[Study of left ventricular function using systolic time intervals in a group of patients with polycythemia vera (Vaquez-Osler disease)].

: Left ventricular performance has been studied in 50 patients affected by primary polycythemia (P.V.) by determining systolic time intervals. 50 normal subjects were used as control group. All cases underwent a pharmacodynamic test with Amyl Nitrite. The results indicate that patients with P.V. present an abnormal behaviour of left ventricular performance after Amyl Nitrite; this alteration is more evident in patients with arterial hypertension. Amyl Nitrite, through its pharmacological action, causes changes in systolic time intervals and reveals a state of latent cardiac failure.