Introduction
Atrial fibrillation (AF), the most frequently encountered clinical
cardiac arrhythmia, is associated with increased mortality and morbidity
rates, largely due to thromboembolic complications and heart failure.
Clinically detecting AF in the early phase is significantly important
for avoiding such events but it is not always easy to do so,
particularly in cases of asymptomatic AF. Although repeated
electrocardiogram (ECG) recording or 24-hour ambulatory ECG monitoring
are considered useful in detecting AF in the early phase, their
sensitivities as such detection tools are totally
limited.1 Recently, continuous rhythm monitoring with
cardiac implantable electronic
devices (CIEDs) has been used to diagnose brief episodes of arrhythmia
including paroxysmal AF, which are recorded as atrial high-rate episodes
(AHREs), particularly in the absence of clinical evidence of
AF.1 By using this approach, new-onset atrial
tachyarrhythmia/AF can be diagnosed earlier in patients with CIEDs in
comparison with in those without CIEDs.
Previous reports have demonstrated that a prior history of heart
failure, the presence of sick sinus syndrome (SSS), and the existence of
a large left-atrial volume index
(LAVI) were independent predictors for new-onset AHRE in patients with
CIEDs.2 Furthermore, new-onset AHRE in patients with
CIED has been linked to increased risks of stroke, systemic embolism,
and worsening heart failure.3–5 As such, predicting
new-onset AHRE following CIED implantation in patients without a history
of AF is key to obtaining good patient outcomes.
P-wave dispersion (PWD), a well-known ECG parameter and predictor of AF,
is defined as the difference between the maximum and the minimum P-wave
durations detected on the body-surface 12-lead ECG.6,7Previous studies have suggested that longer PWD may be associated with
AF occurrence following cardiac surgery, AF recurrence after conversion,
and the appearance of the first AF episode or/and paroxysmal
AF.7–10 Furthermore, it was reported that PWD could
be a sensitive and specific ECG marker for the risk of AF occurrence
with a cutoff value of 40 ms for the identification of patients with a
history of paroxysmal AF.6 However, the connection
between PWD and new-onset AHRE in patients with CIED remains largely
unexamined. In the present study, we therefore sought to elucidate
clinical factors including PWD that are associated with silent AHRE in
CIED patient population.