Use of cardiac imaging in chronic coronary syndromes: the EURECA Imaging registry.

BACKGROUND: The prospective, multicentre EURECA registry assessed the use of imaging and adoption of the European Society of Cardiology (ESC) Guidelines (GL) in patients with chronic coronary syndromes (CCS). METHODS: Between May 2019 and March 2020, 5156 patients were recruited in 73 centres from 24 ESC member countries. The adoption of GL recommendations was evaluated according to clinical presentation and pre-test probability (PTP) of obstructive coronary artery disease (CAD). RESULTS: The mean age of the population was 64 ± 11 years, 60% of patients were males, 42% had PTP >15%, 27% had previous CAD, and ejection fraction was <50% in 5%. Exercise ECG was performed in 32% of patients, stress imaging as the first choice in 40%, and computed tomography coronary angiography (CTCA) in 22%. Invasive coronary angiography (ICA) was the first or downstream test in 17% and 11%, respectively. Obstructive CAD was documented in 24% of patients, inducible ischaemia in 19%, and 13% of patients underwent revascularization. In 44% of patients, the overall diagnostic process did not adopt the GL. In these patients, referral to stress imaging (21% vs. 58%; P < 0.001) or CTCA (17% vs. 30%; P < 0.001) was less frequent, while exercise ECG (43% vs. 22%; P < 0.001) and ICA (48% vs. 15%; P < 0.001) were more frequently performed. The adoption of GL was associated with fewer ICA, higher proportion of diagnosis of obstructive CAD (60% vs. 39%, P < 0.001) and revascularization (54% vs. 37%, P < 0.001), higher quality of life, fewer additional testing, and longer times to late revascularization. CONCLUSIONS: In patients with CCS, current clinical practice does not adopt GL recommendations on the use of diagnostic tests in a significant proportion of patients. When the diagnostic approach adopts GL recommendations, invasive procedures are less frequently used and the diagnostic yield and therapeutic utility are superior.

Hypertriglyceridemia: Molecular and Genetic Landscapes.

Lipid disorders represent one of the most worrisome cardiovascular risk factors. The focus on the impact of lipids on cardiac and vascular health usually concerns low-density lipoprotein cholesterol, while the role of triglycerides (TGs) is given poor attention. The literature provides data on the impact of higher plasma concentrations in TGs on the cardiovascular system and, therefore, on the outcomes and comorbidities of patients. The risk for coronary heart diseases varies from 57 to 76% in patients with hypertriglyceridemia. Specifically, the higher the plasma concentrations in TGs, the higher the incidence and prevalence of death, myocardial infarction, and stroke. Nevertheless, the metabolism of TGs and the exact physiopathologic mechanisms which try to explain the relationship between TGs and cardiovascular outcomes are not completely understood. The aims of this narrative review were as follows: to provide a comprehensive evaluation of the metabolism of triglycerides and a possible suggestion for understanding the targets for counteracting hypertriglyceridemia; to describe the inner physiopathological background for the relationship between vascular and cardiac damages derived from higher plasma concentrations in TGs; and to outline the need for promoting further insights in therapies for reducing TGs plasma levels.

Prognostic impact of patients' management based on anatomic/functional phenotype: a study in patients with chronic coronary syndromes.

