Peak Exercise Stroke Volume Research Articles

Physiological and haemodynamic differences between peak exercise blood pressure and blood pressure-power output slope in healthy women

Abstract Background A hypertensive response to exercise (HRE) is considered indicative of increased arterial stiffness (1). However, HRE is common in individuals with high cardiorespiratory fitness (CRF) (2), which we hypothesize is due to increased stroke volume (SV) and cardiac output (Qc). Purpose This study compared differences in CRF and peak-exercise SV (SVpeak) and Qc (Qcpeak) according to absolute and workload-indexed definitions of exercise hypertension in women. Methods Women free of overt CVD (n=142; 52±8years, BMI: 26.3±4.5kg/m2) underwent exercise cardiac magnetic resonance to quantify SVpeak and Qcpeak, and cardiopulmonary exercise testing to quantify peak VO2, power output (PO) and systolic blood pressure (SBP) responses. SBP-PO slope was determined using linear regression of SBP and PO values obtained every 2-minutes throughout exercise. HRE was defined as peak SBP ≥190mmHg (3), and elevated SBP-PO slope was defined as a slope >90th percentile for sex and age based on previously published values (4). Results 51% and 23% of the cohort met criteria for HRE and elevated SBP-PO slope, respectively, with 16% meeting both criteria. HRE was associated with higher VO2peak (2.03±0.53 vs 1.83±0.44 L/min, P=0.015), peak PO (191±66 vs 167±51 Watts, P=0.014), SVpeak (109±27 vs 98±19 mLs, P=0.008), and Qcpeak (15.1±3.3 vs 13.9±2.8 L/min, P=0.023). In contrast, elevated SBP-PO slope was associated with lower VO2peak (1.57±0.36 vs 2.04±0.48 L/min), peak PO (135±34 vs 192±60Watts) SVpeak (88±13 vs 108±24 mLs) and Qcpeak (12.5±1.8 vs 15.1±3.1 L/min; P<0.001 for all). Overall, the group with HRE and elevated SBP-PO slope had the lowest physical capacity, VO2peak and haemodynamic response to exercise (Figure 1A-D), whilst the opposite trend was seen for those with a HRE and a normal SBP-PO slope. All results remained significant (P<0.05) after adjustment for age, BMI, resting SBP and menopausal status (pre vs peri/post-menopausal). Conclusion Contextualising exercise SBP responses against measures of PO better accounts for confounding from increased Qcpeak, and may improve identification of women with increased arterial stiffness.Figure 1A-D

Exercise Blood Pressure in Heart Failure With Preserved and Reduced Ejection Fraction

ObjectivesThis study aimed to evaluate hemodynamic correlates of inducible blood pressure (BP) pulsatility with exercise in heart failure with preserved ejection fraction (HFpEF), to identify relationships to outcomes, and to compare this with heart failure with reduced ejection fraction (HFrEF). BackgroundIn HFpEF, determinants and consequences of exercise BP pulsatility are not well understood. MethodsWe measured exercise BP in 146 patients with HFpEF who underwent invasive cardiopulmonary exercise testing. Pulsatile BP was evaluated as proportionate pulse pressure (PrPP), the ratio of pulse pressure to systolic pressure. We measured pulmonary arterial catheter pressures, Fick cardiac output, respiratory gas exchange, and arterial stiffness. We correlated BP changes to central hemodynamics and cardiovascular outcome (nonelective cardiovascular hospitalization) and compared findings with 57 patients with HFrEF from the same referral population. ResultsIn HFpEF, only age (standardized beta = 0.593; P < 0.001), exercise stroke volume (standardized beta = 0.349; P < 0.001), and baseline arterial stiffness (standardized beta = 0.182; P = 0.02) were significant predictors of peak exercise PrPP in multivariable analysis (R = 0.661). In HFpEF, lower PrPP was associated with lower risk of cardiovascular events, despite adjustment for confounders (HR:0.53 for PrPP below median; 95% CI: 0.28-0.98; P = 0.043). In HFrEF, lower exercise PrPP was not associated with arterial stiffness but was associated with lower peak exercise stroke volume (P = 0.013) and higher risk of adverse cardiovascular outcomes (P = 0.004). ConclusionsIn HFpEF, greater inducible BP pulsatility measured using exercise PrPP reflects greater arterial stiffness and higher risk of adverse cardiovascular outcomes, in contrast to HFrEF where inducible exercise BP pulsatility relates to stroke volume reserve and favorable outcome.

