Mobile Cardiac Outpatient Telemetry Research Articles

Abstract 4136989: Association of alternating PR intervals with paroxysmal atrioventricular block in patients with right bundle branch block following cardiac surgery

Background: We previously observed a positive correlation between QRS duration and the preceding RP interval in sinus rhythm in certain patients experiencing new onset left bundle branch block (LBBB) after transcatheter aortic valve replacement (TAVR). This unique phenomenon, termed inverse decremental conduction ( IDC ) or Yan conduction, prompted us to investigate whether IDC in the left bundle could manifest as AV conduction in an IDC pattern in patients with preexisting right bundle branch block (RBBB) and its association with atrioventricular block (AVB). Methods: 12 lead ECGs, available in-patient telemetry and mobile cardiac outpatient telemetry were reviewed in patients with sinus rhythm and preexisting RBBB who developed paroxysmal AVB requiring temporary or permanent pacemaker within 7 days following any types of cardiac surgery from 2014 to 2023 in Lankenau Medical Center. Results: A total of 9 patients (5 males) with a mean age of 71±15 years were identified to exhibit PR interval changes consistent with IDC prior to paroxysmal AVB. Among these patients, 6 had undergone TAVR, while the remaining 3 had undergone surgical aortic valve replacement, mitral valve repair, and ventricular septal defect repair, respectively. Specifically, PR interval alternation in the setting of RBBB occurred during sinus rhythm in a pattern that the longer RP interval is followed by a longer PR interval (Figure 1). This pattern exhibits the following features: 1) 8 of 9 patients had RBBB plus left anterior fascicular block (LAFB); 2) PR alternation occurred at sinus rates from 68 to 91 bpm within 5 days following surgical procedures; 3) proximal AVB occurred within 1 to 12 hours after PR interval alternation began. A positive correlation was established between PR and preceding RP interval in 2 of 9 patients whose telemetry data were available for analysis ( Figure 2A ). In a patient with RBBB who developed paroxysmal AVB without IDC changes in the PR interval post TAVR, intracardiac recording showed a decrease in AH interval but an increase in HV interval with slowing heart rates ( Figure 2B ), indicating that decremental conduction in AV node can mask IDC in Purkinje system. Conclusion: 1) PR alternation with longer PR following longer preceding RP interval in presence of RBBB, likely due to IDC in left bundle, heralds paroxysmal AVB; 2) PR interval changes resulting from IDC in left bundle in the setting of RBBB may be masked by decremental conduction in AV node.

260 Comparison of Mobile Cardiac Outpatient Telemetry Initiated From the Emergency Department Versus Other Settings

260 Comparison of Mobile Cardiac Outpatient Telemetry Initiated From the Emergency Department Versus Other Settings

Patterns of perioperative arrhythmias in adult cardiac surgery: A single center study from Sri Lanka

Introduction: There is no published data on perioperative arrhythmias in adults undergoing cardiac surgery in Sri Lanka. The object of this study was to assess the patterns of peri operative arrhythmias in cardiac surgical patients. Methods and material: This is a prospective descriptive study of 100 patients in a single cardiothoracic unit in a tertiary care hospital in Sri Lanka from November 2018 to May 2020. Demographic data and clinical data were assessed in all patients. Furthermore, 24-hour Mobile Cardiac Outpatient Telemetry MCOT was assessed in a subset of patients. Results: There were 72 males and 28 females. The mean age was 60 (range 37-76 years). The majority (76) had undergone isolated coronary artery bypass grafting (CABG). The mortality was 3.5% in routine and 15% in urgent and emergency operations. Arrhythmias where lowest preoperatively (11%). Arterial fibrillation (AF) (6%) and sinus bradycardia (4%) were the commonest arrhythmias seen preoperatively. Arrhythmias were higher during surgery (29%) and ventricular fibrillation (VF) (25%) was the commonest. Arrhythmias were highest post operatively (34%) and (AF) (12%) was the commonest followed by sinus tachycardia (9%). The higher incidence of arrhythmias in the in-hospital postoperative period as compared to the preoperative period was significant (p=0.0001). A limited in-depth study using a mobile cardiac telemetry (MCOT) device showed a higher incidence of AF preoperatively (11%) and postoperatively (16%) but these differences were not significant when compared with that of routine investigations (p=0.18 and p=0.35 respectively). However, the MCOT detected some arrhythmias completely missed by routine ECG recordings, notably supraventricular tachycardia, both preoperatively (22%) and postoperatively (33%). Conclusions: This study has established baseline values of perioperative arrhythmias in the adult cardiac surgical patients in Sri Lanka. The MCOT methodology shows the potential for a more detailed study of arrhythmias and could inform decision-making in arrhythmia prophylaxis.

