Electrocardiogram (ECG) is very crucial and important tool to detect the cardiac problems. For ECG analysis, it is essential to measure ECG parameter accurately. It is very critical in all types of ECG application. The accurate R Peaks detection is starting step in extracting ECG features which is necessary for the other ECG performance stages. It is very essential to detect these R-peaks accurately and efficiently to detect heart diseases or anomalies which create primary source of death in the universe. Hence automatic R-peaks detection in a lengthy duration ECG signal is very meaningful to diagnose the cardiac disorders. Here a latest R-peak exposure algorithm depended on Shannon energy envelope estimator and logic to find peaks has been proposed which uses the simple threshold of Shannon energy.