Exercise Stress Research Articles

Changes in exercise stress echocardiographic parameters before and after transcatheter mitral valve edge-to-edge repair.

The safety and feasibility are still not well known for exercise-induced mitral regurgitation (MR). This study is aimed to assess and compare the hemodynamic and symptomatic changes in patients with significant secondary MR during exercise stress echocardiography (ESE) before and after transcatheter edge-to-edge repair (TEER). The study included a total of 15 patients with secondary MR who underwent ESE before and after TEER using the MitraClip system (Abbott, Abbott Park, IL, USA). Echocardiographic data of ESE were collected both before the procedure and during the follow-up visit at 3months. During the one-year postoperative observation period, the rate of readmission due to heart failure was 13% (n = 2), with no recorded fatalities. Although no significant differences of ESE data were observed in exercise-induced pulmonary hypertension or cardiac output before and after the repair, the severity of MR was significantly improved after the procedure, both at rest (2 [2-3] vs. 1 [1-2], p = 0.0125) and during ESE (3 [3-3] vs. 1 [1-1], p < 0.0001). Furthermore, the New York Heart Association Functional Classification was improved (3 [3-3] vs. 1 [1-1], p < 0.0001) after treatment. For a supplemental analysis, MR during ESE was significantly improved not only in cases with atrial secondary MR but also in ventricular secondary MR. Transcatheter edge-to-edge repair for exercise-induced MR resulted in a significant improvement in postoperative MR severity and subjective symptoms. These results are novel, as they have not been extensively reported previously, particularly among Japanese patients.

Development of artificial intelligence-based slow-motion echocardiography and clinical usefulness for evaluating regional wall motion abnormalities.

The diagnostic accuracy of exercise stress echocardiography (ESE) for myocardial ischemia requires improvement, given that it currently depends on the physicians' experience and image quality. To address this issue, we aimed to develop artificial intelligence (AI)-based slow-motion echocardiography using inter-image interpolation. The clinical usefulness of this method was evaluated for detecting regional wall-motion abnormalities (RWMAs). In this study, an AI-based echocardiographic image-interpolation pipeline was developed using optical flow calculation and prediction for in-between images. The accuracy for detecting RWMAs and image readability among 25 patients with RWMA and 25 healthy volunteers was compared between four cardiologists using slow-motion and conventional ESE. Slow-motion echocardiography was successfully developed for arbitrary time-steps (e.g., 0.125×, and 0.5×) using 1,334 videos. The RWMA detection accuracy showed a numerical improvement, but it was not statistically significant (87.5% in slow-motion echocardiography vs. 81.0% in conventional ESE; odds ratio: 1.43 [95% CI: 0.78-2.62], p = 0.25). Interreader agreement analysis (Fleiss's Kappa) for detecting RWMAs among the four cardiologists were 0.66 (95%CI: 0.55-0.77) for slow-motion ESE and 0.53 (95%CI: 0.42-0.65) for conventional ESE. Additionally, subjective evaluations of image readability using a four-point scale showed a significant improvement for slow-motion echocardiography (2.11 ± 0.73 vs. 1.70 ± 0.78, p < 0.001).In conclusion, we successfully developed slow-motion echocardiography using in-between echocardiographic image interpolation. Although the accuracy for detecting RWMAs did not show a significant improvement with this method, we observed enhanced image readability and interreader agreement. This AI-based approach holds promise in supporting physicians' evaluations.

Abstract 13257: Impact of Epicardial Adipose Tissue and Its Distribution on Cardiac Function in Patients With Diastolic Dysfunction

Background: Epicardial adipose tissue (EAT) was identified as an important risk factor for diastolic dysfunction and affects cardiac structural remodeling. However, within this patient group the impact of increased EAT and its regional distribution on cardiac function is yet unclear. Methods: 68 patients with exertional dyspnea (NYHA≥II), preserved ejection fraction (EF≥50%) and diastolic dysfunction (E/e’≥10) underwent rest and stress right heart catheterization (RHC), transthoracic echocardiography and cardiac magnetic resonance (CMR). EAT volumes were depicted from CMR short-axis stacks. First, the impact of increased total EAT was analyzed. Second, we investigated the association of ventricular and atrial EAT with impaired strain at rest and during exercise stress of the adjacent chambers in multivariable regression analysis. Results: Patients with high EAT had higher HFA-PEFF and H2FPEFF-Scores as well as nt-proBNP levels (p&lt;0.048). Furthermore, they were diagnosed with manifest heart failure with preserved ejection fraction (HFpEF) more frequently (low EAT: 37% vs. high EAT: 64%; p=0.029) and had signs of adverse remodelling indicated by higher T1-times (p&lt;0.001).While both groups had no differences in biventricular volumetry and left ventricular mass (p&gt;0.074), functional analysis in high EAT patients revealed impaired atrial strain at rest and during exercise stress, while ventricular strain was impaired during exercise stress only.The assessment of regional EAT revealed an independent association of higher ventricular and atrial EAT with functional impairment of the adjacent chambers. Conclusion: Patients with diastolic dysfunction and increased EAT show more pronounced signs of diastolic functional failure and structural remodeling. Despite similar morphological characteristics, patients with high EAT show significant cardiac functional impairment, in particular of the atria. Our results indicate that regionally increased EAT directly induces atrial functional failure, which represents a distinct pathophysiological feature in HFpEF.

