Aerobic Exercise Training Combined with Local Strength Exercise Restores Muscle Blood Flow and Maximal Aerobic Capacity in Long-Term Hodgkin Lymphoma Survivors.

BACKGROUND: It is unclear whether muscle blood flow (MBF) is altered in long-term Hodgkin Lymphoma (HL) survivors. We test the hypothesis that: 1) MBF response during mental stress (MS) is impaired in long-term HL survivors; 2) Aerobic exercise training combined with local strength exercise (ET) restores MBF responses during MS in these survivors. METHODS: Eighteen 5-year HL survivors and 10 aged-paired healthy subjects (HC) were studied. Twenty HL survivors were randomly divided into two groups: Exercise-trained (HLT, n=10) and untrained (HLUT, n=10). Maximal aerobic capacity was evaluated by a cardiopulmonary exercise test and forearm blood flow (FBF) by venous occlusion plethysmography. MS was elicited by Stroop Color Word Test. ET was conducted for four months, three/week for 60 minutes each session. The aerobic exercise intensity corresponded to anaerobic threshold up to 10% below the respiratory compensation point. The strength exercises consisted of 2-3 sets of chest press, pulley and squat exercises, 12-15 repetitions each exercise at 30-50% of the maximal voluntary contraction. RESULTS: Baseline was similar in HL survivors and HC, except peak oxygen consumption (peak VO2, p=0.013) and FBF (p=0.006) that were lower in the HL survivors. FBF responses during MS were lower in HL survivors (p<0.001). ET increased peak VO2 (11.59±3.07%, p=0.002), and FBF at rest (33.74±5.13%, p<0.001) and during MS (24±5.31%, p=0.001). Further analysis showed correlation between the changes in peak VO2 and the changes in FBF during MS (r=0.711, p=0.001). CONCLUSION: Long-term HL survivors have impaired MBF responses during MS. ET restores MBF responses during MS.

Interventions reducing mortality in COVID-19 patients: a systematic review of randomized evidence.

INTRODUCTION: COVID-19 pandemic changed the way medical research is published, possibly forever. As the need for rapidity led to the rise of preprint servers, the undeniable drop in the overall quality of scientific publications requires an in-depth review of all available evidence. The present manuscript aims to identify and summarize all treatments which have been reported to reduce mortality in randomized trials in hospitalized COVID-19 patients. EVIDENCE ACQUISITION: Independent investigators searched MEDLINE/PubMed, Scopus, and Embase databases to identify all randomized trials of any intervention influencing mortality in hospitalized COVID-19 patients up to August 18th, 2022. Articles were selected only when they fulfilled all the following: randomized trial design; dealing with any kind of interventions in adult hospitalized COVID-19 patients; and statistically significant reduction in mortality. EVIDENCE SYNTHESIS: We identified 28 interventions (42 manuscripts) reducing mortality in hospitalized COVID-19 patients. About 60% of the studies (26/42) were multicentric, for a total of 1140 centers involved worldwide. Several of these studies were published in high-ranked, peer-reviewed journals. Interventions with randomized evidence of mortality reduction in hospitalized COVID-19 patients belonged to 5 domains: corticosteroids, immunomodulators, antimicrobials, supportive therapies, and other drugs. CONCLUSIONS: Many interventions have the potential to reduce mortality in COVID-19 hospitalized patients. The correct treatment of future pandemics relies on large, multicentric randomized clinical trials for further evaluation of these promising strategies.

Sympathetic neural overdrive and diminished exercise capacity in reduced ejection fraction heart failure related to anthracycline-based chemotherapy.