BACKGROUND: In stable coronary artery disease (CAD), the prognostic interaction between clinical variables and treatment appropriateness based on anatomic/functional phenotype needs to be evaluated. METHODS: 1585 consecutive patients underwent myocardial perfusion scintigraphy and coronary angiography within 90 days. Obstructive CAD (> 70% stenosis) with downstream moderate-to-severe ischemia (> 10%) was considered significant. Coronary revascularization was considered appropriate if all hemodynamically significant lesions were revascularized, while medical therapy only was deemed appropriate in the absence of hemodynamically significant CAD. RESULTS: Obstructive CAD and moderate-to-severe ischemia were documented in 1184 (75%) and 466 (29%) patients, respectively. Over mean follow-up of 4.7 ± 2.5 years, the primary endpoint (cardiac death and non-fatal myocardial infarction) occurred in 132 (8.2%) patients. Of patients with obstructive CAD, 797 (67%) were managed appropriately. Patients' management was inappropriate in 389 patients, because either non-hemodynamically significant lesions were revascularized (50%, including 2 patients with non-obstructive lesions being inappropriately revascularized) or ischemia-causing CAD was left untreated (50%). At multivariate analysis, an inappropriate management (P < .001) was correlated with the primary endpoint, together with previous myocardial infarction (P = .009), lower ejection fraction (P < .001) and higher glucose levels (P < .001). CONCLUSIONS: In stable CAD patients, management based on anatomic/functional phenotyping was correlated with a prognostic advantage at long-term follow-up. Correlation between treatment categories and patients' prognosis. A significantly higher event-rate was observed in patients where hemodynamically significant coronary lesions were left untreated-either because MT was not-adherently chosen or in the case of incomplete revascularization-than in those that were revascularized completely (17.6% vs 5.1%; P < .001). Conversely, the revascularization of non-hemodynamically significant CAD correlated with a higher event-rate than that of similar patients managed medically (13.8% vs 8.3%, P = .04). The event-rate of patients in whom coronary revascularization was performed in the presence of hemodynamically significant CAD ('appropriate revascularization') was similar to those with "No CAD/non-obstructive CAD" (5.1% vs 3.5%; P = NS).

Cardiac sympathetic dysfunction in left ventricular hypertrophy caused by arterial hypertension and degenerative aortic stenosis.

BACKGROUND: To evaluate cardiac sympathetic innervation in hypertensive patients with left ventricular (LV) hypertrophy (H) and aortic stenosis (AS) submitted to transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS: Twenty-two hypertensive elders (82 ± 5 years) with severe AS and significant LVH (> 122 g·m-2 in women and > 149 g·m-2 in men) were compared with 14 patients with uncomplicated essential hypertension (HT) with similar degree of LVH and 10 controls. 123I-metaiodobenzylguanidine (MIBG) and 99mTc-tetrofosmin SPECT acquisitions were obtained to assess sympathetic innervation and LV perfusion. The innervation/perfusion mismatch score was taken as an indicator of cardiac sympathetic dysfunction. The imaging protocol was repeated 6 months after TAVI. Regional MIBG uptake was more heterogeneous in HT and AS patients than controls, and therefore, innervation/perfusion mismatch score was higher in both AS (9 ± 8) and HT (5 ± 2) than controls (1 ± 1, P < .001). On multivariate analysis, significant LVH was the major predictor of impaired LV sympathetic innervation (OR 19.45, 95% CI 1.87-201.92; P = .013). After TAVI, no differences in measures of LV sympathetic innervation were evident, although only a marginal LV mass reduction was observed (- 5.4 ± 2.4 g). CONCLUSIONS: Cardiac sympathetic innervation is impaired in patients with LVH, either with AS or not, and is not impacted significantly by TAVI procedure.

The diagnostic value of SPECT CZT quantitative myocardial blood flow in high-risk patients.

BACKGROUND: The objective of this study was to evaluate the accuracy of global MBF and MFR quantitation performed by myocardial perfusion scintigraphy (MPS) for the detection of multivessel coronary artery disease (CAD). METHODS: 52 CAD patients underwent CZT MPS, with the evaluation of MBF and MFR, followed by invasive coronary angiography (ICA). According to MPS and ICA results, all patients were divided into three groups: (1) non-obstructive CAD and normal MPS scan (control group) (n = 7), (2) one vessel disease (1VD) (n = 16), (3) multivessel disease (MVD) (n = 29). RESULTS: Global absolute MBF and MFR were significantly reduced in MVD patients as compared to those with 1VD [0.93 (IQR 0.76; 1.39) vs 1.94 (1.37; 2.21) mL·min-1·g-1, P = .00012] and [1.4 (IQR 1.02; 1.85) vs 2.3 (1.8; 2.67), P = . 0 004], respectively. The Syntax score correlated with global stress MBF (ρ = - 0.64; P < .0001) and MFR (ρ = - 0.53; P = .0003). ROC analysis showed higher sensitivity and specificity for stress MBF and MFR compared with semiquantitative MPS stress evaluation. Multivariate regression analysis showed that only stress MBF [OR (95% CI) 0.59 (0.42-0.82); P < .0003] was an independent predictor of MVD. CONCLUSIONS: Quantitative myocardial blood flow values assessed with the use of CZT camera may identify high-risk patients, such as those with multivessel disease.

