It is important to recognize cardiogenic shock due to mechanical complications of MI. In this case, pulmonary artery catheterization with oximetry shows stepped-up oxygen saturation in the right ventricle and pulmonary artery that usually occurs with VSR. Although acute mitral regurgitation may cause stepped-up saturations on oximetry, it is usually seen in the peripheral pulmonary arteries and is associated with giant V waves on pulmonary artery tracings. Cardiac rupture usually has a very abrupt course with chest pain, syncope, and sudden death, whereas ventricular aneurysm or pseudoaneurysm alone may not cause a new-onset systolic murmur. VSR usually occurs after 2 to 5 days of acute MI but may also occur in the first 24 hours after MI. Echocardiography with color flow imaging can confirm the diagnosis.
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Seminars in Medical Practice
Hospital Physician Board Review Manuals
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