Cardiotoxicity is the most worrying cardiovascular alteration in patients treated with chemotherapy. To improve the understanding regarding the cardiotoxicity, we studied whether 1) patients with cardiac dysfunction related to anthracycline-based chemotherapy have augmented sympathetic nerve activity and decreased exercise capacity and 2) these responses are similar to those observed in patients with heart failure caused by other etiologies. Sixteen patients with heart failure with reduced ejection fraction related to anthracycline-based chemotherapy with or without chest radiation (HFrEFCA), 10 patients with heart failure with reduced ejection not related to cancer therapy (HFrEF), and 16 age- and body mass index (BMI)-matched healthy control subjects were studied. Left ventricular ejection fraction (LVEF, echocardiography), peak oxygen consumption (peak V̇o2, cardiopulmonary exercise test), muscle sympathetic nerve activity (MSNA, microneurography), and forearm blood flow (FBF, venous occlusion plethysmography) were measured. We found that peak oxygen consumption peak V̇o2 and LVEF were significantly reduced in patients with HFrEFCA compared with that of control subjects (P < 0.0001) but similar to those found in patients with HFrEFCA. The sympathetic nerve activity burst frequency and incidence were significantly higher in patients with HFrEFCA than that in control subjects (P < 0.0001). No differences were found between patients with HFrEF and HFrEFCA. Peak V̇o2 was inversely associated with MSNA burst frequency (r = -0.53, P = 0.002) and burst incidence (r = -0.38, P = 0.01) and directly associated with LVEF (r = 0.71, P < 0.0001). Taken together, we conclude that patients who develop heart failure due to anthracycline-based chemotherapy have sympathetic neural overdrive and reduced exercise capacity. In addition, these physiological changes are similar to those observed in patients with HFrEF.NEW & NOTEWORTHY Patients with heart failure with reduced ejection fraction related to anthracycline-based chemotherapy have increased sympathetic nerve activity and decreased exercise capacity. These alterations in autonomic control and physical capacity are similar to those observed in patients with heart failure due to other etiologies. These findings highlight the importance of special care of oncological patients treated with chemotherapy.

Physical capacity increase in patients with heart failure is associated with improvement in muscle sympathetic nerve activity.

BACKGROUND: Exercise training improves physical capacity in patients with heart failure with reduced ejection fraction (HFrEF), but the mechanisms involved in this response is not fully understood. The aim of this study was to determine if physical capacity increase in patients HFrEF is associated with muscle sympathetic nerve activity (MSNA) reduction and muscle blood flow (MBF) increase. METHODS: The study included 124 patients from a 17-year database, divided according to exercise training status: 1) exercise-trained (ET, n = 83) and 2) untrained (UNT, n = 41). MSNA and MBF were obtained using microneurography and venous occlusion plethysmography, respectively. Physical capacity was evaluated by cardiopulmonary exercise test. Moderate aerobic exercise was performed 3 times/wk. for 4 months. RESULTS: Exercise training increased peak oxygen consumption (V̇O2, 16.1 ± 0.4 vs 18.9 ± 0.5 mL·kg-1·min-1, P < 0.001), LVEF (28 ± 1 vs 30 ± 1%, P = 0.027), MBF (1.57 ± 0.06 vs 2.05 ± 0.09 mL.min-1.100 ml-1, P < 0.001) and muscle vascular conductance (MVC, 1.82 ± 0.07 vs 2.45 ± 0.11 units, P < 0.001). Exercise training significantly decreased MSNA (45 ± 1 vs 32 ± 1 bursts/min, P < 0.001). The logistic regression analyses showed that MSNA [(OR) 0.921, 95% CI 0.883-0.962, P < 0.001] was independently associated with peak V̇O2. CONCLUSIONS: The increase in physical capacity provoked by aerobic exercise in patients with HFrEF is associated with the improvement in MSNA.

High-Sensitivity Troponin I after Cardiac Surgery and 30-Day Mortality.