Relationship of Endothelial Shear Stress with Plaque Features with Coronary CT Angiography and Vasodilating Capability with PET.

Background Advances in three-dimensional reconstruction techniques and computational fluid dynamics of coronary CT angiography (CCTA) data sets make feasible evaluation of endothelial shear stress (ESS) in the vessel wall. Purpose To investigate the relationship between CCTA-derived computational fluid dynamics metrics, anatomic and morphologic characteristics of coronary lesions, and their comparative performance in predicting impaired coronary vasodilating capability assessed by using PET myocardial perfusion imaging (MPI). Materials and Methods In this retrospective study, conducted between October 2019 and September 2020, coronary vessels in patients with stable chest pain and with intermediate probability of coronary artery disease who underwent both CCTA and PET MPI with oxygen 15-labeled water or nitrogen 13 ammonia and quantification of myocardial blood flow were analyzed. CCTA images were used in assessing stenosis severity, lesion-specific total plaque volume (PV), noncalcified PV, calcified PV, and plaque phenotype. PET MPI was used in assessing significant coronary stenosis. The predictive performance of the CCTA-derived parameters was evaluated by using area under the receiver operating characteristic curve (AUC) analysis. Results There were 92 coronary vessels evaluated in 53 patients (mean age, 65 years ± 7; 31 men). ESS was higher in lesions with greater than 50% stenosis versus those without significant stenosis (mean, 15.1 Pa ± 30 vs 4.6 Pa ± 4 vs 3.3 Pa ± 3; P = .004). ESS was higher in functionally significant versus nonsignificant lesions (median, 7 Pa [interquartile range, 5-23 Pa] vs 2.6 Pa [interquartile range, 1.8-5 Pa], respectively; P ≤ .001). Adding ESS to stenosis severity improved prediction (change in AUC, 0.10; 95% CI: 0.04, 0.17; P = .002) for functionally significant lesions. Conclusion The combination of endothelial shear stress with coronary CT angiography (CCTA) stenosis severity improved prediction of an abnormal PET myocardial perfusion imaging result versus CCTA stenosis severity alone. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Kusmirek and Wieben in this issue.

Head-to-head comparison of a CZT-based all-purpose SPECT camera and a dedicated CZT cardiac device for myocardial perfusion and functional analysis.

PURPOSE: To compare the outputs of a novel all-purpose SPECT camera equipped with CZT detectors (Discovery NM/CT 670) with the state-of-the-art represented by a dedicated CZT (Alcyone, Discovery 530c) cardiac camera in patients submitted to myocardial perfusion imaging (MPI). METHODS: We included 19 patients that underwent sequential low-dose 99mTc-tetrofosmin (148-185 MBq during stress and 296-370 MBq at rest) MPI with Alcyone and Discovery 670 cameras. Quantitative (% tracer's uptake) and semi-quantitative analyses of perfusion data were performed for each scan. Moreover, major left ventricular (LV) functional and structural parameters were derived from each camera and compared. RESULTS: The two cameras showed excellent correlation for segmental myocardial % uptake at stress (R = 0.90; P < 0.001) and at rest (R = 0.88; P < 0.001) with narrow Bland-Altman limits of agreement. The level of diagnostic agreement of Discovery 670 and Alcyone cameras regarding perfusion analysis was excellent (Cohen's κ 0.85). Similarly, the two cameras showed excellent correlation in the evaluation of LV ejection fraction (R = 0.95), peak filling rate (R = 0.97), and mass (R = 0.98). CONCLUSIONS: Our preliminary results suggest that MPI with an all-purpose Discovery 670 CZT-SPECT camera is feasible, comparing well with the current state-of-the-art technology.

