Analysis of Atrial Sensed Far‐Field Ventricnlar Signals: A Reassessment

Abstract

Accurate detection of the spontaneous far-field ventricular signal may be used to determine the ventricular activation, and hence, the interval from atrial stimulus to the ventricular R wave (AR interval) using a standard atrial pacing lead. This can be useful in developing a physiological atrial rate responsive (AAIR) pacemaker and in further improving DDD(R) pacing algorithms. In order to better characterize the atrial sensed far-field ventricular signal, 200 consecutive patients undergoing pacemaker implantation were studied. The amplitude of the far-field ventricular signal was significantly smaller than that of the atrial deflection. In all recordings, the slew rate of the atrial deflection was larger than that of the far-field ventricular signal. Subdivision of the recordings by electrode position, pocket location, or QRS duration on the surface ECG resulted in significantly different signal characteristics. The amplitude and slew rate of the far-field ventricular signal were significantly smaller in bipolar versus unipolar sensing. Atrial sensed far-field ventricular recordings could also be obtained in the case of ventricular pacing. Our results indicate that accurate sensing of the far-field ventricular signal from an atrial pacing lead is conceivable in most patients. The different signal characteristics in relation to parameters, such as electrode position, sensing mode, and pocket location, may be useful in determining the optimal conditions for signal sensing.

Atrial Near‐Field and Ventricular Far‐Field Analysis by Automated Signal Processing at Rest and During Exercise

“…1,2 We could not show a significant difference between the two lead positions; however, near-field to far-field ratio tended to be worse with a lead position in the atrial appendage. The effect of alternative atrial stimulation sites on ventricular far-field sensing has still to be investigated.…”

“…Our study supports previous findings that a bipolar configuration is superior in rejecting ventricular far fields depending on the programmed sensitivity. 1,3,10,14 …”

“…[1][2][3]4,6 Several investigators have also reported a decrease of atrial signal amplitude during exercise. [7][8][9] This, however, is not confirmed by more recent data.…”

The Pathophysiologic Basis of Fractionated and Complex Electrograms and the Impact of Recording Techniques on Their Detection and Interpretation

“…However, usually the surface ECG is recorded simultaneously with atrial or ventricular signals, which allows detection of the ventricular component in the atrial recording. 17 More complex and disturbing during atrial recordings may be deflections caused by remote activation in other parts of the atrium, as discussed in the next section. Infarcted myocardium also is notorious for remote complexes caused by activation in healthy surrounding myocardium.…”

The Effect of Bipole Tip-to-Ring Distance in Atrial Electrodes upon Atrial Tachyarrhythmia Sensing Capability in Modern Dual-Chamber Pacemakers

“…Oversensing as well as undersensing also cause adverse device behavior such as induction of atrial pacing therapies and inappropriate tracking of atrial arrhythmias, respectively. [5][6][7] Optimal sensing is therefore crucial in standard pacemakers, cardiac resynchronization devices, and dual-chamber and atrial implantable cardioverter defibrillator systems. In order to prevent 2:1 blanked undersensing of atrial tachyarrhythmias a short post-ventricular atrial blanking period (PVAB) (50 ms or less) is often required.…”