Simultaneous ECG Recordings Research Articles

The comparison of pulsed wave velocity measured with oscillometric method and transthoracic Doppler echocardiography in patients with wide range of cardiovascular risk

Abstract Background Pulse Wave Velocity (PWV) is an important parameter in assessing arterial stiffness and potent predictor of cardiovascular risk, however its clinical usage remains limited. Whereas there is a range of dedicated devices (based on oscillometric or tonometric methods) the inclusion of PWV evaluation to transthoracic echocardiography (TTE) may increase significally its application. Purpose Our aim was to compare PWV measured with oscillometry signed as aPWV with this parameter measured by TTE, signed as ePWV during one examination (within 15 minutes time) and to evaluate the correlations of these parameters with clinical and echocardiographic characteristics. Methods We included 56 patients (mean age 55 years; 65% female), who underwent both TTE with Doppler examination of flow in carotid and femoral artery and ePWV calculation as well as oscillometric measurement of aPVW in the right brachial artery. ePWV was calculated using Doppler spectra registered in the both carotid and femoral arteries as well as a distance between points of measurements as the distance divided by estimated pulse wave transit time (achieved with simultaneous ECG recording). Studied group was divided into low and high cardiovascular risk category according SCORE2 scale for the primary prevention. As a low risk group, LR, we accepted those with score ≤5% including to HR group also secondary prevention patients (high risk group, HR). Results Oscillometric measurements were obtained in 50 patients (aPWV feasibility 89%) and Doppler parameters in all patients (ePWV feasibility 100%). Intra- and interobserver agreement was good for all measurements with coefficients of variation < 15%. PWV parameters, measured by both methods, showed a significant positive correlation with rho = 0.675, p<0.0001 as well as a good discriminatory potential between LR and HR groups (Figure 1). The HR group was older had faster PWV as well as higher LAV, E/E' and IMT values and lower TAPSE (see Table). Moreover, significant correlation between ePWV value and carotid IMT was observed with coefficient rho = 0.576, p = 0.0017, whereas this correlation achieved rho = 0.419, p=0.047 for aPWV. Conclusions ePWV based on Doppler echocardiography is a safe and highly feasible method of PWV measurement, showing good correlation with oscillometric assessment and providing data reflecting well cardiovascular risk as well as IMT of carotid arteries. Table. Comparison between LR and HR groups. Table Legend: T (R-flow) – time from R wave to Doppler spectrum of flow, ePWV or aPWV – pulsed wave velocity assessed with echocardiography or automatically, IMT- intima media thickness, LAV- left atrial volume, E/E’ - early mitral inflow to early mitral annulus motion ratio, LV EF, left ventricular ejection fraction, FAC – fractional area change of the right ventricle, TAPSE- tricuspid annulus plane systolic motion, RV S’ – tricuspid annulus systolic motion with tissue Doppler imaging. aPWV with ePWV correlation in LR and HR Table. Comparison of LR and HR groups

External validation of a machine learning based classification algorithm for ambulatory heart rhythm diagnostics using smartphone-photoplethysmography - the SMARTBEATS algorithm study

