A Case of Iatrogenic Cor Triatriatum Dexter

A sixty-three-year-old man recently developed progressive exercise intolerance, lower extremity edema, and orthostatic hypotension. He had a history of syncope secondary to sick-sinus-syndrome status post permanent pacemaker placement in 2001. A 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. A cardiac CT demonstrated no flow limiting coronary artery disease and redemonstrated severe right atrial dilation with cor triatrium dexter anatomy.  

The 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. Extensive fibrosis encapsulated the right atrial and right ventricular pacing leads. It appeared that this was not true cor triatriatum dexter but rather an anatomic match resulting from 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. Also, the valve was not repairable; 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 then 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 ninety minutes. 

The patient was then transferred to the ICU and extubated the morning of postoperative day one. His postoperative course was notable for intermittent high-grade AV block, and on postoperative day nine he underwent the 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. At two months post-op, he had regained sinus rhythm and was walking a mile daily without dyspnea.

References

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.

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