Published online by Cambridge University Press: 05 July 2014
Echocardiography is an important part of cardiovascular imaging and presents the events in motion as they occur in real life. It utilises sonographic principles, and can be non-invasive, i.e. trans thoracic echocardiography (TTE), or semi-invasive, i.e. transoesophageal echocardiography (TOE).
The technology of ultrasound has evolved over the last century and is now so advanced that in many ways the images are so clear that they are almost as good as direct observations of the heart.
TTE has become an invaluable tool for elucidating derangements in cardiac morphology and physiology. The results can allow surgery to proceed and guide best intra-operative care for high-risk patients. Appropriate post-operative care can be planned in advance and complications anticipated.
The indications for pre-operative TTE are surgery specific, and patient specific. Surgery specific indications for TTE are:
All patients undergoing cardiac surgery. Some operations (e.g. mitral valve surgery, endocarditis surgery) also require TOE
Operations where large blood loss or major intra-operative cardiovascular changes are expected (e.g. aortic surgery).
Patient-specific indications for pre-operative TTE are too many to discuss in detail. However, they can be grouped as follows:
Patients with undiagnosed or symptomatic heart murmurs
Patients with known heart murmurs but increasing symptoms
All patients with congenital heart disease must have a recent TTE or TOE (unless they have had cardiac MRI)
Advanced coronary artery disease listed for major elective surgery
All patients with symptoms of heart failure (breathlessness, high jugular venous pressure, extensive pedal oedema)
All patients with history of paradoxical embolism.