Abstract 16082: Racial Differences Among Patients Undergoing Nuclear Myocardial Perfusion Imaging

Introduction: Noninvasive cardiac stress testing is valuable for early diagnosis and optimizing management of patients with coronary artery disease (CAD). Historically, Black patients have experienced both underdiagnosis and undertreatment of CAD. We evaluated racial disparities in patients undergoing nuclear myocardial perfusion imaging (MPI). Different modalities (MPI (SPECT, PET) vs. stress echocardiography) have variations in accuracy, cost and radiation exposure, which may reflect provider biases. Methods: Patient-reported demographics, clinician-reported cardiac risk factors and MPI study characteristics from a large Connecticut health system (2016 - 2022) were compared for Black and White patients in both general and matched cohorts (1:1 matched for demographics and risk factors). Results: The study included 123,069 cardiac stress tests from 10.5% Black and 76.2% White patients (largely similar to overall Connecticut population: 12.7% Black, 78.8% White). Black patients were younger (56.7±13.3 vs. 62.1±13.4 years, p&lt; 0.001), more likely female (58.7 vs. 44.7%, p&lt;0.001) and had more risk factors (Table 1). Black patients were more likely to undergo MPI (66.6 vs. 50.5%, p&lt;0.001), inpatient or observation status testing (17.0 vs. 8.4%, p&lt; 0.001), with pharmacological rather than exercise stress (53.9 vs. 37.0%, p&lt;0.001) than White patients. On analysis of the 1:1 matched cohort, Black patients younger than 65 years were more likely to undergo MPI than White patients (62.1 vs. 57.4%, p&lt;0.001), while the reverse is seen for patients over 65 years old (37.5 vs. 42.5%, p&lt;0.001). Conclusion: Significant demographic and stress testing pattern differences were found between Black and White patients. These findings may reflect racial disparities in cardiovascular care, including access and clinical referral patterns. Further studies are needed to determine if these differences in stress testing strategies impact downstream clinical outcomes.

Abstract 18379: Implementation of a Fully Automated Procedural Reporting System for Cardiology Fellowship

Introduction: Contemporary cardiovascular fellowship training is based in the principles of competency-based medical education (CBME). Inclusive of CBME, core cardiovascular training statements suggest a minimum number of procedures necessary to achieve levels of training. However, current platforms for procedure logging create an onerous burden on trainees and program leadership which can result in incomplete data capture. There is a paucity of experience with automated case logging tools across training programs. Herein, we present the experience of fully automating trainee case logging within the echo lab at a large cardiovascular fellowship program. Methods: Structured trainee procedure attribution data (patient age, gender, and procedure type) were captured during routine clinical activity within our EHR structured reporting module (Epic Cupid). Attribution was extracted from the EHR reporting warehouse (Epic Clarity) and summarized for trainees weekly via email. Following a weeklong buffer period to allow for corrections, the data were uploaded to the institutional educational reporting platform (MedHub) via a web application programming interface. All stages of this workflow were fully automated. Results: During the post-intervention period (June 2022 to May 2023), 32 cardiovascular fellows participated. Attribution was initially captured for transthoracic and transesophageal echocardiograms and later expanded to include exercise and dobutamine stress echocardiograms. A monthly average of 584 procedures were captured for trainees. There were no attribution errors reported. The intervention was uniformly perceived as helpful by both trainees and leadership with requests for expansion to other cardiovascular procedure types. Conclusion: Fully automated educational experience reporting is feasible in a large cardiovascular training program and can be implemented without change to clinical workflows or administrative burden.

Abstract 12668: Prevalence of Phenotypic Hypertrophic Cardiomyopathy Among Students Referred for Sport Pre-Participation Cardiovascular Screening

Background: Although rare, sudden cardiac death (SCD) is a tragic event for young sports participants and has catastrophic impact on the community. Hypertrophic cardiomyopathy (HCM) is a leading cause of SCD in sports. Comprehensive initial pre-participation physical evaluation (CIPPE) is mandated for middle school, and junior and senior high school students by Pennsylvania Interscholastic Athletic Association (PIAA) primarily for reducing potential sports-related injuries and SCD. Prospective data has been limited in this age group in regard to the prevalence of HCM. Methods: Between 2015 and 2023, we prospectively screened 424 students [age 10-21 (15±2) years, 60% male, 64% Caucasian) referred for cardiovascular disease pre-participation screening based on at least one positive response on the 14-point AHA questionnaire during CIPPE. Evaluation included 12-lead ECG and rhythm strip (100%), transthoracic echo (96.4%), ambulatory heart rhythm monitor (3.8%), treadmill exercise ECG (14.5%), stress echo (2.1%), and cardiac MRI (0.9%). Results: Overall, 1 (0.24%) student was diagnosed with definitive and two were diagnosed with probable HCM [Table-1]. Conclusion: In this prospective cohort of middle school and junior and senior high school students with at least one positive response to the 14-point AHA questionnaire, 1 (0.24%) had definitive and 2 (0.47%) had probable phenotypic HCM.

