In Reply:-The case we reported described the use of transesophageal atrial pacing (TAP) to drive an internal dual chamber pacemaker. This allowed normalization of a chaotic heart rate and efficient synchronization of intraaortic balloon pumping (IABP). The electrical signal generated by the TAP was sensed by the atrial wire of the internal pacemaker, which subsequently activated ventricular pacing. The electrocardiographic signal obtained consisted, then, in an atrial spike, generated by the TAP, followed by a ventricular spike, generated by the internal pacemaker. Finally, the IABP (Datascope System 90, Datascope, Paramus, NJ) was triggered in a dual-chamber pacing mode. The situation described by Roth is quite different, because the TAP has been used solely to directly trigger the IABP. Although an interesting topic, atrial pacing triggering of IABP was not the purpose of our communication. In addition, it has to be noted that, contrary to models 95 and 97, the IABP Datascope System 90 is not designed to permit isolated atrial pacing triggering. It is not surprising, therefore, that the TAP activity was not recognized by the IABP or was recognized as ventricular activity with subsequent inadequate timing. Why the Datascope System 95 did not recognize the TAP spike while in atrial pacing triggering mode in the second case reported by Roth is unclear, and does not meet our personal experience with this material.

Serge M. Broka, M.D., Department of Anesthesiology, University Clinics U.C.L. of Mont-Godinne, B-5530 Yvoir, Belgium.

(Accepted for publication October 18, 1996.)