Convex and Concave Morphology

BER has elevated upward sloping concave ST Segments [3]. This concave nature cannot be used as a discriminator on its own but when seen in conjunction with the other features of BER it may be of help. Pericarditis is also associated with a concave ST morphology; this ‘saddle shape’ is characteristically seen globally throughout the ECG.

It has been reported that a non-concave (i.e. convex or flat) morphology has a sensitivity of 77% and a specificity of 97% for a diagnosis of AMI. This means that a convex or flat morphology can be used as a ‘rule in’ feature for AMI but that morphology alone is a poor feature to use to ‘rule out’ AMI [6].

Do not assume that because the ST segment has a concave shape it cannot be a STEMI.

Learning bite

A convex ST segment shape is more likely to be associated with AMI than a concave shape.