A 64-year-old man with known congenitally corrected transposition of the great arteries (ccTGA), a permanent pacemaker for second-degree atrioventricular block, and prior MI presented with progressive exertional dyspnea, peripheral edema, and hypoxemia.
Transthoracic echocardiography demonstrated atrioventricular and ventriculoarterial discordance consistent with ccTGA. The morphologic right ventricle, which was in the systemic position and located on the left, appeared dilated and hypertrophied with moderately reduced systolic function. The systemic tricuspid valve showed moderate regurgitation and was mildly apically displaced, suggestive of Ebstein-like morphology. The subpulmonary morphologic left ventricle, situated on the right, exhibited preserved size and contractility. The left atrium was markedly dilated.
Given the persistence of low-grade fever, transesophageal echocardiography was performed to assess for possible endocarditis. Incidentally, a quadricuspid pulmonary valve was identified, composed of four distinct cusps of approximately equal size, without evidence of vegetations or significant regurgitant flow (Figure 1). Supplementary Video 1 is a short cine loop of the short-axis view on transesophageal echocardiography.
Quadricuspid pulmonary valve is an extremely rare congenital anomaly, with only isolated case reports described in the literature and an incidence considered markedly lower than that of quadricuspid aortic valve. Its association with ccTGA has not, to our knowledge, been previously reported.1,2 The coexistence of these two rare anomalies raises intriguing questions regarding shared embryological mechanisms and underscores the necessity for comprehensive imaging in patients with complex congenital heart disease.