Hemodynamic and Metabolic Phenotyping of Heart Failure Development and Progression with a Focus on Heart Failure with preserved Ejection Fraction. Insights from Combined Cardiopulmonary and Exercise Echocardiography Stress Testing

Heart failure (HF) is a complex clinical syndrome, characterised by different etiologies and a broad spectrum of left ventricular (LV) functional abnormalities. The International guidelines have suggested a more sophisticated ejection-fraction (EF) based HF classification: reduced EF (<40%; HFrEF), mid-range EF (40-49%; HFmrEF) and preserved EF (≥50%; HFpEF). Since resting indices of LV function (e.g., LVEF or E/e' ratio) are only weakly correlated to exercise tolerance, the ideal condition to test the performance of the whole CV system and unveil early alterations is physical exercise. Cardiopulmonary exercise testing (CPET) has become an essential tool for the evaluation and monitoring of HF. A combined CPET and exercise stress echocardiography (ESE) technique, including lung ultrasound (LUS), proved to be feasible, providing a non-invasive evaluation of cardiovascular, pulmonary and metabolic responses to exercise. Hence, we sought to phenotype HF patients with different LVEF (i.e. HFrEF, HFmrEF and HFpEF) as well as subjects at risk of developing HF and study the "transition to failure", with a focus on HFpEF.