Continuous Electrocardiogram Monitoring Research Articles

Dynamic Risk Stratification of worsening heart failure using a Deep learning enabled Implanted Ambulatory Single lead ECG

Abstract Background and Aims Implantable loop recorders (ILRs) provide continuous single-lead ambulatory electrocardiogram (aECG) monitoring. It is unknown whether these aECGs could be used to identify worsening heart failure. Methods and results We linked ILR aECG from Medtronic device database to the LVEF measurements in Optum® de-identified electronic health record dataset. We trained an AI algorithm (aECG-CNN) on a dataset of 35,741 aECGs from 2247 patients to identify left ventricular ejection fraction (LVEF) ≤ 40% and assessed its performance using the area under the receiver operating characteristic curve (AUROC). aECG-CNN was then used to identify patients with increasing risk of heart-failure hospitalization in a real-world cohort of 909 patients with prior heart failure diagnosis. This dataset provided 12,467 follow up monthly evaluations, with 201 heart failure hospitalizations. For every month, time series features from these predictions were used to categorize patients into high and low risk groups and predict heart failure hospitalization in the next month. The risk of heart-failure hospitalization in the next 30 days was significantly higher in the cohort that aECG-CNN identified as high risk (hazard ratio 1·89; 95% confidence interval 1·28-2·79; p = 0·001) compared to low risk, even after adjusting patient demographics. (Hazard ratio 1·88, 1.27 to 2·79 p = 0·002). Conclusion An AI algorithm trained to detect LVEF ≤40% using ILR aECGs can also readily identify patients at increased risk for HF hospitalizations by monitoring changes in the probability of heart failure over 30 days.

New-onset atrial fibrillation detected by ambulatory ECG monitoring after transcatheter aortic valve implantation.

Little is known about the occurrence of subclinical new-onset atrial fibrillation (NOAF) after transcatheter aortic valve implantation (TAVI). We aimed to evaluate the incidence, predictors, and clinical impact of subclinical NOAF after TAVI. This was a multicentre study, including patients with aortic stenosis (AS) and no previous atrial fibrillation undergoing TAVI, with continuous ambulatory electrocardiogram (AECG) monitoring after TAVI. A total of 700 patients (79±8 years, 49% female, Society of Thoracic Surgeons score 2.9% [1.9-4.0]) undergoing transarterial TAVI were included (85% balloon-expandable valves). AECG was started 1 (0-1) day after TAVI (monitoring time: 14<span class="eij_ref" contenteditable="false" data-id="26797">12</span><span class="eij_ref" contenteditable="false" data-id="18749">13</span><span class="eij_ref" contenteditable="false" data-id="26798">14</span> days). NOAF was detected in 49 patients (7%), with a median duration of 185 (43-421) minutes (atrial fibrillation burden of 0.7% [0.3-2.8]). Anticoagulation was started in 25 NOAF patients (51%). No differences were found in baseline or procedural characteristics, except for a higher AS severity in the NOAF group (peak gradient: no NOAF: 71.9±23.5 mmHg vs NOAF: 85.2±23.8 mmHg; p=0.024; mean gradient: no NOAF: 44.4±14.7 mmHg vs NOAF: 53.8±16.8 mmHg; p=0.004). In the multivariable analysis, the baseline mean transaortic gradient was associated with a higher risk of NOAF after TAVI (odds ratio 1.04, 95% confidence interval: 1.01-1.06 for each mmHg; p=0.006). There were no differences between groups in all-cause mortality (no NOAF: 4.7% vs NOAF: 0%; p=0.122), stroke (no NOAF: 1.4% vs NOAF: 2.0%; p=0.723), or bleeding (no NOAF: 1.9% vs NOAF: 4.1%; p=0.288) from the 30-day to 1-year follow-up. NOAF detected with AECG occurred in 7% of TAVI recipients and was associated with a higher AS severity. NOAF detection determined the start of anticoagulation therapy in about half of the patients, and it was not associated with an increased risk of clinical events at 1-year follow-up.

