Atrial Fibrillation: What You Know, What You Think You Know, and What We Need to Know

Abstract

Atrial fibrillation (AF) has fascinated physicians for over a century, even before the invention of the electrocardiogram. However, it was not until the last few decades that a very intense investigation of it has been undertaken, including research into AF’s epidemiology, pathophysiology, management and outcomes. Unfortunately, all too many clinicians now think that they “understand” AF, especially how best to treat patients who have it.
So, let’s examine what is known. It is clear that AF increases with age and mostly occurs in those over 65 years old. It is associated with increased morbidity and mortality, especially in certain subgroups, eg, heart failure. Appropriate anticoagulation can reduce stroke risk. Men seem to be more prone to AF than women, although the reason for this is not known. Tachycardia-mediated cardiomyopathy can result with prolonged rapid ventricular rates during AF, but it is not clear just how fast the rate must be and for how long for this to occur. AF can recur quickly (IRAF) or soon (ERAF) after cardioversion, but other than some general concepts it is often difficult to predict in whom this will occur.
Well, what do many think they know? As with most disorders having multiple treatment options, “expert opinion” tends to develop on at least two sides of the issues, and AF is no exception. Examples are: rate vs rhythm; level of anticoagulation in CHADS 1 patients; need for sinus rhythm in heart failure; drugs vs ablation; PVI vs multiple other lesions in AF; and even whether triggers or substrate or more important in various forms of AF. Regardless of the often evangelical stands of each side, the truth is there are no “one size fits all” answers to any of these issues.
Now we need to focus on what we need to know to be able to prevent and appropriately treat patients with AF. The most important question about AF lacks an answer-why does it occur in a specific person at a particular point in time. Sure, hypertension is a frequent fellow traveler with AF, but most patients with hypertension do not get AF and patients with AF who have the same BP each day may only get an episode once or twice a year. We need to pour more research money and time into uncovering the mechanism of AF in humans. Likewise, it is important to gain more knowledge on the need for sinus rhythm, and the best approach to maintain it, in a variety of patient subgroups. Stroke is devastating, but so is a major intracranial bleed, and our rather simplistic approach to who needs anticoagulation requires far more refinement.
Thus, in my opinion we have reached the top of the mountain, but only to view the rest of the mountain range ahead of us.