Noninvasive estimation of the left heart pumping function in patients with mild left-sided heat failure

We measured the magnitude of increase in peripheral venous pressure (ΔVP) associated with dynamic leg exercise (2 METS) and that of increase in plasma noradrenaline concentration (ΔDNA) in response to intravenous injection of phentolamine (0.1 mg/kg in 30 sec) in patients with cardiac diseases which primarily affect the left heart (previous NYHA classes I-II). We estimated the left heart pumping function from ΔVP and ΔNA. 1. In 60 patients, we measured cardiac index (CI) and mean pulmonary artery wedge pressure (PAW) using a Swan-Ganz catheter and obtained the increment of CI (ΔCI) and PAW (ΔPAW) in response to dynamic leg exercise. According to the ratio ΔCI/ΔPAW, the criteria for the function of the left heart was categorized into 2 grades; well-functioning with ΔCI/ΔPAW > 0.18 L · min^-1 · M^-2 · mmHg^-1 (W group), and poorly-functioning with ΔCI/ΔPAW ≤ 0.18 L · min^-1 · M^-2 · mmHg^-1 (P group). We also categorized the 60 patients into 2 groups according to ΔVP, namely, those with ΔVP < 35 mmH2O (normal responder, N group) and those with ΔVP ≥ 35 mmH₂O (high responder, H group). 2. In another 80 patients, ΔVP was measured to categorize the patients into N or H group. ΔNA in response to intravenous injection of phentolamine was also measured, and the patients were divided into 2 groups according to ΔNA, i.e., those with ΔNA < 0.353 ng/ml and those with ΔNA ≥ 0.353 ng/ml. Plasma noradrenaline was assayed by high performance liquid chromatography with THI method. When an increased venopressor response (ΔVP ≥ 35 mmH₂O, H group) was associated with a poorly functioning left heart (P group), the positive and negative predictive values were 100% and 91%, respectively. When an increased venopressor response (ΔVP ≥ 35 mmH₂O) was associated with a marked NA response (ΔNA ≥ 0.353 ng/ml), the positive and negative predictive values were 84% and 94%, respectively. The results of this study generally indicates that both ΔVP in response to dynamic leg exercise, and ΔNA to phentolamine injection are considerably accurate indicators of the pumping function of the left heart.