ATRIAL BRADYCARDIA:     Rhythm originating in the atrium at a rate of < 55 beats per minute. (These rates reflect the rate of atrial beats and not necessarily the rate of the ventricular beats (e.g., There may be atrial fibrillation with a rapid ventricular response indicating the atrial rate is > 350 bpm, and […]

ATRIAL COUPLET:     Two (2) premature atrial complexes in a row.

ATRIAL FIBRILLATION:     Rhythm originating in the atrium at a rate of > 350 beats per minute. (These rates reflect the rate of atrial beats and not necessarily the rate of the ventricular beats (e.g., There may be atrial fibrillation with a rapid ventricular response indicating the atrial rate is > 350 bpm, and […]

ATRIAL FLUTTER:     Rhythm originating in the atrium at a rate of 250-350 bpm. (These rates reflect the rate of atrial beats and not necessarily the rate of the ventricular beats (e.g., There may be atrial fibrillation with a rapid ventricular response indicating the atrial rate is > 350 bpm, and the ventricular rate […]

ATRIAL QUADRIGEMINY:     Premature atrial complexes (PACs) occurring every fourth beat.

ATRIAL RUN:     Three or more premature atrial complexes (PACs) in a row.

ATRIAL TACHYCARDIA:     Rhythm originating in the atrium at a rate of 100-250 beats per minute. (These rates reflect the rate of atrial beats and not necessarily the rate of the ventricular beats (e.g., There may be atrial fibrillation with a rapid ventricular response indicating the atrial rate is > 350 bpm, and the […]

ATRIAL TRIGEMINY:     Premature atrial complexes (PACs) occurring every third beat.

ATRIAL TRIPLET:     Three (3) premature atrial complexes (PACs) in a row.