Click on image to view larger version.

Figure 1 Lewis Model of Atrial Flutter

Induced atrial flutter in a normal canine heart. The arrows illustrate the putative re-entrant pathway. I.V.C. = inferior vena cava; P.V. = pulmonary vein; S = site stimulated; S.V.C. = superior vena cava. Reprinted, with permission, from Lewis (14).