Predictor Of Exercise Capacity Research Articles

Body fat predicts exercise capacity in persons with Type 2 Diabetes Mellitus: A machine learning approach.

Diabetes mellitus is associated with increased cardiovascular disease (CVD) related morbidity, mortality and death. Exercise capacity in persons with type 2 diabetes has been shown to be predictive of cardiovascular events. In this study, we used the data from the prospective randomized LOOK AHEAD study and used machine learning algorithms to help predict exercise capacity (measured in Mets) from the baseline data that included cardiovascular history, medications, blood pressure, demographic information, anthropometric and Dual-energy X-Ray Absorptiometry (DXA) measured body composition metrics. We excluded variables with high collinearity and included DXA obtained Subtotal (total minus head) fat percentage and Subtotal lean mass (gms). Thereafter, we used different machine learning methods to predict maximum exercise capacity. The different machine learning models showed a strong predictive performance for both females and males. Our study shows that using baseline data from a large prospective cohort, we can predict maximum exercise capacity in persons with diabetes mellitus. We show that subtotal fat percentage is the most important feature for predicting the exercise capacity for males and females after accounting for other important variables. Until now, BMI and waist circumference were commonly used surrogates for adiposity and there was a relative under-appreciation of body composition metrics for understanding the pathophysiology of CVD. The recognition of body fat percentage as an important marker in determining CVD risk has prognostic implications with respect to cardiovascular morbidity and mortality.

The non-invasive coronary flow reserve predicts exercise capacity in patients undergoing cardiac rehabilitation

The benefit of exercise on peripheral muscles is established but the exact role of the coronary microcirculation in exercise capacity after cardiac rehabilitation (CR) is unclear. Our aim was to test the relationship between non-invasive coronary flow reserve (CFR) and exercise capacity in patients undergoing CR after acute myocardial infarction (AMI). CFR was performed by transthoracic Doppler echocardiography in the left anterior descending artery 24 h after angioplasty (CFR1) and after 20 sessions of CR program (at 4 ± 1 months)(CFR2) in 60 consecutive patients (57 ± 11 years, 30% women) with an anterior AMI successfully treated by primary coronary angioplasty. CFR was performed in a modified parasternale view using intravenous adenosine infusion (0.14 mg/kg/min within 2 minutes). CR program consisted of a half hour of fractioned exercise added of a half hour session of general gymnastics and bodybuilding. To test the exercise capacity, symptom limited exercise echocardiography was performed just after the CFR2, in a semi-supine position, starting at 25 watts, with 20-25 watts increments of workload every two minutes. CFR was measured successfully in all patients, and CFR2 was significantly higher than CFR1 (2.9 ± 0.65 vs. 1.9 ± 0.4, P < 0.001). Though CFR1 was correlated to left ventricular systolic function and its improvement at follow-up (all, P < 0.01), CFR2 was independently related to exercise capacity (mean workload 100 ± 30 watts, percent maximal heart rate 83 ± 12%, no ischemia, no new wall motion abnormalities in all tests) after adjusting for age, sex, and body mass index ( r = 0.6, P < 0.01). CFR predicts exercise capacity in patients undergoing a CR program after AMI. The improvement of CFR contributes to cardiac performance.

Left atrial function and maximal exercise capacity in heart failure with preserved and mid-range ejection fraction.

AimsExercise intolerance is the leading manifestation of heart failure with preserved or mid‐range ejection fraction (HFpEF or HFmrEF), and left atrial (LA) function might contribute to modulating left ventricular filling and pulmonary venous pressures. We aim to assess the association between LA function and maximal exercise capacity in patients with HFpEF or HFmrEF.Methods and resultsSixty‐five patients, prospectively enrolled in the German HFpEF Registry, were analysed. Inclusion criteria were New York Heart Association functional class ≥ II, left ventricular ejection fraction > 40%, structural heart disease or diastolic dysfunction, and elevated levels of N terminal pro brain natriuretic peptide (NT‐proBNP). LA function was evaluated through speckle‐tracking echocardiography by central reading in the Charité Academic Echocardiography core lab. All patients underwent maximal cardiopulmonary exercise test and were classified according to a peak VO2 cut‐off of prognostic value (14 mL/kg/min). NT‐pro‐BNP was measured. Twenty‐nine patients (45%) reached a peak VO2 < 14 mL/kg/min (mean value 12.4 ± 1.5) and 36 patients (55%) peak VO2 ≥ 14 mL/kg/min (mean value 19.4 ± 3.9). There was no significant difference in left ventricular ejection fraction (60 ± 9 vs. 59 ± 8%), left ventricular mass (109 ± 23 vs. 112 ± 32 g/m2), LA volume index (45 ± 17 vs. 47 ± 22 mL/m2), or E/e´ (13.1 ± 4.7 vs. 13.0 ± 6.0) between these groups. In contrast, all LA strain measures were impaired in patients with lower peak VO2 (reservoir strain 14 ± 5 vs. 21 ± 9%, P = 0.002; conduit strain 9 ± 2 vs. 13 ± 4%, P = 0.001; contractile strain 7 ± 4 vs. 11 ± 6%, P = 0.02; reported lower limits of normality for LA reservoir, conduit and contractile strains: 26.1%, 12.0%, and 7.7%). In linear regression analysis, lower values of LA reservoir strain were associated with impaired peak VO2 after adjustment for age, sex, body mass index, heart rhythm (sinus/AFib), and log‐NTproBNP [β 0.29, 95% confidence interval (CI) 0.02–0.30, P = 0.02], with an odds ratio 1.22 (95% CI 1.05–1.42, P = 0.01) for peak VO2 < 14 mL/kg/min for LA reservoir strain decrease after adjustment for these five covariates. Adding left ventricular ejection fraction, it did not influence the results. On the other hand, the addition of LA strain to the adjustment parameters alone described above provided a significant increase of the predictive value for lower peak VO2 values (R 2 0.50 vs. 0.45, P = 0.02). With receiver operating characteristic curve analysis, we identified LA reservoir strain < 22% to have 93% sensitivity and 49% specificity in predicting peak VO2 < 14 mL/kg/min. Using this cut‐off, LA reservoir strain < 22% was associated with peak VO2 < 14 mL/kg/min in logistic regression analysis after comprehensive adjustment for age, sex, body mass index, heart rhythm, and log‐NTproBNP [odds ratio 95% CI 10.4 (1.4–74), P = 0.02].ConclusionsIn this HFpEF and HFmrEF cohort, a reduction in LA reservoir strain was a sensible marker of decreased peak exercise capacity. Therefore, LA reservoir strain might be of clinical value in predicting exercise capacity in patients with HFpEF or HFmrEF.