Abstract Introduction Smartphone-photoplethysmography (PPG) can be used for heart rhythm monitoring. According to current guidelines, ECG verification is required for a new diagnosis of atrial fibrillation (AF). Accurate machine learning (ML) based automatic algorithms have the potential to facilitate clinical applications generating large numbers of PPG recordings, by offloading the need for manual over-read. Purpose The aim of this study was to evaluate the diagnostic performance of an automatic ML-based algorithm for heart rhythm diagnostics using smartphone-PPG recorded by patients with AF in an unsupervised ambulatory setting. Methods Patients undergoing direct current cardioversion (DCCV) at a university hospital for treatment of AF or atrial flutter (AFL) were asked to perform one-minute heart rhythm recordings post-cardioversion at least twice daily for 30 days. All participants were provided with an iPhone 7 smartphone running the CORAI Heart Monitor PPG application simultaneously with a single-lead ECG recording (KardiaMobile). The automatic algorithm uses support vector machines (SVM) to classify heart rhythm from smartphone-PPG recordings. The SVM classifier evaluated here was trained on ambulatory PPG recordings made by patients in a separate cardioversion cohort, ensuring complete independence between training and validation sets. PPG recordings in the validation cohort were analyzed by the automatic algorithm and diagnostic performance was calculated by comparing heart rhythm classification output from the SVM classifier to the heart rhythm diagnosis from the simultaneous ECG recordings. ECG recordings were interpreted independently by two cardiologists and were set as gold standard. Results The SVM classifier was trained on data from 153 patients with 11,749 PPG recordings, of which 5,873 (50.0%) were labelled as AF and 5,876 (50.0%) as sinus rhythm (SR), as assessed by manual reading. In the validation cohort, 280 patients, with a median age of 69.0 years (31% women), registered 18,005 simultaneous PPG and ECG recordings. Recordings interpreted as AFL on ECG (2.0%), as having insufficient quality on ECG (4.9%) or PPG (2.8%), and low certainty algorithmic classifications (1.2%) were excluded, leaving 16,057 PPG recordings. Included ECG recordings consisted of 71.2% interpreted as (SR) and 28.8% as AF. Algorithm classification of the PPG recordings in the validation cohort diagnosed AF (sensitivity) in 99.7% and SR (specificity) in 99.7% of the recordings, with an overall accuracy of 99.7%. F1-score was 99.4% and area under the ROC curve (AUC) was 0.999. Conclusion A machine learning based algorithm for automatic heart rhythm diagnostics showed excellent diagnostic performance for smartphone-PPG recordings in an unsupervised ambulatory setting, minimizing the need for ECG verification in cardioversion populations.

Risk of atrial fibrillation development in adolescent patients with inflammatory bowel disease.

There is increasing evidence linking chronic inflammation to the initiation and continuation of atrial fibrillation (AF). Inflammatory bowel diseases (IBD), namely (Crohn's disease (CD) and ulcerative colitis (UC), are chronic systemic inflammatory disorders with both intestinal and extra-intestinal manifestations. Atrial electromechanical delay (EMD) has been known as an early marker of AF. The objective of this study was to evaluate the atrial electromechanical properties in children and adolescents with IBD during remission. One hundred IBD patients aged 12-17 years (50 with CD and 50 with UC) in remission state and 100 healthy controls were recruited for the study. Atrial electromechanical properties were measured using transthoracic echocardiography, tissue Doppler imaging, and simultaneous surface ECG recording. Interatrial EMD, left intra-atrial, and right intra-atrial EMD were calculated. IBD patients in remission state have significantly prolonged left and right intra-atrial EMD and interatrial EMD compared to healthy controls (P = 0.03, P = 0.02, and P = 0.01 respectively). No statistical difference was observed between CD and UC in terms of inter- and intra-atrial EMDs. Conclusion:Atrial EMD is increased in pediatric patients with IBD indicating the increased risk of AF development. Measurement of atrial EMD parameters might be used to predict the risk of the development of AF in pediatric patients with IBD. What is Known: • There is increasing evidence linking chronic inflammation to the initiation and continuation of atrial fibrillation (AF). • Inflammatory bowel diseases are chronic systemic inflammatory disorders with both intestinal and extra-intestinal manifestations. • Atrial electromechanical delay (EMD) has been reported as an early marker of AF. What is New: • Atrial EMD is increased in pediatric patients with IBD indicating the increased risk of AF development. • Measurement of atrial EMD parameters might be used to predict the risk of the development of AF in pediatric patients with IBD.

Single-lead ECGs with wearable technology: diagnostic accuracy in patients with cardiovascular disease

