Smallness or Absence of Initial Positive Deflections in the Precordial Electrocardiogram and Cardiac Infarction

QS- and QR-Pattern in Leads V 3 and V 4 in Absence of Myocardial Infarction: Electrocardiographic and Vectorcardiographic Study

“…Occurrence of a QS pattern or of a significant Q wave in leads V3 and V4 and on some occasions even in leads V5 and V6, in the absence of myocardial infarction, has been demonstrated in cases of left ventricular hypertrophy,1' , 12,14,15,28 hypertrophy or dilatation of the right ventricle8 10, 12, 13, 19-22, complete or "incomplete" left bundle branch block, 16' 17, 18, 23-26 right bundle branch block,23 and displacement of the heart. 15 In his study of electrocardiograms which may be mistaken for myocardial infarction, Myers emphasized the occurrence of these patterns on several occasions. It seems to be justifiable to suspect that in many instances myocardial infarction has been diagnosed incorrectly on the basis of a QS, QR or QRS pattern in the precordial leads.…”

“…On several occasions a given electrocardiographic QRS complex was designated by some observers as rS while others preferred to call the same complex QS. In order to determine the error which might be due to this factor of difference in interpretation, 15 is good. The material selected for this study contains only cases in which all authors of this paper felt that there was no initial R wave in leads V3 or V4.…”