Abstract 12992: LA Strain Predicts Exercise Capacity in Chronic Kidney Disease

Background: Left atrial (LA) function plays a pivotal role in modulating left ventricular performance particularly during exercise. The aim of our study was to evaluate the relationship between resting LA function by strain analysis as a determinant of exercise capacity in chronic kidney disease (CKD) patients, and evaluate its utility compared to exercise E/e’. Methods: Consecutive Stage 3 and 4 CKD patients without prior cardiac history were prospectively recruited from outpatient nephrology clinics and underwent clinical evaluation, resting and exercise stress echocardiography. Patients needed to be in sinus rhythm without significant valvular disease or ischaemia on stress testing. Resting echocardiographic parameters including E/e’ and phasic LA strain [LA reservoir (LASr), conduit (LAScd) and contractile (LASct) strain] were measured and compared to exercise E/e’. Results: 218 (63.9±11.7yrs, 64% men) CKD patients were recruited. Independent clinical predictors of exercise capacity were age, eGFR, body mass index and gender (p&lt;0.01 for all) while independent resting echocardiographic predictors included E/e’, LASr and LASct (p&lt;0.01 for all). Amongst independent resting echocardiographic predictors, LASr ( r =0.70,p&lt;0.01) demonstrated the strongest correlation to METs achieved. Receiver operating characteristic curves (Figure 1) demonstrated that LASr (AUC 0.83,) had similar predictive value as exercise E/e’ (AUC 0.79; AUC difference of 0.05, p=0.20 on DeLong test). A model combining LASr and clinical metrics showed robust predictive capacity for METs achieved in CKD patients. Conclusions: LASr, a marker of decreased LA compliance is an independent predictor of exercise capacity in Stage 3 and 4 CKD patients, with similar predictive value to exercise E/e’. The use of LASr may serve as a resting biomarker of functional capacity in this population.

Abstract 14611: Indices of Myocardial Work is an Independent Predictor of Exercise Capacity

Introduction: Exercise capacity has been shown to be an independent determinant of cardiovascular outcomes and prognosis. Conventional measures of left ventricular (LV) diastolic dysfunction, including E/e’ and left atrial (LA) metrics, have been shown to be independent predictors of exercise capacity however little is known about its relationship to myocardial energy utility and expenditure. Myocardial work (MW) is a novel non-invasive modality for assessment of myocardial efficiency and may serve to better define this relationship. Hypothesis: Greater wasted myocardial work is associated with reduced exercise capacity. Methods: Patients without prior cardiac disease referred to our echocardiography service for stress echocardiograms were prospectively recruited. These patients underwent comprehensive baseline transthoracic echocardiography (TTE) followed by exercise stress echocardiography. Only patients without structural heart disease on TTE and without ischaemia on stress testing were included. Myocardial work was assessed using EchoPac (v2.2, Chicago Illinois). Reduced exercise capacity was defined as METS achieved of ≤7. Results: 100 consecutive patients meeting inclusion criteria were analysed (45% male, age 56.0±15.7), of which 67% had diabetes and 44% had hypertension. The mean METS achieved was 8.5±3.7. Thirty-nine patients had a poor exercise capacity defined as METS achieved of ≤7. These patients were of older age, had greater indexed LV mass, higher E/e’, larger indexed left atrial volume, greater constructive work, greater wasted work, greater work index and lower work efficiency. On logistics regression, age (p&lt;0.001), and myocardial wasted work (p=0.02) were independent predictors of poor exercise capacity after adjusting for the other clinical and echocardiographic variables. Conclusions: Reduced exercise capacity is independently associated with greater wasted work. Larger studies will be required to validate our findings.

