Use of a Modified, Commercially Available Temporary Pacemaker for R Wave Synchronized Atrial Pacing in Postoperative Junctional Ectopic Tachycardia

Abstract

Junctional ectopic tachycardia (JET) is a life-threatening arrhythmia frequently seen after surgical correction of congenital heart defects. This study evaluates the use of a modified, commercially available temporary dual chamber pacemaker used to reestablish AV synchrony by R wave synchronized atrial pacing, a technique not routinely applied because of a lack of appropriate equipment. Ten consecutive children with postoperative JET (median maximum heart rate 185, range 130-240 beats/min) age 0.3-45 (median 5.2) months were studied. R wave synchronized atrial pacing was performed using the VAT mode with inverse connection of the pacing wires (effectively AVT mode), short postventricular atrial refractory period (100 ms), and long AV (effectively VA) delay. AV delay was adjusted to achieve maximum increase in arterial pressure by optimal AV resynchronization. Pacing was successfully applied in all patients for a median period of 29 (range 10-96) hours until tachycardia cessation and led to an immediate increase in systolic, mean, and pulse pressure by 8.9 +/- 3.2 (P < 0.001), 8.1 +/- 4.0 (P < 0.001), and 11.9 +/- 7.8% (P < 0.005), respectively. Two patients developed pacemaker-mediated tachycardia, which could be easily stopped by AV (effectively VA) delay prolongation. Atrial flutter was induced in one patient by asynchronous atrial pacing during the VAT (effectively AVT) mode and managed by overdrive pacing. In conclusion, R wave synchronized atrial pacing could be easily performed using a modified, commercially available temporary dual chamber pacemaker. Significant hemodynamic benefit was achieved due to optimal AV resynchronization at intrinsic heart rate and spontaneous ventricular activation sequence. R wave synchronized atrial pacing should be included in the standard management protocol of postoperative JET.

Standardized training for AVT pacing in paediatric patients with postoperative junctional ectopic tachycardia

“…AVT pacing, as described by Janoušek et al ., is an innovative and effective pacing technique in paediatric patients suffering from postoperative JET (Entenmann and Michel, ; Haas et al, ; Janoušek et al, ). However, the method is complex in its technical details, and the implementation of AVT pacing remains challenging (Entenmann et al, ).…”

“…Changes in heart rate occur gradually in postoperative JET (Kohli et al, ; Kovacikova et al, ; Laird et al, ; Walsh et al, ). Any sudden rise in the junctional heart rate up to the selected maximum tracking rate of the pacemaker is highly suspect for pacemaker‐induced tachycardia; this can easily be managed by increasing the VA delay or pausing the pacemaker (Janoušek et al, ). Our study demonstrates that a short course of training is sufficient to improve the ability of paediatric intensive care nurses to determine the typical complications associated with AVT pacing.…”

“…In the currently applied technique described by Janušek et al ., AVT pacing is performed by switching the temporary pacing wires of the patient at the inputs of the temporary pacemaker (Janoušek et al, ). Thus, the pacemaker senses signals from the ventricles via the atrial channel and stimulates the atria via the ventricular channel (Entenmann and Michel, ).…”

“…If AP–VS intervals become too short, close or simultaneous contractions of atria and ventricles may occur, recognized as pressure peaks in the central venous pressure curve. An inordinate increase in AP–VS intervals, on the other hand, may trigger pacemaker‐induced tachycardia (Entenmann and Michel, ; Janoušek et al, ).…”

“…It functions by stimulating the atria triggered by the preceding chamber complex (QRS complex). , Janoušek et al (2003 introduced a commercially available pacemaker modified to enable R-wave synchronized AP and thereby established the currently used standard technique of this pacing mode.…”