Comparing the outcomes and costs of cardiac monitoring with implantable loop recorders and mobile cardiac outpatient telemetry following stroke using real-world evidence.

Aim: Patients with ischemic stroke (IS) commonly undergo monitoring to identify atrial fibrillation with mobile cardiac outpatient telemetry (MCOT) or implantable loop recorders (ILRs). The authors compared readmission, healthcare cost and survival in patients monitored post-stroke with either MCOT or ILR. Materials & methods: The authors used claims data from Optum's de-identified Clinformatics® Data Mart Database to identify patients with IS hospitalized from January 2017 to December 2020 who were prescribed ambulatory cardiac monitoring via MCOT or ILR. They compared the costs associated with the initial inpatient visit as well as the rate and causes of readmission, survival and healthcare costs over the following 18months. Datasets were balanced using patient baseline and hospitalization characteristics. Multivariable generalized linear gamma regression was used for cost comparisons. Cox proportional hazard regression was used for survival and readmission analysis. Sub-cohorts were analyzed based on the severity of the index IS. Results: In 2244 patients, readmissions were significantly lower in the MCOT monitored group (30.2%) compared with the ILR group (35.4%) (hazard ratio [HR] 1.23; 95% CI: 1.04-1.46). Average cost over 18months starting with the index IS was $27,429 (USD) lower in the MCOT group (95% CI: $22,353-$32,633). Survival difference bordered on statistical significance and trended to lower mortality in MCOT (8.9%) versus ILR (11.3%) (HR 1.30; 95% CI: 1:00-1.69), led by significance in patients with complications or comorbidities with the index event (MCOT 7.5%, ILR 11.5%; HR 1.62; 95% CI: 1.11-2.36). Conclusion: The use of MCOT versus ILR as the primary monitor following IS was associated with significant decreases in readmission, lower costs for the initial IS and total care over the next 18months, significantly lower mortality for patients with complications and comorbidities at the index stroke, and a trend toward improved survival across all patients.

ECG Smart Monitoring versus Implantable Loop Recorders for Atrial Fibrillation Detection after Cryptogenic Stroke-An Overview for Decision Making.

Up to 20% of patients with ischemic stroke or transient ischemic attack have a prior history of known atrial fibrillation (AF). Additionally, unknown AF can be detected by different monitoring strategies in up to 23% of patients with cryptogenic or non-cardioembolic stroke. However, most studies had substantial gaps in monitoring time, especially early after the index event. Following this, AF rates would be higher if patients underwent continuous monitoring early after stroke, avoiding any gaps in monitoring. The few existing randomized studies focused on patients with cryptogenic stroke but did not focus otherwise specifically on prevention strategies in patients at high risk for AF (patients at higher age or with high CHA2DS2-VASC scores). Besides invasive implantable loop recorders (ILRs), external loop recorders (ELRs) and mobile cardiac outpatient telemetry (MCOT) are non-invasive tools that are commonly used for long-term ECG monitoring in cryptogenic-stroke patients in the ambulatory setting. The role of MCOT and hand-held devices within ECG smart monitoring in the detection of AF for the prevention of and after cryptogenic stroke is currently unclear. This intense review provides an overview of current evidence, techniques, and gaps in knowledge and aims to advise which patients benefit most from the current available devices.

PO-04-043 ALTERNATING PR AND RP INTERVALS PRIOR TO COMPLETE AV BLOCK: THE CHICKEN OR THE EGG?

