From the Guidelines
A peaked P wave on an electrocardiogram (ECG) is primarily caused by right atrial enlargement, also known as P pulmonale, which occurs due to increased pressure or volume load on the right side of the heart, as supported by the American Heart Association electrocardiography and arrhythmias committee 1. This condition is typically characterized by a tall and pointed P wave, usually exceeding 2.5 mm in height in leads II, III, and aVF, as described in the guidelines for the standardization and interpretation of the electrocardiogram 1. The enlarged right atrium generates a stronger electrical signal during depolarization, resulting in the peaked P wave appearance.
Some common causes of right atrial enlargement include:
- Pulmonary hypertension
- Chronic obstructive pulmonary disease (COPD)
- Pulmonary embolism
- Mitral stenosis
- Congenital heart defects
When identifying peaked P waves, it's essential to consider the clinical context and look for other ECG changes that might suggest right heart strain, as recommended by the European Society of Cardiology 1. Treatment focuses on addressing the underlying cause rather than the ECG finding itself, which serves as a valuable diagnostic clue to cardiac and pulmonary conditions. Echocardiography can also be useful in the diagnosis and management of conditions leading to right atrial enlargement, as it provides information on right heart haemodynamics and can help identify alternative diagnoses 1.
From the Research
Causes of Peaked P Wave
A peaked P wave, also known as P pulmonale, is indicative of right atrial enlargement or cor pulmonale. The causes of this condition can be attributed to several factors, including:
- Pulmonary hypertension, which can lead to right ventricular enlargement and cor pulmonale 2, 3
- Parenchymal lung disease, derangements of the ventilatory drive, the respiratory pumping mechanism, or the pulmonary vascular bed 2
- Arterial hypoxemia, hypercapnia, and respiratory acidosis, which can contribute to increased afterload on the right ventricle 2
- Chronic ischemic heart disease, rheumatic mitral stenosis, and circulatory insufficiency 4
ECG Criteria for P Pulmonale
The ECG criteria for P pulmonale include:
- Increased P wave amplitude (≥2mm in lead II and ≥1mm in lead V1) 5
- P wave abnormalities, such as 'P mitrale' and 'P pulmonale', which can be indicative of left-atrial affection or pulmonary hypertension 6
Correlation with Right Atrial Enlargement
Studies have shown that P pulmonale can be used to confirm right atrial enlargement, but it is not a reliable test for diagnosing right atrial enlargement 5. The specificity of P pulmonale for detecting right atrial enlargement is high, but the sensitivity is relatively low 5. Echocardiography is important in evaluating the causes of P wave abnormalities and confirming right atrial enlargement 6, 5