Which of the following conditions is associated with large P waves on an ECG?

AIIMS Patna NO - 2020

Medical & Surgical Nursing

Hard

Appeared in: AIIMS Patna NO - 2020

Explanation

Tricuspid stenosis causes obstruction of blood flow from the right atrium (RA) to the right ventricle.
This leads to increased pressure and volume overload in the RA, resulting in right atrial enlargement.
On an ECG, right atrial enlargement manifests as 'P pulmonale', which is characterized by tall, peaked P waves with an amplitude greater than 2.5 mm in the inferior leads.
Therefore, tricuspid stenosis is directly associated with large (tall) P waves.

Option A: Mitral stenosis primarily causes left atrial enlargement due to obstruction of flow from the left atrium to the left ventricle.
Option C: Aortic regurgitation causes left ventricular volume overload. While it can lead to left atrial enlargement in advanced stages, it is not a primary or direct cause of large P waves.
Option D: Systemic hypertension increases the afterload on the left ventricle, leading to left ventricular hypertrophy and subsequently left atrial enlargement.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain ECG interpretation of P wave abnormalities in valvular heart disease as background academic context rather than a clinical decision trigger.
Identifying the type of P wave abnormality (tall vs. wide) is a crucial nursing skill in ECG interpretation, as it provides a clue to which side of the heart is affected.
Recognizing P pulmonale should prompt a nurse to assess for other signs of right-sided heart failure, such as jugular venous distension, peripheral edema, and hepatomegaly.
What if? If the question specified 'broad, notched P waves', the correct answer would be Mitral stenosis, as this is the classic description of P mitrale resulting from left atrial enlargement.

How to Approach the Question

First, understand the question is asking for the cause of 'large P waves' on an ECG. Recognize that 'large' can mean tall (amplitude) or wide (duration).
Recall or deduce the pathophysiology of each option. Think about which heart chamber is primarily affected by the pressure or volume overload in each condition.
Connect the affected chamber to the ECG finding: Right Atrial Enlargement causes tall P waves (P pulmonale), and Left Atrial Enlargement causes wide P waves (P mitrale).
Evaluate the options: Tricuspid stenosis directly affects the right atrium. Mitral stenosis, aortic regurgitation, and hypertension primarily affect the left side of the heart.
Conclude that tricuspid stenosis is the most direct cause of tall P waves (P pulmonale), making it the best answer for 'large P waves'.

Concept Tested & Keywords

Concept Tested: ECG interpretation of P wave abnormalities in valvular heart disease.
Stem keywords: ECG, large P waves
Lead-in keywords: Which
Negative lead-in flag: false

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