Giant left atrial V-waves in post-myocardial infarction ventricular septal defect

A 54-year-old man developed a post-myocardial infarction ventricular septal defect with a 4:1 shunt. The first cardiac catheterization showed left atrial V-waves of 70 mm Hg. Assessment of the presence or absence of mitral regurgitation was not possible because of ventricular irritability and rapid runoff from left ventricle to right ventricle. At the second catheterization two months later, the left atrial V-waves had fallen to 34 mm Hg. The absence of mitral regurgitation was shown by observing the time difference in appearance of indocyanine green in the right ventricle and the left atrium after left ventricular injection. The defect was repaired by right ventriculotomy with subsequent normalization of left atrial V-waves. This case shows that very large left atrial V-waves may occur in postinfarction ventricular septal defects without mitral regurgitation and that these V-waves may decrease with time, probably reflecting increased left atrial compliance.