Ventricular bigeminy associated with myocardial ischemia in a dog with a colonic torsion: a case report

BackgroundVentricular bigeminy due to myocardial ischemia has been reported in humans as well as in canine patients with obstructive gastrointestinal diseases. This is the first case report of ventricular bigeminy in a dog with a colonic torsion that resolved after fluid resuscitation and restoration of myocardial perfusion.Case presentationAn 11-year-old, male neutered mixed breed dog presented with a one day history of vomiting, tenesmus, and lethargy. Physical examination identified an irregular heart rhythm and intermittent pulse deficits. A ventricular arrhythmia represented by ventricular premature complexes (VPCs) organized in bigeminy, was appreciated on a 3-lead electrocardiogram (ECG) with a single lead (II) view. Abdominal radiographs confirmed a colonic torsion. Prior to anesthetic induction, ventricular bigeminy was non responsive to fentanyl or lidocaine. The patient was anesthetized and intravascular volume deficit was identified by dampened plethysmographic wave amplitude (plethysomographic variability), audible softening of the Doppler sound, and more pronounced pulse deficits. Fluid resuscitation was achieved with a combination of intravenous crystalloid and colloid fluid therapy comprising 7.2% hypertonic saline and 6% hetastarch. The patient’s cardiac rhythm converted to normal sinus after fluid resuscitation. The colonic torsion was surgically corrected. The patient recovered well from anesthesia and was ultimately discharged from the hospital 5 days later.ConclusionsThe present case report highlights that myocardial ischemia can lead to ventricular arrythmias, such as ventricular bigeminy. This is the first documented case of ventricular bigeminy in the canine patient with a colonic torsion. Assessment of patient volume status and appropriate fluid resuscitation along with continuous electrocardiogram (ECG) monitoring are vital to patient stability under general anesthesia.

Comparison of continuous 24-hour and 14-day ECG monitoring for the detection of cardiac arrhythmias in patients with ischemic stroke or syncope.

Previous studies show that using 12-lead electrocardiogram (ECG) or 24-h ECG monitor for the detection of cardiac arrhythmia events in patients with stroke or syncope is ineffective. The 14-day continuous ECG patch has higher detection rates of arrhythmias compared with conventional 24-h ECG monitoring in patients with ischemic stroke or syncope. This cross-sectional study of patients with newly diagnosed ischemic stroke or syncope received a 24-h ECG monitoring and 14-day continuous cardiac monitoring patch and the arrhythmia events were measured. This study enrolled 83 patients with ischemic stroke or syncope. The detection rate of composite cardiac arrhythmias was significantly higher for the 14-day ECG patch than 24-h Holter monitor (69.9% vs. 21.7%, p = .006). In patients with ischemic stroke, the detection rates of cardiac arrhythmias were 63.4% for supraventricular tachycardia (SVT), 7% for ventricular tachycardia (VT), 5.6% for atrial fibrillation (AF), 4.2% for atrioventricular block (AVB), and 1.4% for pause by 14-day ECG patch, respectively. The significant difference in arrhythmic detection rates were found for SVT (45.8%), AF (6%), pause (1.2%), AVB (2.4%), and VT (9.6%) by 14-day ECG patch but not by 24-h Holter monitor in patients with ischemic stroke or syncope. A 14-day ECG patch can be used on patients with ischemic stroke or syncope for the early detection of AF or other cardiac arrhythmia events. The patch can be helpful for physicians in planning medical or mechanical interventions of patients with ischemic stroke and occult AF.

Hemodialysis Efficiency Predictor in End-Stage Kidney Disease Using Real-Time Heart Rate Variability.

Autonomic dysfunction as a long-term complication may occur in end-stage kidney disease (ESKD) patients and can be diagnosed using heart rate variability (HRV) analyzed from electrocardiogram (ECG) recordings. There is limited data about HRV using real-time ECG to predict hemodialysis (HD) efficiency in patients with ESKD who are routinely doing HD in the real world. A total of 50 patients (62.1 ± 10.7 years) with ESKD underwent continuous real-time ECG monitoring (237.4 ± 15.3 min) during HD for HRV using remote monitoring system. Their electrolyte levels were checked before and after HD. We compared HRV according to electrolyte levels. During the monitor, we checked the ECG and electrolyte levels simultaneously a total of 2374 times for all of the patients. Both time and frequency domain HRV were higher when the patients had lower K+ level (<0.5 mEq/L) and P+ level change (<2 mEq/L) before and after HD as compared to those with a higher K+ level (≥0.5 mEq/L) and P+ level change (≥2 mEq/L). Additionally, patients with lower K+ and P+ level change groups had higher incidences of arrhythmic events including atrial/ventricular premature complexes, despite no difference of mean heart rate (p < 0.001). Higher HRV was independently associated with a poorly controlled K+ and P+ level during HD in patients with ESKD. This is consistently evidenced by the independent association between higher HRV, K+ and P+ levels in real time, suggesting that low electrolyte changes before and after HD alone may cause cardiac autonomic dysfunction.

Wearable Technology for Monitoring Electrocardiograms (ECGs) in Adults: A Scoping Review.

