A Case of Iatrogenic Cor Triatriatum Dexter
Herein we present a 63-year-old male with a history of syncope secondary to sick-sinus-syndrome status post permanent pacemaker placement in 2001, who recently developed progressive exercise intolerance, lower extremity edema, and orthostatic hypotension. Workup included an echocardiogram which demonstrated normal left ventricular function, severe tricuspid stenosis with a mean gradient of 9mmHg, severe right atrial dilation, and a membrane dividing the right atrium into two chambers consistent with cor triatriatum dexter for which he was referred to our cardiac surgery clinic. A cardiac CT demonstrated no flow limiting coronary artery disease and re-demonstrated severe right atrial dilation with cor triatrium dexter anatomy.
Surgical approach was via a standard median sternotomy with central aortic and bicaval cannulation. The cavae were snared and a left ventricular vent was placed through the right superior pulmonary vein. Following initiation of cardiopulmonary bypass and antegrade cardioplegic arrest, the right atrium was explored. There was extensive fibrosis encapsulating the right atrial and right ventricular pacing leads. It appeared that this was not true cor triatriatum dexter but an anatomic match as a result of pacemaker lead fibrosis. Sharp dissection was used to unroof the leads and excise surrounding scar tissue that formed the intra-atrial septation. In the process of lead dissection a collection of caseous fluid was encountered and sent for culture. The right ventricular lead fibrosis was obstructing the tricuspid valve orifice area, leading to functional stenosis. The valve was not repairable and therefore a bioprosthetic valve was implanted in standard fashion. Given the extensive debridement required, a bovine pericardial patch augmentation of the right atrium was required to ensure unobstructed flow from both vena cavae into the atrium and across the tricuspid valve. New epicardial pacing leads were placed on the right atrium and right ventricle and tunneled to an infraclavicular pocket. The patient was uneventfully weaned from cardiopulmonary bypass, decannulated, and closed in standard fashion with stainless steel sternal wires. Total cardiopulmonary bypass time was 139 minutes with an aortic cross clamp time of 90 minutes.
The patient was transferred to the ICU and extubated the morning of post-operative day one. His post-operative course was notable for intermittent high-grade AV block, and on post-operative day nine underwent placement of a new pacemaker generator utilizing the epicardial wires placed intra-operatively. Cultures from the collection encasing the explanted endocardial leads grew Cutibacterium acnes. It is unclear if this represented a true lead infection, however, given the new bioprosthetic valve, the patient was discharged on a six-week course of IV antibiotics. He has been seen in follow-up and at two months post-op has regained sinus rhythm and is walking a mile daily without dyspnea.
Reference
Virmani, Renu, Naima Carter-Monroe, and Allen J. Taylor. “Chapter 63 - Congenital Anomalies and Malformations of the Vasculature.” In Vascular Medicine: A Companion to Braunwald’s Heart Disease (Second Edition), edited by Mark A. Creager, Joshua A. Beckman, and Joseph Loscalzo, 771–89. Philadelphia: W.B. Saunders, 2013. https://doi.org/10.1016/B978-1-4377-2930-6.00063-X.
