Expansion
Parasternal, apical and subcostal windows, transthoracic or transoesophageal
Expansion
Standard transthoracic views
- Parasternal long axis: left ventricle, aortic and mitral valves, aortic root, pericardium
- Parasternal short axis: at valve level for the aortic valve and cusps, at papillary muscle level for regional wall motion and the “doughnut” of the left ventricle
- Apical four chamber: all four chambers, ejection fraction, mitral and tricuspid valves, and the interatrial and interventricular septa
- Apical five and two chamber: aortic outflow, and the anterior and inferior walls
- Subcostal: pericardial effusion, right ventricle, and the inferior vena cava with its respiratory collapse as a measure of filling
What it answers
- Left ventricular function, and the ejection fraction, on which heart failure treatment depends
- Valve disease: gradients, valve area, regurgitation severity
- Regional wall motion abnormalities, indicating previous infarction or ischaemia
- Pericardial effusion and tamponade, with right atrial and ventricular collapse
- Pulmonary pressures, estimated from the tricuspid regurgitant jet
- Endocarditis: vegetations, abscess, new regurgitation
- Source of embolism, intracardiac shunt, thrombus
Transoesophageal echo is used when the transthoracic study is inadequate or the question demands better resolution: prosthetic valves, suspected endocarditis with a negative transthoracic study, aortic dissection, left atrial appendage thrombus before cardioversion, and intraoperative assessment. It requires sedation and carries a small risk of oesophageal injury.
Focused bedside echo answers a narrow set of yes or no questions in the unstable patient: gross left ventricular function, right ventricular dilatation, pericardial effusion and volume status, and is not a substitute for a formal study.