AH interval

AH interval

Cardiology A period measured by electrophysiologic studies of the heart, equal to the time between the onset of the first rapid atrial deflection and the His bundle deflection; as the lower right atrium and the His bundle delineate the anatomic boundaries of the AV node, the AHI–usually 55-130 msec is essentially equivalent to the AV nodal conduction time; the AHI is ↓ by atropine and isopreterenol, and ↑ by adenosine, digitalis, some class I antiarrhythmics–eg, moricizine, propranolol, rapid or premature atrial pacing, vagal maneuvers, and verapamil. Cf HV interval.