What is the normal range of ECG?

As a medical professional with expertise in cardiology, I can provide you with the normal range for an ECG, which stands for electrocardiogram. An ECG is a test that measures the electrical activity of the heart and is used to diagnose various heart conditions. The normal range for an ECG includes several key parameters: 1. Heart Rate (HR): Typically between 60 and 100 beats per minute (bpm) for adults at rest. Athletes may have lower heart rates, around 40 to 60 bpm. 2. P Wave: This represents atrial depolarization and should be less than 0.12 seconds in duration and less than 2.5 small squares in height (0.25 mV) on the ECG graph. 3. PR Interval: This is the time from the start of the P wave to the start of the QRS complex, reflecting the time for electrical impulses to be conducted from the atria to the ventricles. It should be between 0.12 and 0.20 seconds. 4. QRS Duration: This is the time it takes for the ventricles to depolarize. For adults, it's normally between 0.06 and 0.10 seconds. In children, it may be slightly shorter. 5. QT Interval: This represents the time from the start of the QRS complex to the end of the T wave, which is the time for one complete heartbeat. The QT interval can vary based on heart rate and should be corrected for it (QTc). The normal QT interval is typically between 0.36 and 0.44 seconds. 6. Axis: The electrical axis of the heart's ventricular depolarization is normally between -30 and +90 degrees in lead II of the ECG. 7. T Wave: This represents ventricular repolarization and should be upright in leads I and II, and may be inverted in lead III, which is normal. 8. ST Segment: This is the period between the end of the S wave and the start of the T wave, and it should be isoelectric, meaning it should be flat and at the same electrical level as the TP segment. Please note that these are general guidelines and individual variations can occur. It's important to interpret ECG results in the context of the patient's overall health status and medical history.

Normal ECG. A normal ECG is illustrated above. Note that the heart is beating in a regular sinus rhythm between 60 - 100 beats per minute (specifically 82 bpm). All the important intervals on this recording are within normal ranges.