Acceptability, Feasibility and Preliminary Evaluation of a Novel, Personalised, Home-Based Physical Activity Intervention for Chronic Heart Failure (Active-at-Home-HF): a Pilot Study

PurposeLess than 10% of heart failure patients in the UK participate in cardiac rehabilitation programmes. The present pilot study evaluated feasibility, acceptability and physiological effects of a novel, personalised, home-based physical activity intervention in chronic heart failure.MethodsTwenty patients (68 ± 7 years old, 20% females) with stable chronic heart failure due to reduced left ventricular ejection fraction (31 ± 8 %) participated in a single-group, pilot study assessing the feasibility and acceptability of a 12-week personalised home-based physical activity intervention aiming to increase daily number of steps by 2000 from baseline (Active-at-Home-HF). Patients completed cardiopulmonary exercise testing with non-invasive gas exchange and haemodynamic measurements and quality of life questionnaire pre- and post-intervention. Patients were supported weekly via telephone and average weekly step count data collected using pedometers.ResultsForty-three patients were screened and 20 recruited into the study. Seventeen patients (85%) completed the intervention, and 15 (75%) achieved the target step count. Average step count per day increased significantly from baseline to 3 weeks by 2546 (5108 ± 3064 to 7654 ± 3849, P = 0.03, n = 17) and was maintained until week 12 (9022 ± 3942). Following completion of the intervention, no adverse events were recorded and quality of life improved by 4 points (26 ± 18 vs. 22 ± 19). Peak exercise stroke volume increased by 19% (127 ± 34 vs. 151 ± 34 m/beat, P = 0.05), while cardiac index increased by 12% (6.8 ± 1.5 vs. 7.6 ± 2.0 L/min/m2, P = 0.19). Workload and oxygen consumption at anaerobic threshold also increased by 16% (49 ± 16 vs. 59 ± 14 watts, P = 0.01) and 10% (11.5 ± 2.9 vs. 12.8 ± 2.2 ml/kg/min, P = 0.39).ConclusionThe Active-at-Home-HF intervention is feasible, acceptable and effective for increasing physical activity in CHF. It may lead to improvements in quality of life, exercise tolerance and haemodynamic function.Trial Registrationwww.clinicaltrials.gov NCT0367727. Retrospectively registered on 17 September 2018.

Improved Maximal Oxygen Uptake Following High-intensity Interval Training Relates To An Increase In Blood Volume

Improved maximal oxygen uptake following high-intensity interval training relates to an increase in blood volume High-intensity interval training (HIT) is an effective training mode for improving maximal oxygen uptake (VO2max). As past research has focused on peripheral adaptations to HIT, little is known about central factors governing cardiac output and thus VO2max. PURPOSE: The aim of this study was to test the hypothesis that HIT-induced improvements in VO2max are accompanied by increases in blood volume (BV) and cardiac stroke volume. Further, we investigated if inter-individual differences in the increase in in VO2max could be attributed to changes in BV. METHODS: Twenty subjects (10 females, 10 males) participated in a 6-week long training intervention consisting of 3 HIT sessions per week. Each session comprised of three 30 s all-out sprints against a breaking force equivalent to 7.5% of body weight. The sprints were separated by 2 min rest. VO2max, peak exercise cardiac output and BV (measured with carbon monoxide rebreathing) was assessed before (PRE) and after (POST) the intervention. RESULTS: VO2max increased by 9% (44.9±7.9 to 48.7±7.8 mL/min/kg) from PRE to POST (P < 0.05) and the increase in BV was 5% (5.4±0.8 to 5.7±0.9 L, P < 0.05) with a corresponding increase in peak exercise stroke volume. Accounting for inter-individual variance, approximately 60% of the change in VO2max could be attributed to changes in BV. CONCLUSION: This is the first study to show that improvements in VO2max with HIT are associated with increased blood volume. This suggest that a large part of HIT-induced improvements in VO2max are mediated by increased oxygen delivery, which at least in part is due to increased blood volume.

P4188Cognitive impairment in the elderly people with preserved ejection fraction is related to the reduced peak exercise stroke volume

P4188Cognitive impairment in the elderly people with preserved ejection fraction is related to the reduced peak exercise stroke volume

Peak exercise stroke volume effects on cognitive impairment in community-dwelling people with preserved ejection fraction.

