The significance of low voltage of the QRS complex in precordial leads: Comparison with low voltage in limb leads

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The significance of low voltage of the QRS complexes in the limb leads of the electrocardiogram has been discussed by many observers. 1 There can be little question that, in many instances, low voltage complexes are a result of severe myocardial disease. However, this is by no means always so, for complexes which are definitely below the accepted limits of normal are often observed when there is only slight myocardial involvement, and even when the heart is normal. Although Willius and Killins 2 attributed to myocardial disease the low voltage which they found in 32 per cent of 140 cases, they feel that low voltage which is unassociated with other graphic abnormalities neither indicates serious myocardial disease necessarily, nor, ipso facto, is of serious prognostic import. The diagnosis of myocardial disease, although it may be suggested, cannot be made positively upon the evidence of low voltage alone. As far as we are aware, the literature contains no study of the significance of low voltage of the QRS complexes in precordial leads. The lack of correspondence between the amplitude of different precordial leads and that of the limb leads is well recognized. 3, 4, 5 Usually, low voltage in the limb leads, even when it results from severe myocardial disease, is accompanied by normal voltage in the precordial leads. Much less frequently have we observed that low voltage was present in both limb and precordial leads. The present study is an attempt to evaluate the factors which are responsible for this agreement, and the significance of curves in which the voltage of the QRS complexes is low in both limb and chest leads.