Background: Breast cancer (BC) survivors treated with anthracycline-based chemotherapy (AC) have increased risk of functional limitation and cardiac dysfunction. We conducted a 12-month randomized controlled trial in 104 early-stage BC patients scheduled for AC to determine if 12-months of exercise training (ExT) could attenuate functional disability (primary endpoint), improve cardiorespiratory fitness (VO 2 peak) and prevent cardiac dysfunction. Methods: Women aged 40-75 years with stage I-III BC scheduled for AC were randomized to 3-4 days/wk of aerobic and resistance ExT for 12-months (n = 52) or usual care ([ UC ], n = 52). Functional measures were performed at baseline, 4-weeks following AC (4-months) and at 12-months comprising: 1) cardiopulmonary exercise testing to quantify VO 2 peak and functional disability (VO 2 peak ≤18.0mL/kg/min), 2) cardiac reserve (response from rest to peak exercise) quantified using exercise cardiac magnetic resonance measures to determine changes in left- and right-ventricular ejection fraction [ LVEF, RVEF ], cardiac output [ CO ], and stroke volume [ SV ]), 3) standard-of-care echocardiography-derived resting LVEF and global longitudinal strain [ GLS ], and 4) biochemistry (troponin and B-type natriuretic peptide [ BNP ]). Results: Among 104 participants randomized, greater study attrition was observed among UC participants (P=0.031) with 93 women assessed at 4-months (ExT: n=49, UC: n=44) and 87 at 12-months (ExT: n=49, UC: n=38). ExT attenuated functional disability at 4-months (OR: 0.32 [95% CI 0.11, 0.94], P=0.03), but not at 12-months (OR: 0.27, [95% CI 0.06, 1.12], P=0.07). In a per-protocol analysis, functional disability was entirely prevented at 12-months among participants adherent to ExT (ExT: 0% vs. UC: 20%, P=0.005). As compared with UC at 12-months, ExT was associated with a net +3.5 mL/kg/min improvement in VO 2 peak that coincided with greater CO, SV, LVEF and RVEF reserve (P<0.001 for all). There was no effect of ExT on resting measures of LV function. Post-chemotherapy troponin increased less in ExT than UC (8-fold vs. 16-fold increase, P=0.002). There were no changes in BNP in either group. Conclusions: In women with early-stage BC undergoing AC, 12-months of ExT did not attenuate functional disability but provided large and clinically meaningful benefits on VO2peak and cardiac reserve. Clinical Trial Registration: URL: https://www.anzctr.org.au/ Unique Identifier: ACTRN12617001408370

Purpose Anthracycline chemotherapy (AC) is associated with acute reductions in cardiopulmonary fitness (V˙O2peak). We sought to determine whether changes in V˙O2peak and cardiac function persisted at 12 months post-AC completion, and whether changes in cardiac function explain the heightened long-term heart failure risk. Methods Women with breast cancer scheduled for AC (n = 28) who participated in a nonrandomized trial of exercise training (ET; n = 14) or usual care (UC; n = 14) during AC completed a follow-up evaluation 12 months post-AC completion (16 months from baseline). At baseline, 4 months, and 16 months, participants underwent a resting echocardiogram (left ventricular ejection fraction; global longitudinal strain), a blood sample (troponin; B-type natriuretic peptide), a cardiopulmonary exercise test, and cardiac MRI measures of stroke volume (SV), heart rate, and cardiac output (Qc) at rest and during intense exercise. Results Seventeen women (UC, n = 8; ET, n = 9) completed evaluation at baseline, 4 months, and 16 months. At 4 months, AC was associated with 18% and 6% reductions in V˙O2peak in the UC and ET groups, respectively, which persisted at 16 months (UC, −16%; ET, −7%) and was not attenuated by ET (interaction, P = 0.10). Exercise Qc was lower at 16 months compared with baseline and 4 months (P < 0.001), which was due to a blunted augmentation of SV during exercise (P = 0.032; a 14% reduction in peak SV), with no changes in heart rate response. There was a small reduction in resting left ventricular ejection fraction (baseline to 4 months) and global longitudinal strain (between 4 and 16 months) and an increase in troponin (baseline to 4 months), but only exercise Qc was associated with V˙O2peak (R 2 = 0.47, P < 0.01). Conclusion Marked reductions in V˙O2peak persisted 12 months after anthracycline-based chemotherapy, which was associated with impaired exercise cardiac function. Clinical Trial Registration: ACTRN12616001602415.

