Patch Monitoring Research Articles

Arrhythmia Detection is Improved by 14-Day Continuous Electrocardiography Patch Monitoring and CHA2DS2-VASc Score.

Arrhythmias are not always easy to capture because they are often paroxysmal or asymptomatic. Using the CHA2DS2-VASc score for arrhythmia risk assessment, a 14-day electrocardiography monitor patch was used to evaluate patients with no documented history of arrhythmia. Ninety-three patients (mean age 59.8 ± 12.0 years, 46.2% female) received 14-day electrocardiography telemonitoring, and 14 patients (15%) were diagnosed with arrhythmias during a follow-up of 1004.4 person-days (mean recorded days 10.8 ± 4.1). The patients who were detected to have arrhythmias were older and had a higher prevalence of heart failure and chronic kidney disease. The result showed that arrhythmias were more likely to develop during a 14-day monitoring period in the patients with a CHA2DS2-VASc score of ≥ 3 or ≥ 4. Atrioventricular block was more likely to be detected in the patients with a CHA2DS2-VASc score of ≥ 3 or ≥ 4 during 7-day or 14-day monitoring periods. Ventricular tachycardia was also more likely to be detected in the patients with a CHA2DS2-VASc score of ≥ 4 or ≥ 5 during a 14-day monitoring period. When evaluating the risk of arrhythmia, a CHA2DS2-VASc score of ≥ 3 or ≥ 4 was associated with a higher risk of any arrhythmias during a 14-day monitoring period, while a CHA2DS2-VASc score of ≥ 4 was associated with a higher risk of any arrhythmias during a 7-day monitoring period. The results may suggest that a 14-day monitoring period is more favorable to detect arrhythmias. Atrioventricular block and ventricular tachycardia were more likely to develop in the patients with a higher CHA2DS2-VASc score.

Arrhythmia patterns during and after hospitalization for COVID-19 infection detected via patch-based mobile cardiac telemetry

BackgroundCoronavirus infection is the cause of the current world-wide pandemic. Cardiovascular complications occur in 20–30% of patients with COVID-19 infection including myocardial injury and arrhythmias. Current understanding of specific arrhythmia type and frequency is limited. ObjectiveWe aimed to analyze arrhythmia type and frequency in patients with COVID infection, identifying arrhythmia patterns over time during hospitalization and post discharge utilizing a patch based mobile cardiac telemetry system. MethodsA prospective cohort study during the COVID-19 pandemic was performed. We included in our study patients hospitalized with COVID-19 infection who had a patch-based mobile telemetry device placed for cardiac monitoring. ResultsQuantitative reports for 59 patients were available for analysis. Arrhythmias were detected in 72.9% of patients and at a consistent frequency throughout the monitoring period in 52.9%–89.5% of patients daily. The majority of arrhythmias were SVT (59.3% of patients) and AF (22.0%). New onset AF was noted in 15.0% of all patients and was significantly associated with older age (OR 1.4 for 5 yrs. difference; 95% CI 1.03–2.13). Of 9 patients who were discharged with continued patch monitoring, 7 (78%) had arrhythmic events during their outpatient monitoring period. ConclusionIn COVID-19 patients arrhythmias were observed throughout hospitalization with a consistent daily frequency. Patients continued to exhibit cardiac arrhythmias after hospital discharge of a type and frequency similar to that seen during hospitalization. These findings suggest that the risk of arrhythmia associated with COVID infection remains elevated throughout the hospital course as well as following hospital discharge.

Abstract 10057: Subclinical Atrial Fibrillation is More Prevalent in Heart Failure with Preserved Ejection Fraction Compared to the General Population

