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Purpose:Transcatheter aortic valve replacement (TAVR) can rapidly improve cardiac sympathetic nervous function (CSNF) within 2 weeks in patients with aortic stenosis (AS). However, it remains unclear whether such short-term improvements will be sustained thereafter. The present study aimed to investigate the mid-term (i.e., 6–12 months) effects of TAVR on CSNF in patients with severe AS using 123I-meta-iodobenzylguanidine (MIBG) imaging.Methods:Patients with severe AS who were scheduled to undergo TAVR between October 2017 and June 2019 were enrolled in this single-centre, prospective, observational study. MIBG imaging was performed at baseline, within 2 weeks after TAVR, and at 6–12 months post-TAVR to evaluate the heart–mediastinum ratio (H/M) and washout rate (WR). Differences between each MIBG parameter at three time points were analysed, and factors involved in the long-term improvement in the late H/M were investigated. Results:Of 183 consecutive patients, 75 (19 men; median age: 86 years) were evaluated. The late H/M significantly improved within 2 weeks after TAVR (P=0.041) and further improved over 6–12 months after TAVR (P=0.041). The WR rapidly improved immediately after TAVR (P=0.003) but remained unchanged at 6–12 months (P=0.827). Multivariate analysis revealed that the baseline mean aortic valve pressure gradient (mPG) was an independent predictor of mid-term improvement in the late H/M (>0.1) (adjusted odds ratio: 0.035; 95% confidence interval: 0.004–0.070; P=0.037). Patients with a high baseline mPG (≥58 mmHg) exhibited a significantly greater increase in the late H/M than those with a low baseline mPG (P=0.029).Conclusions:CSNF, as denoted by the late H/M, demonstrated sustained improvement from within 2 weeks after TAVR until 6–12 months later. Such improvement was related to baseline hemodynamic AS severity.

Previous studies show inconsistent results on the role of innervation imaging (with 123I-mIBG) in predicting late atrial fibrillation (AF) recurrence after catheter ablation (CA). These studies included patients with paroxysmal AF and studied prognostic value of post-CA I-123-mIBG parameters. Current study investigated the ability of pre CA 123-I-mIBG imaging to predict late AF recurrence in patients with persistent AF. 123I-mIBG cardiac imaging was performed before CA in 82 patients with persistent AF. Patient was followed for 12 months. Multivariable analysis demonstrated that late heart-to-mediastinum ratio (H/Mlate) and washout rate (WR) were independent predictors of AF recurrence. ROC-curve analysis data showed that H/Mlate 25.11 (sensitivity 70.6%, specificity 70.8.3%, AUC 0.712, P

We sought to determine the relationship between (99m)Tc-sestamibi washout and myocardial properties in hypertrophic cardiomyopathy (HCM) patients.Twenty-four HCM patients underwent biventricular cardiac catheterization, with a micromanometer-tipped catheter, both at rest and during atrial pacing, echocardiography and myocardial (99m)Tc-sestamibi scintigraphy at rest. The (99m)Tc-sestamibi washout rate (WR) was calculated using initial and delayed planar images. The HCM patients were divided into two groups as follows: Group A consisted of 13 patients showing (99m)Tc-sestamibi WR22.5%; group B of 11 patients showing (99m)Tc-sestamibi WR ≥ 22.5%. Significant correlations were observed between (99m)Tc-sestamibi WR and percentage changes in pressure half-time (T (1/2)), as well as those in the maximum first derivative LV pressure (LV dP/dt (max)) (r = .43, P = .033; r = -.63, P = .001). The percentage changes in LV dP/dt (max) and those in T (1/2) were significantly more reduced in group B than in group A (P.05). The biphasic force-frequency relation was more frequently observed in group B than in group A (82% vs. 18%).Increased (99m)Tc-sestamibi washout is associated with an impaired contractile reserve and prolonged relaxation, suggesting that myocardial (99m)Tc-sestamibi scintigraphy may be useful in noninvasively detecting the early impairment of myocardial function in HCM patients.

