4.2.5 Indications for performing an echocardiogram
Echocardiography can be used to investigate cardiac structure, size and motion from these an assessment of cardiac function can be made. DE provides further information on blood flow and pressures within the chambers and great vessels.
The decision to perform an echocardiogram is usually made to:
· investigate the source and the significance of a cardiac murmur; · investigate underlying heart disease and the effects of a cardiac arrhythmia; · investigate the presence and significance of myocardial disease · investigate the presence and significance of pericardial disease; · evaluate the heart in cases in which cardiac disease is suspected but is not apparent from clinical examination, such as endocarditis in an animal with recurrent pyrexia, or myocardial dysfunction in a case of known exposure to monensin toxicity.
By far the most common of these is investigation of the source and, even more importantly, evaluation of the significance of a cardiac murmur. Although echocardiography, especially DE, is helpful to identify the source of a murmur in particular whether a murmur is functional or is related to cardiac disease, the main purpose of echocardiography is to assess the effects of the disease. The most significant feature is measurement of volume overload which results from valvular regurgitation. Salient features of the echocardiographic examination are described below. Echocardiographic features of each of the common valvular conditions are described in section 6.2.6, section 6.3.3, section 6.5.3 and section 6.6.2.