[Plasma noradrenaline response to phentolamine in "latent" left-sided heart failure]

To estimate the pumping function of the left-sided heart in patients with "latent" left-sided heart failure due to heart disease which primarily affected the left-side of the heart (former NYHA class I and II), we measured (i) the increase of peripheral venous pressure in response to supine mild leg exercise (delta VP), and (ii) the increase of plasma noradrenaline (NA) concentration due to phentolamine (PH) injection (delta NAPH). We divided the patients into well-functioning left-sided heart group (delta CI/delta PAW greater than 0.180 L.min-1.M-2.mmHg-1) and poorly-functioning left-sided heart group (delta CI/delta PAW less than or equal to 0.180 L.min-1.M-2.mmHg-1) on the basis of a ratio (delta CI/delta PAW), relating the increase in cardiac index (delta CI) in response to exercise to the concomitant increase in mean pulmonary artery wedge pressure (delta PAW). This diving line (delta CI/delta PAW = 0.180 L.min-1.M-2.mmHg-1) correlated with delta VP (diving line: delta VP = 35 mmH2O) and with delta NAPH (diving line: delta NAPH = 0.353 ng/ml). Our results suggest that delta VP and delta NAPH reflected the pumping function of the left-sided heart with considerable accuracy.