Electrocardiogram (ECG) showing Lown-Ganong-Levine syndrome

This syndrome is characterized by a short PR interval (<0.12 seconds) and a normal QRS complex due to rapid atrioventricular conduction.

The normal P wave in sinus rhythm is slightly notched since activation of the right atrium precedes that of the left atrium. The P wave is upright in a positive direction in leads I and II. A P wave with a uniform morphology precedes each QRS complex. The rate is between 60 and 100 beats per minute and the cycle length is uniform between sequential P waves and QRS complexes. In addition, the P wave morphology and PR intervals are identical from beat to beat.