Terue Koh

Left ventricular systolic/diastolic function evaluated by quantitative ECG-gated SPECT: comparison with echocardiography and plasma BNP analysis

Objective: The aim of this study was to evaluate the left ventricular (LV) functional parameters calculated using quantitative electrocardiography (ECG)-gated myocardial perfusion single photon emission computed tomography (QGS). In addition to LV systolic parameters, diastolic parameters were compared with those by ultrasound echocardiography (UCG) and also with plasma B-type natriuretic peptide (BNP) concentrations.Methods: We examined 46 patients with various forms of heart disease. By the QGS data with 16 framing data acquisition using technetium (Tc)-99m methoxyisobutylisonitrile (MIBI) perfusion, we calculated the following parameters: LV end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), peak filling rate (PFR), filling rate during the first third of the filling time ( 1/3FR) and first third filling fraction ( 1/3FF). By UCG, we measured mitral early to atrial (E/A) wave velocity ratio and pulmonary venous inflow systolic/diastolic (S/D) ratio as diastolic functional parameters. Plasma BNP concentrations were also measured.Results: There was a significant correlation between LVEDV, ESV and EF measured by QGS and UCG (EDV, r = 0.71, p < 0.001; ESV, r = 0.82, p < 0.001; EF, r = 0.75, p < 0.001). The PFR, 1/3FR and 1/3FF obtained by QGS correlated positively with E/A ratio (PFR, r = 0.54, p < 0.001; 1/3FR, r = 0.61, p < 0.001; 1/3FF, r = 0.42, p < 0.01) and negatively with S/D ratio (PFR, r = -0.40, p < 0.01; 1/3FR, r = -0.38, p < 0.05; 1/3FF, r = -0.39, p < 0.01) obtained by UCG. Plasma BNP concentrations in EF < 50% patients were greater than those in EF ≥ 50% patients (335.2 ± 60.2 vs. 101.2 ± 41.3 pg/m/, p < 0.01, both n = 17). Plasma BNP levels were also compared between higher and lower 1/3FF patients matched for LVEF. Plasma BNP concentrations in 1/3FF < 35% patients were significantly greater than those in 1/3FF ≥ 35% patients (312.9 ± 62.5 vs. 120.5 ± 32.8 pg/m/, p < 0.05, both n = 14).Conclusions: The degree of LV systolic and diastolic dysfunctions evaluated by QGS correlated with that by UCG or BNP. The QGS functional parameters offer useful information regarding cardiac failure.

Prognostic value of ECG-gated thallium-201 single-photon emission tomography in patients with coronary artery disease.

Background: The phenomenon of reversible impairment in LV function has been well described and is known as myocardial stunning.Objective: Thallium-201 myocardial perfusion gated SPECT was used to evaluate myocardial stunning and its incremental prognostic value in patients with coronary artery disease.Patients and Methods: Fifty-six patients (aged 63 ±11 years) with coronary artery disease were included in this study. All subjects underwent exercise thallium scintigraphy. ECG-gated SPECT was obtained both at post-stress (10 minutes after the injection of 111 MBq of thallium at the time of peak exercise) and at rest (180 minutes). The left ventricular ejection fraction (LVEF) and end-systolic and end-diastolic volume (ESV, EDV) were determined by a quantitative gated SPECT (QGS) program.Results: Follow-up was complete in all patients (mean 569 days). The magnitude of the depression of post-stress LVEF relative to the rest LVEF was correlated with the severity of ischemia (p < 0.05). The group with a median LVEF of more than 45% had a significantly higher event-free rate (p < 0.01).Conclusion: Assessment of post-stress left ventricular function by gated-SPECT provides incremental prognostic information and is useful in predicting cardiac events in patients with suspected or definite coronary artery disease.

Iodine-123 BMIPP scintigraphy in the evaluation of patients with heart failure.

Purpose: To investigate whether cardiac parameters obtained by I-123 15-(p-iodophenyl)-3-methyl pentadecanoic acid (BMIPP, a radioactive fatty acid analogue) myocardial scintigraphy are useful as indicators of disease severity and predictors of cardiac events in congestive heart failure (CHF). Material and Methods: Thirty-two CHF patients (functional class: 17 in NYHA II and 15 in NYHA III at the time of this study) were compared with 18 normal control subjects. Myocardial scintigraphy was performed 15 min and 3 hours after I-123 BMIPP injection. The heart-to-mediastinum count ratio of I-123 BMIPP on the initial (H/Mi) and delayed (H/Md) images and the washout rate (WR) were calculated. Results: Both H/Mi and H/Md were lower in CHF than in controls (H/Mi 1.96±0.18 vs. 2.30±0.29; H/Md 1.72±0.15 vs. 1.97±0.21; both P<0.001), but WR was higher in CHF than in controls (WR (%) 23.7±5.7 vs. 18.2±6.0, P<0.01). Both H/Mi (R = 0.42, P<0.05) and H/Md (R = 0.45, P<0.05) correlated positively with the left ventricular (LV) ejection fraction (EF), estimated by echocardiography. The WR correlated positively with the plasma B-type natriuretic peptide (BNP) level (R = 0.47, P<0.01). Kaplan-Meier analysis showed an earlier CHF progression for patients with a lower H/Mi (<1.94). Conclusion: Myocardial metabolic abnormality evaluated by I-123 BMIPP scintigraphy is related to the severity of CHF. Furthermore, it may be useful as a predictor for cardiac events.

Detection of Metabolic Abnormality in Asynergic Regions of Ischemic Human Myocardium Using 31P and 1H Magnetic Resonance Spectroscopy

To assess quantitatively phosphocreatine (PCr), adenosine triphosphate (ATP) and total creatine (CR) in asynergic regions of ischemic human myocardium using phosphorus (31P) and proton magnetic resonance spectroscopy (1H MRS). Patients were divided into two groups: 31P MRS and 1H MRS. In each group, patients were subdivided into three groups using echocardiography: a normokinetic [WN(P) (n = 6) in 31P MRS, WN(H) (n = 10) in 1H MRS], a hypokinetic [WH(P) (n = 13), WH(H) (n = 7)], and a- or dyskinetic wall motion groups [WA(P) (n = 14), WA(H) (n =6)]. They were compared with normal subjects of each group [CNP (n = 10), CN(H) (n = 10)]. 31P MRS spectra were obtained from the anterior and apical regions of the left ventricle by slice-selected 1D CSI. 1H MRS spectra were obtained from the 2 x 2 x 2-cm voxel set in the left ventricular wall by the PRESS method. In the 31P MRS group, myocardial PCr was significantly lower in the WH(P) and WA(P) groups than in the CN(P) group, but myocardial PCr in the WN(P) group did not differ from that in CN(P). A difference in ATP could not be detected among the four groups. In the 1H MRS group, myocardial CR was significantly lower in the WH(H) and WA(H) groups than in the CN(H) group. Myocardial CR in the WNH group did not differ from that in the CN(H). The noninvasive 31P and 1H MRS approach is useful in the assessment of metabolite reduction associated with wall motion abnormality.