The incidence of permanent pacemaker implantation for high-degree AV block after transcatheter aortic valve replacement (TAVR) is approximately 6%, because of mechanical damage to the conduction system. We report a novel ECG marker, i.e. inverse decremental conduction (IDC), that heralds paroxysmal AV block. Case report and exploration of the electrophysiological mechanism. N/A A 73-year-old male with severe symptomatic aortic stenosis underwent TAVR with a balloon-expandable valve. On day 1 post-TAVR, his 12-lead ECG revealed sinus rhythm with a normal PR interval and unchanged RBBB with a left anterior fascicular block (LAFB). The patient was discharged with mobile cardiac outpatient telemetry. Although the patient was asymptomatic, he was asked to come to the emergency department (ED) after his monitor detected a 3.5-second pause during sleep. Shortly after a 12-lead ECG was obtained in the ED, he experienced two sudden cardiac arrests due to complete AV block and asystole requiring CPR and transcutaneous pacing. He underwent emergent implantation of a dual-chamber pacemaker. His ECG in the ED reveals alternating PR intervals (Figure). The first impression of the alternating PR intervals is a dual AV nodal physiology with a 2:1 block in the fast pathway, a relatively benign ECG sign. However, paroxysmal AV block and recent history of TAVR suggested a His-Purkinje injury with block at the subnodal level. More specifically, TAVR-related IDC in the left posterior fascicle (LPF) underlies alternating PR intervals in the setting of RBBB and LAFB. In other words, the PR length is proportional to the preceding RP length, i.e. a longer RP leads to a longer subsequent PR and vice versa due to IDC in LPF. The injured His-Purkinje fibers may lose their all-or-none conduction property and display IDC post-TAVR. This manifests as LBBB with a duration proportional to the preceding RP or RR interval or as prolongation of the PR interval with lengthening of the preceding RP interval in presence of RBBB. IDC in the His-Purkinje may be masked by decremental conduction in the AV node and is often under-recognized. Once the PR interval prolongs with lengthening of the preceding RP interval post-TAVR, unrelated to vagal stimulation, insertion of a temporary or permanent pacemaker is urgently indicated. Alternating PR intervals can be a benign finding, but in this case were linked with paroxysmal AV block secondary to IDC, with resultant cardiac arrest post-TAVR.

Feasibility and Safety of Intravenous Sotalol Loading in Adult Patients With Atrial Fibrillation (DASH-AF)

BackgroundInpatient initiation of sotalol is recommended owing to its proarrhythmic effects. ObjectivesThe DASH-AF (Feasibility and Safety of Intravenous Sotalol Administered as a Loading Dose to Initiate Oral Sotalol Therapy in Adult Patients With Atrial Fibrillation) trial evaluates the safety and feasibility of intravenous (IV) sotalol, achieving a steady state with maximum QTc prolongation within 6 hours instead of the traditional 5-dose inpatient oral (PO) titration. MethodsDASH-AF is a prospective, nonrandomized, multicenter, open-label trial consisting of patients who underwent IV sotalol loading dose to initiate rapid oral therapy for atrial arrhythmias. IV dose was calculated based on the target oral dose as indicated by baseline QTc and renal function. Patients’ QTc (in sinus) was measured via electrocardiography at 15-minute intervals and after IV loading completion. Patients were discharged 4 hours after first oral dose. All patients were monitored via mobile cardiac outpatient telemetry for 72 hours. The control group was composed of patients admitted for the traditional 5 PO doses. Safety outcomes were assessed in both groups. ResultsA total of 120 patients from 3 centers were enrolled from 2021 to 2022 in the IV loading group (compared with type of AF– and renal function–matched patients in the conventional PO loading cohort). This study demonstrated no significant change in ΔQTc in both groups, with a significantly lower number of patients requiring dose adjustment in the IV arm compared with the PO arm (4.1% vs 16.6%; P = 0.003). This led to potential cost savings of up to $3,500.68 per admission. ConclusionsThe DASH-AF trial shows that rapid IV sotalol loading in atrial fibrillation/flutter patients for rhythm control is feasible and safe compared with conventional oral loading with significant cost reduction. (Feasibility and Safety of Intravenous Sotalol Administered as a Loading Dose to Initiate Oral Sotalol Therapy in Adult Patients With Atrial Fibrillation [DASH-AF]; NCT04473807)

Abstract 14949: Wear Time, Frequency of and Time to First Atrial Fibrillation Detection in Patients With a History of Stroke