Abstract 18325: Comparative and Incremental Diagnostic and Prognostic Yield of Exercise ECG, CMR and SPECT in Patients With Suspected Ischaemic Heart Disease: A CE-MARC Sub-Study

Background: Guidelines recommend exercise ECG and stress imaging as first line diagnostic tests for the management of patients with suspected ischemic heart disease (IHD). We compared 1) the accuracy in detection of angiographically defined IHD and 2) the prognostic significance of exercise ECG, single photon emission computed tomography (SPECT) and cardiovascular magnetic resonance (CMR), as well as the sequential use of exercise ECG and an imaging test, in the CE-MARC study. Methods and Results: Of 752 patients in CE-MARC, 580 had exercise ECG and angiography, and 503 also had SPECT and CMR. The sensitivity, specificity, positive and negative predictive values (95%CI) of exercise ECG were 68.3 (61.9,74.0), 72.5 (67.6,76.9), 61.0 (54.8,66.8), 78.4 (73.7,82.5). Exercise ECG was significantly less sensitive than CMR and less specific than CMR and SPECT. Furthermore a positive exercise ECG result was not predictive of MACE at follow-up (HR 1.14 [95% CI 0.75 to 1.72], p = 0.53). Sequential SPECT following an inconclusive exercise ECG compared to SPECT alone resulted in improved sensitivity (86.3% vs. 65.5%) and negative predictive value (79.0% vs. 87.9%) but at a cost of reduced specificity and positive predictive values (83.7% vs. 64.1%; 72.1% vs. 60.7%), and was not prognostically significant (HR 2.31 [95% CI, 0.88 to 6.08], p = 0.091). CMR alone had greater diagnostic and prognostic yield than exercise ECG, SPECT or a combination of the two. Sequential CMR in patients with inconclusive exercise ECG did not outperform CMR alone, but allowed effective prognostication (p = 0.011), contrary to SPECT (p = 0.081). Conclusions: In patients recruited to CE-MARC, exercise ECG was less sensitive than CMR and less specific than both CMR and SPECT. Positive exercise ECG results had no clear prognostic value. CMR alone was more sensitive and offered greater prognostic yield than exercise ECG, SPECT, or a combination of both. Diagnostic and prognostic yield of CMR was not improved by combination with exercise ECG. Importantly, sequential use of CMR, but not SPECT, improved prognostication following an inconclusive exercise ECG.

Abstract 12224: Long Term Mortality in Patients With Low-Risk Myocardial Perfusion Imaging

Introduction: Stress testing is utilized for diagnosis and risk stratification for coronary artery disease, with low-risk myocardial perfusion imaging (MPI) indicating less than 1% cardiac mortality per year. We aimed to determine the long-term cardiac mortality in these patients. Methods: We performed a retrospective observational study of 1,300 patients with low-risk MPI in 2015, including pharmacological and exercise studies in a tertiary care center in Central Massachusetts, USA. Each patient was followed from the time of the MPI study for a total duration of 7 years. All-cause mortality and cardiac death were identified. We calculated the pharmacologic and exercise MPI percentage in patients with cardiac death. A cardiac mortality graph was plotted to observe trends over seven years. Results: Out of the 1,300 patients, 3.2% [n=42; mean age 74.6+/-20 years, 78% male (n=32)] of patients had a cardiac death in the follow-up period of 7 years. The pharmacological MPI group had 5% (n=41) cardiac deaths as compared to 0.2% (n=1) in the exercise MPI with the low Duke Treadmill Score group (p-value 0.04) [Figure 1a]. The cardiac death trend over the seven years revealed the highest mortality in year 6 (19%, n= 8) and the lowest in year 4 (7.1%, n=3) [Figure 1b]. Conclusions: The incidence of long-term cardiac deaths is less than 0.5% each year in patients with low-risk MPI, in both groups. Cardiac mortality was higher in patients who underwent pharmacological stress tests indicating appropriate assessment of underlying cardiac pathology. Exercise MPI depends on multiple variables to be optimal, while all patients undergoing pharmacological MPI are maximally stressed. Extensive, multi-center, controlled studies are necessary to evaluate the differences in risk stratification of low-risk MPI between exercise and pharmacological stress tests.