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The 2020 ESC AF management guideline states that a 30-second single-lead electrocardiogram (sl-ECG) can be used to diagnose atrial fibrillation, but advises caution as most validation studies used small, carefully selected cohorts and are prone to bias. Patients with frequent ectopy, other atrial arrhythmias, and cardiac implantable electronic devices, which are important sources of false-positive detection, are noticeably absent from many studies. Purpose We sought to compare the diagnostic accuracy of the Apple Watch and CART-I ring automated AF detection to physician interpretation of a sl-ECG in a broad cohort of patients with pre-existing cardiovascular disease. Methods This prospective single-centre randomised study recruited patients with known cardiovascular disease in a large UK tertiary centre. All patients underwent simultaneous 12-lead ECG recordings with a 30-second sl-ECG from an Apple Watch Series 6 and a CART-I Ring. The order of devices was randomly assigned. Two cardiologists independently adjudicated all ECGs; any disagreements were resolved by a third cardiologist. The wearable devices’ algorithm labelled ECGs as "AF", "Not AF" or "Unclassified". Unclassified ECGs were categorised as false-positive (no AF on the 12-lead ECG) or false-negative (AF on the 12-lead ECG). Diagnostic accuracy was determined by calculating AF sensitivity and specificity for each device and comparing it to 12-lead ECGs. Results A total of 1600 ECGs from 400 consecutive patients were recorded. Seven patients were excluded due to uninterpretable 12-lead ECGs. The median age was 63 (58-75) years; 24% were female; 75.1% had coronary artery disease; 64% had a history of AF; and 10 % had undergone previous cardiac surgery. Interobserver reproducibility for sl-ECGs was high, with levels of agreement for the Apple Watch and the CART-I ring being 89.8% and 91.1%, respectively (p=0.54). The CART-I ring’s AF sensitivity from automated detection was significantly higher than the Apple Watch’s (mean difference 18.6%; 95%CI 17.0%-20.6%, p=0.03). Physician interpretation of the Apple Watch sl-ECGs led to a significant increase in AF sensitivity and specificity, 95.8% (95% CI: 91.6 %-97.9%) and 90.8 % (95% CI: 86.2 %-93.9%), respectively (Figure 1B). In contrast, physician interpretation of the CART-I ring’s sl-ECG resulted in higher AF sensitivity (94.6% [95% CI: 90.0%-97.1%]) but a marginal decrease in specificity (89.4% [95% CI: 84.8%-92.8%]). There was no statistically significant difference in AF detection between physician-interpreted sl-ECG from the wearable devices: 4.74% difference in AF sensitivity (p=0.12) and 1.32% difference in AF specificity (p=0.75). Conclusion In patients with cardiovascular disease, automatic AF detection algorithms from wearable devices have a higher rate of false-positive detections than previously reported. Physician-interpreted sl-ECGs have excellent diagnostic accuracy for AF.

Mitochondrial Oxidative Stress Mediates Bradyarrhythmia in Leigh Syndrome Mitochondrial Disease Mice.

Mitochondrial oxidative stress has been implicated in aging and several cardiovascular diseases, including heart failure and cardiomyopathy, ventricular tachycardia, and atrial fibrillation. The role of mitochondrial oxidative stress in bradyarrhythmia is less clear. Mice with a germline deletion of Ndufs4 subunit respiratory complex I develop severe mitochondrial encephalomyopathy resembling Leigh Syndrome (LS). Several types of cardiac bradyarrhythmia are present in LS mice, including a frequent sinus node dysfunction and episodic atrioventricular (AV) block. Treatment with the mitochondrial antioxidant Mitotempo or mitochondrial protective peptide SS31 significantly ameliorated the bradyarrhythmia and extended the lifespan of LS mice. Using an ex vivo Langendorff perfused heart with live confocal imaging of mitochondrial and total cellular reactive oxygen species (ROS), we showed increased ROS in the LS heart, which was potentiated by ischemia-reperfusion. A simultaneous ECG recording showed a sinus node dysfunction and AV block concurrent with the severity of the oxidative stress. Treatment with Mitotempo abolished ROS and restored the sinus rhythm. Our study reveals robust evidence of the direct mechanistic roles of mitochondrial and total ROS in bradyarrhythmia in the setting of LS mitochondrial cardiomyopathy. Our study also supports the potential clinical application of mitochondrial-targeted antioxidants or SS31 for the treatment of LS patients.

PO-690-03 ATRIAL ELECTROMECHANICAL DISSOCIATION AS A NOVEL NON-INVASIVE PARAMETER OF EARLY REMODELING PROGRESSION DURING ATRIAL FIBRILLATION

