AF Burden
Currently, AF is classified as paroxysmal, persistent or permanent, but
treatment generally relies on a binary classification (i.e., presence or
absence of AF to determine the decision for
anticoagulation).69 A quantitative approach to define
the burden of AF has been suggested. This factors in the number of
episodes or the proportion of time a patient spends in AF during a
particular monitoring period.70 AF burden has been
noted to have a predictive value for AF-related strokes and thus, could
guide management.70,71 However, even with wearable and
implantable technologies allowing longer monitoring durations, burden of
AF is difficult to determine. Also, the minimum AF duration required for
anticoagulation is not well defined.72
Another scenario in which AF burden becomes important is SCAF. Higher AF
burden along with the traditional risk factors
(CHA2DS2-VASc score) are more likely to
benefit from oral anticoagulants than low to medium burden of AF and
without risk factors.73 A general rule of thumb for
anticoagulation, regardless of indication, is the need to maintain
efficacy while minimizing the bleeding risk.74However, the exact cut-offs are not well defined and leads to
considerable variation in management depending on the
provider.75 With advancements in wearable and
intracardiac monitoring techniques as well as their wider
availability,76 detection of SCAF is also increasing
and the knowledge gaps need to be addressed more clearly. Two highly
anticipated trials Apixaban for the Reduction of Thrombo-Embolism in
Patients With Device-Detected Sub-Clinical Atrial Fibrillation77 and Non-vitamin K Antagonist Oral
Anticoagulants in Patients With Atrial High Rate Episodes78 will likely help inform management in these
patients.
A preliminary study using DNN model has been able to assess AF burden
from 24-hour Holter monitor data.79 Although this
proves feasibility of developing the prototype, translation of such
models into clinical use would require validation and clearer guidelines
as to the importance of AF burden and duration for guiding
anticoagulation therapy.