Abstract 12537: Sedentary Behavior is a Stronger Risk Factor Than Diabetes for Incident Peripheral Artery Disease: Data From the Henry Ford Exercise Testing (FIT) Project

Introduction: Age, diabetes (DM) and smoking are risk factors related to developing peripheral artery disease (PAD). Little is known about the strength of the association of sedentary behavior (SB) or fitness relative to traditional risk factors, and the risk of PAD. Hypothesis: SB and fitness are independently related to risk of PAD, but their relative contribution is less than DM and smoking. Methods: We assessed 41,268 patients (pts) (age= 55±12 yr, 51% male, 64% white) from the Henry Ford Exercise Testing (FIT) who completed a clinically ordered exercise stress test between January 1991 and June 2009. Fitness (metabolic equivalents of task, METs) was estimated from peak treadmill speed and grade. Patients were asked about current exercise habits and coded as sedentary if not performing regular aerobic mode exercise. Patient self-report and medical records were used to determine smoking history and DM. Those with established PAD at the time of testing were excluded. ICD9 codes 440.XX and 443.9 identified first incidence of PAD from test date up to June 2010. Using multivariable Cox regression (Wald X 2 , α &lt;0.05) we report on the top 5 predictors of time to incident PAD in ALL pts and stratified by race. Results: During a median follow-up of 7.1 yr (IQR 4.2-11.1 yr) there were 2,596 (6%) incident diagnoses of PAD. Wald X 2 values were rank ordered (Table). SB and fitness were independently related to time to incident PAD. SB ranked the 3 rd strongest variable for both ALL (HR=2.5 [2.2, 2.9]) and WHITE pts (HR=2.5 [2.1, 2.9]). For BLACK pts SB ranked 2 nd (HR=2.7 [2.1, 3.6]), above DM and smoking. Fitness ranked 5 th for ALL and BLACK pts, and 6 th in WHITE pts. Conclusion: In ALL pts, and WHITE and BLACK pts separately, SB was strongly associated with time to incident PAD, and explained more of the variation in incident PAD than DM. In BLACK pts SB was also stronger than smoking. Further research is needed to clarify the role of SB as a potential emerging modifiable risk factor for the development of PAD.

Abstract 12532: Maximal Exercise Capacity is Inversely Related to Incident Peripheral Artery Disease: Data From the Henry Ford Exercise Testing (FIT) Project

Introduction: Maximal exercise capacity (EC) is a strong, independent predictor of incident coronary and cerebrovascular disease. However, less is known about the relationship between EC and incident peripheral artery disease (PAD). Using data from the Henry Ford Exercise Testing (FIT) Project, we evaluated the relationship between EC and incident PAD. Hypothesis: EC, measured in metabolic equivalents of task (METs), is inversely related to incident PAD. Methods: We assessed 41,268 patients (age= 55±12 yrs, 49% female, and 64% white) who completed a clinically indicated exercise stress test between January 1991 and June 2009 at a Henry Ford Health facility. Patients with established PAD at the time of testing were excluded. METs were estimated from peak treadmill speed and grade and standardized to the equivalent of a 50-year-old male to account for differences in absolute risk for a given MET level by age and sex. METs were categorized as &lt;6, 6-9, 10-11, and &gt; 12. ICD9 codes 440.XX and 443.9 were used to identify first incidence of PAD from the test date through June 2010. Multivariable Cox regression was used to relate METs to incident PAD. Patients were censored at the date of death or last clinic visit. Results: During a median follow-up of 7.1 years (IQR 4.2-11.1 yrs) there were 2,596 (6%) incident diagnoses of PAD. In the adjusted analysis, each 1 MET increase in maximal EC was associated with a 7% lower risk of PAD (aHR=0.93 [0.91, 0.94]). There was a graded, inverse risk of incident PAD by MET category (see Table). A significant interaction was noted for race (overall p=.04; white [HR=0.93 (0.92, 0.95)] vs black [HR=0.91 (0.88, 0.93)], p=.02; white vs other [HR=0.97 (0.87, 1.07)], p=0.47), but not for sex (p=.79). Conclusion: In a diverse cohort that completed a clinically indicated exercise stress test, higher EC measured in METs, is independently and inversely associated with a lower risk of incident PAD.

