Atrial Fibrillation (AF) is the most frequently encountered cardiac arrhythmia. The degree of patient awareness varies widely, from highly symptomatic patients experiencing chest pressure, shortness of breath, dizziness to those who are completely oblivious. The perceived presence or absence of AF does does not lessen the risk of stroke. During a normal cardiac rhythm, known as a sinus rhythm, the upper chambers of the heart contract in synchronous fashion impulsing blood to the lower chambers, known as ventricles. During AF, this rhythm is lost and blood no longers flows well leading to pooling and an increased tendency to form clots (known as thrombi) inside the heart.
If thrombi occur inside the left upper chamber (left atrium) there is the very real possibility of small fragments breaking loose (emboli), and subsequently becoming lodged into the arteries that irrigate the brain resulting in a stroke. The clinical manifestations of a stroke can be devastating, and the loss of function can range from a minor speech impediment to a full blown loss of arm and leg function. The risk of stroke is contingent on a given patient’s clinical history. Prior heart failure, diabetes, and vascular disease among others can be predictive of stroke or other embolic complications [1].
While the variables that increase a person’s risk of stroke may not be able to be undone, there does exist a class of medicines known as anticoagulants which are used to “thin the blood” and lessen the likelihood of such a catastrophic event. The selection of which anticoagulant is prescribed depends on a several factors as examples, a patient’s willingness to use the drug, presence of renal insufficiency or adjunct drugs being used. For the most part, most of these agents are effective and relatively equivalent in preventing stroke [2].
In my next article I will discuss the strengths and weaknesses of the available anticoagulation drugs.
- X iong Q, Proietti M, Senoo K, L ip GY. Asymptomatic versus symptomatic atrial fibrillation: A systematic review of age/gender differences and cardiovascular outcomes. I nt J Cardiol. 2015 May 7?191:172177
- S hields AM, L ip GY. Choosing the right drug to fit the patient when selecting oral anticoagulation for stroke prevention in atrial fibrillation. J Intern Med. 2015 Mar 10. doi: 10.1111/joim.12360.