Introduction: Atrial fibrillation (AF) is a common in patients with heart failure with preserved ejection fraction (HFpEF), and is associated with higher filling pressures, reduced exercise capacity, and reduced survival. The prevalence of subclinical AF in HFpEF remains unknown. Hypothesis: We hypothesized that subclinical AF was more prevalent in individuals with HFpEF when compared to individuals without clinical heart failure history. Methods: We evaluated subclinical AF in 101 HFpEF patients with no prior diagnosis of clinical AF using 14 day ambulatory ECG patch monitoring (Ziopatch XT, iRhythm Technologies). We compared the prevalence of subclinical AF in HFpEF with controls drawn from 3303 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) exam 6 follow-up, excluding those with known heart failure or high H2FpEF score who underwent the same ECG patch monitoring. Case-control comparisons of participants between the ages of 55 to 93 years were performed using multivariable logistic regression to adjust for demographic and clinical comorbidities, as well as patch monitoring duration. Results: 80 HFpEF patients and 1356 MESA participants were included. The HFpEF patients were younger (69 [63, 76] v. 72 [66, 80], p=0.02), more obese (BMI of 36 [30, 45] v. 27 [24, 30], p<0.001) and more likely to have diabetes (34 v. 21%, p=0.01). There was a higher proportion of African Americans in the HFpEF group (57.5 v. 22.8%, p<0.001). The prevalence of subclinical AF was 9.8% in HFpEF group and 6.2% in MESA participants. After multivariable adjustment for age, sex, race, body mass index, hypertension, diabetes, smoking pack-years and total analyzable time on ECG monitor there was a significantly higher odds of subclinical AF in HFpEF compared to MESA (OR 4.26 [1.2, 16.2], p=0.03). Conclusions: HFpEF patients have a higher prevalence of subclinical AF than the general population. Screening for atrial arrhythmias may be appropriate in HFpEF patients for timely initiation of thromboembolic prophylaxis, and may identify individuals at greater risk for clinical decompensation in light of the well documented risks associated with AF in HFpEF.

Abstract 10763: Atrial Fibrillation and Supraventricular Ectopy in Relation to Brain Morphology and Subclinical Vascular Brain Injury: The Multi-Ethnic Study of Atherosclerosis

Introduction: Atrial fibrillation (AF) increases stroke risk and is associated with accelerated cognitive decline. Information is mixed about the relationship of AF and other supraventricular (SV) arrhythmias with brain changes on magnetic resonance imaging (MRI). Hypothesis: Prevalent AF and SV ectopy are associated with reduced gray matter (GM) volume and subclinical vascular brain injury. Methods: In the Multi-Ethnic Study of Atherosclerosis (MESA), participants completed Zio Patch monitoring and brain MRI. Prevalent AF was estimated from ambulatory monitoring, hospital surveillance, Medicare claims, and MESA electrocardiogram (ECG). For secondary analyses, AF was categorized into continuous - AF during 100% of monitoring - and intermittent - prevalent AF with <100% AF during monitoring. Brain MRI measures included GM volume, white matter (WM) lesion volume, WM fractional anisotropy, and presence of cerebral microbleeds (CMBs). Linear and Poisson regression analyses were adjusted for cardiovascular risk factors and socioeconomic status. Results: In MESA, 967 participants without a history of stroke or transient ischemic attack (TIA) completed >24 hours of ECG monitoring (median, 14.0 days) and completed brain MRI a median 17 months later. Mean (standard deviation) age was 72 (8) years; 53% were women. A total of 116 participants had prevalent AF, of whom 20 had continuous AF. Compared with no AF, prevalent AF was associated with lower WM FA (-0.22 standard deviations, 95% CI: -0.39, -0.04) and higher prevalence of CMBs (prevalence ratio: 1.46, 95% CI: 1.18, 1.80). In secondary analyses, compared with no AF, continuous but not intermittent AF was associated with lower GM volume (-18.6 mL, 95% CI: -31.4, -5.8). Rates of premature atrial contractions and runs of SV tachycardia were not significantly associated with brain MRI measures. Conclusions: In a multi-ethnic sample free of a history of stroke or TIA, prevalent AF was associated with lower WM FA, a measure of WM injury, and presence of CMBs. These results highlight the importance of AF prevention for brain health. Further analysis of subclinical infarcts is needed in this sample, and study in other settings is needed to confirm whether greater AF burden is associated with reduced GM volume.

Abstract 10746: Left Atrial Strain and the Risk of Arrhythmias on Extended Ambulatory Cardiac Monitoring: The Multi-Ethnic Study of Atherosclerosis

