R94.31

Abnormal ECG (R94.31): what the ECG shows, common abnormal findings and what happens next.

Abnormal electrocardiogram (ICD-10 R94.31) is a code used when an ECG shows a finding outside the normal range, before or without a final diagnosis. The ECG records the electrical activity of the heart from 12 viewpoints and reflects the heart rate and rhythm, conduction of the impulse, the size and thickness of the heart chambers, blood supply of the heart muscle, and the effects of electrolytes and medicines. An abnormal ECG is therefore not a disease in itself: it can be a harmless normal variant, or the first sign of serious heart disease. Its meaning depends on symptoms, examination and previous ECGs.

ICD-10 R94.31ECGCardiac screening

Standard ECG12 leads, 10 seconds

Compare withprevious ECGs

Computer readingmust be confirmed by a physician

Interpret withsymptoms and examination

Figure 1. Components of a normal ECG beat. Abnormal findings can involve any of them: rhythm and rate, the P wave, PR interval, QRS complex, ST segment, T wave or QT interval.

Common groups of abnormal findings

Rhythm and rate: tachycardia, bradycardia, atrial fibrillation or flutter, extrasystoles
Conduction: AV block, bundle branch or fascicular block, pre-excitation (WPW), long or short QT
Ischaemia and infarction: ST elevation or depression, T-wave inversion, pathological Q waves
Chamber enlargement: left or right ventricular hypertrophy, atrial enlargement
Electrolytes and medicines: peaked T waves in high potassium, U waves in low potassium, effects of digoxin and antiarrhythmics
Other: pericarditis, pulmonary embolism, Brugada pattern, low voltage, technical errors (misplaced electrodes, movement)

What happens next

Computer interpretations are helpful but can over- or under-call abnormalities, so a physician should review the tracing. Comparison with older ECGs shows whether a change is new. Depending on the finding, further tests may include blood tests (electrolytes, troponin, thyroid), echocardiography, Holter monitoring, exercise testing or cardiac imaging. Many findings, especially in athletes and young people, are normal variants.

Call emergency services

for chest pain, severe breathlessness, fainting or very fast or very slow heartbeat, whatever a previous ECG showed.

References

Kligfield P, Gettes LS, Bailey JJ, et al. Recommendations for the standardization and interpretation of the electrocardiogram: part I: the electrocardiogram and its technology. Circulation. 2007;115(10):1306–1324. doi:10.1161/CIRCULATIONAHA.106.180200
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

This article is for general information and does not replace a consultation with a doctor. Diagnosis and treatment must be decided by a physician on the basis of symptoms, examination and tests.

Published on 23 March 2019