In the rapidly evolving landscape of continuous electrocardiogram (ECG) monitoring systems, there is a heightened demand for non-invasive sensors capable of measuring ECGs and detecting heart rate variability (HRV) in diverse populations, ranging from cardiovascular patients to sports enthusiasts. Challenges like device accuracy, patient privacy, signal noise, and long-term safety impede the use of wearable devices in clinical practice. This scoping review aims to assess the performance and safety of novel multi-channel, sensor-based biopotential wearable devices in adults. A comprehensive search strategy was employed on four databases, resulting in 143 records and the inclusion of 12 relevant studies. Most studies focused on healthy adult subjects (n = 6), with some examining controlled groups with atrial fibrillation (AF) (n = 3), long QT syndrome (n = 1), and sleep apnea (n = 1). The investigated bio-sensor devices included chest-worn belts (n = 2), wrist bands (n = 2), adhesive chest strips (n = 2), and wearable textile smart clothes (n = 4). The primary objective of the included studies was to evaluate device performance in terms of accuracy, signal quality, comparability, and visual assessment of ECGs. Safety findings, reported in five articles, indicated no major side effects for long-term/continuous monitoring, with only minor instances of skin irritation. Looking forward, there are ample opportunities to enhance and test these technologies across various physical activity intensities and clinical conditions.

Gender and age characteristics and atrial fibrillation during long-term telemonitoring of the ECG

The aim – to evaluate the possibilities of long-term patch monitoring of the electrocardiogram (ECG) to determine gender and age characteristics of the frequency of detection of atrial fibrillation (AF). Materials and methods. A total of 1,123 patients participated in this 2-year (2021–2023) retrospective multicenter study. Long-term ECG monitoring was performed at the referral of internists and cardiologists of 30 health care institutions according to various clinical indications for this study. For long-term monitoring of the ECG, the innovative device «Mawi Heart Patch» was used – a disposable two-channel device with the possibility of continuous recording of the ECG for up to 7 days. The primary analysis of the records was carried out using Cardio.ai artificial intelligence algorithms, re-decryption and validation by certified doctors. Results. The average age of the study participants was (50.2 ± 16.65) years. There were 599 (53.3 %) women, 524 (46.6 %) men. The average time of ECG monitoring was (81.03 ± 18.5) hours, 74.35 % of the participants had continuous ECG monitoring for 3 days, 20.75 % for 4 days, and 2.58 % for 5 days. In total, AF was diagnosed in 7.93 % of patients, in particular, women and men were 6.51 % and 9.54 % respectively (p &gt; 0.05). In elderly patients, AF was diagnosed statistically significantly more often than in middle-aged patients (18.5 and 3.6 %, respectively, p ˂ 0.001). Among all age groups, the highest frequency of detection of AF was in participants over 75 years old, compared to young (28.8 % vs 3.6 %, p ˂ 0.001) and middle-aged patients (28.8 vs 18.5 %, p ˂ 0.05). Conclusions. The study did not reveal a gender difference in the frequency of diagnosing AF. In patients over 50 years, a significant increase in the frequency of detection of AF was recorded, which tends to increase in the following age periods and reaches a maximum in long-livers (over 90 years). The use of long-term patch ECG monitoring in patients of older age groups expands diagnostic possibilities and makes it possible to prevent complications in time.

Contactless Electrocardiogram Monitoring With Millimeter Wave Radar

The electrocardiogram (ECG) has always been an important biomedical test to diagnose cardiovascular diseases. Current approaches for ECG monitoring are based on body attached electrodes leading to uncomfortable user experience. Therefore, contactless ECG monitoring has drawn tremendous attention, which however remains unsolved. In fact, cardiac electrical-mechanical activities are coupling in a well-coordinated pattern. In this paper, we achieve contactless ECG monitoring by breaking the boundary between the cardiac mechanical and electrical activity. Specifically, we develop a millimeter-wave radar system to contactlessly measure cardiac mechanical activity and reconstruct ECG without any contact in. To measure the cardiac mechanical activity comprehensively, we propose a series of signal processing algorithms to extract 4D cardiac motions from radio frequency (RF) signals. Furthermore, we design a deep neural network to solve the cardiac related domain transformation problem and achieve end-to-end reconstruction mapping from RF input to the ECG output. The experimental results show that our contactless ECG measurements achieve timing accuracy of cardiac electrical events with median error below 14ms and morphology accuracy with median Pearson-Correlation of 90% and median Root-Mean-Square-Error of 0.081mv compared to the groudtruth ECG. These results indicate that the system enables the potential of contactless, continuous and accurate ECG monitoring.

