Diagnostic criteria for left atrial abnormality and right atrial abnormality
Diagnostic criteria for left atrial abnormality and right atrial abnormality — based on ECG findings
Diagnostic criteria for left atrial abnormality (LAA) and right atrial abnormality (RAA) — mostly based on ECG findings, since that’s the classic framework.
Left Atrial Abnormality (LAA)
(reflects LA enlargement or delayed conduction through LA)
ECG Criteria
- P wave in lead II
- Broad, notched (“P mitrale”)
- Duration >120 ms (0.12 s)
- Notch between the two peaks ≥40 ms
- P wave in lead V1
- Biphasic P wave with terminal negative portion ≥1 mm deep and ≥40 ms wide
- Negative component area >40 ms·mm (Morris index)
- Axis: May be leftward.
- Other: Often seen in mitral valve disease, LV diastolic dysfunction, hypertension.
Right Atrial Abnormality (RAA)
(reflects RA enlargement or hypertrophy)
ECG Criteria
- P wave in lead II
- Tall, peaked “P pulmonale”
- Height >2.5 mm in inferior leads (II, III, aVF)
- P wave in lead V1
- Tall initial positive component (>1.5 mm)
- Other leads: P wave >1.5 mm in V1–V2 may support diagnosis.
- Axis: Rightward P wave axis (>75°) possible.
- Common causes: Pulmonary hypertension, tricuspid stenosis/regurgitation, congenital heart disease.
Quick Comparative Table
| Feature | Left Atrial Abnormality (LAA) | Right Atrial Abnormality (RAA) |
|---|---|---|
| P wave morphology | Broad, notched (“P mitrale”) | Tall, peaked (“P pulmonale”) |
| Lead II | Duration >120 ms, notched | Height >2.5 mm |
| Lead V1 | Wide/deep terminal negative part (≥1 mm, ≥40 ms) | Tall initial positive part (>1.5 mm) |
| Axis | May shift leftward | May shift rightward |
| Common causes | Mitral stenosis, HTN, LV diastolic dysfunction | Pulmonary HTN, tricuspid disease, congenital shunts |
1. Which ECG feature is most characteristic of Left Atrial Abnormality (LAA)?
Broad, notched P wave in lead II (“P mitrale”) is typical of LAA.
2. A biphasic P wave in V1 with a deep, wide terminal negative portion suggests:
LAA produces a broad terminal negative deflection of the P wave in V1.
3. Right Atrial Abnormality (RAA) is best indicated by:
RAA manifests as “P pulmonale” – tall, peaked P waves in inferior leads.
4. Which P wave feature in V1 supports RAA?
RAA produces a tall, initial positive component of the biphasic P wave in V1.
5. LAA is commonly associated with which valvular lesion?
Mitral stenosis leads to chronic LA pressure overload → LAA.
6. P pulmonale is most often caused by:
Pulmonary hypertension → RA pressure overload → P pulmonale.
7. Duration of P wave >120 ms in lead II indicates:
Prolonged P wave duration suggests delayed LA activation (LAA).
8. A notched P wave in lead II is classically called:
Broad, notched P wave in lead II is termed “P mitrale”.
9. Which condition does NOT typically cause RAA?
Mitral stenosis is more associated with LAA, not RAA.
10. Morris index refers to:
Morris index = area of terminal negative P wave in V1; >40 ms·mm indicates LAA.
11. Which P wave height in inferior leads supports RAA?
RAA: P pulmonale is defined as P wave height >2.5 mm in II, III, aVF.
12. Which atrial abnormality often coexists with systemic hypertension?
Systemic hypertension → LV diastolic dysfunction → LAA.
13. Which atrial abnormality is more likely in chronic obstructive pulmonary disease (COPD)?
COPD → pulmonary hypertension → RAA (P pulmonale).
14. A tall initial P deflection in V1 is termed:
P pulmonale = tall P waves from RAA.
15. The classic “double-humped” P wave in II suggests:
Double-humped/notched P wave = P mitrale = LAA.
16. A P wave with tall amplitude and narrow base is typical of:
RAA produces tall, peaked P wave (P pulmonale).
17. Which ECG feature differentiates LAA from RAA?
LAA = prolonged P duration; RAA = increased P amplitude.
18. Which condition may cause biatrial abnormality (both LA and RA changes)?
Mixed mitral + tricuspid disease → enlargement of both atria.
19. The terminal negative P component in V1 ≥40 ms wide and ≥1 mm deep suggests:
Terminal negative deflection in V1 = hallmark of LAA.
20. Which atrial abnormality shows P wave axis deviation to the right (>75°)?
RAA can shift P axis rightward, reflecting RA dominance.
