[Echocardiography in pulmonary embolism]

Transthoracic echocardiography rarely confirms a diagnosis of pulmonary embolism by visualizing a thrombus in the pulmonary artery or right heart chambers. However, easily observed morphological and Doppler abnormalities may result from acute pulmonary hypertension: dilatation of the right heart chambers, a very sensitive and reliable sign of severe pulmonary embolism when the ratio of the right/left ventricular dimension > 0.6: abnormal interventricular septal contraction, a very specific sign of massive pulmonary embolism, and increased systolic pulmonary artery pressure. Transthoracic echocardiography allows evaluation of the severity of pulmonary embolism but it is difficult to orientate treatment on Doppler echocardiographic data alone. Transoesophageal echocardiography is a sensitive, specific and well-tolerated investigative method for the detection of proximal emboli in patients with massive pulmonary embolism. The investigation is rapid and can be carried out at the bedside, allowing confirmation of the diagnosis in two thirds of cases and the institution of thrombolytic or surgical therapy without the need for pulmonary angiography. Doppler echocardiography is also useful for following up the haemodynamic changes and the regression of acute cor pulmonale after thrombolysis.