Electromechanical assessment during atrial fibrillation (AF) remains a significant knowledge gap in patient-specific characterization of atrial remodeling. Study electromechanical remodeling progression in a long-term pig model of AF and establish the clinical prognostic value of the atrial electromechanical relationship. Experimental group of pigs with AF (N=15) and a prospective clinical cohort (N=95) of symptomatic AF patients (episode duration ≤6 months) undergoing atrial remodeling characterization. Atrial electromechanical remodeling was assessed using simultaneous surface ECG recordings and tissue Doppler imaging (TDI) signals during echocardiography studies in AF. Electromechanical dissociation (EMD) was defined as faster atrial electrical activation rates (EAR) than the simultaneous counterpart TDI-derived mechanical activation rates (MAR). In patients, the primary outcome was cardioversion within a 24-h window after flecainide. Secondary outcomes were cardioversion of persistent AF and recurrences at 1-year. Pigs developed progressive EMD during the first weeks of AF-related remodeling (5-to-21 weeks after protocol initiation). EMD reached 2.29±2.47 Hz (p=0.04) at 12 weeks after the first recorded AF episode lasting ≥6 seconds. In pigs with long-lasting AF (342.5±86.6 d of self-sustained AF), high-resolution electroanatomical mapping and transesophageal echocardiography imaging demonstrated overt EMD (EAR-MAR=3.49±0.67 Hz) between local EARs from unipolar electrograms and the corresponding spatially and temporally synchronized MARs. In patients (55.0±11.6 years old), regardless of AF classification (paroxysmal or persistent AF), EMD was associated with failure of pharmacological cardioversion within the 24-h window after flecainide. EMD provided the highest increase in certainty for the primary outcome when added to AF classification compared to the increase provided by clinical variables and EARs. EMD was also associated with long-term AF recurrences both in the overall AF population and in the patient subset with persistent AF. Figure 1 summarizes the main study results. Atrial EMD is an early indicator of AF remodeling progression with prognostic value in acute and long-term rhythm control.

When Seizures Trigger "Extreme (Cardiac) Makeover".

This content has been temporarily removed for further corrections

Altered cardiac structure and function is related to seizure frequency in a rat model of chronic acquired temporal lobe epilepsy

ObjectiveThis study aimed to prospectively examine cardiac structure and function in the kainic acid-induced post-status epilepticus (post-KA SE) model of chronic acquired temporal lobe epilepsy (TLE), specifically to examine for changes between the pre-epileptic, early epileptogenesis and the chronic epilepsy stages. We also aimed to examine whether any changes related to the seizure frequency in individual animals. MethodsFour hours of SE was induced in 9 male Wistar rats at 10 weeks of age, with 8 saline treated matched control rats. Echocardiography was performed prior to the induction of SE, two- and 10-weeks post-SE. Two weeks of continuous video-EEG and simultaneous ECG recordings were acquired for two weeks from 11 weeks post-KA SE. The video-EEG recordings were analyzed blindly to quantify the number and severity of spontaneous seizures, and the ECG recordings analyzed for measures of heart rate variability (HRV). PicroSirius red histology was performed to assess cardiac fibrosis, and intracellular Ca2+ levels and cell contractility were measured by microfluorimetry. ResultsAll 9 post-KA SE rats were demonstrated to have spontaneous recurrent seizures on the two-week video-EEG recording acquired from 11 weeks SE (seizure frequency ranging from 0.3 to 10.6 seizures/day with the seizure durations from 11 to 62 s), and none of the 8 control rats. Left ventricular wall thickness was thinner, left ventricular internal dimension was shorter, and ejection fraction was significantly decreased in chronically epileptic rats, and was negatively correlated to seizure frequency in individual rats. Diastolic dysfunction was evident in chronically epileptic rats by a decrease in mitral valve deceleration time and an increase in E/E` ratio. Measures of HRV were reduced in the chronically epileptic rats, indicating abnormalities of cardiac autonomic function. Cardiac fibrosis was significantly increased in epileptic rats, positively correlated to seizure frequency, and negatively correlated to ejection fraction. The cardiac fibrosis was not a consequence of direct effect of KA toxicity, as it was not seen in the 6/10 rats from separate cohort that received similar doses of KA but did not go into SE. Cardiomyocyte length, width, volume, and rate of cell lengthening and shortening were significantly reduced in epileptic rats. SignificanceThe results from this study demonstrate that chronic epilepsy in the post-KA SE rat model of TLE is associated with a progressive deterioration in cardiac structure and function, with a restrictive cardiomyopathy associated with myocardial fibrosis. Positive correlations between seizure frequency and the severity of the cardiac changes were identified. These results provide new insights into the pathophysiology of cardiac disease in chronic epilepsy, and may have relevance for the heterogeneous mechanisms that place these people at risk of sudden unexplained death.