Myocardial characteristics of remote normal regions in patients with myocardial infarction (MI) and left ventricular (LV) remodeling have not been fully elucidated. Thus, we investigated this issue from the viewpoint of myocardial Tl-201 dynamics.In 14 patients with prior anterior MI, 10 with inferior MI, and 14 age-matched patients with atypical chest pain served as controls; exercise stress Tl-201 SPECT and cardiac catheterization were performed. Tl-201 washout rate was calculated for 8 myocardial segments, and LV end-diastolic volume index was obtained as a parameter of LV remodeling. LV end-diastolic volume index was greater in anterior MI patients than in control patients; in contrast, no significant difference was observed between inferior MI patients and control patients. The washout rate in remote normal regions was significantly less in anterior MI patients than in the corresponding segments in control patients (39.8% +/- 8.7% vs 48.4% +/- 4.4%, P.01). There was no significant difference between inferior MI patients and control patients (43.6% +/- 6.9% vs 47.8% +/- 4.5%).Reduced Tl-201 washout rates in remote normal regions are found in patients with anterior MI and LV remodeling. Subclinical myocardial ischemia during exercise in remote normal regions exists and may be related to the pathologic condition of such LV walls.

Adenosine triphosphate stress thallium-201 single-photon emission computed tomography (ATP SPECT) is useful for diagnosis of coronary artery disease, but its usefulness for evaluating the severity of coronary artery stenosis has not been established.We performed region-of-interest analysis of short-axis images obtained by ATP SPECT in 31 patients with single-vessel disease (50% stenosis of the luminal diameter). We selected the lowest and highest washout rates (WR) among the anterior, lateral, and inferior WRs and calculated the ratio of the lowest WR to the highest WR (WR ratio = 0.925+/-0.027 in 14 control subjects). ATP SPECT showed positive results in 29 (94%) of 31 patients. The severity of coronary artery stenosis was inversely correlated with the WR ratio (r = -0.703, P.0001). The sensitivity and specificity of a WR ratioor = 0.660 for the diagnosis of severe coronary stenosis (or =80% stenosis) were 83% and 80%, respectively.Results suggest that ATP SPECT may be useful for assessment of the severity of coronary artery stenosis in patients with single-vessel disease.

Background: Tc99m-Teboroxime (TEBO) has been pursued as a myocardial perfusion agent because of its high extraction fraction. However, to image TEBO accurately on traditional SPECT is difficult due to a fast washout rate and the high hepatic uptake. In this work, we develop and demonstrate a new attenuation correction (AC) technique for dynamic SPECT to improve TEBO's perfusion distribution using a novel energy-based listmode scatter correction (SC) combined with AC. Methods: We recruited five subjects having previous clinically indicated rest-stress AC Tc-99m-MIBI SPECT to receive an adenosine stress TEBO. The Gd-153 transmission study was acquired sequentially prior to the TEBO study on Siemens ECAMTM system modified to acquire listmode data in a rapid phased fanning mode. 10s per phase with 32 phases and 32 projection angles in each phase were acquired in 180o RAO-LPO arc during peak adenosine stress. Listmode data were rebinned into energy spectra of projections. The spectrum at each pixel was corrected using a previously reported energy-based SC technique (IESD). Attenuation maps were reconstructed with a Bayesian iterative approach (BITGA) and AC was performed with MLEM algorithm using the IESD corrected projections. Segmental difference from the polar map samplings (total 90 segments) of non-corrected TEBO (NC) TEBO to AC MIBI were compared with AC TEBO to AC MIBI for assessing the improvements of patients' perfusion distribution after AC. Results: The mean segmental difference between NC TEBO and AC MIBI was 7.5 and reduced to 6.0 after AC (p Conclusion: AC combined with IESD correction demonstrates improved perfusion distribution of TEBO by reducing 20% (p Download : Download full-size image