Data collection and AHRE detection
All patients underwent baseline clinical history-taking, 12-lead ECG
recording, chest X-ray imaging,
transthoracic echocardiography,
and blood sampling as basic examinations prior to DDD pacemaker
implantation. All of the CIEDs implanted had the capacity to record
AHREs; 32 devices were manufactured by St. Jude Medical (Saint Paul, MN,
USA), 25 devices were manufactured by Medtronic (Minneapolis, MN, USA),
18 devices were manufactured by Biotronik (Berlin, Germany), 15 devices
were manufactured by Ela Medical (Montrouge, France), and 11 devices
were manufactured by Boston Scientific (Marlborough, MA, USA). All
patients were assessed at six-month intervals after the initial device
check performed one week postimplantation. Clinical data including the
presence of AHREs during the preceding six-month period were collected
at each follow-up visit via device interrogation. An AHRE was defined as
any episode of sustained atrial tachyarrhythmia (>5 min and
>170 bpm) detected through the atrial lead (Figure
2).13 The atrial sensing threshold was set at 0.5 mV.
To detect the existence of AHRE, a cutoff of five minutes or greater was
employed in this study for the exclusion of over-diagnosis of various
atrial signals such as far-field oversensing and/or sinus
tachycardia.13 Other atrial noises were excluded by
checking the intracardiac ECGs stored in the pacemakers as much as
possible.3 We classified the study population as
patients with and without new-onset AHRE during the initial one year
after CIED implantation.