Abstract 16032: Determinants of Exercise Capacity Assessed Using Combined Stress Echocardiography and Cardiopulmonary Exercise Testing in Patients Treated for Acute Myocardial Infarction

Introduction: Exercise capacity (EC) after acute myocardial infarction (AMI) influences prognosis, but the causes of its reduction are complex and not sufficiently studied. Methods: We prospectively enrolled consecutive patients who underwent percutaneous coronary intervention for their first AMI without residual coronary stenosis and with left ventricular ejection fraction (LVEF) &gt; 40% more than 4 weeks after the AMI. We performed combined stress echocardiography and cardiopulmonary exercise testing (CPET-SE) using a semi-supine cycle ergometer to determine predictors of EC (peak oxygen uptake [VO 2 ]). Results: Among 81 patients (70% male, mean age 58 ± 11 years), 40% suffered AMI with ST-segment elevation (STEMI), and 60% non-STEMI, LVEF was 57 ± 7%; wall motion score index, 1.18 (IQR 1.06 - 1.31); peak VO 2 , 19.5 ± 5.4 mL/kg/min. Multivariate analysis ( Table ) revealed that parameters at peak exercise: heart rate (β = 0.17, p &lt; 0.001), stroke volume (β = 0.09, p &lt; 0.001), and arteriovenous oxygen difference (β = 93.51, p &lt; 0.001) were independently positively correlated with peak VO 2 , with arteriovenous oxygen difference being its strongest contributor. At rest, left ventricular systolic and diastolic function parameters and the extent of myocardial scarring (wall motion score index) did not predict EC (p &gt; 0.05). Conclusions: In patients treated for AMI with normal/mildly reduced LVEF, EC is associated with peak peripheral oxygen extraction as well as peak heart rate and peak stroke volume. CPET-SE is a useful tool to evaluate decreased fitness in this group.

Associations between spleen volume and exercise capacity in advanced heart failure patients with left ventricular assist device

Abstract Background The spleen has been recognized as an important organ with several functions such as a reservoir of blood volume, and an involvement in iron metabolism by processing of aged red blood cells and recycling iron. During exercise, spleen contracts, and red blood cells pooled in the spleen are recruited into the systemic circulation. So far, we reported that spleen size changed in advanced heart failure (HF) with left ventricular assist device (LVAD). In addition, spleen volume was related to pulmonary capillary wedge pressure (PCWP) or right atrial pressure (RAP) as parameters of cardiac preload. However, it remains unclear about the relationship between spleen volume and exercise capacity in advanced HF with LVAD. Purpose The purpose of this study was to investigate the associations between spleen volume and exercise capacity in advanced HF patients with LVAD. Methods We enrolled 27 HF patients (21 males, 45±12 years) with LVAD (HeartMate II™; Abbott, Chicago, IL, USA) for use as a bridge to heart transplantation. All patients underwent blood test, echocardiography, right heart catheterization, computed tomography (CT) and cardiopulmonary exercise testing (CPET). Spleen size was measured by CT volumetry. We excluded patients with splenic infarction or aortic valve closure surgery. Results At baseline, body mass index, blood brain natriuretic peptide levels, hemoglobin levels, left ventricular ejection fraction were 21.4±3.1 kg/m2, 73.8 (51.9–165.8) pg/mL, 12.1 (10.6–13.4) g/dL, 24.8±14.7%, respectively. Total cardiac output (CO), the sum of pump flow and CO of native heart was 4.6±0.9 L/min, and spleen volume was 184.9±48.8 mL. As for parameters of CPET, peak heart rate (HR), peak VO2, and peak O2 pulse were 128±25 beats/min, 14.2±3.3 mL/kg/min, and 6.6±1.9 mL/beat. At rest, there were significant correlations between spleen volume and PCWP (r=0.382, p=0.049), RAP (r=0.406, p=0.035) or pulsatility index (r=0.384, p=0.047), despite no correlations with total CO or pump flow. During exercise, there were significant interrelations of spleen volume with peak VO2 (r=0.451, p=0.018) and peak O2 pulse (r=0.427, p=0.026). Furthermore, peak VO2 was interrelated with peak HR (r=0.481, p=0.011) or hemoglobin levels (r=0.649, p&amp;lt;0.001). Remarkably, spleen volume was significantly correlated with hemoglobin levels (r=0.391, p=0.043) (Figure). Interpreting these results based on Fick's formula, the proportion of native CO to total CO is very small at rest, but increases during exercise. The spleen during exercise may contribute to increased native CO, especially stroke volume. Moreover, the spleen may be related to both cardiac preload and oxygen carrying capacity, resulting in a significant association between spleen volume and peak VO2. Conclusion Spleen volume could be a useful predictor of exercise capacity in advanced HF patients with LVAD, reflecting splenic function to modulate cardiac preload and blood hemoglobin levels. Spleen volume and exercise parameters Funding Acknowledgement Type of funding source: None

Impact of right ventricular contractile reserve on exercise capacity in patients with heart failure: clinical application of low-load exercise stress echocardiography