AimsThe association of vascular dysfunction and amyloid beta deposition attracted attentions for its relationship with cognitive decline. Previous studies show the correlation between the declined cardiac function and the cognitive impairment. In the present study, we analysed the association between cognitive functions and cardiac parameters in community‐dwelling people with preserved ejection fraction without heart failure.Methods and resultsSubjects were 108 Japanese community‐dwelling middle‐aged and older adults with preserved ejection fraction (25 men and 83 women; mean age 74.7 years). Cardiac functional parameters at rest were assessed with B‐type natriuretic peptide and echocardiography. The cardiopulmonary exercise test was used to test these parameters during exercise. Cognitive function was assessed with the Japanese version of the Montreal Cognitive Assessment (MoCA‐J). Other indices were assessed biochemically, physiologically, and physically. There were significant correlations between MoCA‐J score and age (r = −0.388), peak oxygen uptake (VO2, r = 0.201), peak VO2/heart rate (HR, r = 0.243), peak VO2/weight (r = 0.244), peak metabolic equivalents (r = 0.244), usual walking speed (r = −0.200), and the Timed Up and Go test (r = −0.230). Multiple linear regression analysis showed peak VO2/HR was an independent determinant of MoCA‐J score after adjusting for potential confounders (B = 0.424). After 6 months of exercise training with 64 subjects, we found that the per cent change of peak VO2/HR was related to the per cent change of MoCA‐J score (r = 0.296).ConclusionsThese results suggested that peak VO2/HR (an index of stroke volume at peak exercise) might be associated with cognitive impairment based on the vascular cascade hypothesis.

Reliability of Peak Exercise Stroke Volume Assessment by Impedance Cardiography in Patients with Residual Right Outflow Tract Lesions After Congenital Heart Disease Repair.

Global ventricular response to exercise may be useful in follow-up of patients with residual right outflow tract lesions after congenital heart disease repair. In this context, impedance cardiography is considered accurate for stroke volume (SV) measurement during exercise testing, however, to date, only partial assessment of its reliability has been reported. We retrospectively evaluated relative and absolute reliability of peak SV by impedance cardiography during exercise using intraclass correlation (ICC) and standard error of measurement (SEM) in this population. Peak SV was measured in 30 young patients (mean age 14.4years±2.1) with right ventricular outflow tract reconstruction who underwent two cardiopulmonary exercise tests at a mean one-year interval. SV was measured using a signal morphology impedance cardiography analysis device (PhysioFlow®) and was indexed to body surface area. ICC of peak indexed SV measurement was 0.80 and SEM was 10.5%. High heterogeneity was seen when comparing patients according to peak indexed SV; in patients with peak SV<50ml/m2 (15 patients), ICC rose to 0.95 and SEM dropped to 2.7%, while in patients with a peak SV>50ml/m2 relative and absolute reliability decreased (ICC=0.45, SEM=12.2%). Peak exercise SV assessment by a PhysioFlow® device represents a highly reliable method in patients with residual right outflow tract lesions after congenital heart disease repair, especially in patients with peak SV<50ml/m2. In this latter group, a peak SV decrease>7.3% (corresponding to the minimum "true" difference) should be considered a clinically-relevant decrease in global ventricular performance and taken into account when deciding whether to perform residual lesion removal.

CO8-54 - Peak exercise stroke volume in children and adult patients with isolated severe pulmonary regurgitation after right outflow tract surgery

CO8-54 - Peak exercise stroke volume in children and adult patients with isolated severe pulmonary regurgitation after right outflow tract surgery

Peak exercise stroke volume: associations with cardiac structure and diastolic function

One of the most debilitating effects of primary aging is the decline in aerobic exercise capacity. One of its causes is an age-related decline in peak exercise stroke volume. This study's main purpose was to determine the cardiovascular adaptations to aging that most influence peak exercise stroke volume in the elderly. We hypothesized that increased left ventricular (LV) filling and mild concentric LV remodeling would be associated with an increase in peak exercise stroke volume corrected for lean body mass (LBM) and that an increased augmentation index (AI), which is a marker of arterial stiffness, would be associated with a decrease. A second aim was to determine the adaptations to aging that most influence LV concentric remodeling in the elderly. We hypothesized that AI would be a predictor of LV mass/LBM and the LV posterior wall thickness-to-LV radius ratio (h/r). We performed a cross-sectional study of cardiac and vascular adaptations to aging in 52 sedentary, elderly subjects. LV filling [as measured by the early-to-late transmitral flow velocity ratio (E/A)] was inversely correlated with and was an independent predictor of peak exercise stroke volume/LBM and was also a predictor of LV remodeling. AI was a predictor of LV remodeling (LV mass/LBM) but not of peak exercise stroke volume/LBM. We conclude that 1) maintenance of LV filling (E/A <1) is associated with a higher peak exercise stroke volume/LBM in very elderly subjects and thus may be a useful adaptation that enhances stroke volume during peak exercise, 2) LV remodeling and AI are less influential on peak exercise stroke volume/LBM, and 3) AI was the most important predictor of LV remodeling.

Enhanced left ventricular performance in endurance trained older men.

