Every year, nearly 800,000 people in the United States alone suffer a stroke. The vast majority of these strokes are ischemic strokes, in which blood flow is blocked, and the brain is denied the full supply of oxygen it needs to perform all of its life-sustaining functions. While the serious long-term disabilities that result from ischemic strokes are associated with the brain, embolic strokes originate outside the brain – often in the heart.
Approximately one-third of ischemic strokes occur in patients who have an abnormal heartbeat condition known as atrial fibrillation, or Afib for short. Healthy hearts beat in an even rhythm. With each contraction, blood moves from the atria to the ventricles, then to the rest of the body. In Afib hearts, faulty electrical signaling disrupts this flow. The heart beats too quickly and blood clots form, creating the conditions for a stroke.
Physicians can diagnose Afib with an EKG and treat Afib with medication or minimally invasive procedure. However, there is a need for tools to help doctors more accurately predict a patient’s risk for stroke – and to know which treatment plan to pursue depending on a patient’s risk profile. Adding to the uncertainty, another 30% of ischemic strokes are characterized as cryptogenic, a category that includes embolic stroke of undetermined source (ESUS). In these cases, a person will experience a stroke with no history or indication of Afib.