Introduction: Abnormalities in left atrial (LA) function can be identified before the development of overt LA structural changes. Little is known about the relationship between LA mechanics and the risk of subclinical atrial and ventricular arrhythmias. Methods: 1,441 participants of the Multi-Ethnic Study of Atherosclerosis completed speckle-tracking echocardiography and Zio Patch monitoring from 2016-2018 (mean age 73 years, 52% female); participants in atrial fibrillation (AF) during echocardiography or cardiac monitoring were excluded. Absolute values of LA reservoir, booster pump, and conduit strain were measured. We evaluated associations of LA strain measures with atrial arrhythmias (presence of monitor-detected AF, AF burden, frequency of premature atrial contractions [PACs], frequency of supraventricular tachycardia [SVT] runs) and with ventricular arrhythmias (frequency of premature ventricular contractions, presence of non-sustained ventricular tachycardia [NSVT], frequency of NSVT runs). Primary analyses adjusted for demographic variables, blood pressure, smoking, diabetes, and clinical cardiovascular disease (4%). Results: Cardiac monitoring (median 14 days) detected AF in 3%. Each standard deviation (5.4%) lower (worse) LA reservoir strain was associated with a 64% higher risk of monitor-detected AF (95% CI 16-137%), 33% higher PAC frequency (95% CI 22-46%), and 15% higher SVT frequency (95% CI 7-24%). Adjustment for kidney function, NT-proBNP, LA volume, and LV ejection fraction and global longitudinal strain had little impact on associations. Findings were similar for LA booster pump strain and null for LA conduit strain (Figure). Associations of LA reservoir and booster pump strain with ventricular arrhythmias were completely attenuated after adjustment for LV function. Conclusions: In a multi-ethnic community-based cohort, abnormal LA mechanics may be an important risk factor for subclinical atrial arrhythmias.

Abstract 9886: Use of a Smartwatch and App Designed by Stroke Survivors for Atrial Fibrillation Detection in Older Adults After Stroke/Transient Ischemic Event: Preliminary Findings from an Ongoing Randomized Clinical Trial

Background: Atrial fibrillation (AF) is a common cause of ischemic stroke that, though critical to diagnose and treat, often goes undetected. Smartwatches are capable of AF detection, but little is known about their use among stroke survivors. In collaboration with stroke survivors and clinicians, we designed a smartphone-smartwatch system for AF detection. In our ongoing clinical trial, we are examining the performance and user experience of the system in older stroke survivors. Hypothesis: The system will be accurate for AF detection among stroke survivors compared to 14-day ECG patch monitoring; participants will find the system usable and will adhere to daily use over 30 days. Methods: The Pulsewatch study is an ongoing two-phased randomized controlled trial with randomization at two timepoints into control or intervention groups. Phase I (14 days) assesses accuracy and usability of the smartwatch and study app. Phase II (30 days) examines watch wear adherence. The intervention group receives a smartwatch with embedded AF detection and a smartphone app for rhythm and symptom tracking. Eligibility criteria are: > 50 years old, ischemic stroke in the past decade, and no major contraindications to anticoagulation therapy. System accuracy for AF detection is compared to an ECG patch monitor, and usability is assessed via the System Usability Scale. Adherence is defined as daily watch wear time over the monitoring period. Results: To date, 69 participants have been randomized into phase I and 36 into phase II (mean age 65, 41% female, 87% White). The smartwatch system demonstrated a sensitivity of 66.7% (95% CI: 9.4 - 99.2) and specificity of 92.6% (95% CI: 82.1 - 97.9) for detection of 3 AF cases over the 14 day period (91.2% accuracy) compared to the ECG patch. The mean usability score was 65/100 and on average, participants wore the watch on 12/30 days for an average of 1.8 hours (SD 0.7) daily. Conclusion: A smartwatch and app dyad demonstrated reasonable accuracy for AF detection and high usability, though adherence was modest. Use of commercial wearables for AF detection among stroke patients shows promise, but additional data from the ongoing Pulsewatch clinical trial will continue to inform strategies to maximize adherence to these devices among older adults.

Arrhythmia patterns in patients with COVID-19 infection during and post hospitalization detected via a patch-based mobile cardiac telemetry system

