Do ecg changes always mean mi?

No: No. There are multiple reasons why an EKG shows 'changes'. In fact, EKG is a measure of the electrical activity of the heart, and for this reason anything that influence this can cause ekg changes (electrolytes abnormalities, temperature, microvascular problem, disease of conduction sytem, etc..., as well as poor blood supply to the heart, such in the case of MI)

Many ECG diagnoses: An ECG looks at the electrical activity of the heart. There are hundreds of different conditions and diagnoses that will create abnormalities of different types on an ecg. The classic ECG change that is associated with myocardial infarction is elevations in the st segment, but other changes can also signify an mi. Most ECG abnormalities signify other things besides mi.

No: There are many different reasons for ekg changes. Ekg measures electrical activity of the heart and this can be altered with different electrolytes or just having a damage in the circuitry itself. It's a good tool to diagnose a mi.

Ekg: No.. Most are abberations if there are no symptoms if you have chest pain see your doc or go to the er ecgs need to be interpreted along with patient exam.