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    5.8

    5.8

    Novacode 5.8: minor ST-T abnormalities — common, often non-specific, linked to cardiovascular risk factors.

    Code 5.8 (Novacode NC-5.8) — minor ST-T abnormalities. The ECG shows mild changes of the ST segment or T wave, such as slight ST depression, an up-sloping ST, or a flat or low T wave. They are below the thresholds of major ST-T abnormalities, and there are no pathological Q waves. This finding is common and often non-specific, but in population studies it has been linked to a moderately increased cardiovascular risk. The Minnesota equivalents are codes 4-3, 4-4, 5-3 and 5-4.

    Novacode 5Minor ST-T changesRepolarisation
    Novacode criterionST-T score ≥ 10, below major
    Minnesota equivalent4-3, 4-4, 5-3, 5-4
    Q wavesabsent or minor
    Categoryminor
    Normal ST-T compared with slight ST depression and a flat T wave and with a low positive T wave Normal normal ST-T Minor ST ST slightly ↓, flat T Low T T/R < 1/20
    Figure 1. Examples of minor ST-T abnormalities: slight down-sloping ST with flat T (middle) and low positive T (right), compared with normal (left).

    Possible causes

    • Medicines (digoxin, antiarrhythmics, antidepressants), low potassium or magnesium
    • Left ventricular hypertrophy, hypertension, early ischaemia
    • Hypothyroidism, anaemia, obesity, chronic lung disease
    • Tachycardia, hyperventilation, recent meal, posture, anxiety
    • Normal variants

    Clinical significance

    Minor ST-T abnormalities are not diagnostic of a specific disease. In large cohorts they were associated with higher rates of coronary events and cardiovascular death than in people with normal ECGs, partly because they reflect hypertension, diabetes and other risk factors. The practical consequence is to check and treat these risk factors.

    What to do

    Discuss the ECG at a scheduled visit; checking blood pressure, cholesterol, glucose and blood electrolytes is usually advisable. Seek urgent care if you have chest pain, breathlessness or fainting.

    References

    1. Rautaharju PM, Park LP, Chaitman BR, Rautaharju F, Zhang ZM. The Novacode criteria for classification of ECG abnormalities and their clinically significant progression and regression. J Electrocardiol. 1998;31(3):157–187.
    2. 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
    3. 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