electrocardiogram (ECG or EKG)
Signal-Averaged ECG. This test is similar to a standard Electrocardiogram (ECG), but provides greater in-depth information by collecting many heart beats and analyzing them together. The Signal-Averaged Electrocardiogram essentially strengthens some signals while eliminating "background noise" from other signals. These signals are then filtered and averaged, providing an analysis that yields information about patient risk of future Ventricular Tachycardia (rapid heart activity) and/or Ventricular Fibrillation (irregular heart activity). These weak but very important impulses are called "late potentials" and are commonly not evaluated in a standard ECG. Late potentials arise from damaged or scarred areas of heart muscle. Recognizing the presence of these late potentials can be helpful in the following situations:
- To determine risk for ventricular arrhythmia following heart surgery or a heart attack
- To determine the cause of fainting (called syncope)
- To determine if scar tissue is present from a previous heart attack.