Normal ECG Value Ranges
May 22, 2022
Source: Cainiu Health
Dr. Li Man
Introduction
Normal Adult ECG Values:
- P wave duration: 0.08–0.11 seconds; amplitude: < 0.25 mV.
- PR interval: 0.12–0.20 seconds.
- QRS complex duration: 0.06–0.10 seconds;
- In lead V₁, R/S ratio < 1.0;
- In leads V₅ and V₆, R/S ratio > 1.0;
- In leads V₃ and V₄, R/S ratio = 1.0.
Electrocardiography (ECG) is a commonly performed clinical test, characterized by its simplicity, speed, convenience, and cost-effectiveness. It is primarily used to diagnose conditions such as arrhythmias, myocardial ischemia, and electrolyte imbalances. What, then, are the normal reference ranges for ECG parameters?
Normal ECG Parameter Ranges
Normal adult ECG values:
• P wave duration: 0.08–0.11 seconds; amplitude: < 0.25 mV.
• PR interval: 0.12–0.20 seconds.
• QRS complex duration: 0.06–0.10 seconds;
– In lead V1, R/S ratio < 1.0;
– In leads V5 and V6, R/S ratio > 1.0;
– In leads V3 and V4, R/S ratio = 1.0.
• Normal q wave amplitude: < 1/4 of the R-wave amplitude; duration: < 0.04 seconds.
• ST segment: Isoelectric (i.e., aligned with the baseline).
• T wave: Amplitude must be ≥ 1/10 of the corresponding R-wave amplitude and ≥ 1.5 mV in height.
• QT interval: 0.32–0.44 seconds.
The QT interval is measured from the onset of the QRS complex to the end of the T wave, and normally falls within 0.36–0.44 seconds; in females, it may extend up to 0.46 seconds. The QT interval includes the ST segment. ST-segment depression should generally not exceed 0.05 mV, while ST-segment elevation should not exceed 1.1 mV—except in precordial leads, where the upper limit is 0.3 mV.
The above outlines the standard normal reference ranges for ECG parameters. We hope this information is helpful to you. Wishing you good health and happiness!