BACKGROUND: Consensus recommendations regarding the threshold levels of cardiac troponin elevations for the definition of perioperative myocardial infarction and clinically important periprocedural myocardial injury in patients undergoing cardiac surgery range widely (from >10 times to ≥70 times the upper reference limit for the assay). Limited evidence is available to support these recommendations. METHODS: We undertook an international prospective cohort study involving patients 18 years of age or older who underwent cardiac surgery. High-sensitivity cardiac troponin I measurements (upper reference limit, 26 ng per liter) were obtained 3 to 12 hours after surgery and on days 1, 2, and 3 after surgery. We performed Cox analyses using a regression spline that explored the relationship between peak troponin measurements and 30-day mortality, adjusting for scores on the European System for Cardiac Operative Risk Evaluation II (which estimates the risk of death after cardiac surgery on the basis of 18 variables, including age and sex). RESULTS: Of 13,862 patients included in the study, 296 (2.1%) died within 30 days after surgery. Among patients who underwent isolated coronary-artery bypass grafting or aortic-valve replacement or repair, the threshold troponin level, measured within 1 day after surgery, that was associated with an adjusted hazard ratio of more than 1.00 for death within 30 days was 5670 ng per liter (95% confidence interval [CI], 1045 to 8260), a level 218 times the upper reference limit. Among patients who underwent other cardiac surgery, the corresponding threshold troponin level was 12,981 ng per liter (95% CI, 2673 to 16,591), a level 499 times the upper reference limit. CONCLUSIONS: The levels of high-sensitivity troponin I after cardiac surgery that were associated with an increased risk of death within 30 days were substantially higher than levels currently recommended to define clinically important periprocedural myocardial injury. (Funded by the Canadian Institutes of Health Research and others; VISION Cardiac Surgery ClinicalTrials.gov number, NCT01842568.).

Effect of Volatile Anesthetics on Myocardial Infarction After Coronary Artery Surgery: A Post Hoc Analysis of a Randomized Trial.

OBJECTIVE: To investigate the effect of volatile anesthetics on the rates of postoperative myocardial infarction (MI) and cardiac death after coronary artery bypass graft (CABG). DESIGN: A post hoc analysis of a randomized trial. SETTING: Cardiac surgical operating rooms. PARTICIPANTS: Patients undergoing elective, isolated CABG. INTERVENTIONS: Patients were randomized to receive a volatile anesthetic (desflurane, isoflurane, or sevoflurane) or total intravenous anesthesia (TIVA). The primary outcome was hemodynamically relevant MI (MI requiring high-dose inotropic support or prolonged intensive care unit stay) occurring within 48 hours from surgery. The secondary outcome was 1-year death due to cardiac causes. MEASUREMENTS AND MAIN RESULTS: A total of 5,400 patients were enrolled between April 2014 and September 2017 (2,709 patients randomized to the volatile anesthetics group and 2,691 to TIVA). The mean age was 62 ± 8.4 years, and the median baseline ejection fraction was 57% (50-67), without differences between the 2 groups. Patients in the volatile group had a lower incidence of MI with hemodynamic complications both in the per-protocol (14 of 2,530 [0.6%] v 27 of 2,501 [1.1%] in the TIVA group; p = 0.038) and as-treated analyses (16 of 2,708 [0.6%] v 29 of 2,617 [1.1%] in the TIVA group; p = 0.039), but not in the intention-to-treat analysis (17 of 2,663 [0.6%] v 28 of 2,667 [1.0%] in the TIVA group; p = 0.10). Overall, deaths due to cardiac causes were lower in the volatile group (23 of 2,685 [0.9%] v 40 of 2,668 [1.5%] than in the TIVA group; p = 0.03). CONCLUSIONS: An anesthetic regimen, including volatile agents, may be associated with a lower rate of postoperative MI with hemodynamic complication in patients undergoing CABG. Furthermore, it may reduce long-term cardiac mortality.

