This mini-review summarizes the literature regarding the mechanisms of exercise intolerance in patients with heart failure and reduced or preserved ejection fraction (HFREF and HFPEF, respectively). Evidence to date suggests that the reduced peak pulmonary oxygen uptake (pulm V̇o₂) in patients with HFREF compared with healthy controls is due to both central (reduced convective O₂ transport) and peripheral factors (impaired skeletal muscle blood flow, decreased diffusive O₂ transport coupled with abnormal skeletal morphology, and metabolism). Although central and peripheral impairments also limit peak pulm V̇o₂ in HFPEF patients compared with healthy controls, emerging data suggest that the latter may play a relatively greater role in limiting exercise performance in these patients. Unlike HFREF, currently there is limited evidence-based therapies that improve exercise capacity in HFPEF patients, therefore future studies are required to determine whether interventions targeted to improve peripheral vascular and skeletal muscle function result in favorable improvements in peak pulm and leg V̇o2 and their determinants in HFPEF patients.

After completing this course, the reader will be able to:1. Discuss cardiorespiratory fitness and cardiac functional reserve in postmenopausal women treated with chemoendocrine therapy.2. List the cardiovascular risk factors in this study that were found to be less favorable among patients than among controls.3. Explain the significance of peak aerobic power as a predictor of cardiovascular disease.Access and take the CME test online and receive 1 AMA PRA Category 1 Credit ™ at CME.TheOncologist.com CME CME ABSTRACTPurpose. To examine cardiovascular function and risk profile of postmenopausal women treated with chemoendocrine therapy (CET) for hormone receptorpositive operable breast cancer. Methods. Forty-seven breast cancer patients and 11 age-matched healthy controls were studied. Participants performed a cardiopulmonary exercise test with expired gas analysis and impedance cardiography to assess peak aerobic power (VO 2peak ) and cardiovascular function (stroke volume, cardiac output, cardiac power output, and cardiac reserve). Traditional (i.e., body mass index, lipid profile, and fasting insulin and glucose) and novel (i.e., C-reactive protein, brain natriuretic peptide) cardiovascular risk biochemical factors were also assessed.Results. Breast cancer patients had significantly lower peak exercise stroke volume (68 ؎ 9 versus 76 ؎ 11 ml/ beat), cardiac output (10.4 ؎ 1.5 versus 11.7 ؎ 2.4 l/minute), cardiac power output (3.0 ؎ 0.5 versus 3.5 ؎ 0.9 Watts), cardiac power output reserve (1.7 ؎ 0.6 versus 2.4 ؎ 0.8 Watts), and VO 2peak (1.3 ؎ 0.3 versus 1.6 ؎ 0.2 l⅐min ؊1 ) than control subjects (p-values < .05). Patients with the greatest impairment in VO 2peak had the worse cardiovascular risk profile. Exploratory analyses Conclusion. Breast cancer patients treated with adjuvant CET have a significantly and markedly lower cardiorespiratory fitness and cardiac functional reserve compared with age-and sex-matched controls. AI therapy may be associated with a more unfavorable cardiovascular risk profile than TAM. Prospective studies are required to further investigate the clinical value of these findings.

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In clinically stable HFrEF patients, MICT is an effective therapy to attenuate LV remodeling with the greatest benefits occurring with long-term (≥6 months) training. HIIT performed for 2 to 3 months is superior to control, but not MICT, for improvement of LVEF.