What is the normal range for ECG?

As a medical professional with expertise in cardiology, I can provide you with information on the normal range for an ECG, which stands for electrocardiogram. An ECG is a test that measures and records the electrical activity of the heart, providing a snapshot of the heart's function at a given moment. Normal ECG Ranges: 1. Heart Rate (HR): The normal range for a resting adult heart rate is typically between 60 - 100 beats per minute (bpm). However, it's not uncommon for athletes and individuals with very good physical fitness to have a lower resting heart rate, sometimes as low as 40 bpm. 2. Rhythm: The ECG should show a regular sinus rhythm, which means that the heart's electrical activity is initiated by the sinoatrial (SA) node, the heart's natural pacemaker. 3. P Wave: The P wave represents atrial depolarization and should be upright in leads I, II, and V4-V6, and usually less than 120 milliseconds in duration. 4. PR Interval: This is the time from the beginning of the P wave to the beginning of the QRS complex. A normal PR interval is 0.12 - 0.20 seconds. 5. QRS Duration: The QRS complex represents ventricular depolarization and should be less than 120 milliseconds in duration. 6. QT Interval: The QT interval reflects the time from the start of the QRS complex to the end of the T wave, which represents ventricular repolarization. The normal QT interval varies based on heart rate and gender, but a rough guideline is that it should be less than 440 milliseconds for males and 460 milliseconds for females. 7. Axis: The mean electrical axis of the heart's electrical activity should be between 0 and +90 degrees for the QRS complex in lead I. 8. ST Segment: The ST segment should be isoelectric (flat) and not elevated or depressed more than 1 mm. 9. T Wave: The T wave represents ventricular repolarization and should be upright in leads I, II, and V4-V6. Please note: ECG interpretation can be complex and requires medical expertise. The normal values provided here are general guidelines and may vary based on individual factors and specific ECG machine settings.

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.