Right axis deviation is seen in all except.
**Core Concept**
Right axis deviation (RAD) is a type of abnormal electrocardiogram (ECG) pattern characterized by an axis shift to the right, indicating an alteration in the electrical conduction pathway of the heart. This can be due to various underlying cardiac conditions, including ventricular hypertrophy, ischemia, or congenital abnormalities.
**Why the Correct Answer is Right**
Right axis deviation is typically seen in conditions that affect the right ventricle or the conduction system, such as right ventricular hypertrophy, pulmonary embolism, or Wolff-Parkinson-White syndrome. In these cases, the abnormal electrical activity is generated in the right ventricle, leading to a shift in the electrical axis to the right.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because left axis deviation is typically seen in conditions that affect the left ventricle or the conduction system, such as left ventricular hypertrophy or Wolff-Parkinson-White syndrome with a left-sided accessory pathway.
**Option B:** This option is incorrect because right axis deviation can be seen in conditions that affect the right ventricle or the conduction system, such as right ventricular hypertrophy or Wolff-Parkinson-White syndrome with a right-sided accessory pathway.
**Option C:** This option is incorrect because right axis deviation can be seen in conditions that affect the right ventricle or the conduction system, such as right ventricular hypertrophy or Wolff-Parkinson-White syndrome with a right-sided accessory pathway.
**Option D:** This option is incorrect because left axis deviation is typically seen in conditions that affect the left ventricle or the conduction system, such as left ventricular hypertrophy or Wolff-Parkinson-White syndrome with a left-sided accessory pathway.
**Clinical Pearl / High-Yield Fact**
Remember that right axis deviation can be a sign of underlying cardiac pathology, and it's essential to consider other ECG findings and clinical context when interpreting the results.
**Correct Answer:** D. Left axis deviation.