Posts Tagged ‘arrhythmias’

Sudden Cardiac Death

Tuesday, March 9th, 2010

Heart attack survivors and others 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. This can also occur for no known reason.

Risk Factors
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 non-sustained ventricular tachycardia (VT). These rapid heartbeats may or may not be noticeable to you. Non-sustained VT is often the precursor to SCD.
  • Family history of heart arrhythmias.

Early identification is key. If you are at risk it is important to talk to your doctor.

Diagnosis
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.

Heart Rhythm Disorders

Tuesday, March 9th, 2010

Heart rhythm disorders, or arrhythmias, are not something to be ignored.

Arrhythmias may cause the heart to beat too slowly (less than 60 beats per minute is bradycardia) or too fast (greater than 100 beats per minute is tachycardia). Arrhythmias may occur from the upper two chambers of the heart, called atrial arrhythmias or supraventricular arrhythmias or may originate from the lower chambers of the heart, called the ventricles. Some arrhythmias are benign, and have little, if any, clinical significance. Other arrhythmias are malignant, and may be life-threatening. A given arrhythmia may have different clinical significance in different individuals, primarily depending upon whether or not the individual has structural heart disease or, most importantly, diminished cardiac performance (congestive heart failure).

What are the warning signs and symptoms of heart rhythm disorders?
An individual’s response to any particular arrhythmia may vary. Individuals may have no symptoms whatsoever, or may present with sudden, catastrophic collapse followed by loss of consciousness or sudden death. In between these two extremes, is an entire gamut of symptoms including insignificant palpitations to marked fluttering in one’s chest associated with shortness of breath, chest pain, sweating, and lightheadedness. These are important symptoms to recognize and should not be ignored. These should be discussed with your physician to help determine their significance

How are heart rhythm disorders detected?
Your doctor has several ways of evaluating heart rhythm disorders. The electrocardiogram (ECG) is a common, noninvasive, quickly performed test that allows your physician to assess exactly what rhythm your heart is in. This test, however, does not provide any information as to what heart rhythm you may have had at any time in the past, particularly associated with one or more symptoms. To help evaluate rhythm disturbances that may occur while you are not at the doctor’s office, you may have a 24 hour ambulatory electrocardiographic monitoring test (24 hour holter monitor recording) or a long term ECG analysis called an event monitor which may allow for recording of abnormal heart rhythms for 14 days or 1 month. Other adjunctive tests that may be helpful include treadmill testing, or electrophysiology testing, which is an invasive procedure involving placement of catheters into the vascular system.

What are the treatment options for heart rhythm disorders?
Treatment options depend entirely on the severity of the heart rhythm problem. Many heart rhythm problems do not require any treatment at all, other than reassurance. Other heart rhythm problems may be easily treated with various anti-arrhythmic medications. Some rapid heart rhythm problems may be treated with catheter ablation or implantation of a pacemaker-type device known as an implantable cardioversion defibrillator. Finally, and rarely, one may require an open-heart surgical procedure to eliminate the source of heart rhythm problems.