Abstract 14060: Health Disparities in Exercise Performance in Tetralogy of Fallot

Introduction: Patients with tetralogy of Fallot (TOF) from disadvantaged racial and ethnic groups are reported to have worse outcomes, including worse exercise performance. The underlying mechanisms are not fully understood. Hypothesis: We hypothesize that the association of exercise performance with race is mediated by socioeconomic factors. Methods: We conducted a single center retrospective cohort study of TOF patients aged 8 - 30 years who underwent maximal exercise stress testing (EST) from 2007 - 2020. The primary outcome was percent-predicted maximum oxygen consumption (VO2). Addresses were geocoded. The Childhood Opportunity Index (COI) and its three domains represented neighborhood socioeconomic status. Generalized linear models and mediation analysis were used (Figure). Results: We included 154 subjects who underwent 273 ESTs (Table). Correcting for age at EST, sex, outflow tract repair type, and body mass index, those of non-Hispanic Black race had an 8.6% lower percent-predicted VO2 (95% CI -15.0, -2.2) than those of non-Hispanic white race. Mediation analysis showed that the COI mediates 90% of this relationship. By domain, Education is the strongest mediator and alone can account for 75% of this relationship. Conclusions: Disparities exist in exercise performance after TOF repair. Neighborhood-level factors, in particular related to Education, are significant mediators of the relationship between race and exercise performance in TOF. A detailed understanding of the driving mechanisms underlying health disparities, particularly those that are modifiable, is critical to eliminating those disparities at both the patient and societal levels.

Abstract 12142: Treadmill Exercise Stress Echocardiography Exposes Impaired Left Ventricular Function in Patients Recovering From Hospitalization for COVID-19 versus Historical Controls

Usual clinical testing rarely reveals persisting cardiac abnormalities in patients after hospitalization for Covid-19. Such testing may overlook residual changes responsible for increased adverse cardiac events seen post-discharge. To further elucidate patients’ long-term status, we performed exercise stress echocardiography (ESE) in 15 patients age 30-63 without myocarditis 3 to 31 months after hospital discharge. We compared patient outcomes to published data in healthy controls (HC) exercising according to the same protocol. Patients’ treadmill exercise (Bruce protocol), averaging 8.2 min, was halted by dyspnea or fatigue. Baselines before stress averaged the same in recovering patients (RP) and HC except for heart rate (HR): 81±13 bpm for RP and 63±8 for HC (p&lt;0.0001). Peak stress values in RP were compared with HC: Stress revealed significantly lower LVEF and raised E/e’ soon after peak effort in RP compared with HC performing the same exercise. Thus, when stressed, patients with no known cardiac impairment before or during Covid-19 hospitalization showed modest but consistently diminished systolic contractile function and diastolic LV compliance during recovery compared to HC. Peak HR during stress was significantly elevated in RP vs. HC; peak SBP also trended higher. Average systolic pulmonary artery pressures among RP remained normal. Our measurements during ESE uniquely identified residual abnormality in cardiac contractile function not evident in the unstressed condition. This finding exposes a previously-unrecognized residual influence of Covid-19 that may relate to underlying autonomic dysfunction, microvascular disease, or diffuse interstitial changes after subclinical myocarditis and may have long-term implications for clinical management and later prognosis.

Abstract 16481: Comparative Measures of Physical Performance in Healthy Subjects and Patients With Subclinical Heart Failure or Coronary Artery Calcium in the Project Baseline Health Study

Introduction: While exercise stress test is the traditional method for assessing cardiorespiratory fitness, 6-minute walk test (6MWT) and 10-meter walk test (10MWT) can be inexpensive alternatives for physical activity and fitness evaluation. We aim to identify conditions where 6MWT and 10MWT show comparable diagnostic yield to metabolic equivalents of task (MET). Methods: All participants in the Project Baseline Health Study (PBHS) with no missing data were included. Participants were assigned a heart failure (HF) stage according to the 2022 AHA/ACC HF guidelines. Mean and standard deviation (SD) were described for each measurement by HF stages: 0 (healthy), A (presence of risk factors (RF)), and B (presence of RF and LVEF&lt;50%, diastolic dysfunction or LVH); and by coronary artery calcium (CAC) score subgroups: 0, 1-99, ≥100 Agatson units (AU). Multinomial regression was applied to estimate the association of each measurement with HF stage and CAC subgroups adjusted for relevant covariates. Results: 2,181 (87%) of 2,502 PBHS participants had complete data on METs, 6MWT, and 10MWT. The mean (SD) age was 50.1 (17.1) years, with 1224 (56.1%) females. The cohort consisted of participants with Stage 0, A, B (n=711, 742, 372) and CAC = 0, 1-99, ≥ 100 (n=1275, 471, 348). The overall mean (SD) for 6MWT, 10MWT, and METs were 479.8 (79.1) m, 2.0 (0.5) m/s, and 11.6 (4.3), respectively. Each SD decrease of METs was significantly associated with increased odds for more advanced HF stages and CAC subgroups ( Figure A1-B2 ). The 10MWT and 6MWT were also able to differentiate significantly between subclinical stages of HF and compare CAC subgroups 1-99 and ≥100 to CAC=0, although with smaller odds ratios (Figure A1, A2, B1). Conclusions: METs, as measured in a graded exercise test, demonstrated the strongest association with HF stage or CAC subgroup. Based on our findings, there is potential for utilizing the simpler assessments of 10MWT and 6MWT to differentiate between subclinical HF stages.

