Currently risk assessments are determined by measuring the fraction of blood ejected from the heart in any one heartbeat, the ejection fraction. When the ejection fraction falls below 35%, a patient may benefit from an ICD.
It is believed that approximately 60% of patients who receive defibrillators as a result of these assessments may not actually need one. This blood test will determine more accurately which patients do in fact need the defibrillator.
Sudden cardiac death is an unexpected death caused by loss of heart function, or sudden cardiac arrest. The incidence rate is quite high in India - about 10% of all cardiac-related deaths are sudden while the mean age of the patients who die is lower than 60 years. Studies have showed that one-third of the patients who die of SCD had heart attacks in the past and 80% of them were smokers or had risk factors like hypertension and diabetes.
SCD is a condition in which the heart unexpectedly stops beating. When this occurs, blood stops flowing to the brain and other vital organs. If not treated the sufferer dies within minutes.
Our heart has an electrical system that controls the rate and rhythm of the heartbeat. Abnormal functioning of this electrical system can cause irregular heartbeats called arrhythmias. During an arrhythmia, the heart can beat too fast, too slow or with an irregular rhythm. Some arrhythmias can cause the heart to stop pumping blood to the body and this leads to SCA. This, however, is not the same as a heart attack.
A heart attack occurs when the blood flow to part of the heart muscle is blocked but the heart usually doesn't stop beating. People who have heart disease are at higher risk. But people who appear healthy and have no known risk factors can also fall prey to this killer.