Diagnostic value of LV diastolic stunning for detecting coronary artery stenosis in patients with normal wall motion by 16-frame quantitative ECG gated SPECT

Objectives Post-systolic shortening is a sensitive indicator of myocardial ischemia using the echocardiographic strain imaging technique. ECG-gated myocardial perfusion SPECT (GMPS) allows us to assess three dimensional left ventricular (LV) regional analyses. The objective was to test, by means of novel 3-dimensional dyssynchrony evaluation by GMPS, the hypothesis that the regional heterogeneity of myocardial dysfunction assessed by rest image should provide comparable information.

Methods We retrospectively reviewed the data from 65 patients (mean age, 70 ± 6 years; 42men) with normal LV ejection fraction (72 ± 9 %) and normal QRS duration (<120ms) who underwent both coronary angiography and rest 99m Tc-tetrofosmin myocardial perfusion scintigraphy. The study population consisted of 42 patients with significant coronary artery stenosis; (25 with single vessel disease and 17 with multi vessel disease), and the remaining 23 patients had normal coronary artery. Time to Max thickening (TTMT), max thickening and end-systolic thickening were measured derived by the myocardial each 17 segments-specific thickening curve from GMPS. We used standard deviation of TTMT (SD of TTMT/RR) (ms) which corrected for R-R time and thickening delay index (TDI) (%) (=average of each 17segment between max and end-systolic LV thickening) ×100) were calculated as mechanical dyssynchrony parameters.

Results The SD of TTMT/RR and TDI were similar in patients with and without significant coronary artery stenosis (SD of TTMT/RR: 1.9 ± 0.6 vs 2.3 ± 1.3%, TDI :0.6 ± 0.4 vs 0.87 ± 0.1%, respectively; P = NS). In contrast, the SD of TTMT/RR and TDI in patients with multivessel disease was significantly higher than normal subjects from rest image (2.6± 1.7% and 1.2 ± 1.2% , respectively; P < 0.05).

Conclusions The dyssynchrony index using rest GMPS enabled better identification of patients with multivessel coronary artery disease, and was not altered in patients with single vessel disease.