Far-Field R Wave Sensing Causing Prolongation of the Atrial Escape Interval of DDD Pacemakers with Atrial-Based Lower Rate Timing

Diagnostic tools for atrial tachyarrhythmias in implantable pacemakers: a review of technical options and pitfalls

BACKGROUND

Correct pacemaker (PM) diagnosis of paroxysmal atrial tachyarrhythmias is crucial for their prevention and intervention with specific atrial pacing programmes. The PM mode switch to only ventricular pacing after detection of atrial tachyarrhythmias is often used as the parameter to quantify the 'burden' of atrial tachyarrhythmias.

OBJECTIVES

This review addresses potential errors in the detection and diagnosis of atrial tachyarrhythmias, sometimes resulting in incorrect mode switches. The interpretation of PM-stored data of patients with atrial tachyarrhythmias and the results of trials of pace prevention and intervention can be better appreciated with more insight into the technical options and pitfalls.

RESULTS

Literature and clinical experience demonstrate that the correctness of PM-derived diagnosis of atrial tachyarrhythmias depends on 1) the sensitivity setting to detect the onset and perpetuation of atrial tachyarrhythmias frequently characterised by variable and low-voltage signals, 2) the rejection of far-field R wave sensing by the atrial sense amplifier, 3) the facility for verification of mode switches by a high-quality intracardiac registration of the nonmodified atrial electrogram. The configuration of the atrial lead also contributes to the diagnostic performance of the PM.

CONCLUSION

Not only pacing algorithms and diverse technical PM features but also the atrial lead configuration are currently the limiting factors to the fully reliable, automated detection and diagnosis of atrial tachyarrhythmias. If these technical shortcomings can be improved, better signal processing will result. Then atrial pacing to prevent or suppress atrial tachyarrhythmias will be more justified. (Neth Heart J 2008;16:201-10.).

Mode Switching of Dual Chamber Pacemakers from Activation of a Blanked Flutter Search Algorithm by a Single Atrial Event

The Medtronic Kappa 700 and 900 pacemaker family offers a dedicated Blanked Flutter Search algorithm specifically designed for the detection of atrial flutter. This report describes 5 cases that demonstrate how the Blanked Flutter Search algorithm can be activated in the absence of atrial tachycardia, atrial flutter, or sinus tachycardia by a single atrial event (AR) detected in the atrial refractory period of the pacemaker provided it is either preceded or followed by a sensed atrial event (AS).