From the Guidelines
A peaked P wave on an EKG is a significant finding that typically suggests right atrial enlargement, often called P pulmonale, which can occur in conditions like chronic pulmonary disease, pulmonary hypertension, or congenital heart defects affecting the right side of the heart. This finding is significant because it may indicate increased right atrial pressure or workload. The increased amplitude occurs because the enlarged right atrium generates a stronger electrical signal during depolarization. According to the American Heart Association electrocardiography and arrhythmias committee, council on clinical cardiology 1, a tall upright P wave in lead II (greater than 2.5 mm) is characteristic, often with a peaked or pointed appearance.
Key Points to Consider
- Normal P waves should be upright in lead II, less than 2.5 mm in height, and less than 120 ms in duration.
- Abnormally tall or peaked P waves (greater than 2.5 mm in height) suggest right atrial enlargement.
- Right atrial abnormality increases the amplitude of the initial P-wave forces, contrasting with the increase in the later P-wave forces that can result from left atrial abnormality (pseudo-P pulmonale) 1.
- The ECG may provide a signal of hemodynamically significant pulmonary hypertension (PH), with right ventricular hypertrophy and right-axis deviation on ECG seen in 87% and 79%, respectively, of patients with idiopathic pulmonary arterial hypertension (IPAH) 1.
Clinical Implications
When identifying peaked P waves, it's essential to assess other EKG findings and correlate with clinical symptoms, as this finding should prompt further cardiac and pulmonary evaluation to determine the underlying cause and appropriate management. Certain features of the ECG in patients with an established diagnosis of PAH may have prognostic value, such as a P-wave amplitude in lead II of ≥ 0.25 mV, which is associated with a 2.8-fold greater risk of death over a 6-year follow-up period 1. Therefore, a peaked P wave on an EKG should be taken seriously and prompt further investigation to determine the underlying cause and guide management decisions.
From the Research
Significance of a Peaked P Wave on an Electrocardiogram (EKG)
- A peaked P wave, also known as P-pulmonale, is a sign of right atrial enlargement or strain, often related to pulmonary disease or pulmonary hypertension 2, 3, 4.
- The traditional criterion for P-pulmonale is a P-wave amplitude ≥2.5 mm in leads II, III, and aVF, but this has been questioned as being of limited value due to insensitivity 2.
- Studies have shown that P-wave amplitude and vector are dynamic and can reflect reduced right atrial strain once an acute exacerbation of COPD subsides 2.
- The specificity of P-pulmonale for detecting right atrial enlargement is high, but the sensitivity is relatively low, suggesting that it can be used to confirm right atrial enlargement but not as a reliable test for diagnosing it 3.
- P-wave abnormalities, including peaked P waves, have prognostic implications and should trigger the search for associated conditions such as pulmonary hypertension, coronary artery disease, or valvulopathies 4.
Relationship to Pulmonary Hypertension
- Pulmonary arterial hypertension can lead to right ventricular hypertrophy and diastolic dysfunction, causing inhomogeneous atrial conduction and increased P-wave dispersion 5.
- P-wave dispersion has been shown to be an electrocardiographic parameter that can be used to predict atrial arrhythmias and has been linked to functional capacity and invasive and non-invasive haemodynamic parameters in patients with pulmonary arterial hypertension 5.
Genetic Loci Associated with P-Wave Morphology
- Genome-wide association studies have identified several genetic loci associated with P-wave duration and P-wave terminal force, which may serve as predictors for atrial arrhythmias 6.
- Some of these loci have been linked to overall atrial conduction, while others have identified distinct phases of atrial conduction, and may aid in identifying new targets for drugs that modify atrial conduction or treat atrial arrhythmias 6.