Introduction: Telemetry monitoring following cryptogenic stroke (CS) is routinely undertaken to rule out atrial fibrillation (AF) as a stroke source. In patients with stroke of known etiology, AF may represent an alternate mechanism for the incident stroke and predicate anticoagulation. Irrespective of classification, a potential limitation of post-stroke monitoring is the patients’ ability to wear an ambulatory monitor for an extended timeframe. Aim: Identify mobile cardiac outpatient telemetry (MCOT, Philips BioTel Heart) monitor wear time, frequency of AF detection, and time to first AF diagnosis in patients with any history of stroke. Methods: A retrospective review of 7,426 patients prescribed 30-day MCOT with ICD-10 diagnosis codes starting with I63 (cerebral infarct, unspecified) was conducted. Data from 2021 was analyzed for MCOT monitor wear time, occurrence of any AF, and time to first AF detection. Monitor wear time was defined as the time from the first to the last telemetry transmission. Results: The percentage of patients with MCOT monitor wear time of 5, 10, 15, 20, 25 and 30 days was 93%, 87%, 82%, 76%, 67% and 44%, respectively. In this cohort, 748 patients (10.1%) were identified with any AF. Of these patients, the first AF detection occurred in 33% (3.3% of total) in days 1-5 of monitoring, 20% (2.0%) in days 6-10, 15% (1.5%) during days 11-15, 14% (1.4%) during days 16-20, 9% (0.9%) during days 21-25, and 9% (0.9%) during days 26-30. Interestingly, 4% of AF detection (0.4% total) occurred on days 29-30. Conclusions: Patients with cerebral infarcts are capable of adhering to extended MCOT wear times, and 10% of patients with any history of stroke demonstrated AF when prescribed MCOT for 30 days. While most patients had first AF detection within 15 days, 32% of patients had first AF detection between days 16-30. These findings suggest that patients with any history of stroke, regardless of etiology, may benefit from extended duration telemetry monitoring.

Race disparities in atrial fibrillation detection using implantable loop recorder for cryptogenic stroke

Abstract Background Cryptogenic stroke represents about 25–30% of all ischemic strokes. Continuous electrocardiographic monitoring using implantable loop recorder (ILR) can detect asymptomatic and undiagnosed atrial fibrillation (AF). Purpose To assess patient-specific factors in ILR implantation and AF detection in patients with cryptogenic strokes. Methods We retrospectively reviewed 379 patients with cryptogenic stroke indicated for ILR implantation, from January 2017 to June 2021 at our university hospital. We evaluated patient demographic and clinical characteristics to assess the risk factors associated with higher incidence of AF detection, using logistic regression models. Results Of the 379 ILRs implanted, 60.4% were males with 71.2% Caucasian, mean age 67.6 years, and mean BMI 28.5. The mean CHADSVASC score of 3.9 at the time of ischemic stroke. These patients had prior diagnosis of diabetes mellitus (27.4%), hypertension (65.7%), chronic kidney disease (19.5%), coronary artery disease (20%) and congestive heart failure (2%). Of the entire cohort, AF was diagnosed in 16% of patients with 14 months mean follow up. There were more females diagnosed with AF on ILR (20% v. 18.7%, p>0.05). Caucasians were more likely to have AF detected compared to non-Caucasians (OR 2.3, 95% CI, p<0.02). There were 52 patients with mobile cardiac outpatient telemetry (MCOT) before having ILR implantation. AF was not detected on MCOT, but 15% were diagnosed with AF with ILR monitoring. In univariate analysis, increasing age is strongly associated with the detection of AF (p=0.03). Conclusions There continues to exist race disparities in ILR implantation and eventual AF detection, leading to further socioeconomic health disparities. ILR should be considered especially in elderly with cryptogenic stroke given the higher incidence of AF detection. Funding Acknowledgement Type of funding sources: None.

162 Feasibility and Diagnostic Yield of Mobile Cardiac Outpatient Telemetry (MCOT) Initiated from the Emergency Department

Complaints such as syncope, near-syncope, and palpitations remain common presenting ailments in the emergency department (ED), accounting for an estimated >1 million visits per year in the United States alone. In patients who are discharged from the ED, ambulatory electrocardiogram (ECG) monitoring can provide valuable diagnostic information and is recommended by many professional societies. Unfortunately, such monitoring is often underutilized due to concerns about patient compliance, diagnostic yield, and the cumbersome application process of older devices.

A meta-analysis of extended ECG monitoring in detection of atrial fibrillation in patients with cryptogenic stroke

ObjectiveThe aim of this systematic review is to evaluate the various modalities available for extended ECG monitoring in the detection of atrial fibrillation (AF) following a cryptogenic stroke.MethodsMEDLINE (Ovid), EMBASE...

