リードレスペースメーカ植込みによる三尖弁乳頭筋断裂の1例

Papillary Muscle Rupture of Tricuspid Valve due to Leadless Pacemaker Implantation：Report of a Case

はじめに　本邦初のリードレスペースメーカ（LP）であるMicra（Medtronic社）は，2017年に発売されて以降多くの植込み手術が施行されている．しかしながら，LPは植込みに際し従来の経静脈ペースメーカに比べ，心室穿孔を始めとした重篤な合併症が多いことが報告されている1）．われわれはLPの再植込み術に際し乳頭筋断裂による重症三尖弁閉鎖不全（TR）と続発する低酸素症に陥った症例を経験し，手術介入によって救命しえたので報告する．

Leadless pacemaker （LP） is reported to have serious complications including cardiac tamponade and ventricular perforation during and after implantation. We report a case of severe tricuspid regurgitation （TR） caused by papillary muscle rupture and hypoxia during LP re-implantation, which required surgical intervention. The patient was an 88-year-old man who had undergone LP implantation for complete atrioventricular block 2 years before. Due to the battery depletion, the additional LP was implanted. After the procedure, he developed persistent hypoxemia despite 9 l oxygen administration. He was hemodynamically stable. On the second postoperative day, a transthoracic echocardiogram revealed papillary muscle rupture of the tricuspid valve. A bubble test was performed, which revealed a right-to-left shunt through the patent foramen ovale （PFO）. Tricuspid valve replacement and PFO closure were performed. The patient had a good postoperative course and was moved to cardiology department on postoperative day 14. We report this case with a review of the literature.