Variation in body habitus and chest wall anatomy may also sometimes account for unexpected ECG findings.That said, it is even less common to see a terminal r’ in lead V2 of an otherwise healthy adult - although it still is possible. An r’ in lead V1 ( and even incomplete RBBB ) are not necessarily abnormal findings in a small but significant percentage of otherwise young, healthy adults - since ventricular depolarization of this portion of the RV is sometimes slightly delayed relative to LV depolarization as a normal phenomenon. This means that the last component of ventricular depolarization from the viewpoint of leads V1 and V2 is directed toward the right (ie, toward the right ventricular outflow track ). The terminal r’ in leads V1 and V2 of ECG #1 in Figure-1 is subtle (!) - but it is present ( BLUE arrows in the blow-up leads from V1 and V2 ).It is especially unlikely to see such a prominent negative component to the P in V1 in an otherwise healthy younger-to-middle-aged adult - although it still is possible. That said, most of the time - the depth and width of a “normal” negative component to the P wave in leads V1 and/or V2 will not be nearly as prominent, as it is in lead V1 of ECG #1. There may normally be a negative component to the P wave in leads V1 and/or V2 - especially if atrial size and/or pressure is increased (ie, one of the ECG criteria for left atrial abnormality is a deep negative component to the P wave in lead V1 ).Re-recording the ECG in the correct position will verify or refute your suspicions. The computer will often not recognize these misplacements.Ĥ. Placement of V1 and V2 too high is very common and results in multiple mimics of pathology.ģ. Here are other cases with lead misplacement:Ģ. She had a normal echocardiogram, with normal shortening and thickening of the septum. We placed the leads in the correct position and this was the result: American Journal of Emergency Medicine 36(5):865-8. Misplacing V1 and V2 can have clinical consequences (full text). These are commonly a result of high lead placement.īrooks Walsh ( ) has a great article on this topic, though he does not discuss septal Q-waves as a result: Another clue to leads too high are the R'-waves in V1 and V2. Think about it: when lead V2 is high, all atrial depolarization (proceeding caudally) is away from the lead and thus negative. It should be upright, but it is mostly negative. How can we tell if our lead placement hypothesis is correct? With downward depolarization of the septum, it will be away from a high V2, but have a small deflection towards V2 when V2 is placed lower (correctly, just to the left of the septum). Septal Q-waves may be caused by placing leads V1 and V2 too high. The computer read was "Septal MI, age indeterminate" A middle-aged woman presented with chest pain.
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