Abstract Background The peak oxygen uptake (VO2) evaluated by the cardiopulmonary exercise test (CPX) is an established marker of exercise capacity in patients with heart failure (HF). In particular, peak VO2 &amp;lt;14 ml/kg/min is used to be one of the criteria for heart transplantation. However, given exercise intolerance in patients with HF, it is difficult for refractory HF patients to reach sufficient exercise load. A recent report has highlighted significant impact of right ventricular (RV) function on mortality and urgent heart transplantation. Taken together, we hypothesized that the assessment of RV function was helpful to predict exercise capacity by using low-load exercise stress echocardiography (low-load ESE) in patients with HF. Purpose We evaluated whether RV dysfunction assessed by the low-load ESE determined a low peak VO2 &amp;lt;14 ml/kg/min in patients with HF. Methods We studied 67 consecutive hospitalized patients with HF (mean age, 65 years; 75% male; mean LV ejection fraction, 36%) who underwent ESE and CPX after stabilized HF condition, and the time interval of CPX and ESE tests was within 48 hours. CPX was performed using an upright cycle ergometer by a ramp protocol, while ESE was performed using ergometer in semi-supine position and the workload was generally increased by 25 watts every 3 minutes. The low-load ESE was defined as the 25 watts exercise. The increments of RV s' velocity at tricuspid annulus and RV strain in the free wall were considered as a preservation of RV contractile reserve. Among the study population, 26 patients were performed right heart catheterization and RV dP/dt/Pmax was estimated as an invasive marker of RV contractility. Results The achieved intensity of exercise was 50.4±21.0 watts, and all patients completed the low-load ESE. The invasive study showed that the change of RV s' velocity during the low-load ESE significantly correlated with RV dP/dt/Pmax (r=0.706, p&amp;lt;0.001). As shown in Figure, the non-invasive parameters of RV contractile reserve during the low-load ESE were significantly correlated with peak VO2 (RV s' velocity: r=0.787, p&amp;lt;0.001; RV strain: r=0.244, p=0.047). ROC analysis showed that the change of RV s' velocity during the low-load ESE correctly identified patients with peak VO2 &amp;lt;14 ml/kg/min (AUC=0.95, sensitivity 92.3%, specificity 85.2%). In terms of inter- and intra-observer variabilities, ICCs of the change of RV s' velocity were 0.86 and 0.96, and ICCs of the changes of RV strain were 0.63 and 0.70, respectively. Conclusion The change of RV s' velocity during the low-load ESE could determine exercise tolerance in patients with HF. The assessment of RV contractile reserve might be clinically useful to discriminate high risk HF patients. Figure 1 Funding Acknowledgement Type of funding source: None

Aorta size mismatch predicts decreased exercise capacity in patients with successfully repaired coarctation of the aorta

ObjectiveCoarctation of the aorta (CoA) is associated with decreased exercise capacity despite successful repair with no residual stenosis; however, the hemodynamic mechanism remains unknown. This study aims to correlate aortic arch geometry with exercise capacity in patients with successfully repaired CoA and explain hemodynamic changes using 3-dimensional–printed aorta models in a mock circulatory flow loop. MethodsA retrospective chart review identified patients with CoA repair who had cardiac magnetic resonance imaging and an exercise stress test. Measurements included aorta diameters, arch height to diameter ratio, left ventricular function, and percent descending aorta (%DAo) flow. Each aorta was printed 3-dimensionally for the flow loop. Flow and pressure were measured at the ascending aorta (AAo) and DAo during simulated rest and exercise. Measurements were correlated with percent predicted peak oxygen consumption (VO2 max). ResultsFifteen patients (mean age 26.8 ± 8.6 years) had a VO2 max between 47% and 126% predicted (mean 92 ± 20%) with normal left ventricular function. DAo diameter and %DAo flow positively correlated with VO2 (P = .007 and P = .04, respectively). AAo to DAo diameter ratio (DAAo/DDAo) negatively correlated with VO2 (P < .001). From flow loop simulations, the ratio of %DAo flow in exercise to rest negatively correlated with VO2 (P = .02) and positively correlated with DAAo/DDAo (P < .01). ConclusionsThis study suggests aorta size mismatch (DAAo/DDAo) is a novel, clinically important measurement predicting exercise capacity in patients with successful CoA repair, likely due to increased resistance and altered flow distribution. Aorta size mismatch and %DAo flow are targets for further clinical evaluation in repaired CoA.

Associations between hemodynamic parameters at rest and exercise capacity in patients with implantable left ventricular assist devices.

Hemodynamic parameters at rest are known to correlate poorly with peak oxygen uptake (VO2) in heart failure. However, we hypothesized that hemodynamic parameters at rest could predict exercise capacity in patients with left ventricular assist device (LVAD), because LVAD pump rotational speed does not respond during exercise. Therefore, we investigated the relationships between hemodynamic parameters at rest (measured with right heart catheterization) and exercise capacity (measured with cardiopulmonary exercise testing) in patients with implantable LVAD. We performed a retrospective medical record review of patients who received implantable LVAD at our institution from November 2013 to December 2017. A total of 20 patients were enrolled in this study (15 males; mean age, 45.8 years; median duration of LVAD support, 356 days). The mean peak VO2 and cardiac index (CI) were 13.5 mL/kg/min and 2.6 L/min/m2, respectively. CI and hemoglobin level were significantly associated with peak VO2 (CI: r = 0.632, p = 0.003; hemoglobin: r = 0.520, p = 0.019). In addition, pulmonary capillary wedge pressure, right atrial pressure, and right ventricular stroke work index were also significantly associated with peak VO2. In multiple linear regression analysis, CI and hemoglobin level remained independent predictors of peak VO2 (CI: β = 0.559, p = 0.006; hemoglobin: β = 0.414, p = 0.049). CI at rest and hemoglobin level are associated with poor exercise capacity in patients with LVAD.

