SECTION EDITORS: JEFFREY TABAS, MD; PAUL D. VAROSY, MD; GREGORY M. MARCUS, MD; NORA GOLDSCHLAGER, MD
Initial evaluation of the ECG showed sinus rhythm with regular PP intervals and QRS complexes of 2 different morphological appearances and amplitudes that occurred regularly in an alternating fashion, consistent with electrical alternans. However, closer inspection of these alternating QRS complexes revealed that one included a delta wave (Figure 2, arrows) and the other did not. This pattern is consistent with alternating conduction via an accessory pathway and the normal atrioventricular (AV) node His-Purkinje system; therefore, electrical alternans was not present.
Electrocardiographic Findings in a Young Man With Tachycardia and Hypotension—Discussion. Arch Intern Med. 2012;172(15):1126-1127. doi:10.1001/archinte.172.15.1126