Aims Atrial fibrillation (AF) is more common in athletes and may be associated with adverse left atrial (LA) remodelling. We compared LA structure and function in athletes and non-athletes with and without AF. Methods and results Individuals (144) were recruited from four groups (each n = 36): (i) endurance athletes with paroxysmal AF, (ii) endurance athletes without AF, (iii) non-athletes with paroxysmal AF, and (iv) non-athletic healthy controls. Detailed echocardiograms were performed. Athletes had 35% larger LA volumes and 51% larger left ventricular (LV) volumes vs. non-athletes. Non-athletes with AF had increased LA size compared with controls. LA/LV volume ratios were similar in both athlete groups and non-athlete controls, but LA volumes were differentially increased in non-athletes with AF. Diastolic function was impaired in non-athletes with AF vs. non-athletes without, while athletes with and without AF had normal diastolic function. Compared with non-AF athletes, athletes with AF had increased LA minimum volumes (22.6 ± 5.6 vs. 19.2 ± 6.7 mL/m2, P = 0.033), with reduced LA emptying fraction (0.49 ± 0.06 vs. 0.55 ± 0.12, P = 0.02), and LA expansion index (1.0 ± 0.3 vs. 1.2 ± 0.5, P = 0.03). LA reservoir and contractile strain were decreased in athletes and similar to non-athletes with AF. Conclusion Functional associations differed between athletes and non-athletes with AF, suggesting different pathophysiological mechanisms. Diastolic dysfunction and reduced strain defined non-athletes with AF. Athletes had low atrial strain and those with AF had enlarged LA volumes and reduced atrial emptying, but preserved LV diastolic parameters. Thus, AF in athletes may be triggered by an atrial myopathy from exercise-induced haemodynamic stretch consequent to increased cardiac output.

Background: Pediatric cancer survivors are at increased risk of cardiac dysfunction and heart failure. Reduced peak oxygen consumption (peak VO 2) is associated with impaired cardiac reserve (defined as the increase in cardiac function from rest to peak exercise) and heart failure risk, but it is unclear whether this relationship exists in pediatric cancer survivors. This study sought to investigate the presence of reduced peak VO 2 in pediatric cancer survivors with increased risk of heart failure, and to assess its relationship with resting cardiac function and cardiac haemodynamics and systolic function during exercise. Methods: Twenty pediatric cancer survivors (8-24 years; 10 male) treated with anthracycline chemotherapy ± radiation underwent cardiopulmonary exercise testing to quantify peak VO 2 , with a value < 85% of predicted defined as impaired peak VO 2. Resting cardiac function was assessed using 2-and 3-dimensional echocardiography, with cardiac reserve quantified from resting and peak exercise heart rate, stroke volume index (SVI) and cardiac index (CI) using exercise cardiovascular magnetic resonance (CMR). Results: Twelve of 20 survivors (60%) had reduced peak VO 2 (70 ± 16% vs. 97 ± 14% of age and gender predicted). There were no differences in echocardiographic or CMR measurements of resting cardiac function between survivors with normal or impaired peak VO 2. However, those with reduced peak VO 2 had diminished cardiac reserve, with a lesser increase in CI and SVI during exercise (Interaction P < 0.01 for both), whilst the heart rate response was similar (P = 0.71). Conclusions: Whilst exercise intolerance is common among pediatric cancer survivors, it is poorly explained by resting measures of cardiac function. In contrast, impaired exercise capacity is associated with impaired haemodynamics and systolic functional reserve measured during exercise. Consequently, measures of cardiopulmonary fitness and cardiac reserve may aid in early identification of survivors with heightened risk of long-term heart failure.

Aims Left ventricular ejection fraction (LVEF) is standard of care for evaluating chemotherapy-associated cardiotoxicity, although global longitudinal strain (GLS) offers advantages. However, neither change in LVEF or GLS has been associated with short-term symptoms, functional capacity, or long-term heart failure (HF) risk. We sought to determine whether an integrative measure of cardiovascular function (VO2peak) that is strongly associated with HF risk would be more sensitive to cardiac damage induced by cancer treatment than LVEF, GLS, or cardiac biomarkers. Methods and results Patients (n = 206, 53 ± 13 years, 35% male) scheduled to commence anti-cancer treatment completed assessment prior to, and within 6 months after therapy. Changes in echocardiographic measures of LV function (LVEF, GLS), cardiac biomarkers (troponin and BNP), and cardiorespiratory fitness (VO2peak) were measured. LV function was normal prior to treatment (LVEF 61 ± 5%; GLS −19.4 ± 2.1), but VO2peak was only 88 ± 26% of age-predicted. After treatment, VO2peak was reduced by 7 ± 15% (equivalent of 7 years normal ageing, P &lt; 0.0001) and the rates of functional disability (defined as VO2peak ≤ 18 mL/min/kg) almost doubled (15% vs. 26%, P = 0.016). In contrast, small, reductions in LVEF (59 ± 5% vs. 58 ± 5%, P = 0.03) and GLS (−19.4 ± 2.1 vs. −18.9 ± 2.2, P = 0.002) and an increase in troponin levels (4.0 ± 6.9 vs. 26.4 ± 26.2 ng/mL, P &lt; 0.0001) were observed. Conclusion Anti-cancer treatment is associated with marked reductions in functional capacity that occur independent of reductions in LVEF and GLS. The assessment of VO2peak prior to, and following treatment may be a more sensitive means of identifying patients at increased risk of HF.