Predictors of ventricular ablation's success: Viability, innervation, or mismatch?

AIMS: Sympathetic dys-innervation may play an important role in the development of post-ischemic ventricular arrhythmias (VA). Aim of this study was to prove that perfusion/innervation mismatch (PIM) evaluated by SPECT can identify areas of local abnormal ventricular activities (LAVA) on electroanatomic mapping (EAM). METHODS: Sixteen patients referred to post-ischemic VA catheter ablation underwent pre-procedural and 1-month post-ablation 123I-MIBG/99mTc-tetrofosmin rest SPECT myocardial imaging. PIM was defined according to the segmental distributions of 99mTc-tetrofosmin and 123I-MIBG. A 17-segment LV analysis was used for either SPECT or LV EAM voltage map. All patients were followed up clinically for at least 1 year. RESULTS: Before ablation, the mean voltage in the PIM segments was higher than in the scarred ones but lower than in the normal regions. The presence of PIM in a specific LV zone was an independent predictor of LAVA. After ablation, PIM value was significantly reduced, mainly due to an increase in perfusion summed rest score, in particular in patients that were responders to ablation. CONCLUSIONS: PIM may associate with VA substrate expressed by LAVA and might provide a novel guide for substrate ablation. A significant reduction of PIM could predict a positive clinical response to ablation.

Absolute myocardial blood flows derived by dynamic CZT scan vs invasive fractional flow reserve: Correlation and accuracy.

PURPOSE: To define the diagnostic power of absolute myocardial blood flow (MBF) evaluation on dynamic CZT imaging in intermediate risk patients in comparison with invasive coronary angiography (ICA) and fractional flow reserve (FFR). METHODS: Twenty-three stable CAD patients underwent one-day dynamic rest-stress 99mTc-Sestamibi myocardial perfusion imaging by CZT camera. Stress and rest MBF values were calculated semi-automatically using a net retention model by Leppo. Coronary flow reserve (CFR) and flow difference (FD) [MBF stress - MBF rest] were also estimated. A total of 28 vessels were functionally quantified with FFR: 19 (68%) vessels with a stenosis ≥ 70% and 9 (32%) with < 70% stenotic lesions. RESULTS: The mean global MBFs at rest and during stress were 0.36 (IQR 0.33-0.54) mL/min/g and 0.67 (IQR 0.55-0.81) mL/min/g, respectively, with an average CFR of 1.80 (IQR 1.35-2.24). Moderate correlations between stenosis severity and FFR (r = 0.45; P = .01), stress MBF (r = -0.46; P = .01) and FD (r = -0.37; P = .04) were detected. FFR abnormalities were best predicted by absolute stress MBF, CFR and FD with values of ≤ 0.54 mL/min/g (sensitivity 61.5%; specificity 93.3%), ≤ 1.48 (sensitivity 69.2%; specificity 93.3%) and ≤ 0.18 mL/min/g (sensitivity 69.2%; specificity 100%), respectively. CONCLUSIONS: The values of stress MBF, CFR and FD obtained through dynamic CZT acquisitions compare well with invasive FFR. The clinical use of dynamic acquisition of myocardial perfusion imaging by CZT may help cardiologist in the detection of hemodynamically significant CAD.

Left ventricular eccentricity index measured with SPECT myocardial perfusion imaging: An additional parameter of adverse cardiac remodeling.