The Utility of a Novel Electrocardiogram Patch Using Dry Electrodes Technology for Arrhythmia Detection During Exercise and Prolonged Monitoring: Proof-of-Concept Study.

Accurate detection of myocardial ischemia and arrhythmias during free-living exercise could play a pivotal role in screening and monitoring for the prevention of exercise-related cardiovascular events in high-risk populations. Although remote electrocardiogram (ECG) solutions are emerging rapidly, existing technology is neither designed nor validated for continuous use during vigorous exercise. In this proof-of-concept study, we evaluated the usability, signal quality, and accuracy for arrhythmia detection of a single-lead ECG patch platform featuring self-adhesive dry electrode technology in individuals with chronic coronary syndrome. This sensor was evaluated during exercise and for prolonged, continuous monitoring. We recruited a total of 6 consecutive patients with chronic coronary syndrome scheduled for an exercise stress test (EST) as part of routine cardiac follow-up. Traditional 12-lead ECG recording was combined with monitoring with the ECG patch. Following the EST, the participants continuously wore the sensor for 5 days. Intraclass correlation coefficients (ICC) and Wilcoxon signed rank tests were used to assess the utility of detecting arrhythmias with the patch by comparing the evaluations of 2 blinded assessors. Signal quality during EST and prolonged monitoring was evaluated by using a signal quality indicator. Additionally, connection time was calculated for prolonged ECG monitoring. The comfort and usability of the patch were evaluated by a web-based self-assessment questionnaire. A total of 6 male patients with chronic coronary syndrome (mean age 69.8, SD 6.2 years) completed the study protocol. The patch was worn for a mean of 118.3 (SD 5.6) hours. The level of agreement between the patch and 12-lead ECG was excellent for the detection of premature atrial contractions and premature ventricular contractions during the whole test (ICC=0.998, ICC=1.000). No significant differences in the total number of premature atrial contractions and premature ventricular contractions were detected neither during the entire exercise test (P=.79 and P=.18, respectively) nor during the exercise and recovery stages separately (P=.41, P=.66, P=.18, and P=.66). A total of 1 episode of atrial fibrillation was detected by both methods. Total connection time during recording was between 88% and 100% for all participants. There were no reports of skin irritation, erythema, or pain while wearing the patch. This proof-of-concept study showed that this innovative ECG patch based on self-adhesive dry electrode technology can potentially be used for arrhythmia detection during vigorous exercise. The results suggest that the wearable patch is also usable for prolonged continuous ECG monitoring in free-living conditions and can therefore be of potential use in cardiac rehabilitation and tele-monitoring for the prevention of exercise-related cardiovascular events. Future efforts will focus on optimizing signal quality over time and conducting a larger-scale validation study focusing on both arrhythmia and ischemia detection.

Real-time heart rate variability according to ambulatory glucose profile in patients with diabetes mellitus.

Autonomic neuropathy commonly occurs as a long-term complication of diabetes mellitus (DM) and can be diagnosed based on heart rate variability (HRV), calculated from electrocardiogram (ECG) recordings. There are limited data on HRV using real-time ECG and ambulatory glucose monitoring in patients with DM. The aim of this study was to investigate real-time HRV according to ambulatory glucose levels in patients with DM. A total of 43 patients (66.3 ± 7.5 years) with DM underwent continuous real-time ECG monitoring (225.7 ± 107.3 h) for HRV and ambulatory glucose monitoring using a remote monitoring system. We compared the HRV according to the ambulatory glucose profile. Data were analyzed according to the target in glucose range (TIR). There were no significant differences in the baseline characteristics of the patients according to the TIR. During monitoring, we checked ECG and ambulatory glucose levels (a total of 15,090 times) simultaneously for all patients. Both time- and frequency-domain HRVs were lower when the patients had poorly controlled glucose levels (TIR < 70%) compared with well controlled glucose levels (TIR > 70%). In addition, heart and respiratory rates increased with real-time glucose levels (P < 0.001). Poorly controlled glucose levels were independently associated with lower HRV in patients with DM. This was further substantiated by the independent continuous association between real-time measurements of hyperglycemia and lower HRV. These data strongly suggest that cardiac autonomic dysfunction is caused by elevated blood sugar levels.

Routine transthoracic echocardiography in ischaemic stroke or transient ischaemic attack of undetermined cause: aprospective multicentre study.

