[Dependence of the arterial blood pressure on cardiac filling in severe orthostatic hypotension].
The present study aimed at an investigation of the relation between arterial blood pressure and cardiac filling in patients with severe postural hypotension. Seven patients aged 49 to 84 years were studied during head-up tilt at three different tilt angles (median values: 0, 25, and 45 degrees) using intraarterial blood pressure recordings and estimates of left ventricular volumes by radioisotope ventriculography. Mean arterial blood pressure was reduced from 105 mmHg (79-129) in the horizontal position to 97 mmHg (61-112) and 83 mmHg (36-93; p < 0.0001), respectively, in parallel with a reduction in left ventricular end-diastolic volume index from 59 ml m-2 (30-65) to 36 ml m-2 (23-44) and 22 ml m-2 (16-38; p < 0.001). Left ventricular contractility was high, and the postural reductions in cardiac output were unopposed by vasoconstriction. The study has demonstrated that blood pressure is strongly dependent upon cardiac filling in severe postural hypotension, and has underlined the importance of intravascular volume expansion as a measure against postural hypotension.
Klinisk fysiologisk/nuklearmedicinsk afdeling, Frederiksberg Hospital.
J
J
Mehlsen
C
C
Haedersdal
K H
KH
Stokholm
D000368:Aged; D001794:Blood Pressure; D006801:Humans; D007024:Hypotension, Orthostatic / Q000503:physiopathology*; D008875:Middle Aged; D009200:Myocardial Contraction; D013599:Systole
Det arterielle blodtryks afhaengighed af hjertets fyldning ved svaer ortostatisk hypotension.