The carotid and ECG pulses as indices for nuclear cardiography imaging

Nuclear cardiography has emerged from nuclear medicine to help the cardiologist in assessing the heart's performance. One of the examinations practiced is imaging of the cardiac muscle at its two extreme phases: End-Systole (ES) and End-Diastole (ED). Images of those two phases of the cardiac cycle may provide information for the calculation of Ejection Fraction (EF) and the asynergy and dysynergy of the heart muscle. We found that the methods used by the commercially available devices to trigger the image formation by the gamma camera are not precise, because they use only the ECG as the triggering pulse. If the carotid pulse is used to define ES, and ECG for ED, the two extreme phases are defined much more precisely and the image accumulation follows the change of rate from beat to beat. (orig.)