Changes in Electroencephalography and Cardiac Autonomic Function During Craft Activities: Experimental Evidence for the Effectiveness of Occupational Therapy.

Occupational therapy often uses craft activities as therapeutic tools, but their therapeutic effectiveness has not yet been adequately demonstrated. The aim of this study was to examine changes in frontal midline theta rhythm (Fmθ) and autonomic nervous responses during craft activities, and to explore the physiological mechanisms underlying the therapeutic effectiveness of occupational therapy. To achieve this, we employed a simple craft activity as a task to induce Fmθ and performed simultaneous EEG and ECG recordings. For participants in which Fmθ activities were provoked, parasympathetic and sympathetic activities were evaluated during the appearance of Fmθ and rest periods using the Lorenz plot analysis. Both parasympathetic and sympathetic indices increased with the appearance of Fmθ compared to during resting periods. This suggests that a relaxed-concentration state is achieved by concentrating on craft activities. Furthermore, the appearance of Fmθ positively correlated with parasympathetic activity, and theta band activity in the frontal area were associated with sympathetic activity. This suggests that there is a close relationship between cardiac autonomic function and Fmθ activity.

Sodium-Calcium Exchanger (NCX1) is Essential for Atrioventricular Node Automaticity and Conduction, as Revealed through Atrial-Specific Knockout of NCX1

The atrioventricular node (AVN), unlike the sinoatrial node (SAN), can act as an oscillator and conductor of the proximal cardiac conduction system. Using a sarcolipin cre-induced atrial-specific sodium-calcium exchanger 1 (NCX1) KO mouse, we previously demonstrated that NCX1 (and the calcium clock) is an essential component of SAN automaticity (Groenke et al., 2013; Torrente et al., 2015). Here, we used the same mouse to test the hypothesis that NCX1 and the calcium clock are necessary components of AVN automaticity and conduction. qPCR analysis confirmed a 79% reduction of NCX mRNA in AVN tissue, and ECGs demonstrated a slow junctional escape rhythm driving the heart rate. Voltage mapping and confocal imaging of isolated NCX1 KO AVN tissue showed slowed or absent AVN automaticity compared to WT, as action potential and calcium transient rates decreased by 94% (p <0.05) and 78% (p <0.01), respectively. To characterize the conduction properties of the AVN in NCX1 KO mice, we used in vivo catheter pacing of the atrium and simultaneous recording of surface ECG. Resting heart rates in control mice were 542 +/- 16.65 BPM (cycle length of 111 +/- 3.32 ms) and could be paced up to 954 +/- 18.86 BPM (63 +/- 1.23 ms) before developing atrioventricular block (43% increase). In line with their slow junctional rhythm at rest, NCX KO mice had a reduced resting heart rate of 356.8 +/- 12.24 BPM (169 +/- 5.83 ms) and could only tolerate a 17% increase in pacing rate (436 +/-27.48 BPM or 140 +/- 10.44 ms) before exhibiting AV Block. Thus, lack of NCX1 in atrial tissue results in abnormal AVN automaticity and conduction. These data indicate an essential role for NCX1 in AVN function.

P6538Validity of two weeks daily self pulse-palpation for opportunistic screening for atrial fibrillation among patients 65 years and older

Abstract Background Pulse-palpation is recommended (ESC IA) for single time-point screening for atrial fibrillation (AF). AF may, however, be paroxysmal which can make AF detection difficult to detect on single time-point measurement. Intermittent ECG recording is a sensitive method to detect AF. However, the role of pulse-palpation for AF detection has not been validated against simultaneous ECG recordings. Purpose To study the validity of AF detection using self pulse-palpation simultaneously with hand-hold ECG recording 3 times daily for two weeks for AF. Method Patients 65 years and older visiting four primary health care centers, four any reason, were invited to AF screening from July 2017 to December 2018. Hand-held intermittent ECG recordings, 30 seconds three times a day, was offered to participants without AF for a period of 2 weeks. Patients were instructed how to take their own pulse, simultaneously with intermittent ECG measurement and in written to note whether it was irregular or not. Results A total of 1010 patients (mean age 73 years, 61% women) participated in the study, 27 new cases of AF (mostly paroxysmal) were detected. Totally 53 782 simultaneous ECG-recordings and pulse-measurements were registered. AF was verified in 311 ECG-recordings but the pulse was palpated as irregular only in 77 of these recordings (25% sensitivity per measurement-occasion). Of those 27 detected AF cases, 15 cases felt their pulse as irregular at least at once occasion (56% sensitivity per individuals). 187 individuals without AF felt their pulse as irregular in at least one occasion. The specificity per measurement-occasion and per individuals were 98% and 81% respectively. Diagnostic odds ratio was 5.3. AF 27 patients No AF 983 patients Irregular pulse 202 individuals 15 187 Regular pulse 808 individuals 12 796 Sensitivity 56% Specificity 81% Positive Predictive Value 7% Negative Predictive Value 99% AF 311 measurements No AF 53471 measurements Irregular pulse 1046 measurements 77 969 Regular pulse 52,736 measurements 234 52,502 Sensitivity 25% Specificity 98% Positive Predictive Value 7% Negative Predictive Value 99% Conclusion AF screening using own pulse-palpation 3 times daily for two weeks is feasible but has a low sensitivity for AF detection. Acknowledgement/Funding This study was supported by the Swedish Heart and Lung Foundation, Pfizer, Boehringer-Ingelheim and Bayer

