Figure 8.

(A) Patient with acute myocardial infarction at subacute stage with V₁–V₆ Q waves and correctly placed precordial leads (A.1). Small changes of leftward misplacement of V₃–V₆ electrodes (A.2) cause significantly modified QRS morphology with qR in V₆. According to classical nomenclature, the first ECG (A.1.1) would be interpreted as necrosis spreading to low lateral wall, and the second ECG (A.1.2) as no recorded spreading. A.2: Patient with inferolateral infarction (R ≥ S1 in V₁) and QR in V₆ (A2.1). After slight rightward displacement of the precordial leads, the QR pattern in V₆ disappears. B.1: ECG of a healthy 45‐year‐old man with V₆ > V₅ voltage, which obliges us to review the placement of these two electrodes. B.2: Interchange between the two black colored electrodes, V₅ and the ground lead (IEC), which imitates interchange between V₆ and V₅. In this case, we can observe the loss of S in V₅ that is present in V₄ and V₆.