Correct!
4. 1 and 3
Lipomatous hypertrophy of the interatrial septum was previously considered a rare entity with an incidence rate of 2.2 to 8% as diagnosed with transthoracic and transesophageal echocardiograms, respectively (2). Most individuals with this condition are asymptomatic, and that is presumably the reason for its underdiagnosis. Unlike lipomas, lipomatous hypertrophy is not encapsulated and as a result is able to infiltrate myocardial fibers causing disturbances in conduction system and hemodynamics of the heart. In symptomatic patients, manifestations can include superior vena cava syndrome, cardiac arrhythmias, pericardial effusion, heart failure and sudden cardiac death (2).
Answer 2 is wrong because patients who are hypotensive from inflow obstruction respond to increasing preload and not reduction. Our patient responded well to increased preload through volume resuscitation and decreased positive end expiratory pressure. He was extubated the same day, which further improved his systemic hemodynamics. The patient received cardiac MRI to further delineate the exact nature and location of the mass, and identify locally affected structures.
The patient later confirmed that he had experienced a similar episode of syncope 15 years ago in Denver. He recalls cardiac biopsy was performed and was told it was "fat" consistent with CT Chest findings of extensive lipomatous infiltration. Pericardial takedown was attempted at that time was unsuccessful.
It is important to note that while transthoracic echocardiography can confirm the presence of a cardiac mass-like lesion, further characterization requires cardiac CT angiography or cardiac MRI (4). Characteristic features on CTA imaging include minimal to no contrast enhacement, septal location and sparing of the fossa ovalis (4). Biopsy is usually not required for diagnosis (4).
Our working theory is that the lipomatous infiltration decreased preload by compressing the inflow tracts and right atrium, compounded by increased cardiac demand due to peripheral vasodilation which resulted from the release of toxic metabolites and cytokines after torniquet removal.
Indications for treatment include marginal obstruction of superior vena cava or right atrium (5). intervention of choice is surgical excision of the lesion and septum plasty (5). Based on our experience, a decrease in preload should be especially be avoided in these patients, especially in the setting of possible inflow tract obstruction due to lipomatous infiltration.
Given the patient’s extensive infiltration, history of unsuccessful surgery in the past and dramatic response to an increased preload, surgery was not attempted. he was discharged with a course of antibiotics for osteomyelitis.
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