Guidelines recommend routine transthoracic echocardiography (TTE) after ischaemic stroke or transient ischaemic attack of undetermined cause; yet, only limited scientific evidence exists. Therefore, we aimed to determine in these patients the prevalence of TTE-detected major cardiac sources of embolism (CSE), which are abnormalities leading to therapeutic changes. Six Dutch hospitals conducted aprospective observational study that enrolled patients with ischaemic stroke or transient ischaemic attack of undetermined cause. Patients underwent TTE after comprehensive diagnostic evaluation on stroke units, including blood chemistry, 12-lead electrocardiogram (ECG), ≥ 24 h continuous ECG monitoring, brain imaging and cervical artery imaging. Primary outcome measure was the proportion of patients with TTE-detected major CSE. From March 2018 to October 2020, 1084 patients, aged 66.6 ± 12.5 years, were enrolled; 456 (42.1%) patients were female and 869 (80.2%) had ischaemic stroke. TTE detected major CSE in only 11(1.0%) patients. Ten (90.9%) of these patients also had major ECG abnormalities (previous infarction, major repolarisation abnormalities, or previously unknown left bundle branch block) that would have warranted TTE assessment regardless of stroke evaluation. Such ECG abnormalities were present in 11.1% of the total study population. Asingle patient (0.1%) showed amajor CSE despite having no ECG abnormality. This multicentre cross-sectional study in patients who-after workup on contemporary stroke units-were diagnosed with ischaemic stroke or transient ischaemic attack of undetermined cause found TTE-detected major CSE in only 1% of all patients. Most of these patients also had major ECG abnormalities. These findings question the value of routine TTE assessment in this clinical setting.

Can heart rate variability identify a high-risk state of upcoming seizure?

Heart rate variability (HRV) is an accessible and convenient means to assess the sympathetic/parasympathetic balance. Autonomic dysfunctions may reflect a pro-ictal state and occur before the seizure onset. Previous studies have reported HRV-based models to identify preictal states in continuous electrocardiogram (EKG) monitoring. Here, we evaluated the ability of HRV metrics extracted from daily single resting-state periods to estimate the risk of upcoming seizure(s) using probabilistic forecasts. Daily standardized 10-min vigilance-controlled EKG periods were recorded in 15 patients with drug-resistant focal epilepsy who underwent intracerebral electroencephalography (EEG). Analyses of a total of 156 periods, based on machine learning approaches, suggested that HRV features can identify preictal states with a median AUC of 0.75 [0.68;0.99]. Pseudoprospective daily forecasts yielded a median Brier score of 0.3 [0.18;0.48]. About 60% of preictal days were correctly forecasted, while false positive predictions were noticed in 24% of interictal days. Daily resting HRV seems to capture information on autonomic variations that may reflect a pro-ictal state. The method could be embedded in an ambulatory clinical seizure prediction device, but additional modalities (prodromes, EEG-based features, etc.) should be associated to improve its performance.

Stroke on ECG: a cerebral T-wave change secondary to acute carbon monoxide poisoning

In clinical management of carbon monoxide (CO) poisoning, serum cardiac enzyme biomarkers and electrocardiogram (ECG) are both highly recommended emergency check-ups to evaluate myocardial injuries. Medical imaging – including head CT or MRI – are not routine for CO poisoning emergency management. We herein report on a comatose patient who was diagnosed with cerebral infarction secondary to 24 hours previous acute CO poisoning, warned by a typical cerebral-type T waves on ECG in advance, and confirmed by a head MRI. Fortunately, the patient made a full recovery based on a timely treatment with medications and hyperbaric oxygen (HBO2) therapy. We would like to propose that a vital, stable, conscious CO poisoning patient who remains a higher risk for hemorrhagic or ischemic stroke should be closely monitored for potential neurological abnormalities, and a continuous ECG monitoring should be reinforced throughout the treatment. A head MRI or CT is a priority in evaluating the secondary cerebral stroke and should be arranged immediately in the event of an abnormal ECG or if unusual new symptoms are apparent.

Magnetic Manipulation of Locomotive Liquid Electrodes for Wireless Active Cardiac Monitoring.

For electrocardiogram (ECG) detection, the position of conventional patch-type electrodes based on solid-state metals are difficult to manipulate after attachment and also can lead to poor interface with stretchable, rough skin surfaces. Herein, we present a liquid form of ECG electrodes that can be magnetically reconfigured on human skin by providing its conformal interfacing. These electrodes consist of biocompatible liquid-metal droplets where magnetic particles are homogeneously dispersed, and their conformal contact with skin can yield significantly low impedance as well as high signal-to-noise ratio of ECG peaks. These electrodes are also capable of complex motions such as linear movements, splitting, and merging under external magnetic fields. Furthermore, magnetic manipulation of each electrode position on human skin enables precise monitoring of ECG signals with the change in ECG vectors. The integration of liquid-state electrodes with electronic circuitry demonstrates wireless and continuous ECG monitoring while magnetically moving this entire system on human skin.

