Left ventricular systolic and diastolic dyssynchrony assessed by phase analysis of gated SPECT myocardial perfusion imaging: a comparison with speckle tracking echocardiography

The objective of this study was to compare left ventricular (LV) systolic and diastolic dyssynchrony parameters measured by phase analysis on gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with those measured by speckle tracking echocardiography (STE). Two patient groups were enrolled from the Chang Bing Show Chwan Memorial Hospital. The systolic group consisted of patients with reduced LV ejection fraction (LVEF) of < 50 % as assessed by routine echocardiography. The diastolic group consisted of patients with normal LVEF (> 50 %) and diastolic dysfunction according to routine echocardiography (E/A < 1, E/E' > 8). LV systolic and diastolic dyssynchrony parameters were calculated using STE as the maximal peak-time delay between peak radial strains of two opposing LV walls and as the standard deviation of the time to peak radial strains in 6 mid-LV segments. All of the patients had gated SPECT MPI within 6 +/- A 11 days post STE. Phase analysis was performed on the resting gated SPECT MPI images to calculate systolic and diastolic phase standard deviation and phase histogram bandwidth as markers of LV systolic and diastolic dyssynchrony, respectively. Fifty-two consecutive patients (40 men, mean age = 66 +/- A 13 years, LVEF = 34.4 +/- A 10.2 %) were enrolled in the systolic group, whereas 30 consecutive patients (15 men, mean age = 69 +/- A 11 years, LVEF = 72.3 +/- A 4.7 %, E/A all < 1, E/E' = 11.7 +/- A 2.2) were enrolled in the diastolic group. LV systolic and diastolic dyssynchrony parameters measured by phase analysis of gated SPECT MPI and STE were correlated well in both systolic and diastolic groups, respectively. Phase analysis on gated SPECT MPI showed good correlations with STE and is suitable for the assessment of LV systolic and diastolic dyssynchrony. As assessed with the phase analysis and STE techniques, the patients with severe LV systolic dysfunction had severe LV systolic dyssynchrony, but the patients with LV diastolic dysfunction were not necessarily with LV diastolic dyssynchrony, indicating that the LV diastolic dyssynchrony parameters characterized independent mechanisms of LV regional diastolic function.