Effect of volatile anesthetics on myocardial infarction after coronary artery surgery: a post hoc analysis of a randomized trial

OBJECTIVE: To investigate the effect of volatile anesthetics on the rates of postoperative myocardial infarction (MI) and cardiac death after coronary artery bypass graft (CABG). DESIGN: A post hoc analysis of a randomized trial. SETTING: Cardiac surgical operating rooms. PARTICIPANTS: Patients undergoing elective, isolated CABG. INTERVENTIONS: Patients were randomized to receive a volatile anesthetic (desflurane, isoflurane, or sevoflurane) or total intravenous anesthesia (TIVA). The primary outcome was hemodynamically relevant MI (MI requiring high-dose inotropic support or prolonged intensive care unit stay) occurring within 48 hours from surgery. The secondary outcome was 1-year death due to cardiac causes. Measurements and main Results: A total of 5,400 patients were enrolled between April 2014 and September 2017 (2,709 patients randomized to the volatile anesthetics group and 2,691 to TIVA). The mean age was 62 ± 8.4 years, and the median baseline ejection fraction was 57% (50-67), without differences between the 2 groups. Patients in the volatile group had a lower incidence of MI with hemodynamic complications both in the per-protocol (14 of 2,530 [0.6%] v 27 of 2,501 [1.1%] in the TIVA group; p = 0.038) and as-treated analyses (16 of 2,708 [0.6%] v 29 of 2,617 [1.1%] in the TIVA group; p = 0.039), but not in the intention-to-treat analysis (17 of 2,663 [0.6%] v 28 of 2,667 [1.0%] in the TIVA group; p = 0.10). Overall, deaths due to cardiac causes were lower in the volatile group (23 of 2,685 [0.9%] v 40 of 2,668 [1.5%] than in the TIVA group; p = 0.03). CONCLUSIONS: An anesthetic regimen, including volatile agents, may be associated with a lower rate of postoperative MI with hemodynamic complication in patients undergoing CABG. Furthermore, it may reduce long-term cardiac mortality.

Latin American surgical outcomes study: study protocol for a multicentre international observational cohort study of patient outcomes after surgery in Latin American countries.

Background: Reported data suggest that 4.2 million deaths will occur within 30 days of surgery worldwide each year, half of which are in low- and middle-income countries. Postoperative complications are a leading cause of long-term morbidity and mortality. Patients who survive and leave the hospital after surgical complications regularly experience reductions in long-term survival and functional independence, resulting in increased costs. With a high volume of surgery performed, there is a growing perception of the substantial impact of even minor enhancements in perioperative care. The Latin American Surgical Outcomes Study (LASOS) is an international, multicentre, prospective cohort study of adults submitted to in-patient surgery in Latin America aiming to provide detailed data describing postoperative complications and surgical mortality. Methods: LASOS is a 7 day cohort study of adults undergoing surgery in Latin America. Details of preoperative risk factors, intraoperative care, and postoperative outcomes will be collected. The primary outcome will be in-hospital postoperative complications of any cause. Secondary outcomes include in-hospital all-cause mortality, duration of hospital stay after surgery, and admission to a critical care unit within 30 days after surgery during the index hospitalisation. Results: The LASOS results will be published in peer-reviewed journals, reported and presented at international meetings, and widely disseminated to patients and public in participating countries via mainstream and social media. Conclusions: The LASOS may augment our understanding of postoperative complications and surgial mortality in Latin America. Clinical trial registration: NCT05169164.

High risk coronavirus disease 2019: The primary results of the CoronaHeart multi-center cohort study

BACKGROUND: Patients with Coronavirus Disease 2019 (COVID-19) may present high risk features during hospitalization, including cardiovascular manifestations. However, less is known about the factors that may further increase the risk of death in these patients. METHODS: We included patients with COVID-19 and high risk features according to clinical and/or laboratory criteria at 21 sites in Brazil from June 10th to October 23rd of 2020. All variables were collected until hospital discharge or in-hospital death. RESULTS: A total of 2546 participants were included (mean age 65 years; 60.3% male). Overall, 70.8% were admitted to intensive care units and 54.2% had elevated troponin levels. In-hospital mortality was 41.7%. An interaction among sex, age and mortality was found (p = 0.007). Younger women presented higher rates of death than men (30.0% vs 22.9%), while older men presented higher rates of death than women (57.6% vs 49.2%). The strongest factors associated with in-hospital mortality were need for mechanical ventilation (odds ratio [OR] 8.2, 95% confidence interval [CI] 5.4­12.7), elevated C-reactive protein (OR 2.3, 95% CI 1.7­2.9), cancer (OR 1.8, 95 %CI 1.2­2.9), and elevated troponin levels (OR 1.8, 95% CI 1.4­2.3). A risk score was developed for risk assessment of in-hospital mortality. CONCLUSIONS: This cohort showed that patients with COVID-19 and high risk features have an elevated rate of in-hospital mortality with differences according to age and sex. These results highlight unique aspects of this population and might help identifying patients who may benefit from more careful initial surveillance and potential subsequent interventional therapies

