An electrocardiogram (ECG) is a common heart health test, but a normal result doesn't guarantee a healthy heart. The electrical system is measured by ECG, but it cannot detect blockages or structural ...

An electrocardiogram, or ECG, is a standard test that records your heart’s electrical activity – offering a quick and painless way to identify irregular heart rhythms and other potential issues. But ...

In a “normal” electrocardiogram (ECG), the transition of the QRS axis in the precordial leads occurs between leads V 3 and V 4 (i.e., there is a dominant S in V 3 and a dominant R in V 4).