The Effect of Atrial Fibrillation Hemodynamics on Regulation of Cerebral Blood Flow

This is a prospective study evaluating 10 subjects referred for elective direct current
cardioversion (DCCV) of atrial fibrillation. Subjects will be seen at Parkland Health and
Hospital System.

After full consent is obtained and explanation of the research, each subject will undergo a
series of entirely non-invasive tests including Transcranial Doppler ultrasound (TCD), manual
cuff blood pressure (BP), beat to beat BP monitoring by a Portapress monitor, and respiratory
tidal CO2. These measurements will be taken after laying the patient in a supine position for
10 minutes and subsequently after standing for 10 minutes. Measurements will also be taken
after full body squat -stand repetition at 20 second intervals (0.05 Hz) x 5 minutes.
Patients who are unable to squat may rise from a seated position on a chair. This protocol
has been easy to follow even for debilitated patients with Alzheimers Disease in Dr. Zhang
and Dr. Levine's laboratory. The subject will then undergo elective DCCV as planned for
standard of care. The above measurements and with respective body positions will then be
repeated 30 minutes later if the patient has been successfully converted to normal sinus
rhythm by DCCV.

The experimental testing will take approximately 1 ½ to 2 hours to complete.

Inclusion Criteria:

- Subjects with atrial fibrillation scheduled for DCCV

- Subjects must be at least 18 years of age

- Subjects must have the ability to understand and sign informed consent and be willing
to comply with full testing and evaluation

Exclusion Criteria:

- Subjects in sinus rhythm without assessment of any prior atrial fibrillation by this
research team

- Subjects unable to understand and given informed consent