High risk coronavirus disease 2019: The primary results of the CoronaHeart multi-center cohort study.

BACKGROUND: Patients with Coronavirus Disease 2019 (COVID-19) may present high risk features during hospitalization, including cardiovascular manifestations. However, less is known about the factors that may further increase the risk of death in these patients. METHODS: We included patients with COVID-19 and high risk features according to clinical and/or laboratory criteria at 21 sites in Brazil from June 10th to October 23rd of 2020. All variables were collected until hospital discharge or in-hospital death. RESULTS: A total of 2546 participants were included (mean age 65 years; 60.3% male). Overall, 70.8% were admitted to intensive care units and 54.2% had elevated troponin levels. In-hospital mortality was 41.7%. An interaction among sex, age and mortality was found (p = 0.007). Younger women presented higher rates of death than men (30.0% vs 22.9%), while older men presented higher rates of death than women (57.6% vs 49.2%). The strongest factors associated with in-hospital mortality were need for mechanical ventilation (odds ratio [OR] 8.2, 95% confidence interval [CI] 5.4-12.7), elevated C-reactive protein (OR 2.3, 95% CI 1.7-2.9), cancer (OR 1.8, 95 %CI 1.2-2.9), and elevated troponin levels (OR 1.8, 95% CI 1.4-2.3). A risk score was developed for risk assessment of in-hospital mortality. CONCLUSIONS: This cohort showed that patients with COVID-19 and high risk features have an elevated rate of in-hospital mortality with differences according to age and sex. These results highlight unique aspects of this population and might help identifying patients who may benefit from more careful initial surveillance and potential subsequent interventional therapies.

Platelet Reactivity and Coagulation Markers in Patients with COVID-19.

INTRODUTION: COVID-19 is associated with an increased risk of thrombotic events. However, the contribution of platelet reactivity (PR) to the aetiology of the increased thrombotic risk associated with COVID-19 remains unclear. Our aim was to evaluate PR in stable patients diagnosed with COVID-19 and hospitalized with respiratory symptoms (mainly dyspnoea and dry cough), in comparison with a control group comprised of non-hospitalized healthy controls. METHODS: Observational, case control study that included patients with confirmed COVID-19 (COVID-19 group, n = 60) and healthy individuals matched by age and sex (control group, n = 60). Multiplate electrode aggregometry (MEA) tests were used to assess PR with adenosine diphosphate (MEA-ADP, low PR defined as < 53 AUC), arachidonic acid (MEA-ASPI, low PR < 86 AUC) and thrombin receptor-activating peptide 6 (MEA-TRAP, low PR < 97 AUC) in both groups. RESULTS: The rates of low PR with MEA-ADP were 27.5% in the COVID-19 group and 21.7% in the control group (OR = 1.60, p = 0.20); with MEA-ASPI, the rates were, respectively, 37.5% and 22.5% (OR = 3.67, p < 0.001); and with MEA-TRAP, the incidences were 48.5% and 18.8%, respectively (OR = 9.58, p < 0.001). Levels of D-dimer, fibrinogen, and plasminogen activator inhibitor 1 (PAI-1) were higher in the COVID-19 group in comparison with the control group (all p < 0.05). Thromboelastometry was utilized in a subgroup of patients and showed a hypercoagulable state in the COVID-19 group. CONCLUSION: Patients hospitalized with non-severe COVID-19 had lower PR compared to healthy controls, despite having higher levels of D-dimer, fibrinogen, and PAI-1, and hypercoagulability by thromboelastometry. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT04447131.