Abstract 11702: Development of Artificial Intelligence-Based Slow-Motion Echocardiography and Clinical Usefulness for Evaluating Regional Wall Motion Abnormalities

Introduction: Improvement in accuracy and image readability of stress echocardiography needs to be addressed, given that the accuracy depends on the physicians’ experience and image quality. The study aimed to develop an artificial intelligence (AI) based slow-motion echocardiography by inter-image interpolation and evaluate the clinical usefulness for detecting regional wall motion abnormalities (RWMAs). Methods: An AI-based image interpolation pipeline was developed with the optical flow calculation between echocardiographic images and predicting in-between images. In a cohort of patients with RWMA (n=25) and healthy volunteers (n=25), the accuracy for detecting RWMAs and image-reliabilities among four cardiologists was evaluated using slow-motion and conventional exercise stress echocardiography. Results: The development of slow-motion echocardiography were successfully performed at any arbitrary-time steps (e.g., 0.125x, 0.25x, and 0.5x). The accuracy for detecting RWMAs was numerically improved, while not statistically significant (87.5% in slow-motion echocardiography vs 81.0% in conventional stress echocardiography, odds ratio: 1.43 (95% confidence interval 0.78-2.62, p=0.25). Inter-reader agreement analysis demonstrated the level of agreements (Fleiss’s Kappa) for detecting RWMAs was 0.66 (95%CI: 0.55-0.77) in slow-motion echocardiography, and 0.53 (95%CI: 0.42-0.65) in conventional stress echocardiography. As for the four-point scale subjectively-evaluated image readability, the mean score was significantly improved using slow-motion echocardiography (2.11±0.73vs 1.70±0.78, p&lt;0.001). Conclusions: Slow-motion echocardiography was successfully developed. There was no significant improvement in the accuracy for detecting RWMAs using the developed slow-motion echocardiography, while the image readability and inter-reader agreement were improved.

Abstract 16196: E/e' Predicts Exercise Capacity in Participants Undergoing Exercise Stress Test

Introduction: The ratio of early transmitral flow velocity (E) to early diastolic mitral annular velocity (e’) is a surrogate for left ventricular (LV) filling pressure. Post-stress E/e’ has been shown to predict exercise capacity, but few studies have investigated this correlation with baseline E/e’. Our aim was to evaluate the relationship between baseline E/e’ and exercise capacity during stress test. Methods: All patients undergoing exercise stress testing at University of Virginia from 1/2015 through 9/2015 with the required echo data were included in this study. E/e’ was categorized into quartiles. ANOVA was used to evaluate the relationship between quartiles of E/e’ and exercise duration or METS. Multivariate linear regression was used to adjust for the variables: age, sex, ejection fraction, systolic blood pressure, heart rate, and regional wall motion abnormalities. Results: Baseline characteristics of the 312 participants based on E/e’ quartiles are shown in Table 1; those with higher E/e’, on average, had higher baseline SBP, were older, and had a higher percentage of females. There was a significant difference in exercise duration and METS between E/e’ quartiles (Table 2A) [p &lt; 0.001]. There was an inverse correlation between E/e’ and exercise capacity; the significance was more pronounced with increasing E/e’ (Table 2A) and was present even after adjusting for multiple covariates (Table 2B). Conclusions: Baseline E/e’ correlates with exercise capacity (both duration of exercise and total METS achieved). This suggests that elevated LV filling pressures at rest can predict exercise capacity and may be targeted in future studies to improve exercise tolerance.

Abstract 13995: Remote, Smart Device Based Cardiac Rehabilitation After Myocardial Infarction - Smart Rehab Study

Introduction: After myocardial infarction (MI), increasing functional capacity is an important goal of cardiac rehabilitation, that improves prognosis. However, standard cardiac rehabilitation is not accessible to many patients. Telemedicine programs are emerging as promising alternatives to in-person programs, but evidence confirming its benefits is lacking. Hypothesis: Smart device based remote cardiac rehabilitation can improve functional capacity assessed by VO2peak after MI. Methods: Patients were offered participation at the time of hospitalization for MI. One month after MI, patients underwent a cardiopulmonary exercise test, 6-minute walking test (6MWT) and were randomized 1:1. In the intervention group, patients received a smart watch to track the recommended number of steps, that was derived from the 6MWT. Adherence to the recommendations was telemonitored by a study nurse, with an over the phone motivation talk if compliance was unsatisfactory. In the control group, patients were recommended 150 minutes/week of moderate intensity exercise. Exercise stress tests were repeated after 3 months. Results: In total, 59 patients (mean age 51.5±10.4 years, 10.2% women, 67.8% STEMI, 96.6% PCI, mean discharge EF 48±10%) were included in the study. At baseline, there was no difference in clinical characteristics and functional capacity between the intervention (n=29) and control (n=30) groups. After 3 months of the intervention, VO2peak improved in the intervention arm with between group difference of 1.56 ml/kg/min (95%CI 0.06-3.05, p=0.041), with no difference in 6-minute walking distance (p=0.11). The effect of intervention differed by baseline functional capacity (p for interaction &lt;0.01). Among patients with VO2peak at baseline ≤95% predicted, the between-group VO2peak difference after 3 months was 2.46 ml/kg/min (95% CI 0.78-4.13, p=0.005), and also oxygen uptake efficiency slope (between group difference 235, 95% CI 43-428, p=0.02) and 6-minute walking distance improved (between group difference 60m, 95% CI 1.5-119, p=0.045). Conclusions: Smart device based remote cardiac rehabilitation improves functional capacity after myocardial infarction, particularly in those with decreased functional capacity. NCT03926312