BACKGROUND: Single-photon emission computed-tomography (SPECT) allows the quantification of LV eccentricity index (EI), a measure of cardiac remodeling. We sought to evaluate the feasibility of EI measurement with SPECT myocardial perfusion imaging and its interactions with relevant LV functional and structural parameters. METHODS AND RESULTS: Four-hundred and fifty-six patients underwent myocardial perfusion imaging on a Cadmium-Zinc-Telluride (CZT) camera. The summed rest, stress, and difference scores were calculated. From rest images, the LV end-diastolic (EDV) and end-systolic volumes, ejection fraction (EF), and peak filling rate (PFR) were calculated. In every patient, the EI, ranging from 0 (sphere) to 1 (line), was computed using a dedicated software (QGS/QPS; Cedars-Sinai Medical Center). Three-hundred and thirty-eight/456 (74%) patients showed a normal EF (>50%), while 26% had LV systolic dysfunction. The EI was computed from CZT images with excellent reproducibility (interclass correlation coefficient: 0.99, 95% CI 0.98-0.99). More impaired EI values correlated with the presence of a more abnormal LV perfusion (P < .001), function (EF and PFR, P < .001), and structure (EDV, P < .001). On multivariate analysis, higher EDV (P < .001) and depressed EF (P = .014) values were independent predictors of abnormal EI. CONCLUSIONS: The evaluation of LV eccentricity is feasible on gated CZT images. Abnormal EI associates with significant cardiac structural and functional abnormalities.

Emerging F-18-Labelled PET Myocardial Perfusion Tracers.

PURPOSE OF REVIEW: PET myocardial perfusion imaging (MPI) is an established modality for the evaluation of ischemic heart disease and quantitation of myocardial blood flow (MBF). New F-18-labelled radiopharmaceuticals have been recently developed to overcome some of the limitations of currently used tracers such as the need of an on-site cyclotron. The characteristics of the new tracers and the clinical results obtained so far will be reviewed. RECENT FINDINGS: Most of the interest in the field of 18F-labelled radiotracers for PET MPI has been concentrated on MC-1 inhibitors, the prototype of which is 18F-flurpiridaz. It was shown in experimental and clinical reports that these radiotracers allow good quality rest/stress MPI studies and a reliable quantitation of MBF. Recent evidence suggests that PET MPI with 18F-flurpiridaz may provide a superior diagnostic accuracy for obstructive CAD even if a large comparative clinical trial with SPECT is still ongoing.

Noninvasive CT-based hemodynamic assessment of coronary lesions derived from fast computational analysis: a comparison against fractional flow reserve.

OBJECTIVES: Application of computational fluid dynamics (CFD) to three-dimensional CTCA datasets has been shown to provide accurate assessment of the hemodynamic significance of a coronary lesion. We aim to test the feasibility of calculating a novel CTCA-based virtual functional assessment index (vFAI) of coronary stenoses > 30% and ≤ 90% by using an automated in-house-developed software and to evaluate its efficacy as compared to the invasively measured fractional flow reserve (FFR). METHODS AND RESULTS: In 63 patients with chest pain symptoms and intermediate (20-90%) pre-test likelihood of coronary artery disease undergoing CTCA and invasive coronary angiography with FFR measurement, vFAI calculations were performed after 3D reconstruction of the coronary vessels and flow simulations using the finite element method. A total of 74 vessels were analyzed. Mean CTCA processing time was 25(± 10) min. There was a strong correlation between vFAI and FFR, (R = 0.93, p < 0.001) and a very good agreement between the two parameters by the Bland-Altman method of analysis. The mean difference of measurements from the two methods was 0.03 (SD = 0.033), indicating a small systematic overestimation of the FFR by vFAI. Using a receiver-operating characteristic curve analysis, the optimal vFAI cutoff value for identifying an FFR threshold of ≤ 0.8 was ≤ 0.82 (95% CI 0.81 to 0.88). CONCLUSIONS: vFAI can be effectively derived from the application of computational fluid dynamics to three-dimensional CTCA datasets. In patients with coronary stenosis severity > 30% and ≤ 90%, vFAI performs well against FFR and may efficiently distinguish between hemodynamically significant from non-significant lesions. KEY POINTS: Virtual functional assessment index (vFAI) can be effectively derived from 3D CTCA datasets. In patients with coronary stenoses severity > 30% and ≤ 90%, vFAI performs well against FFR. vFAI may efficiently distinguish between functionally significant from non-significant lesions.

