Some patients with syncope have a disorder of cardiac conduction and benefit from implantation of a pacemaker. Electrophysiological testing can help to identify these patients. 

Patient selection: syncope


Outcome: permanent pacing


Indications from electrophysiologic testing - one or more of the following:

(1) prolonged His-ventricular (HV) interval in milliseconds (HV >= 70 ms)

(2) induction of atrioventricular block by atrial pacing

(3) intra- or infrahisian atrioventricular block during class I drug (procainamide, ajmaline, other) administration

(4) prolonged HV interval (HV >100) during class I drug (procainamide, ajmaline, other) administration


The sensitivity of electrophysiologic testing for patients requiring a pacemaker is about 70%, with additional patients identified on follow-up (which involves placement of an implantable loop recorder).

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