Leftsided flutter in a healthy heart

Patient

22-year-old male with no prior history; emergency hospitalization for palpitations;

Trace

This tracing shows a regular tachycardia of 170 bpm; the QRS complexes are narrow allowing eliminating the diagnosis of ventricular tachycardia; there is a noteworthy electrical alternation (alternation between 2 QRS with identical axes but with different amplitudes); the atrial activity is difficult to identify, complicating the differentiation between an atrial tachycardia and a junctional tachycardia (intranodal reentry or reentry over an accessory pathway);

Trace

Flash administration of an Adenosine ampule was used to facilitate the diagnosis; the slowing of the ventricles allows demonstrating a regular atrial tachycardia at a rate identical to that of the ventricles of the preceding tracing; the atrial activity is monomorphic, fragmented and positive in V1; there is no pattern of common flutter in the inferior leads; these elements suggest the diagnosis of atrial tachycardia/left flutter;

Exergue

A leftsided atrial flutter pattern (reentry in the left atrium) is reflected on the electrocardiogram by 1) the presence of a rapid, ectopic, regular and monomorphic activity, 2) the presence of an atrial, mostly positive, depolarization in V1, 3) a lack of sawtooth pattern in the inferior territory.