Understanding The Critical Connection Between AFib and Stroke
As a clinical AI (Artificial Intelligence) company focused on early disease detection, one of our early focus areas was the link between atrial fibrillation (AFib) and risk of stroke [1]. In the US, AFib may be responsible for over 70,000 strokes yearly [2]. One of our goals is to help provider organizations identify undiagnosed cases of AFib so providers can manage and reduce their patients’ long-term health risks.
What is AFib and How Does it Relate to Stroke?
AFib is characterized by a quivering or chaotic heartbeat, stemming from the heart’s upper chambers, which disrupts the heart’s effectiveness and rhythm. This erratic pattern hampers the atria from emptying fully, causing blood to pool and form clots. When an AFib-related clot breaks free, it can travel to the brain causing an ischemic stroke – one of the gravest complications linked to the arrhythmia. In fact, research indicates AFib underlies approximately 20% of all strokes [3].
The increased Stroke Risk in AFib Patients
For patients with AFib, the risk of stroke increases based on other factors like age, hypertension, diabetes and prior stroke – all considered in the CHA2DS 2-VASc scoring system. A score of 2 or greater indicates the need for stroke prevention therapy. For patients with multiple risk factors, annual stroke risk may exceed 5% without intervention.
Preventing Stroke in AFib Patients
Standard treatment involves blood-thinning medications to prevent clots. Options include warfarin and direct-acting anticoagulants (DOACs) like apixaban and rivaroxaban. Warfarin requires frequent monitoring but has long been effective. DOACs have overtaken warfarin in guidelines due to their fixed dosing and lack of routine monitoring needs.
Catheter ablation is also an option for certain patients. This procedure uses radiofrequency energy or cryotherapy to scar or destroy heart tissue, disrupting abnormal electrical signals.
For patients where AFib is the sole or primary stroke risk factor, successful ablation to eliminate AFib episodes may obviate the need for long-term anticoagulation in many cases. While not proper for all AFib patients, catheter ablation provides another pathway to stroke prevention by potentially curing the underlying arrhythmia when medications fail.
Another newer option, for those unable or unwilling to take anticoagulants, is left atrial appendage closure. This involves implanting a device via catheter to seal off the area where 90% of AFib-related clots form. Studies show it significantly reduces stroke risk, comparable to anticoagulants, for eligible patients. Clinicians may calculate and review a patient’s HAS-BLED score to determine if anticoagulants present a major bleeding risk.
A Commitment to Combatting Stroke Through AFib Management
Through early detection of previously undiagnosed AFib cases and risk stratification tools, our goal is to help more at-risk patients access life-saving preventative care. By empowering clinicians with these insights, we hope to reduce the number of strokes attributed to untreated cardiac arrhythmias. With the right management, patients need not live in fear of future neurological events.
[1] Atrial flutter also creates stroke risk. Our discussion of AFib risks also applies to atrial flutter.
