Noninvasive Diagnosis and Treatment of Atrial Flutter Utilizing Previously Implanted Dual Chamber Pacemaker

Patients with previously implanted dual chamber pacemakers (PM) may develop atrial flutter (AFL). The Siemens‐Pacesetter AFP and Genesis PM have the capability of noninvasively synchronizing to a standard external electrophysiology (EP) stimulator. Any arrhythmia termination or induction protocol may be used with a refractory period limitation of approximately 127 msec (472 ppm). The PM stimulation sequence is directly controlled by the APS Model 370EP Programmer which acts as an interface between the PM and EP stimulator. All testing is conducted with the PM functioning in a single chamber mode. The external EP stimulation is detected by the programmer and a 37 KHz coded radio frequency transmission is used to control the PM stimulation in a 1:1 fashion. Real‐time intracardiac electrograms (IEG) can be recorded from either the atrial (A) or ventricular lead. The IEG can be used for: (1) hard‐copy for diagnosis and cycle length determination; (2) monitoring during and after the procedure; and (3) a synchronization signal to the EP stimulator. Two patients presented with three episodes of AFL with A rates ranging from 220–290 bpm. An A‐IEG was obtained in each case to document the exact rhythm and rate. Rapid A pacing from 300–340 ppm was accomplished using a standard external rapid A pacemaker in concert with the 370EP programmer and PM. In two episodes, the AFL accelerated to transient A fibrillation followed by spontaneous conversion to sinus rhythm (SR). In the other episode, the AFL converted directly to SR. We conclude that: (I) AFL can be easily terminated noninvasively utilizing this system; (2) IEG telemetry (particularly of A activity) via PM is valuable in the diagnosis of rhythm disturbances; and (3) this system allows the utilization of standard stimulation protocols to assess AV conduction and interrupt tachyarrhythmias.