Stress-induced alteration of left ventricular eccentricity: An additional marker of multivessel CAD.

BACKGROUND: Abnormal left ventricular (LV) eccentricity index (EI) is a marker of adverse cardiac remodeling. However, the interaction between stress-induced alterations of EI and major cardiac parameters has not been explored. We sought to evaluate the relationship between LV EI and coronary artery disease (CAD) burden in patients submitted to myocardial perfusion imaging (MPI). METHODS AND RESULTS: Three-hundred and forty-three patients underwent MPI and coronary angiography. LV ejection fraction (EF) and EI were computed from gated stress images as measures of stress-induced functional impairment. One-hundred and thirty-six (40%), 122 (35%), and 85 (25%) patients had normal coronary arteries, single-vessel CAD, and multivessel CAD, respectively. Post-stress EI was lower in patients with multivessel CAD than in those with normal coronary arteries and single-vessel CAD (P = 0.001). This relationship was confirmed only in patients undergoing exercise stress test, where a lower post-stress EI predicted the presence of multivessel CAD (P = 0.039). CONCLUSIONS: Post-stress alterations of LV EI on MPI may unmask the presence of multivessel CAD.

Interactions between myocardial sympathetic denervation and left ventricular mechanical dyssynchrony: A CZT analysis.

BACKGROUND: A correlation between left ventricular (LV) dyssynchrony (LVD) and impaired myocardial sympathetic tone has been hypothesized. We sought to assess the interactions between regional LV sympathetic innervation, perfusion, and mechanical dyssynchrony. METHODS: Eighty-three patients underwent evaluation of LV perfusion and sympathetic innervation on 99mTc-tetrofosmin/123I-metaiodobenzylguanidine (123I-MIBG) imaging. The summed rest score and summed 123I-MIBG score (SS-MIBG) were computed. The extent of "innervation/perfusion" mismatch was defined as the number of denervated LV segments with relatively preserved perfusion. LVD was evaluated on phase analysis and the wall with latest mechanical activation identified. RESULTS: LVD was revealed in 36 (43%) patients. Patients with LVD had more abnormal values of SRS (21 ± 9 vs 10 ± 8, P < 0.001) and SS-MIBG (29 ± 9 vs 17 ± 11, P < 0.001) than those without LVD. The presence of LVD also clustered with a higher burden of "innervation/perfusion" mismatch (P = 0.019). On per-wall analysis, LV walls with delayed mechanical activation showed a higher burden of "innervation/perfusion" mismatch (2.3 ± 1.4 segments) than normally contracting walls (1.3 ± 1.2 segments; P < 0.001). On multivariate analysis, the extent of "innervation/perfusion" mismatch was the only predictor of delayed mechanical activation (P = 0.029). CONCLUSIONS: Patients with LVD show an elevated burden of "innervation/perfusion" mismatch that is concentrated at the level of the most dyssynchronous walls.

Evaluation of left ventricular mass on cadmium-zinc-telluride imaging: Validation against cardiac magnetic resonance.

