Patients with heart failure (HF) and reduced ejection fraction (HFrEF) display exercise intolerance measured objectively as decreased peak oxygen uptake (VO₂).¹ In accordance with Fick’s principal and law of diffusion, reduced peak VO₂ is the result of impaired convective and diffusive O₂ transport.^2,3 Endurance training improves peak VO₂ in clinically stable HFrEF patients secondary to central and peripheral adaptations that result in increased cardiac output and O₂ distribution and extraction in skeletal muscle.¹ We report, using invasive hemodynamic and pulmonary gas exchange measures, exercise changes in VO₂ and its determinants in an avid cyclist with severe cardiac limitation because of advanced HFrEF.

A 55-year-old male patient who had been a lifelong marathon runner was diagnosed with idiopathic nonischemic dilated cardiomyopathy 5 years before evaluation. He had a history of atrial fibrillation and was on optimal doses of carvedilol, lisinopril, and spironolactone. His ejection fraction was 20% to 25%, but he had remained in New York Heart Association class I and was able to continue cycling and intense daily exercise. In the past year, he was hospitalized twice for acutely decompensated HF, with gradually worsening effort intolerance. Given the increasing need for hospitalization, he was referred for invasive exercise testing as part of a transplant evaluation workup.

Laboratories revealed hemoglobin 13.3 g/dL, creatinine 1.5 mg/dL, sodium 132 mmol/L, troponin 0.06 ng/mL, and NT-proBNP (N-terminal pro-B-type natriuretic peptide) 14 080 pg/mL. Echocardiography showed ejection …

心力衰竭（HF）和射血分数降低（HFrEF）的患者表现出的运动耐量客观测量为峰值摄氧量（VO ₂）降低。¹根据菲克原理和扩散定律，降低的峰值VO ₂是对流和扩散O ₂传输受损的结果。^2，3耐力训练提高峰值VO ₂在临床上稳定的患者HFREF继发于中枢和外周的适应其导致心输出量增加和O ₂在骨骼肌分布和提取。^1个我们报告，使用有创血流动力学和肺气体交换措施，在因严重的HFrEF而导致严重心脏受限的狂热自行车运动员中，VO ₂及其决定因素的运动变化。

评估前5年，一名55岁的男性患者曾是终身马拉松运动员，被诊断出患有特发性非缺血性扩张型心肌病。他有房颤病史，并以卡维地洛，赖诺普利和螺内酯的最佳剂量服用。他的射血分数为20％到25％，但他仍处于纽约心脏协会的I级，并且能够继续骑自行车和进行日常剧烈运动。在过去的一年中，他因急性代偿性HF住院两次，并逐渐加重了患者的耐受力。鉴于对住院的需求日益增加，他被要求进行有创运动测试，作为移植评估工作的一部分。

实验室显示血红蛋白13.3 g / dL，肌酐1.5 mg / dL，钠132 mmol / L，肌钙蛋白0.06 ng / mL和NT-proBNP（N端pro-B型利尿钠肽）14080 pg / mL。超声心动图显示射血…