BackgroundCoronavirus infection (COVID-19) is the cause of the current world-wide pandemic. Cardiovascular complications occur in 20–30% of patients with COVID-19 infection including myocardial injury and arrhythmias. Current understanding of specific arrhythmia type and frequency is limited. In response to COVID-19 pandemic and overwhelmed hospital critical care and telemetry recourses, patch-based cardiac monitoring system received emergency Food and Drug Administration (FDA) approval for inpatient monitoring. A patch-based cardiac telemetry system has been shown to be useful for patient management during the COVID-19 pandemic and provides detailed analysis of cardiac rhythms.PurposeTo analyze arrhythmia type and frequency in patients with COVID-19 infection, identifying arrhythmia patterns over time during hospitalization and after discharge.MethodsA prospective cohort study during the COVID-19 pandemic was performed. We included patients hospitalized with COVID-19 infection who had a patch-based mobile telemetry device placed for cardiac monitoring. A quantitative analysis including type, frequency and duration of detected arrhythmias was performed at the end of the monitoring period.ResultsA total of 103 patients hospitalized with COVID-19 diagnosis underwent monitoring. Quantitative reports for 59 patients were available for analysis, among those 59% were males, median age 65 (IQR 56–76) yrs. Mean wear time was 6.8±5.0 days. Arrhythmias were detected in 72.9% of patients. Majority of arrhythmias were SVT (59.3% of patients) and AF (22.0%). Episodes of AF duration >30 min were detected in 12 patients. New onset AF was noted in 15.0% of patients and was significantly associated with age (OR 1.4 for 5 yrs difference; 95% CI 1.01–2.05). Brady arrhythmias (2nd degree, 3rd degree AV bock, pause≥3 seconds) were seen in 18.7% of patients. Arrhythmias were consistently detected throughout the monitoring period in 52.9%-89.5% of patients daily (Figure 1). In 9 patients who were discharged with continued patch monitoring, 3 patients (33.3%) had arrhythmic events during their outpatient monitoring period.ConclusionA majority of patients hospitalized with COVID-19 infection had arrhythmias detected by patch cardiac monitor. Arrhythmias were observed throughout hospitalization with a consistent daily frequency. Patients continued to exhibit cardiac arrhythmias after hospital discharge of a type similar to that seen during hospitalization. New onset AF often occurred and was associated with older age. Inpatient application of a patch cardiac telemetry with continued monitoring as outpatient is feasible and effective in detecting occult arrhythmias in patients with COVID-19 infection.Funding AcknowledgementType of funding sources: None. Daily frequency of arrhythmias detected

Delayed repolarization and ventricular tachycardia in patients with heart failure and preserved ejection fraction.

Sudden death is the most common mode of mortality in patients with heart failure and preserved ejection fraction (HFpEF). Ventricular arrhythmias (VA) have been suspected as the etiology but the supporting evidence in patients with HFpEF is scarce. We sought to investigate VA prevalence, and to determine if VA are associated with prolonged repolarization, in patients with HFpEF. In a retrospective case-control study design, Cedars-Sinai patients who underwent prolonged ambulatory electrocardiographic monitoring (Zio Patch) between 2016 and 2018 were screened for a clinical diagnosis of HFpEF. Patients with normal diastolic and systolic function who underwent Zio Patch monitoring were also reviewed as controls. Multivariable logistic regression was used to compare the prevalence of rhythm disturbances in patients with and without HFpEF. Ventricular tachycardia (VT) was more prevalent in patients with HFpEF (37% vs. 16% in controls, p = 0.001). Most episodes were non-sustained except for one case of sustained VT in a patient with HFpEF. Covariate-adjusted logistic regression including HFpEF diagnosis, age, sex, body mass index, and the presence of comorbidities revealed that only HFpEF was associated with increased risk of VT (relative risk 2.86, p = 0.023). Subgroup-analyses revealed an association between increased QTc interval and risk of VT (460 ± 38 ms in HFpEF patients with VT vs. 445 ± 28 ms in HFpEF patients without VT, p = 0.03). Non-sustained VT was more prevalent in patients with HFpEF compared to patients without HFpEF, and QTc interval prolongation was associated with VT in HFpEF.

Patch versus traditional ambulatory ECG monitoring in children

BackgroundPatch ambulatory electrocardiogram (ECG) monitors may provide an advantage over traditional wired ambulatory ECG devices, such as Holter and event monitors, but there is limited data comparing their clinical impact in the pediatric population. ObjectiveThis study sought to directly compare traditional wired ambulatory ECG devices to a patch ambulatory monitor in terms of clinical impact and ability to detect significant arrhythmias. MethodsThis retrospective cohort study included outpatients 0–18 years old who received ambulatory ECG monitoring at our institution. A cohort consisting of all patients evaluated with a Holter or event monitor between 5/2011–2/2013 (prior to patch ECG use) was compared with a time-matched cohort from 2015 to 2017 when patch monitors (Zio) were the sole ambulatory ECG devices used in our practice. Chart review was conducted to determine the clinical impact of all monitor results. ResultsCardiologists prescribed patch monitors more frequently than traditional monitors (1 per 11.5 vs 21.8 clinical encounters, p < 0.0001). The primary indication for monitoring differed, with patch monitors being used more often for patient-reported symptoms including palpitations, pre-syncope, or syncope (38.6% vs 23.8%, p < 0.01). Detection rates of serious arrhythmias were similar, when assessing results that led to new intervention (6.2% versus 7.7%, p = 0.55) or increased clinical surveillance (5.0% vs 4.2%, p = 0.82). Yet, patch monitoring more frequently yielded results that allowed patients to be discharged from cardiology follow-up (46.8% vs 36.8%, p = 0.01). ConclusionsIn terms of diagnosing serious arrhythmias that escalated clinical management, patch ambulatory ECG monitors provided similar clinical impact as traditional monitors, but they more often provided results that allowed discharge from cardiology care.

