If the terminal component of the diphasic P wave in lead V1 is larger and wider, what condition is indicated?

If the terminal component of the diphasic P wave in lead V1 is larger and wider, what condition is indicated?

• A. Right atrial enlargement
• B. Left ventricular hypertrophy
• C. Left atrial enlargement
• D. Cardiac ischemia

Answer: (C)

A larger and wider terminal component of the diphasic P wave in lead V1 is an indicative sign of left atrial enlargement. This alteration in the P wave morphology occurs because when the left atrium is enlarged, it takes longer for the electrical impulse to travel through this enlarged muscle, resulting in a delayed activation and a more pronounced terminal portion of the P wave.

In the context of left atrial enlargement, the morphology of the P wave changes primarily due to the increase in volume of the left atrium, which can be caused by conditions such as mitral valve disease or chronic hypertension. Clinicians often look for specific patterns in the EKG to provide valuable insights into structural changes in the heart, and the noted characteristics of the P wave in V1 serve as a fundamental diagnostic tool in assessing atrial size and functionality.