Bubble in the Heart
A Rare Cause of Mitral Regurgitation
A 50-year-old male patient was referred after an episode of collapse in the early hours after partying all night. At the time of presentation, findings from the general physical, neurological, and cardiovascular examinations were unremarkable other than a grade III/IV holosystolic murmur in the mitral area radiating to the axilla. No abnormality was observed on chest x-ray films and ECGs. He had twice undergone echocardiography before the current admission and was known to have a cardiac murmur related to mitral valve prolapse and mitral regurgitation. Two-dimensional (Figure 1) and color Doppler (Figure 2) echocardiography demonstrated a flail posterior mitral valve leaflet and significant mitral regurgitation. There was suspicion of an echogenic structure in the left ventricular cavity on the color Doppler images. The other valvular structures were normal. There was no evidence of any obstruction observed during left ventricular inflow and outflow. For further evaluation of the suspicious mass, contrast echocardiography was performed. This clearly showed a cystic mass attached to the ventricular aspect anterior of the mitral valve (Figure 3). Surgical excision with repair of the mitral valve was performed successfully (Figure 4). Histological examination confirmed the mass to be a giant blood cyst of the mitral valve.
Blood cysts are congenital cysts that are found on the endocardium, particularly along the lines of closure of the heart valves. Commonly identified in neonates and children, in most cases they regress spontaneously, but there have been cases of their persistence into adulthood. They are often asymptomatic but may be associated with a variety of presentations, such as embolization, obstruction, and regurgitation. Consensus is lacking with respect to the optimal management of blood cysts and has ranged from surgical excision to serial monitoring, with resection reserved for only symptomatic cysts. The low echogenicity of the cyst could have precluded diagnosis on routine 2-dimensional and color Doppler echocardiography. However, imaging improvement of the tissue-blood interface by contrast echocardiography enables easy identification of such structures.
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