The normal P wave is inveed in lead
**Core Concept**
The P wave on an electrocardiogram (ECG) represents the depolarization of the atria. In a normal ECG, the P wave should be upright in leads II, III, and aVF, as well as in lead aVL. However, in certain leads, the P wave can be inverted due to the orientation of the cardiac electrical axis.
**Why the Correct Answer is Right**
In lead aVR, the P wave is typically inverted due to the unique orientation of the lead relative to the heart. Lead aVR is placed on the right arm and is oriented in the opposite direction of the other leads. As a result, when the atria depolarize, the electrical signal is directed away from lead aVR, causing the P wave to be inverted. This is a normal variant and is not indicative of any underlying cardiac condition.
**Why Each Wrong Option is Incorrect**
**Option A:** This is not a valid lead on an ECG.
**Option B:** Leads II, III, and aVF are typically upright in a normal ECG, not inverted.
**Option C:** Lead V1 is a precordial lead that shows the depolarization of the right ventricle, not the atria.
**Clinical Pearl / High-Yield Fact**
When interpreting an ECG, it's essential to remember that the P wave in lead aVR can be inverted in a normal individual. This is a common exam trap, and students should be aware of this normal variant to avoid misinterpreting ECGs.
**Correct Answer: D. Lead aVR.**