Is cholesterol testing a good indicator of future heart problems? is an ecg a good way to measure if your heart is working properly/heart health?

Risk factors: High cholesterol is only one of the risk factors for coronary artery disease, among other risks such as diabetes, hypertension, smoking, and family history. Ecg evaluates heart rhythm and can diagnose some problems with the heart but is a very limited test. Depending on symptoms, further testing may be recommended.

No to both: Good cholesterol is one of many risk factors. Very low cholesterol is protective but not a guarantee of heart health. The majority of people who have heart attacks have "normal" cholesterol (within the normal range). The ekg is an insensitive tool, especially at rest. It's ability to detect heart disease improves during exercise (stress tests) but remains imperfect. No single test is perfect.

Cardiac status: There is no simple way of determining whether you will have future problems unless you are already in trouble. Cholesterol is but one of many risk factors and a normal ECG is good but no guarantee. You should discuss your status with your doctor who can give you an estimate of your status.