Abstract 16414: Prognostic Value of Exercise Tolerance and Exercise-Associated Diastolic Dysfunction in Elderly Patients Referred for Exercise Stress Echocardiography

Aim: We studied the prognostic value of exercise tolerance, measured in metabolic equivalents of tasks (METs), and exercise-associated diastolic dysfunction (Ex-DD) in elderly patients referred for exercise stress echocardiography (ExE). Methods: Retrospectively, 583 patients (70±6 years, 57% women, EF: 61±5%) who underwent ExE using the Bruce protocol and were ≥60 years of age were included and followed for death or cardiac hospitalization. Ex-DD was defined as the presence of abnormal resting tissue Doppler mitral annular velocity (e') and post-exercise E/e' ratio. Results: During a median follow-up period of 3.7 years, 13 patients died, 70 were hospitalized, and 77 had combined outcome. 151 (26%) patients had Ex-DD and had more combined outcome compared to no Ex-DD (29 [19%] vs. 48 [11%], p=0.01). The average workload during ExE was 8.3±2.8 METs. Receiver operating characteristic curve identified that METs &lt;8.5 best predicts the combined outcome. As such, patients were classified into 260 with METs ≥ 8.5 and 323 with METs &lt; 8.5. Patients with METs &lt; 8.5 were older, had worse risk profiles, poorer resting and post-exercise diastolic variables, more Ex-DD (32% vs. 19%, p&lt;0.001), and more outcomes (55 [17%] vs. 22 [9%], p=0.002) compared to METs ≥ 8.5. Both Ex-DD (HR: 1.9, 95% CI: 1.2-2.9) and METs &lt; 8.5 (HR: 1.9, 95% CI: 1.1-3.1) independently predicted the combined outcome. The presence of both METs &lt; 8.5 and Ex-DD conferred the highest risk (HR: 2.9, 95% CI: 1.5-5.6) and remained significant after adjustment and propensity score matching, while the presence of either alone carried an intermediate risk (HR: 1.9, 95% CI: 1.1-3.5), which became non-significant after adjustment and matching. Conclusions: poor exercise capacity is associated with an adverse prognosis, irrespective of resting or Ex-DD. METs &lt; 8.5 had particularly poor prognosis when combined with Ex-DD, while either alone did not predict outcomes.

Abstract 15269: Effect of a Systemic Right Ventricle With A Biventricular Circulation on Cardiorespiratory Fitness

Background: The clinical care of adults with a systemic right ventricle with biventricular circulation (sRV-biV) is influenced by cardiorespiratory fitness (CRF) evaluation. However, prognostic markers for CRF are derived from analyses of adults with a systemic left ventricle (sLV). While some studies suggest that CRF is lower in adults with sRV-biV compared to those with a sLV, they have not controlled for key clinical characteristics and ventricular function of the systemic ventricle. Research Question: Is CRF lower in adults with a sRV-biV compared to adults with sLV matched for clinical characteristics and systemic ventricular function? Methods: A retrospective cross-sectional comparison of exercise stress test results was performed comparing 24 adults with sRV-biV to 24 adults with a sLV matched for sex (4 females), age (sRV-biV: 46 ± 9 years, sLV: 46 ± 11 years), body mass index (sRV-biV: 28 ± 4 kg/m 2 , sLV: 27 ± 4 kg/m 2 ), ejection fraction of the systemic ventricle (normal: 2, mild: 4, moderate: 11, severe: 7), NYHA class (I: 6, II: 17, III: 1), and doses of diuretics (spironolactone ≤ 25 mg: 24, furosemide ≤ 80 mg: 24 ). Peak VO 2 was compared between groups with Wilcoxon signed-rank tests. Effect sizes are reported as Cohen’s d . Results: Peak VO 2 did not differ significantly between groups (sRV-biV: 20.3 ± 4.2 vs. sLV: 20.9 ± 6.0 mL/kg/min, p=0.43, d =0.18). When patients were dichotomized according to the Weber criterion for optimal versus suboptimal CRF (sLV peak VO 2 &gt; or ≤ 20 mL/kg/min), peak VO 2 was lower in sRV-biV in those with optimal CRF (sRV-biV: 21.0 ± 4.8 vs sLV: 26.6 ± 5.1 mL/kg/min, p=0.006, d =0.72). In contrast, peak VO 2 was greater in sRV-biV in those with suboptimal CRF (sRV-biV: 19.3 ± 3.5 vs. sLV: 16.9 ± 2.0 mL/kg/min, p=0.12, d =NA). Conclusion: Although peak VO 2 values are similar among patients with a sRV-biV and matched controls with a sLV, differences are observed when stratified according to the Weber criteria for optimal CRF. These results may reflect different pathophysiological adaptive mechanisms of a sRV vs sLV. Further studies are required to establish specific prognostic thresholds for patients with sRV-biV.