Flow diagram of the differential diagnosis and clinical decision making in a rare case of contrast-induced encephalopathy following cardiac catheterization: a case report

BackgroundContrast-induced encephalopathy (CIE) is considered as an uncommon complication following cardiac catheterization. Due to the varied manifestations, CIE has no formal diagnostic criteria. In fact, the incidence of CIE may be greatly underestimated because of the difficulty in its differential diagnosis with other cerebrovascular complications. Thus, making a flow diagram according to patients’ clinical symptoms and examinations after cardiac catheterization to help clinicians diagnose CIE is important and needed.Case presentationIn this report, we describe a case of probable CIE in a 66-year-old Chinese man with hypertension who underwent cardiac catheterization with stents placement in the bifurcation lesion, during which 80 ml iopromide contrast was used. About 2 h following the procedure, the patient lost his consciousness suddenly and suffered from a status epilepticus. Malignant arrhythmias were not found through continuous electrocardiogram monitoring, but mild ST-segment elevation was displayed in leads I and aVL. The echocardiography, plasma glucose and electrolyte levels were normal. Emergency re-angiography with percutaneous transluminal coronary angioplasty was performed in the culprit lesion, which involved 60 ml iopromide contrast. However, the patient remained unconsciousness and epilepticus. Non-contrast computed tomography (CT) of the head showed cortical and subarachnoid enhancement as well as prolonged retention of contrast media in the middle cerebral artery. With supportive treatment of intravenous hydration, sedative and dehydrant, the patient recovered 3 h later and finally discharged without any neurological deficits.ConclusionsCIE is an acute reversible encephalopathy induced by contrast media. It is exceptionally challenging to make the diagnosis of CIE following cardiac catheterization since there is a lack of consensus on the definition of CIE. Via this case we reviewed the related literatures, through which a flow diagram of the differential diagnosis and clinical decision making was given, which could help to differentiate CIE from other neurological complications following cardiac catheterization.

0613 Actigraphy-Based Sleep Disruption and Diurnal Biomarkers of Autonomic Function in Paroxysmal Atrial Fibrillation

Abstract Introduction Sleep architectural disruption is associated with atrial fibrillation (AF), however, associated autonomic influences remain unclear and it is unknown if this detriment persists during wakefulness. We hypothesize diurnal-patterned associations of sleep disruption and autonomic dysfunction in patients with paroxysmal AF Methods We analyzed data from the Sleep Apnea and Atrial Fibrillation Biomarkers and Electrophysiologic Atrial Triggers (SAFEBEAT) study designed to examine paroxysmal AF and sleep apnea involving simultaneous collection of continuous electrocardiogram monitoring (Heartrak Telemetry®) and actigraphy (Actiwatch GTX) for 7-21 days. Heart rate variability (HRV) measures in frequency and time domains were used as surrogates of autonomic function and averaged per sleep/wake per day. A linear mixed-effects model assuming compound symmetry correlation structure was used to assess the relationship of HRV with actigraphy-derived sleep data. Results The analytic sample (age 60.1±12 years, body mass index 32.6±6.7 kg/m², 36% female, 75% White) included 108 participants with paroxysmal AF. Significant associations were observed between sleep indices and HRV measures during wakefulness: a) Sleep latency with high-frequency power (HFP), b) total sleep time, wakefulness after sleep onset (WASO) and number of awakenings with low-frequency power (LFP), and c) Sleep efficiency with standard deviation of normal R-R intervals (SDNN) and coefficient of variation (CV). During sleep, a) total sleep time was associated with LFP/HFP ratio (LHR), and b) number of awakenings with LHR. Significant sleep-wake interactions were observed between a) Sleep latency and HFP, b) Sleep efficiency with SDNN and CV, c) WASO with SDNN, CV, and LFP, and d) number of awakenings with CV and LFP. Conclusion Our novel findings indicate actigraphy-based measures of sleep disruption were associated with autonomic function alterations and these relationships exhibited diurnal variability in patients with paroxysmal AF. Results provide unique insights into differential relationships of immediate (during sleep) versus sustained (during wakefulness) autonomic dysfunction related to sleep disruption which may contribute to atrial arrhythmogenesis Support (if any)

The use of a new ECG patch for exercise and prolonged monitoring: usability, evaluation of signal quality and utility to detect arrhythmias

