Cerebral Blood Flow, Heart Rate, and Blood Pressure Patterns during the Tilt Test in Common Orthostatic Syndromes

Figure 7

This example shows combination of (1) primary cerebral autoregulatory failure (pCAF); (2) severe orthostatic hypotension with reduced orthostatic CBFv; and (3) atrial fibrillation. Supine BP is elevated while supine CBFv is reduced. The pattern of elevated BP and reduced CBFv during supine position is due to abnormal cerebral vasoconstriction consistent with pCAF. There was severe OH with a progressive decrease in BP during the tilt. Diastolic CBFv was reduced during the tilt but less than systolic CBFv that can be seen in mild cerebral vasodilatation that compensates for reduced orthostatic BP. HR responses to the tilt were absent. Note random, noise-like pattern of HR due atrial fibrillation. The HR fluctuated wildly (50–180 BPM) and not all electrical systoles were transmitted in the mechanical systoles (c) resulting in marked variations of BP and CBFv. Supine hypertension and orthostatic hypotension are a marker of severe autonomic adrenergic failure. Green boxes represent mean blood pressure obtained from the arm. Data from 69-year-old man with multiple system atrophy.

(a)

(b)

(c)