Psychosocial measures in relation to smartwatch alerts for atrial fibrillation detection

Psychosocial measures in relation to smartwatch alerts for atrial fibrillation detection

Costs and outcomes of mobile cardiac outpatient telemetry monitoring post-transcatheter aortic valve replacement.

Aim: To estimate the costs and outcomes of transcatheter aortic valve replacement (TAVR) recipients based on the use of mobile cardiac outpatient telemetry (MCOT) monitoring. Materials & methods: A retrospective database study was conducted to estimate costs, contribution margins (CMs), pacemaker insertions and other outcomes for patients undergoing TAVR procedures with MCOT monitoring post-procedure versus non-MCOT monitoring. Results: A total of 4164 patients were identified (283 MCOT monitoring and 3881 non-MCOT monitoring). The rate of pacemaker insertion following hospital discharge was higher in the MCOT cohort (6.6MCOT vs 2.1% non-MCOT; p=0.007). MCOT use was associated with lower costs and improved CMs of the index TAVR admission (costs: US$40,569 MCOT vs $43,289 non-MCOT; p=0.003; CMs: US$7087 MCOT vs $5177 non-MCOT; p=0.047) with no difference through the subsequent 60-day period following discharge. Conclusion: MCOT for ambulatory cardiac monitoring post-TAVR discharge is associated with higher rates of pacemaker insertion, at no overall greater costs.

Use of Ambulatory Patch Monitoring Devices to Supplement Inpatient Telemetry—A Descriptive Study of a Single-center Experience During the Coronavirus Disease 2019 Pandemic

To accommodate the surge in patients with coronavirus disease 2019 during the spring of 2020, outpatient areas in our health system were repurposed as inpatient units. These spaces often lacked the same resources as the standard inpatient unit, including telemetry equipment. We utilized mobile cardiac outpatient telemetry (MCOT) in place of traditional telemetry and suggest that MCOT is an appropriate substitution only for patients at low risk of developing arrhythmia given the prolonged time to notification of the care team regarding events and imprecise measurements of the corrected QT interval when compared to 12-lead electrocardiography.

Mobile Cardiac Outpatient Telemetry Patch vs Implantable Loop Recorder in Cryptogenic Stroke Patients in the US – Cost-Minimization Model

PurposeThe aim of this study was to compare costs and outcomes of mobile cardiac outpatient telemetry (MCOT) patch followed by implantable loop recorder (ILR) compared to ILR alone in cryptogenic stroke patients from the US health-care payors’ perspective.Patients and MethodsA quantitative decision tree cost-minimization simulation model was developed. Eligible patients were 18 years of age or older and were diagnosed with having a cryptogenic stroke, without previously documented atrial fibrillation (AF). All patients were assigned first to one then to the alternative monitoring strategies. Following AF detection, patients were initiated on oral anticoagulants (OAC). The model assessed direct costs for one year attributed to MCOT patch followed by ILR or ILR alone using a monitoring duration of 30 days post-cryptogenic stroke.ResultsIn the base case modeling, the MCOT patch arm detected 4.6 more patients with AFs compared to the ILR alone arm in a cohort of 1000 patients (209 vs 45 patients with detected AFs, respectively). Using MCOT patch followed by ILR in half of the patients initially undiagnosed with AF leads to significant cost savings of US$4,083,214 compared to ILR alone in a cohort of 1000 patients. Cost per patient with detected AF was significantly lower in the MCOT patch arm $29,598 vs $228,507 in the ILR only arm.ConclusionAn initial strategy of 30-day electrocardiogram (ECG) monitoring with MCOT patch in diagnosis of AF in cryptogenic stroke patients realizes significant cost-savings compared to proceeding directly to ILR only. Almost 8 times lower costs were achieved with improved detection rates and reduction of secondary stroke risk due to new anticoagulant use in subjects with MCOT patch detected AF. These results strengthen emerging recommendations for prolonged ECG monitoring in secondary stroke prevention.

Rhythm monitoring strategies for atrial fibrillation detection in patients with cryptogenic stroke: A systematic review and meta-analysis.

