What is Sudden Cardiac Death?
Heart attack survivors may be at risk of Sudden Cardiac Death (SCD). A heart attack can damage heart tissue causing your heart to misbehave electrically. Abnormal and dangerously fast electrical signals, or arrhythmias limit your heart's ability to pump blood to the body and brain.
Most patients have no obvious symptoms of SCD so it is important to be familiar with the possible risk factors. Risk factors may include:
- Previous Heart Attack: A heart attack is a mechanical problem with the plumbing of your heart. A blockage in one of the arteries nourishing your heart prevents blood and oxygen from reaching your heart muscle, therefore part of your heart tissue dies.
- Impaired Pumping Function of the Heart Muscle: The pumping function of your heart or "ejection fraction" after a heart attack may be impaired. This is due to scarring of the tissue of your heart due to the heart attack.
- Rapid Heart Rhythms: You could experience a very brief period of short bursts of fast heartbeats called nonsustained ventricular tachycardia (VT). These rapid heartbeats may or may not be noticeable to you. Nonsustained VT is often the precursor to SCD.
- Early identification is key. If you are at risk it is important to talk to your doctor.
If you have had a heart attack, your doctor may perform one or more of the tests below to make a diagnosis.
- Echocardiogram - The Echocardiogram will determine your heart's pumping function or "ejection fraction". During this test, ultrasound waves are bounced off your heart muscle to provide a moving image. Based on the results of this test your doctor will determine if further testing is needed.
- Holter Monitoring - A Holter Monitor is an external monitor that is worn on a 24-hour outpatient basis. The monitor records your heart's electrical activity including any episodes of arrhythmia. Your doctor will analyze the recording to see if there are any abnormal rhythms, either rapid or slow or irregular.
- Electrophysiology (EP) Testing - EP testing is commonly conducted in an electrophysiology lab. Wires will be threaded from your groin up into your heart. Then, an electrical stimulus will be delivered through the wires in an attempt to excite your heart into a fast rhythm. If your heart is stimulated into VT, medications will be administered intravenously to try and suppress the arrhythmia. While you are on the medications, the stimulus will be delivered again to see if your heart can still be induced into VT.