Atrial rate variations in atrioventricular block patients: influences of ventricular rate and atrioventricular delay

Atrial rate variations (ARV) of nine atrioventricular (AV) block patients loaded with VDD pacemakers were analyzed with pacemaker-off mode, programmed at different fixed ventricular pacing rates (60, 90, 120 bpm) and with different AV delays in VDD pacing (80, 120, 160, 200 ms) to study the influences of ventricular rate and AV delay. ARV were measured by PP intervals on the atrial electrocardiogram (ECG) that was non-invasively recorded from an esophageal lead. In results, all ARV measures had no significant difference under different AV delays. Although no significant difference existed among all ARV frequency domain measures, the locations of the major powers were very diverse for different individuals under different pacing rates. However during pacemaker-off mode, the major spectral powers of ARV were centered on the band above 0.4 Hz.