A 35-year-old male with history of recurrent arrhythmias presented for
pulmonary vein isolation. He underwent pre-procedural screening for
thromboembolism risk with transesophageal echocardiogram. He had an
incidental finding of a rare fenestrated membrane overlying his left
atrial appendage. Additional work-up throughout his clinical course
revealed genetic mutations in the LMNA and SNTA1 genes. There have been
no previous reported genetic mutations reported in cases with LAA
membranes.