Electrophysiologic evaluation in 5 patients with pre-excitation syndrome revealed highly variable accessory pathway properties, including unusual conduction blocks and multiple re-entry types.
Case Report (n=5)
Electrophysiologic evaluation reveals highly variable properties of accessory pathways in pre-excitation syndrome, which has important implications for drug and surgical management.
Electrophysiologic evaluation in five patients who exhibited manifestations of the pre-excitation syndrome and/or supraventricular tachycardia provided functional evidence that the properties of the accessory fibers may be quite variable. The unusual responses to electrical stimulation in these patients included: 1) failure to depolarize the His bundle from the site of ventricular pre-excitation; 2) supraventricular tachycardia with two types of re-entry; 3) anterograde block in the accessory pathway with intact retrograde conduction; and 4) retrograde delay or block in the accessory pathway and atrioventricular (A-V) node with intact anterograde conduction. Understanding these variations may provide important therapeutic implications regarding drug and surgical management. In addition to these anomalies in conduction over accessory pathways we demonstrated in these patients the occurrence of retrograde functional right bundle branch block and retrograde "gap" phenomenon, and ventricular reciprocation without recording intervening atrial discharge.
Zipes et al. (1974) conducted a case report in Pre-excitation syndrome and/or supraventricular tachycardia (n=5). Electrophysiologic evaluation was evaluated on Unusual responses to electrical stimulation. Electrophysiologic evaluation in 5 patients with pre-excitation syndrome revealed highly variable accessory pathway properties, including unusual conduction blocks and multiple re-entry types.