Management of Far‐Field R Wave Sensing for the Avoidance of Inappropriate Mode Switch in Dual Chamber Pacemakers: Results of the FFS‐Test Study

Abstract

Individual adjustment of the PVAB significantly reduces the incidence of inappropriate mode switch due to FFS.

Use of an Atrial Lead with Very Short Tip-To-Ring Spacing Avoids Oversensing of Far-Field R-Wave

“…Far-field R-wave signals remained stable in their coupling intervals and amplitudes during a three months observation period in a previous study [8]. Considering the pathophysiology of far-field R-wave formation [24], we believe that our results are likely to be valid also in a mid-term follow-up provided that major atrial and ventricular remodeling or cardiac disease progression does not occur.…”

“…Based on previous published results the incidence of inappropriate mode switch due to FFS is 5% among patients with individual optimization of the PVAB [8]. Given a significance level of 5%, a power of 80%, and the lower limit of the observed 95% confidence interval exceeding −10%, a total of 75 complete data sets per group were calculated to determine non-inferiority.…”

“…However, this decision making is highly dependant on the reliability of the data provided by the device. Far-field R-wave sensing (FFS) has been identified as the most common cause of inappropriate mode switch in dual chamber pacemakers [7], [8]. False positive mode switches can result in a loss of atrioventricular synchrony in atrioventricular block and can cause impaired hemodynamics, potential proarrhythmic effects, and pacemaker syndrome.…”

“…Current strategies to avoid inappropriate mode switch from DDD(R) to DDI(R) mode and to optimize the quality of stored data include the programming of a reduced atrial sensitivity [9], [10] or the individual adjustment of the postventricular atrial blanking period (PAVB) [8], [10]–[12]. Each of these strategies encounters its own problems.…”

“…Reducing the atrial sensitivity runs the risk of undersensing during atrial tachyarrhythmias [13], [14] and can therefore end in an underestimation of the atrial tachyarrhythmia burden. Adjusting the PVAB – although highly effective in avoiding inappropriate mode switch [8], [10]–[12] – encounters some extra time for individual optimization of the parameter in follow-up visits and it is not devoid of tachyarrhythmia misclassification as a 2∶1 lock-in of atrial signals may occur with atrial flutter [15].…”