Limited usefulness of resting hemodynamic assessments in predicting exercise capacity in hypertensive patients.

Reliable assessments of reduced exercise capacity based on resting tests are one of the major challenges in clinical practice. The aim of this study was to evaluate the relationship between hemodynamic parameters obtained via resting tests (echocardiography and impedance cardiography (ICG)) and objective parameters of exercise capacity assessed via cardiopulmonary exercise testing and exercise ICG in patients with controlled arterial hypertension (AH). The left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), diastolic function parameters (e', E/A, E/e'), cardiac output (CO), stroke volume (SV), and systemic vascular resistance index were evaluated for any correlations with selected parameters of exercise capacity, such as peak oxygen uptake (VO2) and peak CO in 93 people with AH (mean age 54 years, 47 women). Statistically relevant correlations occurred between indices of exercise capacity (peak VO2; peak CO) and only the following hemodynamic parameters: diastolic blood pressure (R = 0.23, p = 0.026; R = 0.24, p = 0.021; respectively), e' (R = 0.32, p = 0.002; R = 0.24, p = 0.027), E/e' (R = 0.35, p < 0.001; ns), E/A (R = 0.23, p = 0.030; R = 0.21, p = 0.047), SV at rest (ns; R = 0.24, p = 0.019), and CO at rest (ns; R = 0.21, borderline p = 0.052). No significant correlations between the exercise capacity parameters and either LVEF or GLS were observed. No hemodynamic parameter proved to be an independent correlate of either peak VO2 or peak CO. The association between hemodynamic parameters at rest and parameters of exercise capacity was weak and limited to selected parameters of diastolic function. Exercise capacity assessment in patients with AH based on resting tests alone is insufficiently reliable and should be supplemented with exercise tests.

Two-dimensional speckle tracking echocardiography detected interventricular dyssynchrony predicts exercise capacity and disease severity in pre-capillary pulmonary hypertension.

BackgroundRight ventricular (RV) intraventricular mechanical dyssynchrony detected by two-dimensional speckle tracking echocardiography (2D-STE) has been reported to be correlated with a decrease in RV contractile efficiency in pulmonary hypertension (PH) patients, while little attention has been paid to biventricular dysfunction. Therefore, we aimed to evaluate the predictive value of 2D-STE detected interventricular dyssynchrony for exercise capacity and disease severity in patients with pre-capillary PH (PcPH).MethodsConventional transthoracic echocardiography, 2D-STE and cardiopulmonary exercise tests (CPETs) were performed in all participants. Intra- and interventricular dyssynchrony were calculated as the standard deviation (SD) of the time intervals corrected for heart rate between QRS onset and peak longitudinal strain. Multivariate linear regression analyses were performed to identify independent predictors of peak oxygen consumption (PVO2) during the CPET. Multivariable logistical regression modeling was used to analyze the associations between interventricular dyssynchrony and risk assessment.ResultsSixty-six PcPH patients were consecutively recruited (19 male and 47 female, average 35 years old). WHO functional class, N-terminal pro-brain natriuretic peptide (BNP) and body mass index were included as independent predictors in the first multivariate regression analysis of clinical data without echocardiographic parameters (Model-1, r2=0.423, P<0.001). We subsequently added conventional echocardiographic parameters and 2D-STE parameters to the clinical data, RV fractional area change (Model-2, r2=0.417, P<0.001), RV global longitudinal strain (Model-3, r2=0.454, P=0.001), RV intraventricular dyssynchrony (Model-4: r2=0.474, P<0.001) and interventricular dyssynchrony (Model-5, r2=0.483, P<0.001) were identified as independent predictors of PVO2. Interventricular dyssynchrony, calculated as the SD of the time intervals of nine segments, was independently associated with risk assessment (odd ratio 1.027, 95% CI: 1.003–1.052, P=0.03). The area under the receiver-operating characteristic curve (AUC) was 0.73 (P<0.001).ConclusionsInterventricular dyssynchrony detected by 2D-STE contributed to a better evaluation of exercise capacity and disease severity in PcPH patients.

