Echocardiography

Ease of use, rapid data provision, portability, and safety mean that echocardiography has become the principal investigation for a variety of cardiac conditions. A modern, transthoracic echocardiography examination combines real-time two-dimensional imaging of the myocardium and valves with information about velocity and direction of blood flow obtained by Doppler and colour flow mapping. A complete examination can be performed in most patients in less than 30 min.

Valvular heart disease—echocardiography has revolutionized the diagnosis and follow-up of patients with these conditions. Serial cardiac catheterization to assess severity and progress of valvular stenosis has been almost completely superseded by Doppler echocardiography, and the role of invasive investigation is increasingly limited to the assessment of the coronary arteries prior to revascularization.

Transoesophageal echocardiography—this is now a routine investigation in many centres. Under sedation, an ultrasound probe is passed into the oesophagus to a position behind the heart, producing excellent resolution of cardiac structures. It is used diagnostically in many emergency situations, including aortic dissection and suspected prosthetic mechanical valve dysfunction, and as an additional method of monitoring cardiac performance during cardiac and noncardiac surgery.

Other technological developments—these include (1) stress echocardiography—used to detect occult coronary disease and predict cardiac risk; (2) use of contrast agents—these improve visualization of the endocardium in patients with poor acoustic windows and allow some estimation of myocardial perfusion; and (3) real-time three-dimensional imaging—this is available on most new machines and allows detailed assessment of myocardial and valvular function.