Enhanced detection of cardiac arrhythmias utilizing 14-day continuous ECG patch monitoring

BackgroundTo evaluate the performance of a single‑lead, 14-day continuous electrocardiogram (ECG) patch for the detection of arrhythmias compared to conventional 24-h monitoring. MethodsThis prospective clinical trial enrolled patients suspected of arrhythmias but not diagnosed by 12‑lead ECGs. Each patient underwent a 24-h Holter and 14-day ECG patch simultaneously. Seven types of arrhythmias were classified: supraventricular tachycardia (SVT, repetitive atrial beats >4 beats), irregular SVT without P wave (>4 beats), AF/AFL (irregular SVT without P wave ≥30 s), pause ≥3 s, atrioventricular block (AVB; Mobitz type II, third-degree, two to one or high degree AVB), ventricular tachycardia (VT), and polymorphic VT. ResultsA total of 158 patients were recruited (mean wear time:12.3 ± 3.2 days). The overall arrhythmia detection rate was higher with 14-day ECG patches (59.5%) compared to 24-h Holter (19.0%, P < 0.001). Up to 87.2% of arrhythmias recorded with 14-day ECG patches were not associated with symptoms. The 14-day ECG patch was associated with higher detection rates compared to the 24-h Holter in patients with SVT (52.5% versus 15.8%, P < 0.001), irregular SVT without P wave (12.7% versus 4.4%, P = 0.002), AF/AFL (9.5% versus 3.8%, P = 0.042), and critical arrhythmias (pause ≥3 s, AVB, VT, polymorphic VT) (16.5% versus 2.5%, P < 0.001). The 14-day ECG patch detected more than 2 types of arrhythmias in 5.1% of patients. No serious adverse events in patients wearing the 14-day ECG patch were reported. ConclusionsThe 14-day ECG patch outperformed 24-h Holter to detect overall, asymptomatic, critical and multiple arrhythmias. It is safe and has the potential to identify individuals with hidden arrhythmias, especially those with critical arrhythmias.

Diagnostic Utility of Smartwatch Technology for Atrial Fibrillation Detection – A Systematic Analysis

Smartphone technologies have been recently developed to assess heart rate and rhythm, but their role in accurately detecting atrial fibrillation (AF) remains unknown. We sought to perform a meta-analysis using prospective studies comparing Smartwatch technology with current monitoring standards for AF detection (ECG, Holter, Patch Monitor, ILR). We performed a comprehensive literature search for prospective studies comparing Smartwatch technology simultaneously with current monitoring standards (ECG, Holter, and Patch monitor) for AF detection since inception to November 25th, 2019. The outcome studied was the accuracy of AF detection. Accuracy was determined with concomitant usage of ECG monitoring, Holter monitoring, loop recorder, or patch monitoring. A total of 9 observational studies were included comparing smartwatch technology, 3 using single-lead ECG monitoring, and six studies using photoplethysmography with routine AF monitoring strategies. A total of 1559 patients were enrolled (mean age 63.5 years, 39.5% had an AF history). The mean monitoring time was 75.6 days. Smartwatch was non-inferior to composite ECG monitoring strategies (OR 1.06, 95% CI 0.93 - 1.21, p=0.37), composite 12 lead ECG/Holter monitoring (OR 0.90, 95% CI 0.62 - 1.30, p=0.57) and patch monitoring (OR 1.28, 95% CI 0.84 - 1.94, p=0.24) for AF detection. The sensitivity and specificity for AF detection using a smartwatch was 95% and 94%, respectively. Smartwatch based single-lead ECG and photoplethysmography appear to be reasonable alternatives for AF monitoring.

Comparison of Arrhythmia Detection by 24-Hour Holter and 14-Day Continuous Electrocardiography Patch Monitoring.