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): ITEA. Background Accurate detection of myocardial ischemia and arrhythmia’s during free-living exercise could play a pivotal role in optimizing screening and monitoring of individuals with underlying cardiovascular disease. Although remote electrocardiogram (ECG) solutions are emerging rapidly, these applications are generally not designed nor validated for continuous use during vigorous exercise. Purpose In this proof-of-concept study, we evaluated the usability, signal quality and arrhythmia detection of a new self-adhesive dry electrode ECG patch, the Nighthawk Vital Signs patch, during exercise and prolonged continuous ECG monitoring in individuals with chronic coronary syndrome (CCS). Methods Six consecutive CCS patients scheduled for an exercise stress test as part of routine cardiac follow-up were recruited. The traditional 12-lead exercise ECG was combined with monitoring with the 1-lead patch. Following the exercise test, the subjects continuously wore the sensor for five days. Intraclass correlation coefficients (ICC) and Wilcoxon signed-rank tests were used to assess the utility to detect arrhythmias with the patch. Signal quality for ECG recording was evaluated by using a signal quality indicator (SQI) based on the average QRS complex. Connection time and signal-to-noise ratio (SNR) were additionally calculated for prolonged ECG monitoring. Comfort and usability of the patch were evaluated by an online questionnaire. Results Six male patients with CCS (mean age 69.8 ± 6.2 years) completed the protocol. The mean time the patch was worn, was 118.3 hours (SD 5.6). The level of agreement between the patch and the 12-lead ECG was excellent for amount of premature atrial contractions (PAC’s) and premature ventricular contractions (PVC’s) during exercise stage, recovery stage and total test duration (ICC = 0.998, 0.998, 1.000, 1.000, 0.998, 1.000). There were no significant differences in the total amount of PAC’s and PVC’s detected with both methods during the exercise test (p = 0.785 and 0.180, respectively). One episode of atrial fibrillation was detected identically on both recorded ECG’s. Signal quality based on average QRS SQI during exercise did decrease slightly during (sub)maximal effort. Total connection time during recording was above 88% in all subjects and the SNR was above the target limit of 18dB. There were no reports on skin irritation, erythema or pain. Conclusion The Nighthawk Vital Signs ECG patch based on self-adhesive dry electrodes technology can be used for accurate arrhythmia detection during vigorous exercise. The sensor is also usable for prolonged ECG monitoring in free-living conditions and can therefore be of potential use in cardiac rehabilitation and telemonitoring for prevention of exercise-related cardiovascular events. However, more research is needed in order to analyze the signal quality over time together with a larger-scale validation study focusing on both arrhythmia and ischemia detection.

P162 ARRHYTHMIC MITRAL VALVE PROLAPSE OCCURRING AS ABORTED SUDDEN CARDIAC DEATH

Abstract Mitral valve prolapse (MVP) is the common valvular heart disease, with a prevalence about 1–3% in the population. MVP is characterized on echocardiography by an abnormal systolic displacement of mitral valve leaflets into left atrium (LA) ≥ 2 mm above the mitral annulus. We described a clinical case of a 15 years–old boy with a first clinical presentation of out–of–hospital cardiac arrest related to ventricular fibrillation (VF) with a successful resuscitation after 2 DC shocks. Retrospectively, an episode of loss of awareness reported as post–minational. No familiar history of sudden cardiac death (SCD) or MVP was noticed. In the emergency room, the patient was hemodynamically unstable and was sedated and intubated. The surface electrocardiogram (ECG) showed sinus rhythm, QRS with fragmentation, and frequent monomorphic isolated premature ventricular contractions (PVCs) with RBBB/LAFB configuration.Frequent monomorphic PVCs with bigeminy was observed during continuous ECG monitoring, so the patient was treated with magnesium sulphate and metoprolol. The patient was subsequently weaned from ventilation support, presenting good gas exchange and without neurological sequalae. The 24h Holter monitoring showed an average of 53 bpm, extremely rare supraventricular extrasystoles, high incidence of monomorphic PVCs (23% of the total beats) with 4 couplets. Transthoracic echocardiography documented normal size and thickness with systolic function (GLS –21%, mild asynchrony of posterior basal segments), bi–leaflet prolapse associated to mild–moderate mitral regurgitation, and mitral annular disjunction (MAD) of 6.2 mm. The late gadolinium enhancement cardiac magnetic resonance showed bi–leaflet prolapse with mild insufficiency and maximum MAD 9 mm, mild LA dilatation, and slightly dilated both ventricles, without regional wall motion abnormalities; no scar or fibrosis at the late gadolinium enhancement was observed. According to guidelines, the patient received a subcutaneous implantable cardiac defibrillator for the secondary prevention of SCD and maintained under betablockers in order to control the arrhythmic burden. The genetic sampling did not show any pathogenetic mutation potentially related to cardiomyopathies or channelopathies. This case show an arrhythmic MVP complex with probably posterior papillary muscle source. The early PVCs with R/T constituted a possible trigger of VF. The betablocker therapy exhibited a full suppression of extrasystolic burden.