Atrial function in Fontan patients assessed by CMR: Relation with exercise capacity and long-term outcomes

ObjectiveTo assess the role of atrial function on exercise capacity and clinical events in Fontan patients. DesignWe included 96 Fontan patients from 6 tertiary centers, aged 12.8 (IQR 10.1–15.6) years, who underwent cardiac magnetic resonance imaging and cardiopulmonary exercise testing within 12 months of each other from 2004 to 2017. Intra-atrial lateral tunnel (ILT) and extracardiac conduit (ECC) patients were matched 1:1 with regard to age, gender and dominant ventricle.The pulmonary venous atrium was manually segmented in all phases and slices. Atrial function was assessed by volume-time curves. Furthermore, atrial longitudinal and circumferential feature tracking strain was assessed.We determined the relation between atrial function and exercise capacity, assessed by peak oxygen uptake and VE/VCO2 slope, and events (mortality, listing for transplant, re-intervention, arrhythmia) during follow-up. ResultsAtrial maximal and minimal volumes did not differ between ILT and ECC patients. ECC patients had higher reservoir function (21.1 [16.4–28.0]% vs 18.2 [10.9–22.2]%, p = .03), lower conduit function and lower total circumferential strain (13.8 ± 5.1% vs 18.0 ± 8.7%, p = .01), compared to ILT patients.Only for ECC patients, a better late peak circumferential strain rate predicted better VE/VCO2 slope. No other parameter of atrial function predicted peak oxygen uptake or VE/VCO2 slope.During a median follow-up of 6.2 years, 42 patients reached the composite end-point. No atrial function parameters predicted events during follow-up. ConclusionsECC patients have higher atrial reservoir function and lower conduit function. Atrial function did not predict exercise capacity or events during follow-up.

Predictors of exercise capacity following septal myectomy in patients with hypertrophic cardiomyopathy.

Patients with hypertrophic obstructive cardiomyopathy (HOCM) have impaired exercise capacity. The gold standard therapy for patients with HOCM is septal myectomy surgery; however, changes in maximum oxygen uptake (VO2peak) following myectomy are variable, with VO2peak decreasing in some patients. Therefore, we evaluated changes in VO2peak following surgical myectomy to determine clinical predictors of those exhibiting decreased VO2peak post-myectomy. HOCM patients (N = 295) who performed symptom limited cardiopulmonary exercise testing prior to and following surgical myectomy were included for analysis. The VO2peak non-responder group (n = 128) was defined as <0% change in VO2peak from pre- to post-myectomy. Step-wise regression models using demographics, clinical, and physiologic characteristics were created to determine predictors of hypertrophic cardiomyopathy patients in the VO2peak non-responder group. Independent predictors of the VO2peak non-responder group included higher pre-myectomy VO2peak (% predicted), older age, women, history of dyslipidemia, lack of cardiac rehabilitation enrollment, and lower body mass index (all p < 0.03). Forty-three (14.6%) patients reached the primary end-point of all-cause mortality during a median follow up of 11.25 years (interquartile range 6.94 to 16.40). After adjustment for age, sex, beta-blocker use, coronary artery disease history, and body mass index, the VO2peak non-responder group had greater risk of death compared with the VO2peak responder group (adjusted hazard ratio: 1.77, 95% confidence interval: 1.06-3.34, p = 0.01). This large hypertrophic cardiomyopathy cohort demonstrated that demographic (i.e. female sex), lack of cardiac rehabilitation enrollment, and cardiovascular risk factors (i.e. history of dyslipidemia) are predictive of those patients that did not exhibit increases in VO2peak following septal myectomy surgery.

P1779 Myocardial work is a predictor of exercise tolerance in patients with dilated cardiomyopathy and left ventricular dyssynchrony

Abstract Background the assessment of myocardial work (MW) by pressure-strain loops is a recently introduced tool for the assessment of myocardial performance. Aim of the present study is to evaluate the relationship between myocardial work and exercise tolerance in patients with dilated cardiomyopathy (DCM) Methods 51 patients with DCM (mean age 57 ± 13 years, left entricular ejection fraction : 32 ± 9%) underwent cardiopulmonary exercise test (CPET) to assess exercise performance. Trans-thoracic echocardiography (TTE) was performed CPET. The following indices of myocardial work (MW) were measured regionally and globally: constructive work (CW), wasted work (WW), and work efficiency (WE). Left ventricular (LV) dyssynchrony (DYS) was defined by the presence of septal flash or apical rocking at TTE. Results LV-DYS was observed in 16 (31%) patients and associated with lower LV ejection fraction (LVEF), GLS, global and septal WE, and higher global and septal WW (Table 1). In patients with LV-DYS, septal WE was the only predictor of exercise peak VO2max at multivariable analysis (Figure 1), whereas LVEF (β=0.47, p = 0.05) and age (β=-0.42, 47, p= 0.04) were predictors of exercise capacity in patients without LV-DYS. Conclusions In patients with DCM, LV-DYS is associated with an heterogeneous distribution of myocardial work. Septal WE is the best predictor of exercise performance in these patients. Table 1 All n = 51 No-dyssynchrony n = 35 (69%) LV-Dyssynchrony n = 16 (31%) p-value LVEF, % 32 ± 9 34 ± 10 28 ± 7 0.04 GLS, % -12 ± 3 -13 ± 3 -10 ± 3 0.001 GCW, mmHg% 1325 ± 398 1342 ± 354 1287 ± 491 0.65 GWW, mmHg% 201 ± 147 154 ± 95 304 ±191 &amp;lt;0.0001 GWE, % 85 ± 9 88 ± 7 78 ±10 &amp;lt;0.0001 CWsept, mmHg% 1172 ± 459 1274 ± 398 949 ± 516 0.017 CWlat, mmHg% 1518 471 1472 ± 386 1620 ± 622 0.30 WWsept, mmHg% 283 ± 275 174 ± 98 522 ±376 &amp;lt;0.0001 WWlat, mmHg% 135 ± 88 117 ± 81 176 ± 92 0.02 WEsept, % 78 ± 16 84 ± 9 62± 18* &amp;lt;0.0001 WElat, % 90 ± 7 91 ± 7 88 ± 7 0.16 Abstract P1779 Figure.