Although 24-hour Holter monitoring is routinely used for patients with suspected paroxysmal arrhythmia, its sensitivity in detecting such arrhythmias is insufficient. We compared a 14-day electrocardiography (ECG) monitor patch - a single-use, noninvasive, waterproof, continuous monitoring patch - with a 24-hour Holter monitor in 32 consecutive patients with suspected arrhythmia. The 14-day ECG patch was well tolerated, and its rates of detection of relevant arrhythmias on days 1, 3, 7, and 14 were 13%, 28%, 47%, and 66%, respectively. The detection rate of paroxysmal arrhythmias was significantly higher for the 14-day ECG patch than for the 24-hour Holter monitor (66% vs. 9%, p < 0.001). Among the 32 patients, 202 atrial fibrillation or atrial flutter episodes were detected in 6 patients (22%) with the 14-day ECG patch; however, only 1 atrial fibrillation episode was detected in a patient (3%, p < 0.05) with the 24-hour Holter monitor. Other clinically relevant arrhythmias recorded on the 14-day ECG patch included 21 (65.5%) episodes of supraventricular tachycardia, 2 (6.3%) long pause, and 2 (6.3%) ventricular arrhythmias. The mean dermal response score immediately after removal of the 14-day ECG patch from the patients was 0.64, which indicated minimal erythema. The 14-day ECG patch was well tolerated and allowed for longer continuous monitoring than the 24-hour Holter monitor, thus resulting in improved clinical accuracy in the detection of paroxysmal arrhythmias. Future studies should examine the long-term effectiveness of 14-day ECG patches for managing selected patients.

PO334 Cardioprotective Effects of Testosterone Suggested by Ultra High-Resolution Electrophysiological Measurements of iPSC-Derived Cardiomyocyte Activity

Coronavirus infection is the cause of the current world-wide pandemic. Cardiovascular complications occur in 20–30% of patients with COVID-19 infection including myocardial injury and arrhythmias. Current understanding of specific arrhythmia type and frequency is limited.We aimed to analyze arrhythmia type and frequency in patients with COVID infection, identifying arrhythmia patterns over time during hospitalization and post discharge utilizing a patch based mobile cardiac telemetry system.A prospective cohort study during the COVID-19 pandemic was performed. We included in our study patients hospitalized with COVID-19 infection who had a patch-based mobile telemetry device placed for cardiac monitoring.Quantitative reports for 59 patients were available for analysis. Arrhythmias were detected in 72.9% of patients and at a consistent frequency throughout the monitoring period in 52.9%–89.5% of patients daily. The majority of arrhythmias were SVT (59.3% of patients) and AF (22.0%). New onset AF was noted in 15.0% of all patients and was significantly associated with older age (OR 1.4 for 5 yrs. difference; 95% CI 1.03–2.13). Of 9 patients who were discharged with continued patch monitoring, 7 (78%) had arrhythmic events during their outpatient monitoring period.In COVID-19 patients arrhythmias were observed throughout hospitalization with a consistent daily frequency. Patients continued to exhibit cardiac arrhythmias after hospital discharge of a type and frequency similar to that seen during hospitalization. These findings suggest that the risk of arrhythmia associated with COVID infection remains elevated throughout the hospital course as well as following hospital discharge.

