The Mechanism of Flutter Electrical Alternans

We have had the opportunity to observe the occurrence of flutter electrical alternans in which two distinct populations of flutter waves are present and which alternate in 1:1 and 2:1 patterns. The flutter alternans whether 2:1 or 3:1, was concordant with the pattern of preceding ventricular conduction (ventriculophasic variation). This concordance occurred reproducibly and remained consistent. Our example of flutter alternans probably represents mechanical artefact caused by catheter movement during ventricular mechanical systole. We reproduced this pattern consistently at a slower rate during coronary sinus pacing. These findings appear to suggest an explanation for certain types of so-called atrial flutter electrical alternans.