Predictors of exercise capacity in patients with atrial correction of transposition of great arteries.

To examine the relationship of clinical, biochemical and imaging parameters to maximum oxygen uptake in patients after atrial correction of transposition of great arteries. Exercise tolerance is a key determinant of quality of life in patients with adult congenital heart disease. It is determined by a large scale of factors often different from general cardiology. 86 consecutive patients after Senning correction of TGA were subjected to clinical and echocardiographic examination, Holter monitoring, blood tests of NT-proBNP, MRI of the heart and exercise test. Parameters of these examinations were correlated to VO2 max. The average age of patients was 28±3.5 years. The average systemic right ventricular function determined by MRI was 51.9±7.9 %. The average NT-proBPN was 124.3±23.6 ng/l, VO2 max. 31.7±6.5 ml/kg/min and the heart rate reserve 106±24 /min. Neither systemic right ventricular systolic function nor NT-proBPN predicted VO2 max., whereas the heart rate reserve did (p=0.003). An inability to increase heart rate during exercise noted in a considerable number of patients after atrial switch of TGA caused a decreased exercise tolerance. It is not solely the global systolic function of either ventricle that influences the exercise performance, rather it is the ability to increase heart rate and overall cardiac output appropriately (Tab. 3, Fig. 6, Ref. 28).

1679 E/e predicts exercise capacity and adverse cardiovascular outcomes in patients with chronic kidney disease

Abstract Funding Acknowledgements Nil OnBehalf NA Background Patients with chronic kidney disease(CKD) have reduced physical fitness that contributes to the disproportionately elevated risk of cardiovascular disease in this population. Our aim was to assess the association between E/e’ and exercise capacity in CKD patients and the prognostic role of E/e’. Methods Patients with Stage 3/4 CKD, without previous cardiac disease were prospectively recruited. Recruited patients underwent transthoracic echocardiogram and exercise stress echocardiogram with assessment of exercise E/e’. Patients were compared, one to one, to age, gender and risk factor matched controls and were followed annually for 5 years for cardiovascular death and major adverse cardiovascular events (MACE). Exercise capacity was assessed as metabolic equivalents (METs) with reduced exercise capacity defined as METS of ≤7. Raised exercise E/e’ was defined as exercise E/average e’ of &amp;gt;13. Results 156 CKD patients (62.8 ± 10.6 yrs, male 62%) were compared to 156 matched controls. CKD patients had higher rates of anemia (p &amp;lt; 0.01), larger left ventricular indexed mass (p &amp;lt; 0.01), larger LAVI (p &amp;lt; 0.01) and higher resting (p &amp;lt; 0.01) and exercise E/e’ (p &amp;lt; 0.01). Overall, CKD patients achieved lower METs (p &amp;lt; 0.01) with exercise and a greater proportion of CKD patients had METs ≤7 (p &amp;lt; 0.01). Receiver operating curves (Figure1) showed exercise E/e’ (AUC 0.89, CI 0.84-0.95, p &amp;lt; 0.01) to be the strongest predictor of reduced exercise capacity in CKD patients. Exercise E/e’ of &amp;gt;13 was also associated with higher rates of cardiovascular death and MACE amongst CKD patients. Conclusion Exercise E/e’ is a strong predictor of exercise capacity amongst CKD patients, who commonly have reduced exercise capacity presumably consequent to diastolic dysfunction. Raised exercise E/e’ in CKD patients is predictor of cardiovascular death and MACE. Abstract 1679 Figure.

