition, the data showed that there was good qualitative correlation when comparing between the morphology of the ECGs recorded using both devices.

Right bundle branch block and middle septal fiber block with or without left anterior fascicular block manifested as aberrant conduction in apparent healthy individuals: Electro-vectorcardiographic characterization

BackgroundRight bundle branch block (RBBB) evident in the precordial ECG leads may be associated with evidence of left bundle branch involvement in the limb leads. Any of the components of the left bundle can be involved, and this complex interventricular conduction abnormality has previously been described in patients with underlying heart disease. ObjectivesTo analyze the electro-vectorcardiographic manifestations of RBBB with left middle septal fiber block (LMSFB), with or without left anterior fascicular block (LAFB) in premature atrial beats of patients without apparent structural heart disease. MethodsTwelve patients (8 men/4 women; mean age: 32±8years) with premature atrial contractions with this conduction abnormality were included. Surface 12 simultaneous lead ECG recordings and the corresponding vectorcardiographic loops were analyzed. ResultsThe QRS complexes with RBBB and also LMSFB persisted for between 150 and 190ms. There were no q waves in lead I. The maximum spatial vector (72–86ms) was directed posteriorly, superiorly, and leftward, and the terminal forces were oriented anteriorly, inferiorly and rightward. In 10 patients, small q waves were apparent in leads V1–V2 and the frontal QRS axis was −60° and −70°, with the 46ms vector located at −50°±5. All of these patients most probably had LAFB in addition to LMSFB. In two patients, the initial electrical forces were directed anteriorly, inferiorly, and leftward, and the 46ms vector axis in the frontal plane was 6° and 11°, respectively, indicating absence of LAFB. ConclusionsThe combination of RBBB and LMSFB occurring in patients without apparent structural heart disease may be related to the simultaneous occurrence of block of conduction through these components of the Purkinje network. The anterior fascicle of the left bundle may also be involved.

Effects of dronedarone and amiodarone on atrial fibrillatory rate in patients with persistent atrial fibrillation

Current guidelines for the management of atrial fibrillation (AF) recommend dronedarone for the prevention of recurring AF [1]. Especially in patients with structural heart disease, e.g. hypertension with left ventricular hypertrophy, dronedarone is a welcome alternative to amiodarone due to its favorable safety profile. However, the antiarrhythmic efficacy of dronedarone is lower than that of amiodarone as exemplified in the DIONYSOS trial [2]. This observation is supported by experimental studies showing much weaker atrial electrophysiologic effects and anti-AF efficacy of dronedarone compared with amiodarone in a canine AF model [3]. However, there is a lack of studies investigating specific antiarrhythmic effects of amiodarone and dronedarone in human AF that are, moreover, restricted to in-vitro experiments of human atrial myocytes [4]. Consequently, we applied time–frequency analysis to the surface ECG for determination of atrial fibrillatory rate (AFR) as a measure of atrial refractoriness for in-vivo monitoring of amiodarone and dronedarone effects in patients with persistent AF. In patients with persistent AFN7 days but b1 year, 2-minute 12 lead ECG recordings were made at baseline and after 3 days of antiarrhythmic drug treatment with all subjects relaxed in a supine position after a 5-minute equilibration period. Dronedarone (2×400 mg/day) or amiodarone (1,200 mg/day loading dose) was initiated prior to external electrical cardioversion on an inpatient basis under continuous electrocardiographic monitoring. All patients were adequately anticoagulated using either oral anticoagulation therapy with an international normalized ratio between 2 and 3 or weight-adapted low molecular weight heparin following exclusion of left atrial thrombus formation by transesophageal echocardiography. Twenty-one consecutive patients treated with dronedarone were prospectively included in our AF registry and matched for age and genderwith 20patientswhowere treatedwith amiodarone. The clinical characteristics of the study population are summarized in Table 1 and showed no difference between the two groups. All patients provided informed consent for study participation, i.e. acquisition and analysis of baseline and on-treatment ECG for evaluation of drug effects. Time–frequency analysis was performed a posteriori on ECG lead V1 as described previously (Fig. 1) [5]. Briefly, after analog-to-digital conversion (1,000 Hz, 12 bit, 0.05–300 Hz) and high-pass filtering to remove baseline wander, QRST complexes were subtracted using spatiotemporal QRST cancelation (Fig. 1, top). One frequency estimate of the atrial signal was obtained every second from overlapping 2.5-second windows by short-term Fourier transform (segment-wise Fast Fourier transform). Thus, this instantaneous signal was represented in a spectral profile. Subsequently, the frequency of the atrial signal was trended as a function of time and mean atrial frequency determined. Frequencies were converted to AFR with its unit fibrillations per minute (fpm; AFR=frequency∗60). All continuous variables are presented as mean±one standard deviation. ECG parameters before and after drug administration were compared using Student's t-test for paired data. Differences in ECG parameter changes between dronedarone and amiodarone were evaluated using t-test for unpaired data. A p valueb .05 was considered statistically significant. The authors of this manuscript certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology. At baseline, mean AFR measured 396±44 fpm in the dronedarone group, comparable to 410±32 fpm in the amiodarone group. AFR was reduced by 25±23 fpm with dronedarone (pb .001 for on-treatment vs. baseline) and by 70±29 fpm with amiodarone (pb .001 for on-treatment vs. baseline). The amiodarone-induced AFR reduction was significantly higher than the AFR reduction with dronedarone (pb .001 for amiodarone vs. dronedarone; Fig. 2, left). Ventricular rate at baseline showed no difference between the dronedarone and the amiodarone group. Both drugs slowed ventricular rate significantly; dronedarone by 18±19 beats per minute (bpm, pb .001 for on-treatment vs. baseline) and amiodarone by 9±12 bpm, (p=.002 for on-treatment vs. baseline). There was a trend for greater magnitude of ventricular rate slowingwith dronedarone comparedwith amiodarone (p=.086; Fig. 2, right). Class I and III antiarrhythmic drugs have been shown to increase atrial cycle length (decrease AFR) which coincides with increased refractoriness and decreased conduction velocity [6]. Previous studies [5,7–9] have subsequently demonstrated a substantial AFR