Hisian Electrogram
Pronunciation: HIZ-ee-an
A specialized recording that captures electrical activity from the His bundle. Used for precise assessment of atrioventricular conduction and localization of conduction delays.
Full Definition
A Hisian electrogram is a specialized intracardiac recording obtained from a catheter positioned at the His bundle, located at the superior aspect of the interventricular septum. This recording displays the characteristic A-H-V pattern, representing atrial activation, His bundle depolarization, and ventricular activation respectively. The His electrogram is essential for differentiating the levels of atrioventricular conduction delay or block, distinguishing between atrial, nodal, and infra-Hisian conduction abnormalities. Normal A-H intervals range from 50-120 milliseconds, while H-V intervals typically measure 35-55 milliseconds. Hisian recordings are crucial during ablation procedures near the AV node and for diagnosing complex conduction disorders. The technique requires precise catheter positioning and careful signal interpretation.
Usage
Usage note: Named after Wilhelm His Jr. Essential for precise conduction system assessment.
In Context
- "The Hisian electrogram revealed prolonged A-H conduction consistent with AV nodal disease." — electrophysiology study report
- "His bundle recordings were monitored throughout the slow pathway modification procedure." — procedural documentation