NOVEL INVESTIGATIVE TOOLS IN PATIENTS WITH SUSPECTED INHERITED HEART RHYTHM DISORDERS

Patients with inherited heart rhythm disorders (IHRD) attend regional specialty clinics to undergo a series of cardiac investigations, including ECG, Holter monitor, and exercise tests. Cardiac patch monitors may help reduce the burden of hospital-based testing and extend the ability to capture ambient arrhythmias, changes in heart rate with daily activities and physiologic exercise. We compared home-based patch monitoring to conventional Holter monitoring and exercise testing. Patients assessed at St. Paul’s Hospital from the BC Inherited Arrhythmia Clinic (catchment 4.6 million persons) underwent single ECG lead patch monitoring for seven days (Icentia CardioSTAT device) in a prospective feasibility study, compared to conventional testing modalities. Corrected QT intervals were measured and calculated according to Bazett’s formula. 39 patients underwent seven-day patch monitoring (median age 44 years (range 15-70), 61% male). In a follow-up interview, 76% of patients expressed satisfaction and preferred the device over Holter monitor. The median duration of monitoring was 7.0 days (range 2.0-7.3), with 12% noise during the first 24-hours (median 176 minutes, range 25min-12h). All but one patient was in sinus rhythm throughout (one patient with known atrial fibrillation). The median HR, PAC and PVC burden, and supraventricular and ventricular runs are reported, with strong correlations in all variables between monitoring modalities, except for PVC burden and supraventricular runs (Table). Patch monitors demonstrated variability in ectopic burden over seven days (PACs: 114±451 over 24-hours vs. 161±527 over seven days; PVCs: 388±942 over 24-hours vs. 428±972 over seven days). Compared to the median PAC and PVC burden over seven days, Holter monitoring under- or overestimated ectopy by over 20% in 84% of cases (PAC variation: median 7%, range -100 to +43,000%; PVC variation: median 33%, range -100 to +867%). Corrected QT intervals correlated across monitoring modalities at rest (Figure, Pearson Correlation 0.781 and 0.776), but demonstrated poor correlation at peak heart rate compared to exercise testing (Pearson Correlation 0.098 and 0.161). Most patients (82%) did not reach 85% of the age-predicted maximum heart rate on the patch monitor. The cardiac patch monitor is a reliable option in the diagnostic work-up of patients with suspected IHRD, with basic measurements consistent with other devices. The burden of PACs and PVCs varies significantly day-to-day, and prolonged monitoring may provide for more reliable quantification and improved arrhythmia detection in patients with suspected IHRD. QTc measurements were reproducible at rest, but correlation at peak heart rates was poor and requires further investigation.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Rationale and design of a large-scale, app-based study to identify cardiac arrhythmias using a smartwatch: The Apple Heart Study

BackgroundSmartwatch and fitness band wearable consumer electronics can passively measure pulse rate from the wrist using photoplethysmography (PPG). Identification of pulse irregularity or variability from these data has the potential to identify atrial fibrillation or atrial flutter (AF, collectively). The rapidly expanding consumer base of these devices allows for detection of undiagnosed AF at scale.MethodsThe Apple Heart Study is a prospective, single arm pragmatic study that has enrolled 419,093 participants (NCT03335800). The primary objective is to measure the proportion of participants with an irregular pulse detected by the Apple Watch (Apple Inc, Cupertino, CA) with AF on subsequent ambulatory ECG patch monitoring. The secondary objectives are to: 1) characterize the concordance of pulse irregularity notification episodes from the Apple Watch with simultaneously recorded ambulatory ECGs; 2) estimate the rate of initial contact with a health care provider within 3 months after notification of pulse irregularity. The study is conducted virtually, with screening, consent and data collection performed electronically from within an accompanying smartphone app. Study visits are performed by telehealth study physicians via video chat through the app, and ambulatory ECG patches are mailed to the participants.ConclusionsThe results of this trial will provide initial evidence for the ability of a smartwatch algorithm to identify pulse irregularity and variability which may reflect previously unknown AF. The Apple Heart Study will help provide a foundation for how wearable technology can inform the clinical approach to AF identification and screening. (Am Heart J 2019;207:66–75.)

Sudden cardiac death preceded by ST segment elevations during ECG patch monitoring

A 58-year-old male underwent ambulatory ECG monitoring with continuous patch monitoring (Zio XT Patch) for the complaint of episodic dyspnea. In the period of monitoring the patient suffered sudden cardiac death (SCD) with continuous ECG recording showing pronounced ST segment elevations followed by bradycardia and death. This report highlights the growing potential of continuous ST segment monitoring, and features the infrequent entity of ischemic electromechanical dissociation with bradyarrhythmia as a cause of SCD.

HIV and Ventricular Arrhythmia Susceptibility: Insights from Cardiac Patch Monitoring

The use of novel adhesive patch electrocardiographic monitoring for extended time periods has the potential to improve our detection and pathophysiologic understanding of ambient arrhythmias. Here we present a case of torsade de pointes in an HIV-infected individual highlighting the multiple mechanisms that may contribute to increased ventricular arrhythmia susceptibility and sudden cardiac death risk in such people.

