Atrial cycle length alternans during typical atrial flutter: What is the mechanism?

Atrial Tachycardia with Cycle Length Alternans

“…The differential diagnosis for NCT with alternating CL includes a regularly irregular AT, [1][2][3][4][5][6] orthodromic atrioventricular (AV) reciprocating tachycardia (AVRT) using 2 distinct retrograde accessory pathways, [6][7][8][9][10][11][12][13][14][15] and atypical AV nodal re-entry tachycardia (AVNRT) with multiple retrograde AV nodal pathways. [16][17][18][19][20][21][22][23][24][25] Multiple supraventricular tachycardias with multiple re-entry circuits are also relatively common in a patient during EPS.…”