LV Diastolic Dysfunction and Inappropriate LV Filling Pressure Escalation: The Core of Exercise Intolerance in Heart...

Exercise intolerance is the most common symptom of patients with heart failure (HF), regardless of the phenotypes. We aim to investigate the determinants of exercise capacity in chronic stable HF with reduced, mildly reduced, preserved, and recovered ejection fraction (EF).

Ambulatory HF subjects were recruited for a combined cardiopulmonary exercise test and exercise stress echocardiography. Impaired exercise capacity was referred to a peak oxygen consumption of <14 mL/kg/min, and a relationship between minute ventilation and carbon dioxide production of >34 was defined as ventilatory inefficiency.

Among 66 participants, there were 16 HF with reduced EF, 18 HF with mildly reduced EF, 12 HF preserved EF, and 20 HF recovered EF. Diastolic dysfunction indices were independently predictive of impaired exercise capacity (odds ratio [OR], 3.847; 95% confidence interval [CI], 1.369-10.810). Global longitudinal strain (GLS) at rest was independently correlated with ventilatory inefficiency (OR, 1.404; 95% CI, 1.050-1.877). Among the exercise indices, the peak medial E/e' to cardiac output (CO) ratio was independently associated with impaired exercise capacity (OR, 3.478; 95% CI, 1.313-9.214) and peak GLS was best related to ventilatory inefficiency (OR, 1.403; 95% CI, 1.076-1.828).

Among resting and exertional echocardiographic variables, the peak medial E/e' to CO ratio, a non-invasive assessment of exertional left ventricular filling pressure indexed to CO, was the major determinant of exercise capacity in patients with different HF phenotypes.