Fast mode switching algorithms in dual chamber pacemakers are preferable to avoid high paced ventricular rates, but require special functions to prevent loss of AV synchrony and mode oscillations.
What are the optimal characteristics and programming considerations for mode switching algorithms in dual chamber pacemakers?
Fast mode switching algorithms with appropriate rate smoothing and sensing adjustments optimize dual chamber pacemaker performance in patients with paroxysmal atrial tachyarrhythmias.
Dual chamber systems are currently implanted in an increasing number of patients with a pacing indication and paroxysmal atrial tachyarrhythmias (ATAs). To avoid tracking of high atrial rates during ATA while providing AV synchronous pacing during sinus rhythm and AV block, automatic mode switching (MS) to a nontracking mode has been developed. Several concepts of MS algorithms have been introduced differing in sensitivity and specificity of ATA detection, delay between ATA onset and MS, pacing mode during MS, rapidity of MS termination upon detection of sinus rhythm, and special algorithms pertinent to MS. This review classifies and analyzes algorithms that are integrated into MS concepts and outlines considerations on optimal MS performance. Based on simulations and clinical studies, fast MS concepts avoiding high paced ventricular rates seem preferable but require special functions to avoid loss of AV synchrony by inappropriate MS. Similarly, fast return to tracking mode after ATA cessation seems preferable but requires algorithms to prevent mode oscillations. Sudden ventricular rate changes have to be avoided by rate smoothing functions, and an appropriate ventricular rate during nontracking mode has to be provided by rate responsive pacing. Programming of the device includes individual optimization of atrial sensitivity, atrial blanking times, and tachycardia detection rates. In addition, a high signal-to-noise ratio by careful atrial lead implantation, narrowly spaced bipolar atrial leads and a good sensing amplifier, together with special algorithms for atrial sensing adjustment improve the performance of MS algorithms.
Carsten W. Israel (Fri,) conducted a review in Paroxysmal atrial tachyarrhythmias with a pacing indication. Automatic mode switching (MS) algorithms was evaluated. Fast mode switching algorithms in dual chamber pacemakers are preferable to avoid high paced ventricular rates, but require special functions to prevent loss of AV synchrony and mode oscillations.