1167 Atrial strain predicts exercise capacity in patients with the fontan circulation

Abstract Funding Acknowledgements None Introduction Atrial function has recently emerged as a valuable parameter, particularly for evaluation of ventricular diastolic dysfunction and heart failure. There is a strong need for reliable echocardiographic predictors of exercise capacity in univentricular hearts, but their particular anatomy makes it challenging. In this work we aimed to characterize the relationship between atrial strain and exercise parameters in the Fontan population. Methods Fontan patients followed in our outpatient clinic were prospectively evaluated with cardiopulmonary exercise test and transthoracic echocardiogram. The dominant atrium, i.e. the atrium connected to the dominant atrioventricular valve, was assessed with speckle-tracking echocardiography for active (εact), conduit (εcon), and reservoir (εres) strain; and εact/εres ratio. A single cardiac loop from the 4 chamber view was selected for this analysis and the ‘zero’ strain reference for atrial deformation analysis was set at the onset of the electrocardiogram P wave. Exercise capacity defined as the percentage of peak oxygen uptake (VO2), comparing with predicted values, was chosen as the dependent variable. Independent variables were selected among clinical and echocardiographic data. Statistical analysis was performed using SPSS version 23. T-student test was used for binomial and continuous variable correlation; single and multivariable linear regression was used for continuous variable correlation. Statistical significance was defined as p-value &amp;lt; 0.05. Results Fifty-two Fontan patients were assessed. Nineteen (37%) were excluded due to inadequate deformation tracking of the atrial wall. Mean age was 18.0 years (SD 6.9, min. 10.0 - max. 36.0), mean age at Fontan surgery was 7.0 years (SD 2.9, min. 3.0 – max. 18.0). Peak VO2 as a percentage of the predicted value was 66.5% (SD 18.8, min. 36.4 – max. 118.6). εact was -11.1% (SD 3.7, min. -21.1 – max. -4.8), εcon was 10.6% (SD 6.5, min. -0.5 – max. 6.5), εres was 21.7% (SD 5.2, min. 13.2 – max. 34.4) and εact/εres ratio was 0.54 (SD 0.23, min. 0.22 – max. 1.04). On univariate analysis, all atrial strain variables correlated with peak VO2. After adjusting for collinearity, multivariable regression defined age (estimate -1.6, 95% CI: -2.5 to -0.9, p-value &amp;lt; 0.001) and εact strain (estimate 1.8, 95% CI: 0.5 to 3.2, p-value = 0.011) as the strongest predictors of peak VO2 (r2= 0.479). Conclusion Peak VO2 defines exercise capacity and is a strong marker of prognosis in Fontan patients. There are very few echocardiographic variables capable of predicting it, in part due to a variable cardiac anatomy. We showed that atrial strain rate is a novel echocardiographic parameter that predicts peak VO2. In the Fontan circulation, a higher reliance on active atrial contraction for ventricular filling predicts lower exercise capacity. Therefore, atrial strain rate, whenever measurable, may provide a new method of risk stratification in this population. Abstract 1167 Figure. Example of atrial strain curve.

Predictors of pre-rehabilitation exercise capacity in elderly European cardiac patients - The EU-CaRE study.

Functional capacity is an important endpoint for therapies oriented to older adults with cardiovascular diseases. The literature on predictors of exercise capacity is sparse in the elderly population. In a longitudinal European study on effectiveness of cardiac rehabilitation of seven European countries in elderly (>65 years) coronary artery disease or valvular heart disease patients, predictors for baseline exercise capacity were determined, and reference ranges for elderly cardiac patients provided. Mixed models were performed in 1282 patients (mean age 72.9 ± 5.4 years, 79% male) for peak oxygen consumption relative to weight (peak VO2; ml/kg per min) with centre as random factor and patient anthropometric, demographic, social, psychological and nutritional parameters, as well as disease aetiology, procedure, comorbidities and cardiovascular risk factors as fixed factors. The most important predictors for low peak VO2 were coronary artery bypass grafting or valve surgery, low resting forced expiratory volume, reduced left ventricular ejection fraction, nephropathy and peripheral arterial disease. Each cumulative comorbidity or cardiovascular risk factors reduced exercise capacity by 1.7 ml/kg per min and 1.1 ml/kg per min, respectively. Males had a higher peak VO2 per body mass but not per lean mass. Haemoglobin was significantly linked to peak VO2 in both surgery and non-surgery patients. Surgical procedures, cumulative comorbidities and cardiovascular risk factors were the factors with the strongest relation to reduced exercise capacity in the elderly. Expression of peak VO2 per lean mass rather than body mass allows a more appropriate comparison between sexes. Haemoglobin is strongly related to peak VO2 and should be considered in studies assessing exercise capacity, especially in studies on patients after cardiac surgery.

Long-term follow-up of patients undergoing standardized bicycle exercise stress testing: new recommendations for grading of exercise capacity are clinically relevant.

A new grading of exercise capacity during bicycle stress testing has been proposed in Sweden based on the new reference material ('the Kalmar material'), which has not been validated. We aimed to examine the prognostic information of the new grading of exercise capacity during exercise stress testing. Data on all bicycle exercise tests performed at the Department of Clinical Physiology in Kalmar between May 2005 and October 2016 were cross-linked with the Causes of Death Register (until 30 April 2019) and the National Patient Register (until 12 December 2017). Exercise capacity was graded based on predicted exercise capacity: ≥120% (good), 75 to <120% (normal), 70 to <75% (mildly reduced), 50 to <70% (moderately reduced) and <50% (severely reduced). Associations with all-cause mortality, cardiovascular mortality and hospitalization for ischaemic heart disease (IHD) and heart failure were analysed using Cox regression. A total of 13887 patients were followed a median of 7·7years (interquartile range 5·0-10·8); 1809 patients died (546 from cardiovascular disease). Compared to normal exercise capacity, reduction of exercise capacity was strongly associated with increased all-cause mortality [(hazard ratio; 95% confidence interval): mild (3·0; 2·6-3·5); moderate (4·4; 3·9-4·9); and severe reduction (8·5; 7·2-10·0)]. Reduced exercise capacity was also associated with increased risks of cardiovascular hospitalization and mortality. Reduced exercise capacity is associated with increased all-cause and cardiovascular mortality, as well as increased risk of future IHD and heart failure diagnosis and hospitalization. In patients with reduced exercise capacity, mortality is progressively increased with worsening grade of exercise capacity.