Diagnosis

Diagnosis

When a patient comes to the hospital with chest pain, the following diagnostic steps are usually taken to determine any heart problems, and, if present, their severity.

• The patient will report all symptoms so that a health professional can rule out either a non-heart problem or possible other serious accompany conditions.
• An electrocardiogram (ECG) reading is taken, which records the waves made the heart. It is the key tool for determining if heart problems are causing chest pain and, if so, how severe they are.
• Blood tests showing elevated levels of certain factors (troponins and CK-MB) indicate heart damage. (The doctor will not wait for results, however, before administering treatment if a heart attack is strongly suspected.)
• Imaging tests, including echocardiogram and perfusion scintigraphy, help rule out a heart attack if there is any question.

Electrocardiogram (ECG)

An electrocardiogram (ECG or EKG) measures and records the electrical activity of the heart. The waves measured by the ECG correspond to the contraction and relaxation pattern of the different parts of the heart. Specific waves seen on an ECG are named with letters:

• P. The P wave is associated with the contractions of the atria (the two chambers in the heart that receive blood from outside).
• QRS. The QRS is a series of waves associated with ventricular contractions. (The ventricles are two major pumping chambers in the heart.)
• T and U. These waves follow the ventricular contractions.

Click the icon to see an image of a normal sinus rhythm.

Doctors use a term called the P-Q or P-R interval, which is the time taken for an electrical impulse to travel from the atria to the ventricle.

The most important wave patterns in diagnosing and determining treatment for a heart attack are called ST elevations and Q waves.

Elevated ST Segments: Heart Attack. Elevated ST segments are strong indicators of a heart attack in patients with symptoms and other indicators. They suggest that an artery to the heart is blocked and that the full thickness of the heart muscle is damaged. When this finding coincides with a heart attack, the condition is sometimes referred to as either as a Q-wave myocardial infarction or a STEMI (ST-segment elevation myocardial infarction). STEMI heart attacks are very severe and usually have complete artery blockage. ST-elevations are strong indicators for aggressive treatments (thrombolytic drugs or angioplasty) to reopen blood vessels. (ST segment elevations do not always mean the patient has a heart attack. Also, some patients do not have elevated ST segments. Other factors are important in making a diagnosis.)