1.22
Code 1.22 — Minnesota Code 1-2-2: moderate Q/QS wave by duration. This code is assigned when the Q wave lasts 0.03–0.04 s in the leads of one anatomical region. Such a Q wave is wider than a normal septal q but does not reach the 0.04-s threshold of a major Q wave. It indicates a possible or probable previous myocardial infarction, especially when T-wave or ST-segment changes are present in the same leads.
What the code means
Q-wave duration is the most reproducible Q-wave measurement. Between 30 and 40 ms lies a "grey zone": some people have such Q waves without heart disease, while in others they are the trace of a limited infarction. The T wave often helps: a Q wave of this width together with an inverted or flat T wave in the same leads makes previous infarction considerably more likely.
Criteria by lead group
| Region | Leads examined | Code 1-2-2 criterion |
|---|---|---|
| Anterolateral | I, aVL, V6 | Q duration ≥ 0.03 and < 0.04 s in lead I or V6 |
| Posterior (inferior) | II, III, aVF | Q duration ≥ 0.03 and < 0.04 s in lead II |
| Anterior | V1–V5 | Q duration ≥ 0.03 and < 0.04 s in any of V2–V5 |
About T-wave changes
The T wave is the most labile wave of the ECG. Low-amplitude or inverted T waves can result from many causes — ischaemia, hypertrophy, electrolyte disorders, medicines, hyperventilation, posture or even a meal — so they are interpreted together with the Q wave and the clinical picture. A combination of a moderate Q wave with T-wave inversion in the same territory is treated as a probable sign of previous infarction.
Next steps
- Compare with previous ECGs; repeat the ECG with correct electrode placement.
- Echocardiography to look for regional wall-motion abnormalities.
- Risk-factor assessment and, if indicated, stress testing or coronary imaging.
if the change is new and accompanied by chest pain, breathlessness, sweating or fainting.
References
- Prineas RJ, Crow RS, Zhang ZM. The Minnesota Code Manual of Electrocardiographic Findings. 2nd ed. London: Springer; 2010. doi:10.1007/978-1-84882-778-3
- Thygesen K, Alpert JS, Jaffe AS, et al. Fourth universal definition of myocardial infarction (2018). Eur Heart J. 2019;40(3):237–269. doi:10.1093/eurheartj/ehy462
- Rautaharju PM, Surawicz B, Gettes LS. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part IV: the ST segment, T and U waves, and the QT interval. Circulation. 2009;119(10):e241–e250. doi:10.1161/CIRCULATIONAHA.108.191096
This article is for general information and does not replace a consultation with a doctor. ECG findings must be interpreted by a physician together with symptoms and other tests.
Published on 14 May 2019