THE SIGNIFICANCE OF DEEP S WAVES IN LEADS II AND III

Abstract

The ecg pattern S2S3 in which the amplitude of the S wave in leads II and III exceeds that of the R wave, in the absence of an S wave in lead I, was sought in 655 cases. These consisted of 200 healthy subjects, 20 with obesity only, 21 with emphysema, 161 with a raised systemic blood pressure, 200 with cardiac infarction, and 53 with cardiomyopathy. This distinctive ecg indicates a fault within the myocardium in the antero-lateral aspect of the left ventricle. Muscular hypertrophy alone, as in systemic hypertension, did not produce the pattern, nor did an alteration in the position of the heart as found in many of the cases with obesity or emphysema. Naturally, cardiac infarction provided the most frequent cause of the myocardial lesion, when the S2S3 pattern was usually accompanied by other cardiographic changes, but it was also common in patients with cardiomyopathy. Sometimes, the pattern was a lone index of a cardiac infarct. Exceptionally, the S2S3 pattern was a solitary abnormality in a subject without symptoms, and especially without chest pain. In these rare instances we have regarded the sign, although without pathological proof, as expressing either an impedance of conduction in a peripheral radicle of the left bundle from a small lesion or an immaterial congenital agenesis of this distal portion. In a patient with chest pain that suggests a cardiac origin the presence of this distinctive cardiographic sign, either alone or in company with changes not in the meantime universally accredited as being significant, is likely to be evidence of cardiac infarction. It is this that allocates to the S2S3 pattern an importance not generally appreciated.