Core temperature decline prior to sleep onset is associated with nocturnal heart rate variability

Impaired thermoregulation is associated with poor sleep and autonomic dysfunction. Previous studies demonstrate an association between core body temperature (CBT) dipping and an increase in heart rate variability (HRV) prior to sleep onset. However, the relationship between the rate of CBT decline prior to sleep onset and nocturnal HRV has not been established. The purpose of this study was to investigate the relationship between the rate of CBT decline prior to sleep onset and nocturnal HRV in objectively poor sleepers. We hypothesized a blunted pre-sleep CBT decline would correspond to reduced nocturnal HRV. Fifteen participants (9 males, 6 females; age, 33±4 years; BMI 27±1 kg/m 2 ) underwent an 8-hour overnight sleep opportunity with continuous polysomnography (PSG) and 2-lead electrocardiogram monitoring. A temperature monitoring pill (CoreTempTM, HQ Inc., Palmetto, FL) was ingested with a standardized dinner to record CBT every 10 seconds throughout the sleep period. Core temperature was sampled every 5 minutes from the core temperature tracing one hour prior to sleep onset until final awakening. The rate of CBT decline prior to sleep onset was measured as the slope of CBT values from 1 hour prior to lights out until PSG sleep onset. Nocturnal HRV measures including the root mean squared of successive differences (RMSSD), percentage of R-R intervals (RRI) varying by greater than 50 ms (pNN50), and the high frequency (HF) power of the RRI were determined across the night in stage 2 (N2), stage 3 (SWS), and rapid eye movement (REM) sleep stages. Bivariate correlations were performed to assess the association between CBT rate of decline and nocturnal HRV measures. An inverse correlation was observed between the rate of CBT prior to sleep onset and the RRI in N2 (R= -0.743, p=0.002), SWS (R = -0.730, P = 0.002), and REM (R = -0.708, P = 0.003). Additionally, the rate of pre-sleep CBT decline was inversely correlated with time domain HRV measures in N2 (pNN50: R= -0.598, p= 0.019; RMSSD: R = -0.557, P = 0.031) and SWS (pNN50: R = -0.542, P = 0.037; RMSSD: R = -0.591, P = 0.020). A blunted rate of CBT was further correlated to decreased HF log10 in N2 (R= -0.592, p= 0.020) and REM (R= -0.602, p= 0.018). Our results indicate an association between blunted core temperature decline prior to sleep onset and reduced nocturnal HRV. These findings suggest that adequate thermoregulation prior to sleep onset may have lasting associations with nocturnal cardiac autonomic function. Support is provided by the National Institutes of Health (AA-024892, U54GM115371; P20GM103474). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

High-power chargers for electric vehicles: are they safe for patients with pacemakers and defibrillators?

Battery electric vehicle (BEV) sales and use are rapidly expanding. Battery electric vehicles, along with their charging stations, are a potential source of electromagnetic interference (EMI) for patients with cardiac implantable electronic devices (CIEDs). The new 'high-power' charging stations have the potential to create strong electromagnetic fields and induce EMI in CIEDs, and their safety has not been evaluated. A total of 130 CIED patients performed 561 charges of four BEVs and a test vehicle (350 kW charge capacity) using high-power charging stations under continuous 6-lead electrocardiogram monitoring. The charging cable was placed directly over the CIED, and devices were programmed to maximize the chance of EMI detection. Cardiac implantable electronic devices were re-interrogated after patients charged all BEVs and the test vehicle for evidence of EMI. There were no incidences of EMI, specifically no over-sensing, pacing inhibition, inappropriate tachycardia detection, mode switching, or spontaneous reprogramming. The risk of EMI on a patient-based analysis is 0/130 [95% confidence interval (CI) 0%-2%], and the risk of EMI on a charge-based analysis is 0/561 (95% CI 0%-0.6%). The effective magnetic field along the charging cable was 38.65 µT and at the charging station was 77.9 µT. The use of electric cars with high-power chargers by patients with cardiac devices appears to be safe with no evidence of clinically relevant EMI. Reasonable caution, by minimizing the time spent in close proximity with the charging cables, is still advised as the occurrence of very rare events cannot be excluded from our results.