Far‐Field QRS Complex Sensing Via the Atrial Pacemaker Lead. II. Prevalence, Clinical Significance and Possibility of Intraoperative Prediction in DDD Pacing.

Abstract

To study the prevalence and significance of far-field QRS complex sensing via unipolar atrial electrodes, we attempted to provoke this phenomenon postoperatively in 119 patients with DDD pacemakers. It occurred in 42 patients (35%), with different types of atrial electrodes. In 27 cases with documented far-field QRS complex sensing, selection of an adequate atrial amplifier sensitivity eliminated the problem; in the remaining 15 cases, other program adjustments were necessary. In all patients DDD pacing could be maintained, and no reoperations were required. In a retrospective analysis of a subgroup of 26 patients, all having received endocardial unipolar carbon tip electrodes in the right atrial appendage, the possibility of predicting subsequent far-field QRS complex sensing was studied. The occurrence thereof was not significantly related to patient age or sex, indication for pacing, or routinely obtained electrophysiological measurements. Potential far-field QRS complex sensing via the atrial electrode is significantly common in patients with DDD pacemakers. Patient characteristics and intraoperatively measured intraatrial signal amplitudes are not useful in predicting the postoperative occurrence of the phenomenon. As a rule, it can be handled effectively by pulse generator reprogramming.

Incessant atrioventricular dissociation due to far-field QRS oversensing and recurrent mode switch in a dual chamber pacemaker

“…Far-field QRS are oversensed in one third of patients implanted with DDD pacemakers using unipolar atrial leads and high atrial sensitivities (0•7 mV), but prevalence is decreased with reduced sensitivities (only 2% with 2 mV) [6,10] . Mean far-field QRS amplitudes of 0•9 to 1•6 mV and of 0•3 to 0•6 mV have been reported using unipolar and bipolar atrial leads respectively [6,9] .…”

Devices for Cardiac Resynchronization

“…The dominant cause of spurious mode switching is oversensing of far-field R-waves (FFRW) [93,94,95,96,97]. Detection of atrial tachyarrhythmias results in reversion to a nontracking mode (DDI or VDI).…”

Morphology‐Enhanced Atrial Event Classification Improves Sensing in Pacemakers

“…The algorithm consists of two basic elements: a learning phase and a classification phase. Since morphology and timing of FFRWs differ depending on patients' anatomy, lead characteristics and position, 10,15,[17][18][19] a learning phase is needed in each patient to acquire individual reference FFRW characteristics. 13 In this study, segments 0-3 h, 6-9 h, 12-15 h, and 18-21 h of each 24-hour Holter recording were used for learning, the remainder for classification.…”