Fig 1.
Example of continuous raw data.
From top to bottom: electrocardiogram, beat-to-beat blood pressure, end tidal CO2 and cerebral blood flow velocity.
Fig 2.
Representative examples of control, HYCH and POTS.
Fig 3.
21 y/o woman presented with a sudden onset of shortness of breath, chest pain, fatigue and dizziness 2 years ago. Previously highly functioning women is on disability. Heart rate and blood pressure responses to tilt were normal (A). Patient was hypocapnic even at supine with end tidal CO2 < 35 mmHg. End tidal CO2 declined to 15 mmHg during the tilt which was associated with a drop of mean cerebral blood flow velocity (CBFv) about 50%. Just before the tilt the end tidal CO2 increased to 35 mmHg that temporarily normalized CBFv demonstrating that the decline in CBFv was due to hypocapnia.
Fig 4.
Superimposed end tidal CO2 and mean cerebral blood flow velocity from the same patient as in Fig 3.
Table 1.
Frequency of symptoms in patients with HYCH and POTS.
Fig 5.
Comparison of HYCH, POTS and controls.
The hemodynamic variables were analyzed during supine position and at the minute 1, 5 and 10 of the tilt. Red circle shows significance difference compared to controls. A. CBFv = mean blood flow velocity, B. CBFv difference = percent difference in CBFv compared to supine baseline; C. ET = end tidal CO2; D. HR = heart rate, E. CVR = cerebrovascular resistance, F. MBP = mean blood pressure;, G. RF = respiratory frequency.