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

Figure 8

Mixed syncope. In this subject, initial slowing of HR from 123 to 81 BPM (thin red arrow) is not cardioinhibitory response but reflects a functioning baroreflex since it is associated with elevation of BP (thin black arrow) and CBFv (thin blue arrow). The onset of the cardioinhibitory reaction is marked by the vertical red line with HR 108 BPM (thick red arrow) and coincides with a BP drop (thick black arrow) and patient became quickly unconscious. The pulsatility index increased during syncope (systolic CBFv increased and diastolic CFBv decreased) which is consistent with cerebral vasodilatation. The vasodilatation started early (thick blue arrows), and the changes were discernible in the doppler audio signal before noticeable changes in heart rate or BP. The cardiac slowing followed with delayed BP decrease being characteristic of cardioinhibitory syncope. Patient lost consciousness when the systolic BP declined below 60 mmHg, as expected. Data from 20 y/o woman.