Automatic Removal of Cardiac Interference (ARCI): A New Approach for EEG Data.

EEG recordings are generally affected by interference from physiological and non-physiological sources which may obscure underlying brain activity and hinder effective EEG analysis. In particular, cardiac interference can be caused by the electrical activity of the heart and/or cardiovascular activity related to blood flow. Successful EEG application in sports science settings requires a method for artifact removal that is automatic and flexible enough to be applied in a variety of acquisition conditions without requiring simultaneous ECG recordings that could restrict movement. We developed an automatic method for classifying and removing both electrical cardiac and cardiovascular artifacts (ARCI) that does not require additional ECG recording. Our method employs independent component analysis (ICA) to isolate data independent components (ICs) and identifies the artifactual ICs by evaluating specific IC features in the time and frequency domains. We applied ARCI to EEG datasets with cued artifacts and acquired during an eyes-closed condition. Data were recorded using a standard EEG wet cap with either 128 or 64 electrodes and using a novel dry electrode cap with either 97 or 64 dry electrodes. All data were decomposed into different numbers of components to evaluate the effect of ICA decomposition level on effective cardiac artifact detection. ARCI performance was evaluated by comparing automatic ICs classifications with classifications performed by experienced investigators. Automatic and investigator classifications were highly consistent resulting in an overall accuracy greater than 99% in all datasets and decomposition levels, and an average sensitivity greater than 90%. Best results were attained when data were decomposed into a fewer number of components where the method achieved perfect sensitivity (100%). Performance was also evaluated by comparing automatic component classification with externally recorded ECG. Results showed that ICs automatically classified as artifactual were significantly correlated with ECG activity whereas the other ICs were not. We also assessed that the interference affecting EEG signals was reduced by more than 82% after automatic artifact removal. Overall, ARCI represents a significant step in the detection and removal of cardiac-related EEG artifacts and can be applied in a variety of acquisition settings making it ideal for sports science applications.

Efficacy and safety of carvedilol in combination with bronchodilators in patients with CHF of ischemic origin and COPD.

Objective. To study the effectiveness of carvedilol, tiotropium bromide and indacaterol in complex therapy on clinical and functional parameters in patients with CHF of ischemic origin in combination with COPD.&#x0D; Material and methods. The study included 98 patients aged 45–75 years, suffering from CHF II–III FC with post-infarction cardiosclerosis, LV ejection fraction less than 45% and COPD of 2–3 degrees (GOLD). In addition to basic therapy all patients received carvedilol and were divided into 3 groups: tiotropium was administered in the 1st (36 people), indacaterol in the 2nd (32 people), and a combination of tiotropium and indacaterol in the 3rd (30 people). At baseline and after 6 months of follow-up, the clinical condition, exercise tolerance were assessed, the quality of life was assessed using the clinical state rating scale (SHOX) and MRC dyspnea scale, questionnaires of University of Minnesota (MLHFQ) and St. George’s Hospital (SGRQ). EchoCG, 24-hour blood pressure monitoring with simultaneous ECG recording, and spirometry test were performed.&#x0D; Results. The use of carvedilol in combination with tiotropium and indacaterol (both in mono and in combination) as part of complex therapy of CHF II–III FC of ischemic genesis with COPD is safe and effective: the clinical condition of patients improved, quality of life, frequency and duration of ischemia episodes decreased significantly, significantly increased LVEF, decreased pulmonary hypertension, improved condition of the bronchopulmonary system.

