What is the normal range for the ST segment?

As a medical professional with expertise in cardiology, I can provide you with information on the normal range for the ST segment in an electrocardiogram (ECG). The ST segment is a crucial part of the ECG that represents the period between the end of the atrial depolarization and the beginning of the ventricular repolarization. It is typically measured from the J point, which is the junction between the QRS complex and the ST segment, up to the beginning of the T wave. The normal range for the ST segment is quite specific and can vary based on the lead being observed on the ECG. Generally, the ST segment should be relatively flat and isoelectric (at the same electrical level as the baseline). Elevations or depressions of the ST segment can be indicative of various cardiac conditions. For the limb leads (I, II, III, aVR, aVL, aVF), the ST segment is usually at the baseline level and should not deviate more than 0.5 to 1 mm (0.05 to 0.1 mV) above or below the baseline. For the chest leads (V1 to V6), the ST segment may normally show a slight concave upward elevation, especially in leads V2 to V4, and should not elevate more than 1 mm (0.1 mV) in men or 1.5 mm (0.15 mV) in women. It's important to note that the ST segment can be influenced by factors such as heart rate, body position, and the presence of other medical conditions. Any significant deviation from the normal range should be evaluated by a healthcare professional for proper diagnosis and management.

In electrocardiography, the ST segment connects the QRS complex and the T wave and has a duration of 0.005 to 0.150 sec (5 to 150 ms). It starts at the J point (junction between the QRS complex and ST segment) and ends at the beginning of the T wave.