Alterations in left ventricular volumes induced by Valsalva manoeuvre.

Five patients were studied with left ventriculography during different phases of the Valsalva manoeuvre.Small doses of contrast medium allowed adequate repetitive visualization of the left ventricle for volume calculation.During strain phase, the volume of the left ventricle decreased by nearly 50 per cent in each case, and stroke volume and cardiac output also dropped strikingly.Release of straining was attended by a sharp rebound of left ventricular volume to control levels, with a transient surge of increased cardiac output 42 per cent above that of the resting state.The Valsalva manoeuvre, when forcefully performed, produces transient but dramatic alterations in venous return, stroke volume, and arterial pres- sure (Stone, Lyon, and Teirstein, I965; Goldblatt et al., I963).The various phases of the Valsalva manoeuvre as defined by Hamilton are associated with well-delineated haemodynamic alterations (Stone et al., I965; Goldblatt et al., I963; Hamilton, Woodbury, and Harper, 1936).Phase i, correspond- ing to the initiation of strain, results in a transient rise in arterial pressure and a rapid decline in venous return.Phase 2, representing the entire duration of the strain phase, has been correlated with falling arterial pressure and increasing heart rate.During the latter portion of this phase, a gradual increase in blood pressure occurs.Phase 3, the abrupt release of the Valsalva manoeuvre, produces a sudden fall of arterial blood pressure and rapid rise of venous return, at a time when the heart rate remains raised.Phase 4 corresponds to the rising blood pressure and pulse pressure seen as the cardiac output in- creases due to the surge of venous return.In normal subjects, arterial blood pressure and pulse pressure exceed control values, and a reflex bradycardia en- sues (Stone et al., I965; Hamilton et al., 1936).