The age-associated decline in aerobic exercise capacity is partially reversible by endurance exercise training. Moderate-intensity endurance exercise training increases aerobic exercise capacity mediated, in part, by improvement of stroke volume and left ventricular performance in older men. The present study was designed to characterize the nature of cardiovascular adaptations to strenuous endurance exercise of long duration and to delineate the mechanisms underlying increased stroke volume and cardiac output in highly trained older endurance athletes. Nine male master athletes (MA: 64 +/- 2 years old, mean +/- SEM) and 9 older sedentary healthy men (controls: 63 +/- 1 year) were studied. Left ventricular systolic function was evaluated with the use of cardiac blood pool imaging and echocardiography. Maximal O2 uptake (VO2max) was 50.4 +/- 1.7 mL.kg-1 x min-1 in the MA and 29.6 +/- 1.4 mL.kg-1 x min-1 (P = .0001) in controls. Systolic and mean blood pressures at rest and during exercise were not different in the two groups. Left ventricular systolic function at peak exercise was higher in the MA than in sedentary controls as evidenced by (1) a higher left ventricular functional reserve (delta EF: 12.4 +/- 2 versus 5.6 +/- 2.5, P = .05), (2) a large decrease in end-systolic volume during exercise (MA: 56 +/- 4 mL at rest and 42 +/- 5 mL at peak exercise, P = .007; controls: 43 +/- 2 mL at rest and 42 +/- 6 mL at peak exercise, P = .35) with no differences in systolic blood pressure, (3) a higher left ventricular fractional shortening at peak exercise (MA: 52 +/- 2.6%; controls: 45 +/- 1%, P = .046) at comparable values for end-systolic wall stress (MA: 56 +/- 12 g/cm2; controls: 53 +/- 7 g/cm2, P = .50), and (4) a greater decrease in end-systolic diameter at peak exercise in the MA than in controls (MA: -1.2 +/- 0.16 cm versus -0.57 +/- 0.13 cm, P = .014) despite no significant differences between the changes in end-systolic wall stress during exercise (MA: -15.5 +/- 7.5 g/cm2, controls: -11.0 +/- 9.0 g/cm2, P = .6). MA had a larger end-diastolic volume at rest (153 +/- 6 versus 132 +/- 4 mL, P = .009) with a normal wall thickness-to-radius ratio (0.34 +/- 0.02). Peak exercise stroke volume was higher (P = .023) in the MA (132 +/- 6 mL/min) than in the sedentary controls (111 +/- 6 mL/min). Changes in stroke volume correlated strongly with changes in ejection fraction in the MA (r = .80, P = .010) but not in sedentary controls (r = .59, P = .097). Further, changes in stroke volume from rest to exercise correlated strongly with changes in end-diastolic volume in both MA (r = .78, P = .013) and sedentary controls (r = .73, P = .026), suggestive of reliance of stroke volume on end-diastolic volume and preload. However, for a given increase in end-diastolic volume, the rise in stroke volume during exercise was significantly larger in the MA than in controls, which, in the absence of differences in mean blood pressures, indicates that enhanced left ventricular systolic function independent of preload plays an additional role in maintaining a higher stroke volume at peak exercise in the highly trained older men. Cardiac adaptations in older endurance trained men are characterized by volume-overload left ventricular hypertrophy and enhancement of left ventricular systolic performance at peak exercise. These adaptive responses contribute to enhanced stroke volume at peak exercise in older endurance trained men.

Cardiopulmonary Exercise Testing in DDD Compared to VYI Pacing Modes

To compare the effect of DDD and VVI pacing modes on exercise cardiopulmonary performance, 10 patients underwent rest and exercise first-pass radionuclide angiography in conjunction with gas exchange analysis in one pacing mode first, and 1 week later in the other mode. There were 9 males and 1 female, ages 50-79 years (mean 66). All patients had complete heart block with intact sinus mechanism. Of the 10 patients, 4 had clinical symptoms compatible with the pacemaker syndrome while in VVI. All 4 patients with pacemaker syndrome reported subjective improvement while in DDD mode. Compared with VVI mode, patients in DDD mode demonstrated a larger increase in heart rate (p < 0.001) and in oxygen uptake (p < 0.05) with exercise. There was no significant difference in peak workload, exercise duration, and peak systolic blood pressure. Both the peak exercise stroke volume and the end-diastolic volume were smaller (p < 0.002 and p < 0.01, respectively). The cardiac output and the ejection fraction increased with exercise in either mode. The cardiac output increase was the same in both modes. The ejection fraction increase was higher in WI than in DDD mode (p < 0.01). The subjective improvement in those patients with pacemaker syndrome by DDD pacing did not correlate with any measured parameter. In conclusion, cardiac output increases with exercise in both modes in different ways. In DDD mode the increase was mainly due to the heart rate increase, whereas in WI the increase was mainly due to the stroke volume increase.