Patients with COVID-19 who experience a myocardial infarction have complex coronary morphology and high in-hospital mortality: Primary results of a nationwide angiographic study.

OBJECTIVES: We aimed to explore angiographic patterns and in-hospital outcomes of patients with concomitant coronavirus disease-19 (COVID-19) and myocardial infarction (MI). BACKGROUND: Patients with COVID-19 may experience MI during the course of the viral infection. However, this association is currently poorly understood. METHODS: This is a multicenter prospective study of consecutive patients with concomitant COVID-19 and MI who underwent coronary angiography. Quantitative and qualitative coronary angiography were analyzed by two observers in an independent core lab. RESULTS: A total of 152 patients were included, of whom 142 (93.4%) had COVID-19 diagnosis confirmation. The median time between symptom onset and hospital admission was 5 (1-10) days. A total of 83 (54.6%) patients presented with ST-elevation MI. The median angiographic Syntax score was 16 (9.0-25.3) and 69.0% had multi-vessel disease. At least one complex lesion was found in 73.0% of patients, 51.3% had a thrombus containing lesion, and 57.9% had myocardial blush grades 0/1. The overall in-hospital mortality was 23.7%. ST-segment elevation MI presentation and baseline myocardial blush grades 0 or 1 were independently associated with a higher risk of death (HR 2.75, 95%CI 1.30-5.80 and HR 3.73, 95%CI 1.61-8.61, respectively). CONCLUSIONS: Patients who have a MI in the context of ongoing COVID-19 mostly present complex coronary morphologies, implying a background of prior atherosclerotic disease superimposed on a thrombotic milieu. The in-hospital prognosis is poor with a markedly high mortality, prompting further investigation to better clarify this newly described condition.

Patients with COVID-19 who experience a myocardial infarction have complex coronary morphology and high in-hospital mortality: Primary results of a nationwide angiographic study

OBJECTIVES: We aimed to explore angiographic patterns and in-hospital outcomes of patients with concomitant coronavirus disease-19 (COVID-19) and myocardial infarction (MI). BACKGROUND: Patients with COVID-19 may experience MI during the course of the viral infection. However, this association is currently poorly understood. METHODS: This is a multicenter prospective study of consecutive patients with concomitant COVID-19 and MI who underwent coronary angiography. Quantitative and qualitative coronary angiography were analyzed by two observers in an independent core lab. RESULTS: A total of 152 patients were included, of whom 142 (93.4%) had COVID-19 diagnosis confirmation. The median time between symptom onset and hospital admission was 5 (1­10) days. A total of 83 (54.6%) patients presented with ST elevation MI. The median angiographic Syntax score was 16 (9.0­25.3) and 69.0% had multi-vessel disease. At least one complex lesion was found in 73.0% of patients, 51.3% had a thrombus containing lesion, and 57.9% had myocardial blush grades 0/1. The overall in-hospital mortality was 23.7%. ST-segment elevation MI presentation and baseline myocardial blush grades 0 or 1 were independently associated with a higher risk of death (HR 2.75, 95%CI 1.30­5.80 and HR 3.73, 95%CI 1.61­8.61, respectively). CONCLUSIONS: Patients who have a MI in the context of ongoing COVID-19 mostly present complex coronary morphologies, implying a background of prior atherosclerotic disease superimposed on a thrombotic milieu. The in-hospital prognosis is poor with a markedly high mortality, prompting further investigation to better clarify this newly described condition.

Platelet Reactivity in Patients With Acute Coronary Syndromes Awaiting Surgical Revascularization.