BACKGROUND: Single-photon emission computed tomography has shown relevant limitations in the quantification of left ventricular (LV) mass. We sought to compare the estimates of LV mass on Cadmium-Zinc-Telluride (CZT) myocardial perfusion imaging (MPI) as compared to cardiac magnetic resonance (CMR). METHODS AND RESULTS: Twenty-five patients underwent MPI on a CZT camera and CMR on a 1.5 T scanner within 12 ± 3 weeks. LV mass was quantified on CZT images using two softwares: 4D-MSPECT (4DM) and Emory Cardiac Toolbox (ECTb). LV mass by CMR was quantified using MASS software (Medis, Leiden, The Netherlands). LV mass values obtained with 4DM and ECTb were highly reproducible [intraclass correlation coefficients .98 (95% CI .97-.99), and .98 (95% CI 0.97-.99), respectively]. The mean LVM mass values were 151 ± 44 g on CMR, 151 ± 43 g with 4DM (P = NS vs CMR), and 157 ± 42 g with ECTb (P < .001 vs CMR; P = .007 vs 4DM) CZT images. There was an excellent correlation between LV mass values between CMR and both 4DM (R2 = .95; P < .001) and ECTb (R2 = .98; P < .001) with narrow limits of agreement (- 13.6% to + 13.4% for 4DM, and - 5.6% to + 14.1% for ECTb). CONCLUSIONS: The evaluation of LV mass is feasible on CZT images, showing excellent agreement with CMR.

Relationships between left ventricular sympathetic innervation and diastolic dysfunction: the role of myocardial innervation/perfusion mismatch.

BACKGROUND: A possible relationship between cardiac sympathetic denervation and left ventricular (LV) diastolic dysfunction has been suggested. However, an evaluation of the interactions between myocardial adrenergic tone and LV perfusion and diastolic function is lacking. METHODS AND RESULTS: Seventy-two patients underwent 99mTc-tetrofosmin/123I-metaiodobenzylguanidine (123I-MIBG) cardiac Cadmium-Zinc-Telluride (CZT) imaging. The summed rest score (SRS) and summed 123I-MIBG score (SS-MIBG) were computed as measures of regional perfusion and innervation heterogeneities. LV segments showing an impaired innervation, despite a relatively preserved perfusion (99mTc-tetrofosmin-123I-MIBG tracers' uptake ≥25%), were individuated (innervation/perfusion mismatch). The peak filling rate (PFR) was computed as a measure of LV diastolic function. Nineteen of the 72 (26%) patients presented a normal LV diastolic function, while 29 (40%) and 24 (34%) had a mild and overt diastolic dysfunction. Subjects with diastolic dysfunction showed more abnormal SRS and SS-MIBG values (P < 0.001). In the global population, 502/1224 (41%) LV segments showed an innervation/perfusion mismatch. A modest correlation between the extent of cardiac innervation/perfusion mismatch and PFR values was evident (R = -0.27, P = 0.029). On multivariate analysis, the extent of regional innervation/perfusion mismatch remained an independent predictor of overt LV diastolic abnormalities (P = 0.017). CONCLUSIONS: The burden of LV regions showing an innervation/perfusion mismatch associates with the occurrence of overt diastolic dysfunction.

Myocardial 123I-metaiodobenzylguanidine imaging in hypertension and left ventricular hypertrophy.

Sympathetic nervous system plays a pivotal role in essential hypertension and in the development of left ventricular hypertrophy. Moreover, cardiac sympathetic dys-regulation has been demonstrated as a key con-causal factor in the genesis and progression of pathologic conditions such as congestive heart failure and ischemic heart disease to which hypertension predisposes as a risk factor. However, despite its fundamental role in cardiac pathophysiology, the evaluation of cardiac sympathetic nervous system has never gained a wide clinical application, remaining mostly a research tool. In this context, nuclear imaging techniques are the only modalities to allow the direct evaluation of cardiac sympathetic nervous integrity, giving the chance to obtain objective measures of the sympathetic tone. This review, while summarizing the general profile of currently available tests for autonomic evaluation, focuses on 123I-metaiodobenzylguanidine nuclear imaging as a preferential tool to assess cardiac sympathetic status. Specifically, the review discusses the available evidence on cardiac 123I-metaiodobenzylguanidine scintigraphy in arterial hypertension and left ventricular hypertrophy and its diagnostic and prognostic potential in congestive heart failure and ischemic heart disease.