Rare case of dual-loop biatrial tachycardia involving epicardial connections between the right-sided pulmonary venous carina and right atrium

Introduction: There are only a few reports of atrial flutter related to the epicardial connections, referred to as an “intercaval bundle.” Methods: A 71-year-old man was referred for ablation of recurrent atrial flutter. Results: Three-dimensional electroanatomical mapping of the left atrium showed two different earliest activation sites inside the right pulmonary vein isolation line. Subsequent mapping of the right atrium showed that the earliest site was on the posterior side of the superior vena cava. Application of radiofrequency energy at the carina stopped the tachycardia. Conclusion: The tachycardia circuit was assumed to be a dual-loop reentry involving the intercaval bundle.