Heart Disease Heart Attack FAQ's

Answers to Your Medical Health Questions

Heart Disease

Dr. Razavi

Hospital: When to go and What to Expect

When should you take your self to the hospital if you think you are having a heart attack?

Timing is everything1. If you think you are having a heart attack, call 911 ASAP. Do not drive yourself to the hospital or have someone else drive you. Call 911 which is different than calling an ambulance.

What is the difference between calling 911 and calling an ambulance?

There are private ambulance services that may be called to transport you to the hospital.

What can they do in the hospital to tell if you are having a heart attack?

An electrocardiogram (ECG or EKG) is a is a painless non-invasive test that measures the electrical activity of the heart. Finding out how long a wave takes to travel from one part of the heart to the next shows if the electrical activity is normal or slow, fast or irregular. It can be used to detect if damage has been done to the heart muscle and in what general area of the heart the damage may have occurred. It also detects the rate and rythym of the heart.

Blood tests are done to detect cardiac enzymes. The blood test most commonly used to confirm the existence of heart muscle damage is the creatine kinase (CK). A small fraction of the CK enzyme, CK-MB, is often measured as well. CK-MB shows an increase above normal in a person's blood test about six hours after the start of a heart attack. It reaches its peak level in about 18 hours and returns to normal in 24 to 36 hours.

Tests can measure the amount of other cardiac muscle proteins called troponins, specifically troponin T (cTnT) and troponin I (cTnI). These proteins control the mechanism which contracts or squeezes the heart muscle. Troponins specific to heart muscle can detect minor heart muscle injury ("microinfarction") not detected by CK-MB. Normally the level of these special heart enzymes in the blood is very low because these enzymes normally exist and stay inside the heart muscle cells. When the heart muscle is damaged, these enzymes are released into the blood stream. It increases significantly within several hours (on average four to six hours) of heart muscle damage. It peaks at 10 to 24 hours and can be detected for up to 10 to 14 days. Levels of these cardiac enzymes compared to normal help doctors deteremine if you have a heart attack underway and its severity.

Echocardiogram is a painless non-invasive imaging study which allows real-time imaging of the heart. It can assess how well the heart is or is not pumping. It uses high-frequency sound waves (ultrasound) to create an image of the heart . The sound waves measure the speed and direction of blood flow as well as wall motion and thickness of the heart chambers. It is commonly used for the evaluation of cardiac anatomy and physiology. It is similar to an ultrasound that is performed on pregnant women.

Cardiac catheterization is an invasive procedure used to detect the blocked arteries. See the page on operations for details.

CT coronary angiogram is a newer imaging study which may be done in some centers as a screening test for chest pains that are more atypical.

Coronary CT angiography (CCTA) has a relatively low technical burden for both the operator and patient and is quick to perform. The scanning time to acquire a three-dimensional dataset of the entire heart can take as little as 15 seconds. There are two types of CT scanners used for CCTA: electron beam computed tomography (EBCT), and multidetector row or multislice CT scanners (MDCT or MSCT). MDCT scanners are much more widely available than EBCT scanners; as a result, most CCTA procedures are currently performed with MDCT scanners. To facilitate scanning and optimize image quality, most patients undergoing CCTA with current MDCT equipment receive oral or intravenous beta blockers to slow the heart rate to less than 60 to 70 beats/min. Sublingual nitroglycerin is sometimes given immediately before the scan to achieve maximal vasodilation.

Radiation exposure DCT scanners typically have higher spatial but lower temporal resolution than EBCT, and they impart a higher effective radiation dose to the patient when used for CCTA. In comparison, the effective radiation dose is 0.04 to 0.06 mSv from a routine chest x-ray, 2.0 to 5.0 mSv from an average diagnostic x-ray coronary angiogram, and the average annual background radiation in the United States is approximately 3.6 mSv.

LimitationsThe following patient-related factors can interfere with the diagnostic quality of CCTA images:

These technical and image quality problems may be overcome with improvements in future generations of CT scanners.

Injection of iodinated contrast medium is required for both EBCT and MDCT coronary angiography. Thus, CCTA is contraindicated in patients with a history of allergy to iodinated contrast medium and relatively contraindicated in patients at high risk for contrast nephropathy (eg, diabetics with a serum creatinine concentration above 2.0 mg/dL.

How long does a heart attack patient need to stay in the hospital?

It varies depending on how complicated the case may be. In general 3 days is the average stay for an uncomplicated heart attack.