Smith, Joshua R.

Background Cardiac rehabilitation (CR) leads to increased exercise capacity (VO 2 peak) and risk reduction of major adverse cardiovascular events (MACEs). Women exhibit blunted VO 2 peak improvements following CR. The purpose was to examine sex differences in the clinical predictors of VO 2 peak improvement and odds of MACEs following CR. Methods From 1999 to 2017, all consecutive patients undergoing cardiopulmonary exercise testing before and after CR were included. Sex differences in peak exercise metrics in response to CR were compared. Multiple logistic regression models were fit to assess clinical predictors of VO 2 peak improvement (defined as >0% from pre‐CR) and MACEs following CR for men and women. Results A total of 513 men and 158 women were included. Men had greater increases in VO 2 peak than women following CR ( P =0.001). For men, independent predictors of VO 2 peak improvement following CR included higher CR session attendance (odds ratio [OR], 1.04 [95% CI, 1.02–1.06]), peripheral artery disease (OR, 0.47 [95% CI, 0.25–0.86]), and pre‐CR VO 2 peak (OR, 0.98 [95% CI, 0.97–0.99]) (all, P <0.02). Independent predictors of lower odds of MACEs following CR in men included higher number of CR sessions (OR, 0.97 [95% CI, 0.95–0.99]), pre‐CR VO 2 peak (OR, 0.98 [95% CI, 0.97–0.99]), surgical CR indication (OR, 0.34 [95% CI, 0.18–0.68]), and no history of peripheral artery disease (OR, 2.94 [95% CI, 1.60–5.38]) (all, P <0.02). For women, the selected clinical characteristics were not statistically significant independent predictors of VO 2 peak improvement or odds of MACEs (except for diabetes) following CR. Conclusions These findings suggest that clinical predictors of VO 2 peak improvement and odds of MACEs following CR are sex specific.

Heart failure with preserved ejection fraction (HFpEF) is associated with exercise intolerance, with respiratory muscle dysfunction as a contributing factor. Patients with HFpEF have exaggerated cardiovascular responses to respiratory muscle metaboreflex activation. In this study, we determined the impact of inspiratory muscle training (IMT) on the respiratory muscle metaboreflex in HFpEF. We found that 8 wk of IMT improved inspiratory muscle strength and attenuated the respiratory muscle metaboreflex-mediated cardiovascular responses in patients with HFpEF.

Abstract Aims Oxygen consumption at peak exercise is widely used to assess functional impairment in heart failure with preserved ejection fraction (HFpEF), but few patients exercise to this intensity in daily living. Alternative metrics that quantify submaximal fitness may provide more patient-centred evaluations, but the pathophysiology of submaximal exercise intolerance in HFpEF is unexplored. Methods and results Patients with HFpEF underwent invasive haemodynamic cardiopulmonary exercise testing with blood lactate measurement during exercise to volitional fatigue. Lactate threshold (LT) was defined as the exercise workload at which arterial lactate exceeded &gt;2.0 mmol/L, taken as a measure of submaximal fitness. Of patients with HFpEF (n = 286), 194 (68%) reached LT at a workload of 40 W or less (LT ≤40 W), while 92 (32%) reached a workload exceeding 40 W at LT (LT &gt;40 W). As compared to LT &gt;40 W, patients with LT ≤40 W were more likely to be female, anaemic, and had greater pulmonary vascular disease (all p &lt; 0.01). During 20 W exercise, participants with LT ≤40 W had higher pulmonary artery pressure, biventricular filling pressures, minute ventilation and respiratory drive, higher perceived dyspnoea and fatigue ratings, greater arterial–venous oxygen content difference, despite similar cardiac output and oxygen delivery. At peak exercise, most of these differences were no longer apparent. Findings were replicated using non-invasively-measured workload at ventilatory threshold. Conclusions Two-thirds of patients with HFpEF reach LT at workloads typical of activities of daily living. Patients with HFpEF and impaired submaximal fitness are more likely to be female, have greater pulmonary vascular disease and anaemia severity, and display greater haemodynamic, symptomatic, and ventilatory control abnormalities during low-level exercise, which are not apparent at maximal exertion. These findings have therapeutic implications and suggest a potentially important role for wider evaluation of submaximal fitness in addition to peak aerobic capacity.

Introduction: Cardiac rehabilitation (CR) is a cornerstone of secondary prevention for cardiovascular disease (CVD). CR participation is associated with improvements in secondary CVD risk factor management. However, it is unclear if CR participation is associated with maintained improvements in CVD risk factor management following CR completion. Purpose: The aim of this study was to assess the impact of CR participation on CVD risk factor management at 1 and 3 years following CR completion. Methods: This retrospective study analyzed 911 patients (73% male) enrolled in the CR program at Mayo Clinic from 2013 to 2020. Patient demographics, clinical characteristics, and CVD risk factor management were examined pre and post CR as part of clinical practice and assessed passively at 1 and 3 years following CR. Secondary prevention CVD risk factor goals included total cholesterol (<200 mg/dL), HDL cholesterol (>40 mg/dL), LDL cholesterol (<100 mg/dL), triglycerides (<150 mg/dL), systolic and diastolic blood pressure (<130 and <80 mmHg), and body mass index (BMI) (18.5-24.9 kg/m 2 ). Results: The mean age was 66±12 years and on average 33±9 CR sessions were attended. Table 1 shows the percentage (%) of patients meeting the secondary prevention CVD risk factor goals. The % of patients meeting the goals for total cholesterol, LDL, triglycerides, and diastolic blood pressure were higher post than pre CR. There were no changes in the % of patients meeting the goals for total cholesterol or LDL at 1 and 3 year follow up compared to post CR. At 1 and 3 year follow up, there was a lower % of patients meeting the goals for systolic and diastolic blood pressure and triglycerides (at 1 year follow up only) than post CR. No changes were present in the % of patients meeting the goals for HDL and BMI at any timepoint (all, p>0.09). Conclusions: CR participation was associated with maintained improvements in lipid management, but not in triglycerides or blood pressure control at 1 and 3 years following CR.