CHICAGO, Dec. 7, 2010 /PRNewswire-USNewswire/ — One
evening last March, Larry Ambrose left his bed in the middle of the
night to check the time. Much to the 71-year-old’s surprise, he was
only able to see three out of the four glowing numbers on the
digital clock in his kitchen. Ambrose returned to bed, but within
days was hospitalized for what was later diagnosed as a stroke.
After extensive testing, his physicians told him they could not
determine the cause.
Cryptogenic stroke, or stroke of undetermined cause, accounts
for 25 percent of all strokes. In many of these cases, physicians
believe atrial fibrillation may occur without the patient’s
knowledge, causing the stroke. To better understand the connection
between atrial fibrillation and stroke, Northwestern Medicine
physician researchers from cardiology and neurology have teamed up
to monitor people diagnosed with a cryptogenic strokes for
intermittent atrial fibrillation as part of a study called CRYSTAL
AF (Study of Continuous Cardiac Monitoring to Assess Atrial
Fibrillation after Cryptogenic Stroke).
During atrial fibrillation, the most common type of arrhythmia
(abnormal heart beat), the heart’s upper chambers, or atria, quiver
rather than beat; this allows blood to stay in the chamber and
potentially cause a clot. If the clot travels from the heart and
reaches the brain, a stroke is imminent. “Patients with atrial
fibrillation are at a greater risk for stroke than the general
population,” said Rod Passman, MD, medical director for the Center
for Atrial Fibrillation at the Bluhm Cardiovascular Institute of
Northwestern Memorial Hospital and associate professor of
cardiology at Northwestern University’s Feinberg School of
Medicine. “Fifteen percent of all strokes are in patients with
The CRYSTAL AF trial will enroll approximately 450 people who
have been diagnosed with a cryptogenic stroke across 55 centers.
Approximately half will be