Abstract 16128: The Winslow Pathway and Internal Mammary Artery Harvesting in Patients With Aortoiliac Occlusive Disease

Introduction We present a case where the left Internal Mammary Artery (IMA) was not a straightforward choice as the grafted vessel in a patient undergoing Coronary Artery Bypass Grafting (CABG). Case Presentation Patient was a 66 years old female with Hypertension, Hyperlipidemia, hypothyroidism, and tobacco use disorder. Evaluation for a motor vehicle accident secondary to a syncopal episode, and intermittent chest tightness over the past few months, showed ST depressions on ambulatory electrocardiographic monitoring, reversible ischemia in the anterior and apical walls on Exercise Stress Test and severe multivessel coronary artery disease involving the distal main left coronary artery and its branches on Coronary Angiography. CABG was advised. Preoperative peripheral angiogram showed bilateral common iliac artery occlusion, precluding IABP placement. Selective angiography of the left IMA showed the left IMA to be the major vessel supplying collateral circulation to the left iliac system. Patient subsequently underwent CABG with bilateral Saphenous Vein Harvest. Discussion IMA harvesting in patients with Aortoiliac Occlusive Disease (AOD) with prominent collaterals through the subclavian-IMA-inferior epigastric-external iliac pathway, AKA the Winslow Pathway (WP), can result in limb threatening ischemia, and elective IMA angiography and/or doppler flow evaluation before CABG can help identify this important collateral pathway. Alternative approaches in patients with AOD include simultaneous coronary and peripheral revascularization, completely avoiding IMA harvesting or in some cases, angioplasty, although there is no consensus thus far.

Abstract 14461: Impact of Intermittent vs Persistent Left Ventricle Outflow Tract Obstruction on Left Atrial Strain and Diastolic Function in a Young Hypertrophic Cardiomyopathy Cohort

Background: Adolescents and young adults with hypertrophic cardiomyopathy (HCM) and persistent left ventricular outflow tract obstruction (LVOTO) have larger left atrial volume (LAV) and abnormal diastolic function and left atrial (LA) strain compared to those without resting LVOTO. It is unknown whether intermittent LVOTO with exercise results in smaller LAV and improved diastolic function and LA strain indices compared to persistent LVOTO. Methods: All HCM patients with echo and exercise stress echocardiography (ESE) from 2014-2022 at a single center were enrolled. The cohort was divided into 3 ESE hemodynamics groups: 1) No LVOTO (all gradients &lt; 30 mmHg, n=48); 2) Intermittent LVOTO (no rest gradient, exercise ≥30 mmHg, n=41); 3) Persistent LVOTO (rest/exercise ≥30mm Hg, n=29). LAV (biplane method), LAV Z scores, LV lateral e’, lateral e’ Z scores, LA reservoir (LASr), conduit (LAScd), and contractile (LASct) strain (TOMTEC Arena AutoSTRAIN) were analyzed. For each parameter, mean values were compared across groups using one-way analysis of variance. The Bonferroni method was used to compare Group 2 to 1 and 3. Results: 118 patients (31% F, median age 17 yrs, range 7-39) formed the cohort. Mean LAV was 64.9, 65.1, and 79.5 ml in Groups 1, 2, and 3 respectively. Differences in group means were found for LAV Z score, lateral e’, lateral e’ Z score, LASr, and LAScd (all p≤0.01). In Group 2 vs 3, LAV Z score was significantly lower (0.46 v 1.89) and LV lateral e’, lateral e’ Z score, and LAScd were significantly higher (lateral e’: 13.1 v 9.0 cm/s; lateral e’ Z score: -2.0 v -3.4; LAScd: 26.0 v 21.1%) (Fig 1). LASr did not differ significantly in Group 2 vs 3. No significant differences were found in Group 2 vs 1. Conclusion: In one of the largest young HCM cohorts, intermittent obstruction was associated with smaller LAV, better diastolic indices, and higher LA conduit strain versus persistent obstruction. Longer follow-up is needed to assess change as those with intermittent LVOTO age.