A 68-year-old male was brought into the Accident and Emergency Department with severe chest pain and an ECG consistent with a recent anterior myocardial infarction. According to his wife he had been experiencing pain for three days but over the previous three hours the pain had become very intense. He was diabetic. On arrival at hospital he received IV tenectoplase. Two hours after thrombolysis he dropped his blood pressure and became very breathless. On examination the heart rate was 120 beats/min and regular. The blood pressure was 80 mmHg systolic. Auscultation over the precordium revealed a pansystolic
murmur. Auscultation of the lungs revealed widespread inspiratory crackles.
What is the immediate investigation of choice to ascertain the cause of the deterioration?
a. Transoesophageal echocardiography.
b. Transthoracic echocardiogram.
c. Swann–Ganz right heart catheter.
d. Chest X-ray.
e. 12-lead ECG.
The patient has developed severe pulmonary oedema after a myocardial infarction. He also has a pansystolic murmur, indicating that he may have mitral regurgitation due to papillary muscle rupture or a ventricular septal defect. Echocardiography would be the most practical method of differentiating between the possibilities. As the patient is so unstable, a transthoracic echocardiogram is preferable to transoesophageal echocardiogram. In general, transthoracic echo is better at visualizing a VSD than transoesophageal echocardiogram; however, the latter is superior in the diagnosis of papillary muscle rupture. The indications for transoesophagel echo cardiography in routine clinical practice are listed in the table below. Swan–Ganz right heart catheterization may
also help but it is invasive and requires the patient to lie supine. Mitral regurgitation is diagnosed by demonstrating a high PCWP with large v-waves. VSD is diagnosed by demonstrating a left-toright shunt at the level of the ventricles (step up in oxygen saturation in the right ventricle).