Atrial flutter may occasionally be intermittent. Three examples of this phenomenon are shown here. The upper strip is from a 63 year old female. It demonstrates several short bursts of atrial flutter. The first P wave on the strip appears to be a sinus P wave. It is followed by several (probably 4) flutter waves. The next sinus beat, preceding the third QRS complex, is also followed by a series of flutter waves which terminate spontaneously.
The middle tracing is from a 75 year old male. It shows sinus rhythm with frequent atrial premature beats, some of which initiate short bursts of atrial flutter. The wide QRS complexes suggest right bundle branch block and are aberrantly conducted supraventricular beats.
The lower tracing demonstrates atrial flutter with variable AV block that terminates spontaneously and then resumes after a single sinus beat. The two wide QRS complexes that resemble right bundle branch block are aberrantly conducted beats.