Undetected paroxysmal atrial fibrillation in chronic heart failure patients: is it clinically relevant to catch the atrial phantom?

Abstract

Chronic heart failure (CHF) is frequently accompanied by atrial fibrillation (AF). How often AF occurs in CHF patients is difficult to know since many episodes come and go undetected because of lacking symptoms. Therefore, assessing the total burden of AF calls for continuous rhythm monitoring. At present, we do not know whether assessing burden of AF is clinically relevant. Furthermore, we do not know whether AF has any impact on survival in CHF patients, since previous clinical studies show conflicting results. Caldwell et al. 1 shed light on this issue by retrospectively studying cardiac resynchronization therapy device downloads in 162 patients with CHF in order to address two questions. First, what is the prevalence of asymptomatic paroxysmal AF (PAF) in CHF patients? Secondly, what is the subsequent effect on mortality, thrombo-embolism and all-cause hospitalizations? They defined AF as a mode-switch event with an atrial rate >200 bpm for a minimum of 30 s. Using medical records, patients were divided into four groups: (i) patients who remained in sinus rhythm (SR), (ii) patients in chronic AF, (iii) patients who were known to have paroxysmal AF (known PAF), and (iv) patients thought to be persistently in SR in whom episodes of AF were newly identified (new PAF). One quarter of patients developed new PAF but AF burden was low. During the mean follow-up period of 424 days, no statistically significant differences in outcome between the SR, new PAF, and known PAF patients were found. There was, however, a trend towards higher mortality in patients with new PAF which matches with an important observation in the Euro Heart Survey on AF in which patients with first documented AF had higher mortality than patients with known PAF or persistent AF.2 Similarly, Pozzoli et al. 3 showed that new onset AF in a previously … *Corresponding author. Tel: +31 43 387 50 93, Fax: +31 43 387 51 04, Email: hjgm.crijns{at}mumc.nl