Does an ECG / EKG rule out all cardiac problems?
No. ECG/EKG (electrocardiogram) is the recording of the electrical activity of the heart. Only those disorders which have produced an abnormality in the electrical activity of the heart can be detected on ECG. Whole lot of tests are there to detect other cardiac abnormalities, but the common ones are X-ray chest, echocardiography (ultrasound imaging of the heart), stress ECG, Holter (24 hour ECG monitoring), cardiac enzymes, cardiac catheterisation and angiography.
ECG/EKG: Test recording the electrical activity of the heart
Echocardiogram: Ultrasound imaging of the heart
Cardiac enzymes: Enzymes released into the blood when there is a damage to heart muscle, usually used in detection of heart attack
Cardiac catheterisation: Introducing small tubes called catheters into the heart through blood vessels to study the structure and function of the heart
Angiography: Injection of contrast material into the blood vessel and recording the images using X-rays or other equipment. Dyeless angiography without injecting contrast material is possible with magnetic resonance imaging.