ObjectiveTo summarize data on atrial fibrillation (AF) detection rates and predictors across different rhythm monitoring strategies in patients with cryptogenic stroke (CS) or embolic stroke of undetermined source (ESUS).MethodsMEDLINE, Embase, and Web of Science were searched to identify all published studies providing relevant data through July 6, 2020. Random-effects meta-analysis method was used to pool estimates.ResultsWe included 47 studies reporting on a pooled population of 8,215 patients with CS or ESUS. Using implantable cardiac monitor (ICM), the pooled rate of AF was 12.2% (95% CI 9.4–15.0) at 3 months, 16.0% (95% CI 13.2–18.8) at 6 months, 18.7% (95% CI 15.7–21.7) at 12 months, 22.8% (95% CI 19.1–26.5) at 24 months, and 28.5% (95% CI 17.6–39.3) at 36 months. AF rates were significantly higher in patients with ESUS vs CS (22.0% vs 14.2%; p < 0.001) at 6 months, and in studies using Reveal LINQ vs Reveal XT ICM (19.1% vs 13.0%; p = 0.001) at 12 months. Using mobile cardiac outpatient telemetry (MCOT), the pooled rate of AF was 13.7% (95% CI 10.2–17.2) at 1 month. Predictors of AF detection with ICM included older age, CHA2DS2-VASc score, left atrial enlargement, P wave maximal duration and prolonged PR interval.ConclusionThe yield of ICM increases with the duration of monitoring. More than a quarter of patients with CS or ESUS will be diagnosed with AF during follow-up. About one in seven patients had AF detected within a month of MCOT, suggesting that a non-invasive rhythm monitoring strategy should be considered before invasive monitoring.

Antiarrhythmic drug loading at home using remote monitoring: a virtual feasibility study during COVID-19 social distancing.

The epidemiological necessity for distancing during the COVID-19 pandemic has resulted in postponement of non-emergent hospitalizations and increase use of telemedicine. The feasibility of virtual antiarrhythmic drug (AAD) loading specifically with digital QTc electrocardiographic monitoring (EM) in conjunction with telemedicine video visits is not well established.We tested the hypothesis that existing digital health technologies and virtual communication platforms could provide EM and support medically guided AAD loading for patients with symptomatic tachyarrhythmia in the ambulatory setting, while reducing physical contact between patient and healthcare system.A prospective pilot, case series approved by the institutional ethics committee, entailing three subjects with symptomatic arrhythmia during the COVID-19 pandemic who were enrolled for virtual AAD loading at home. Clinicians met with participants twice daily via video visits conducted after QTc analysis (Kardia 6L mobile sensor) and telemetry review (Mobile Cardiac Outpatient Telemetry of silent arrhythmias). Participants received direct instruction to either terminate the study or proceed with the next single dose of AAD.All participants completed contactless loading of 5 AAD doses, without untoward event. Scheduled video visits allowed dialogue and participant counseling where decision making was guided by remote review of EM. Participant adherence with transmissions and scheduled visits was 98.3%; a single electrocardiogram was delayed beyond the two-hours-post-dose schedule. This virtual approach reduced overall expenditures based on retrospective comparison with previous AAD load hospitalizations.We found that a ‘virtual hospitalization’ for AAD loading with remote electrocardiographic monitoring and twice daily virtual rounding is feasible using existing digital health technologies.

Abstract P709: Risk Factors Associated With Atrial Fibrillation Detection by Mobile Cardiac Outpatient Telemetry Following Acute Ischemic Stroke

Background: Mobile Cardiac outpatient telemetry (MCOT) is often used for patients (pts) with cryptogenic ischemic stroke following hospital discharge to detect atrial fibrillation (AFib) but criteria for patient selection remains a subject of debate. Methods: We identified 297 pts hospitalized with acute ischemic stroke who had an inpatient transthoracic echocardiogram (TTE) and underwent MCOT upon discharge between 2016 and 2018 at a large academic comprehensive stroke center. Pts characteristics between AFib vs. no AFib were compared by Fisher’s exact test for categorical and Wilcoxon rank-sum test for continuous variables. A multivariable stepwise logistic regression model was developed to determine the predictors of AFib detection. Statistical hypotheses were tested as two-sided at 0.05 level of significance. Results: Of the 297 pts, AFib was detected in 24 (8.1%) on 30-day MCOT. Pts with AFib detected were older, white, and have had a larger left atrial area (Table). The final logistic model demonstrated that white race (vs. non-white) (OR 4.86, 1.53-15.41), left atrial area (OR 1.15, 1.05-1.25) and left ventricular internal diameter in diastole (OR 0.33, 0.16-0.67) were associated with AFib detection by MCOT. Conclusion: Although rates of AFib detection on 30-day MCOT post-discharge was low, there are important patient characteristics and TTE features that can improve patient selection. Further studies are needed to determine if this data can be used prospectively to clinically decide which pts with cryptogenic stroke should be given 30-day MCT to detect atrial fibrillation.