11 Investigating the effectiveness of 1, 3 and 5 day holter monitoring: should it be limited to 24 h

Introduction Ambulatory ECG – Holter monitoring –provides a continuous 3 lead ECG over the course of 1 to 5 days. The non-invasive Cardiology Department has a very long outpatient waiting list for Cardiac Holter Monitoring with an increasing demand for extended monitoring, from 72 h up to 120 h. Due in part to evidence that the longer the monitor is recording the more arrhythmias are diagnosed.1,2 The aim of this audit is to investigate on what day of monitoring an arrhythmia is first detected, thus evaluating the benefit of extended recording. Methods This audit was carried out in Beaumont Hospital in 2015 with the data collected from the non-invasive cardiology department. A full review of all extended monitoring conducted in 2014 was undertaken. The report for each day was reviewed and documented, which includes information on the indication for the holter monitor, what rhythm was detected and if there were abnormal results what day that they first occurred were documented. Results In 2014 there were a total of 427 extended holter monitoring performed. Of the 427 results reviewed 167 (39%) were for 48 h,​126 (30%) were for 72 h and 134 (31%) were for 120 h. 191 of the recordings (45%) had abnormal result. Of the 191 holter reports with abnormal results – 150 (79%) first showed the abnormal results on day 1, 25 (13%) on the second day, 12 (6%) on the third day with 4 (2%) on day 4 and 2 (1%) on day five. Discussion The results clearly show that the majority of abnormal arrhythmias are found with the first day of monitoring. The number of abnormal results that are detected after the initial 24 h period decreases significantly with only minimal arrhythmias detected on day 4 or 5. Therefore if we were to limit holter monitors to 24–72 h the amount of arrhythmias detected per day of recording would increase dramatically. Other methods of testing, eg loop recorders, may be more suitable for extended monitoring beyond this period.

Diagnostic Yield of Extended Cardiac Patch Monitoring in Patients with Stroke or TIA.

Background: It is important to evaluate patients with transient ischemic attack (TIA) or stroke for atrial fibrillation (AF) because the detection of AF changes the recommended anti-thrombotic regimen from treatment with an antiplatelet agent to oral anticoagulation. This study describes the diagnostic yield of a patch-based, single-use, and water-resistant 14-day continuous cardiac rhythm monitor (ZIO Patch) in patients with stroke or TIA.Methods: We obtained data from the manufacturer and servicer of the ZIO Patch (iRhythm Technologies). Patients who were monitored between January 2012 and June 2013 and whose indication for monitoring was TIA or stroke were included. The duration of monitoring, the number and type of arrhythmias, and the time to first arrhythmia were documented.Results: One thousand one hundred seventy-one monitoring reports were analyzed. The mean monitor wear time was 10.9 days and the median wear time was 13.0 days (interquartile range 7.2–14.0). The median analyzable time relative to the total wear time was 98.7% (IQR 96.0–99.5%). AF was present in 5.0% of all reports. The mean duration before the first episode of paroxysmal AF (PAF) was 1.5 days and the median duration was 0.4 days. 14.3% of first PAF episodes occurred after 48 h. The mean PAF burden was 12.7% of the total monitoring duration.Conclusion: Excellent quality of the recordings and very good patient compliance coupled with a substantial proportion of AF detection beyond the first 48 h of monitoring suggest that the cardiac patch is superior to conventional 48-h Holter monitors for AF detection in patients with stroke or TIA.

Diagnostic Yield of Patch Ambulatory Electrocardiogram Monitoring in Children (from a National Registry)

The diagnostic yield of continuous electrocardiographic (ECG) monitoring in children for periods longer than a Holter monitor is unclear. The aim of this study was to characterize diagnostic yield, arrhythmia type, and time to first arrhythmia using a clinical repository of national ambulatory ECG data in children. A cross-sectional study was performed in 3,209 consecutive children receiving a 14-day adhesive patch monitor (Zio Patch) for clinical indications from January 2011 to December 2013. Of the 3,209 children (56% female, mean age 12.5 ± 4.4 years, range 1 month to 17 years), 390 had arrhythmias detected, making the diagnostic yield 12.2%. Of these, 137 patients (4.3%) had arrhythmias deemed clinically significant to warrant urgent physician notification. The most frequent indications for monitoring were palpitations (n = 1,138 [35.5%]), syncope (n = 450 [14.0%]), unspecified tachycardia (n = 291 [9.1%]), supraventricular tachycardia (n = 264 [8.2%]), and chest pain (n = 261 [8.1%]). Arrhythmias were detected in 10.0% of patients with palpitations, 6.7% of patients with syncope, 14.8% of patients with tachycardia, 22.7% of patients with supraventricular tachycardia, and 6.5% of patients with chest pain. The mean times to first detected and first symptom-triggered arrhythmias were 2.7 ± 3.0 and 3.3 ± 3.3 days, respectively. Forty-four percent of first detected arrhythmias and 50.4% of the first symptom-triggered arrhythmias occurred beyond 48 hours of monitoring. In conclusion, the diagnostic yield of continuous ECG patch monitoring in children was substantial beyond 48 hours and should be considered in children who are candidates for longer term ECG monitoring.