Robust estimation of cardiac inter-beat intervals using photoplethysmography

The feasibility of using photoplethysmography (PPG) for estimating heart rate variability (HRV) has been the subject of many recent studies with contradicting results. Accurate measurement of cardiac cycles is more challenging in PPG than ECG due to its inherent characteristics.We developed a PPG-only algorithm by computing a robust set of medians of the interbeat intervals between adjacent peaks, upslopes, and troughs. Abnormal intervals are detected and excluded by applying our criteria.We tested our algorithm on a large database from high-risk ICU patients containing arrhythmias and significant amounts of artifact. The average difference between PPG-based and ECG-based parameters is < 1% for pNN50, < 1 bpm for meanHR, < 1 ms for SDNN, < 3 ms for meanNN, and < 4 ms for SDSD and RMSSD.Our performance testing shows that the pulse rate variability (PRV) parameters are comparable to the HRV parameters from simultaneous ECG recordings.

Efficient noise-tolerant estimation of heart rate variability using single-channel photoplethysmography

BackgroundThe feasibility of using photoplethysmography (PPG) for estimating heart rate variability (HRV) has been the subject of many recent studies with contradicting results. Accurate measurement of cardiac cycles is more challenging in PPG than ECG due to its inherent characteristics. MethodsWe developed a PPG-only algorithm by computing a robust set of medians of the interbeat intervals between adjacent peaks, upslopes, and troughs. Abnormal intervals are detected and excluded by applying our criteria. ResultsWe tested our algorithm on a large database from high-risk ICU patients containing arrhythmias and significant amounts of artifact. The average difference between PPG-based and ECG-based parameters is <1% for pNN50, <1bpm for meanHR, <1ms for SDNN, <3ms for meanNN, and <4ms for SDSD and RMSSD. ConclusionsOur performance testing shows that the pulse rate variability (PRV) parameters are comparable to the HRV parameters from simultaneous ECG recordings.

Investigation of a Micro-test for Circulatory Autonomic Nervous System Responses.

Aims and Objectives: The autonomic nervous system plays an important role in homeostasis and organismic recreation, control of immune function, inflammation, and bone growth. It also regulates blood pressure and orthostasis via vagal and sympathetic pathways. Besides recording of heart rate variability (HRV), which characterizes medium (1–5 min) and long term (circadian) autonomic tone or modulation, no gentle tests of short-term autonomic reactivity and control are available. In 1976 Nogier described a short time cardiovascular response (“Réflexe Auriculo Cardiaque”, RAC) which could be used to investigate short term autonomic reactions without changing system characteristics and thus being repeatable in short intervals. In this paper, we investigated the possible application of the Nogier reaction as a micro-test for the identification of a disturbed sensitivity or reactivity of the autonomic nervous system.Methods: We statistically analyzed cardiovascular signals derived during the application of small repeated stimuli utilizing methods of signal averaging to characterize the physiological background. Specifically, the Nogier reaction was investigated using simultaneous recordings of ECG, pulse waves, and respiration.Results: Significant fast (delay 1–5 s) and slower (delay 6–12 s) cardio-autonomic responses to different stimuli which characterize short term were observed. From time characteristics and type of signals where they occur we deduce that fast changes observed in heart rate are vagal reactions to the small stimuli whereas slower changes observed in pulse waves stem from sympathetic nervous system responses.Conclusions: The investigated autonomic micro-test opens the possibility to differentially investigate both limbs of the autonomic nervous system with minimal stimuli. It can be performed within seconds and does not change the set point of the system in opposition to less subtle tests such as Valsalva maneuver. Therefore, it is well-suited for quick, repeated measurements of autonomic nervous system reactivity.

PocketECG: A New Noninvasive Method for Continuous and Real-Time ECG Monitoring-Initial Results in Children and Adolescents.