Left Atrial Mechanics Assessed Early during Hospitalization for Cryptogenic Stroke Are Associated with Occult Atrial Fibrillation: A Speckle-Tracking Strain Echocardiography Study

Occult atrial fibrillation (AF) is an important contributor to cryptogenic stroke, yet remains difficult to unmask at presentation. This study investigated the predictive value of left atrial (LA) mechanics by strain echocardiography during stroke hospitalization for the presence of AF as detected on early 30-day monitoring and routine clinical follow-up. Left atrial mechanics were studied by strain echocardiography in a retrospective cohort of 191 patients with cryptogenic stroke and 30-day mobile cardiac outpatient telemetry poststroke to diagnose AF. After this, AF was diagnosed via routine clinical follow-up. The independent and incremental value of measures of LA size and mechanics (i.e., strain and strain rate in the reservoir, conduit, and booster pump phase) to predict AF on top of clinical characteristics was assessed. Of 191 patients, 15% (n=28) developed AF, of which 10 were observed during 30-day mobile cardiac outpatient telemetry and 18 were observed at a median follow-up of 25 (interquartile range, 10-43) months. Median time from embolic stroke to strain echocardiography was 1day (interquartile range, 1-2days). Left atrial mechanics were significantly worse in AF (P<.05 for all), despite largely similar baseline cardiovascular risk profile. Booster pump strain rate was the strongest predictor for AF, independent of age, LA volume index, E/e', and reservoir strain (odds ratio=2.88 per SD increase; 95% confidence interval, 1.29-6.41; P=.010). Adding LA strain reservoir strain and booster pump function significantly enhanced a multivariate model to predict AF. Freedom from AF was significantly lower in subjects with a booster pump strain rate (at stroke presentation) worse than -0.67sec-1, as derived from receiver operator curve analysis (P<.001). Left atrial mechanics and particularly the LA booster pump function assessed early during hospitalization for cryptogenic stroke can identify patients at greater likelihood of future diagnosis of AF. These findings could in part relate to LA mechanical stunning after spontaneous cardioversion, which-when identified by early strain echocardiography-can inform further risk stratification and decision-making.

Abstract WP254: Predictors of Atrial Fibrillation Detection by Mobile Cardiac Output Telemetry After Hospital Discharge for Acute Ischemic Stroke

Background: Patients with cryptogenic stroke without atrial fibrillation (AF) detected in the hospital often undergo 30-day mobile cardiac outpatient telemetry (MCOT) to increase the AF detection rate. We sought to determine the clinical and transthoracic echocardiogram (TTE) characteristics associated with AF detection by MCOT. Methods: We analyzed a cohort of admissions from 2005 to 2016 with an acute ischemic stroke diagnosis, an inpatient TTE, and an MCOT performed upon discharge. Each admission was treated as a unique observation. Cases with subsequent AF vs. no AF on MCOT were compared by Chi-squared tests if variables were categorical and t-tests if continuous. A multivariable stepwise logistic regression model was created to determine the predictors of AF detection as a function of variables which were significant in univariate analysis and not significantly collinear. Results: Of the 4,880 inpatient hospitalizations for acute ischemic stroke with an TTE performed during admission, there were 283 cases which underwent MCOT (10.4 cases/year in 2005-2014, 90 cases/year in 2015-2016). There were 23 (8.10%) cases of AF on MCOT, and they were more likely to be older, white, admitted earlier during the study, and have larger left atrial anterior-posterior and medial-lateral dimensions (Table). A multivariable model demonstrated that age greater than the median of 66 yr (OR 3.25, 1.21-8.74) and left atrial anterior-posterior dimension greater than the median of 40cm (OR 5.86, 2.38-14. 43) were strong predictors of AF detection by MCOT (c-statistic 0.78). Conclusions: We observed low rates of AF on 30-day MCOT post-discharge. Left atrial anatomic dimension is predictive of a higher rate of early AF detection after adjusting for age. This TTE feature, coupled with clinical information, may improve patient selection for MCOTs and potentially avoid the need for more expensive implantable loop monitors in those for whom MOCT does not yield an answer.