Radiofrequency catheter ablation of common atrial flutter: Role of the Eustachian valve

Introduction: During radiofrequency catheter ablation of a common atrial flutter between the tricuspid annulus and the Eustachian valve "septal isthmus", double potentials were recorded along the Eustachian valve, previously described as an anatomical line of conduction block between the coronary sinus ostium and the inferior vena cava. Results: Just before flutter termination, lengthening and beat to beat delay variations between the 2 components of the double potentials were correlated with simultaneous modifications of the flutter cycle length. Conclusion: The "septal isthmus" is a common pathway for the flutter wavefront and the impulse generating the second component of the double potential. It is also a good target for flutter ablation.