Vectorcardiography in myocardial infarction.

Standard limb leads and unipolar electrocardiography can provide valuable information in the diagnosis of myocardial infarction but there are occasions when the cardiographic changes are inconclusive. It may be difficult to differentiate between pericarditis and myocardial infarction. The electrocardiographic changes in posterior or lateral infarction are not always characteristic. It is not always possible to decide whether there has been a fresh infarct superimposed on (a) a previous infarct, (b) left ventricular hypertrophy, or (c) bundle-branch block. An unusual anatomical position of the heart can lead to great difficulties in the interpretation of electrocardiographic changes. The introduction of improved cathode ray oscilloscopes has led to a renewed interest in vectorcardiography and a hope that, either alone or in conjunction with electrocardiography, it might throw fresh light on the diagnosis of myocardial infarction. Up to the present, however, there have been conflicting opinions as to its comparative value.