Evaluation of patients with chest pain by radionuclide ventriculography: Comparison of phase and 2-harmonic analysis

Fourier-series analysis (FSA) of time activity curves has been used to enhance the detection of regional abnormalities in function of the left ventricle (LV) on radionuclide ventriculograms (RVGs). Phase, or first harmonic analysis, does not permit separate determination of systolic and diastolic function. The retention of 2 harmonics (2-H) in the FSA allows definition of both systolic and diastolic parameters, including time to peak ejection rate (TPER) and time to peak filling rate (TPFR). The authors compared regional phase and 2-H analysis in 42 patients with normal LV function by conventional analysis of resting RVGs. All patients had ejection fraction greater than 50% and normal regional wall motion. Diagnoses, established by cardiac characterization, included coronary artery disease (CAD) and chest pain but normal coronary arteries (NCA). Normal homogeneity of LV function was established in 12 normal volunteers by computing the standard deviation of the distribution of LV pixels for TPER, TPFR and phase angle on the 350 LAO views. Thus, in patients with CAD but normal conventional analysis of RVGs, 2-H analysis detected abnormal diastolic filling in 70% whereas phase analysis was abnormal in only 15%. In patients with NCA, abnormalities by either phase or 2-H analysis were infrequent. These data suggest that 2-H analysis may be of value in the investigation of patients with chest pain but normal LV function