Long-term ECG is widely used in diagnosis and assessment of many cardiac symptoms which may be caused by dangerous arrhythmias that sometimes can be difficult to document. The PocketECG system is a new technological solution for a long-term, noninvasive, continuous and real-time ECG monitoring that provides automatic diagnosis of dysrhythmias. ECG data transmission occurs over a mobile network. The goal of this study was to assess the reliability of long-term ECG recordings acquired with the PocketECG system. One hundred and fifteen patients (43 girls and 72 boys) of an average age of 15.5±2.5years were examined at the Department of Cardiology at the Children's Memorial Health Institute. Two simultaneous 24-h ECG recordings were conducted: one with a Holter monitor and one with the PocketECG system. A linear correlation was demonstrated between the two methods with regard to the recorded QRS complexes [H=1173.0 (-1946.40; 4838.50)+PocketECG*0.98 (0.94; 1.02)]. Mean diurnal heart rhythms were comparable (p>0.05) despite the fact that the slowest and the fastest rates were different. The rate of detection for ventricular, supraventricular dysrhythmias and pauses in ventricular rhythm were comparable in both methods. The PocketECG system for continuous and real-time ECG recording is a reliable method for the assessment of heart rhythm and dysrhythmias in children and adolescents.

Atrial Electromechanical Properties in Inflammatory Bowel Disease

There is much evidence linking inflammation to the initiation and continuation of atrial fibrillation (AF). Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic systemic inflammatory disorders. Atrial electromechanical delay (EMD) has been known as an early marker of AF. The objectives of this study were to evaluate the atrial electromechanical properties in patients with IBD. Fifty-two patients with IBD and 26 healthy controls were recruited in the study. Twenty-five of patients with IBD were on active period, and the remaining 27 were on remission period. Atrial electromechanical properties were measured by using transthoracic echocardiography and tissue Doppler imaging and simultaneous surface ECG recording. Interatrial EMD, left intraatrial EMD, and right intraatrial EMD were calculated. Patients on activation with IBD had significantly prolonged left and right intraatrial EMDs and interatrial EMD compared to patients on remission (P = 0.048, P = 0.036, P < 0.001, respectively) and healthy controls (P < 0.001, for all comparisons). Left and right intraatrial EMDs and interatrial EMD were also found to be higher when patients on remission with IBD compared with healthy controls. No statistical difference was observed between UC and CD in terms of inter- and intraatrial EMDs. Atrial electromechanical conduction is prolonged in IBD, and exposure to chronic inflammation may lead to structural and electrophysiological changes in the atrial tissue that causes slow conduction. Measurement of atrial EMD parameters might be used to predict the risk for the development of AF in patients with IBD.

Analysis of heart sounds using time-frequency visual representations

Phonocardiogram (PCG) is a pre-eminent tool to visualise the normal and abnormal heart sounds which helps the physician in the early detection of cardiac murmurs. PCG is a non-stationary signal with the rapid changes in frequency within one cardiac cycle. Hence, the choice of proper segmentation technique is a crucial factor in determining the success or failure of expert systems in the automated analysis of PCG signals. The normal and abnormal PCG signals from the publicly available database were used in this study. Fast Fourier Transform (FFT) and Discrete Wavelet Transform (DWT) were implemented to visualise the various components in the PCG signals. When FFT was applied to the normal and abnormal PCG signals, the resultant spectrums for both the signals were not much distinguishable. S1 and S2 heart sounds had overlapping frequencies. Moreover, preserving the time and frequency resolution is imperative in analysing the abnormal signals. DWT was implemented and visualised using time-frequency indicators. The study concludes that the DWT is more preferred for analysing the non-stationary PCG signal and it would be a less expensive technique to visualise the heart sounds. Simultaneous recording of ECG and PCG signal will provide a better visualisation of cardiac murmurs.

Open platform, eight‐channel, portable bio‐potential and activity data logger for wearable medical device development

The design of a wearable, portable and reconfigurable physical activity and an eight-channel bio-potential data logger, capable of increasing compliance by enabling customised feedback (i.e. calories expenditure and amount of physical activity) is presented while recording clinically meaningful information regarding a subject's health. Here an application of the device to the cardio-vascular system comprising simultaneous recording of ECG and activity in both resting and under-stress conditions is presented (clinical trials are performed under the supervision of expert cardiologists at Prince of Wales Hospital NSW, Australia). The designed device (based around the low-power LPC1768 ARM processor and the bio-potential front-end ADS1298) is an open-source one and is provided under the GPL GNU 3.0 collaborative licence.