BACKGROUND: Dual antiplatelet therapy is recommended for patients with acute coronary syndromes (ACS). Approximately 10% to 15% of these patients will undergo coronary artery bypass graft (CABG) surgery for index events, and current guidelines recommend stopping clopidogrel at least 5 days before CABG. This waiting time has clinical and economic implications. OBJECTIVES: This study aimed to evaluate if a platelet reactivity-based strategy is noninferior to standard of care for 24-h post-CABG bleeding. METHODS: In this randomized, open label noninferiority trial, 190 patients admitted with ACS with indications for CABG and on aspirin and P2Y12 receptor inhibitors, were assigned to either control group, P2Y12 receptor inhibitor withdrawn 5 to 7 days before CABG, or intervention group, daily measurements of platelet reactivity by Multiplate analyzer (Roche Diagnostics GmbH, Vienna, Austria) with CABG planned the next working day after platelet reactivity normalization (pre-defined as ≥46 aggregation units). RESULTS: Within the first 24 h of CABG, the median chest tube drainage was 350 ml (interquartile range [IQR]: 250 to 475 ml) and 350 ml (IQR: 255 to 500 ml) in the intervention and control groups, respectively (p for noninferiority <0.001). The median waiting period between the decision to undergo CABG and the procedure was 112 h (IQR: 66 to 142 h) and 136 h (IQR: 112 to 161 h) (p < 0.001), respectively. In the intention-to-treat analysis, a 6.4% decrease in the median in-hospital expenses was observed in the intervention group (p = 0.014), with 11.2% decrease in the analysis per protocol (p = 0.003). CONCLUSIONS: A strategy based on platelet reactivity-guided is noninferior to the standard of care in patients with ACS awaiting CABG regarding peri-operative bleeding, significantly shortens the waiting time to CABG, and decreases hospital expenses. (Evaluation of Platelet Aggregability in the Release of CABG in Patients With ACS With DAPT; NCT02516267).

Breast Cancer Promotes Cardiac Dysfunction Through Deregulation of Cardiomyocyte Ca2+-Handling Protein Expression That is Not Reversed by Exercise Training.

Background Patients treated for breast cancer have a high incidence of cardiovascular complications. In this study, we evaluated the impact of breast cancer on cardiac function and cardiomyocyte Ca2+-handling protein expression. We also investigated whether exercise training (ET) would prevent these potential alterations. Methods and Results Transgenic mice with spontaneous breast cancer (mouse mammary tumor virus-polyomavirus middle T antigen [MMTV-PyMT+], n=15) and littermate mice with no cancer (MMTV-PyMT-, n=14) were studied. For the ET analysis, MMTV-PyMT+ were divided into sedentary (n=10) and exercise-trained (n=12) groups. Cardiac function was evaluated by echocardiography with speckle-tracking imaging. Exercise tolerance test was conducted on a treadmill. Both studies were performed when the tumor became palpable and when it reached 1 cm3. After euthanasia, Ca2+-handling protein expression (Western blot) was evaluated. Exercise capacity was reduced in MMTV-PyMT+ compared with MMTV-PyMT- (Pinteraction=0.031). Longitudinal strain (Pgroup <0.001) and strain rate (Pgroup=0.030) were impaired. Cardiomyocyte phospholamban was increased (P=0.011), whereas phospho-phospholamban and sodium/calcium exchanger were decreased (P=0.038 and P=0.017, respectively) in MMTV-PyMT+. No significant difference in sarcoplasmic or endoplasmic reticulum calcium 2 ATPase (SERCA2a) was found. SERCA2a/phospholamban ratio was reduced (P=0.007). ET was not associated with increased exercise capacity. ET decreased left ventricular end-systolic diameter (Pgroup=0.038) and end-diastolic volume (Pgroup=0.026). Other morphological and functional cardiac parameters were not improved by ET in MMTV-PyMT+. ET did not improve cardiomyocyte Ca2+-handling protein expression. Conclusions Breast cancer is associated with decreased exercise capacity and subclinical left ventricular dysfunction in MMTV-PyMT+, which is at least partly associated with dysregulation of cardiomyocyte Ca2+ handling. ET did not prevent or reverse these changes.