The value of cardiac sympathetic activity and mechanical dyssynchrony as cardiac resynchronization therapy response predictors: comparison between patients with ischemic and non-ischemic heart failure.

BACKGROUND: Impaired cardiac sympathetic activity and mechanical dyssynchrony (MD) are associated with poor prognosis in patients with heart failure (HF) after cardiac resynchronization therapy (CRT). The study aims to assess the significance of scintigraphic evaluation of cardiac sympathetic innervation and contractility in predicting response to CRT in patients with ischemic and non-ischemic chronic HF. METHODS AND RESULTS: The study includes 58 HF patients, who were referred for CRT. Prior to CRT all patients underwent 123I-metaiodobenzylguanidine (123I-MIBG) imaging and gated myocardial perfusion imaging (MPI) using a cadmium-zinc-telluride (CZT) SPECT/CT device. At a one-year follow-up post-CRT, the delayed heart-to-mediastinum 123I-MIBG uptake ratio was an independent predictor of CRT response in non-ischemic HF patients (OR 1.469; 95% CI 1.076-2.007, p = .003). In ischemic HF patients the MD index histogram bandwidth (HBW) obtained by CZT-gated MPI had a predictive value (OR 1.06, 95% CI 1.001-1.112, p = .005) to CRT response. CONCLUSION: CRT response can be predicted by cardiac 123I-MIBG scintigraphy, specifically by the heart-to-mediastinum ratio in non-ischemic HF and by the MD index HBW in ischemic HF. These results suggest the value of a potentially useful algorithm to improve outcomes in HF patients who are candidates for CRT.

Low-dose dobutamine stress gated blood pool SPECT assessment of left ventricular contractile reserve in ischemic cardiomyopathy: a feasibility study.

PURPOSE: The purpose of the present study was to evaluate the feasibility of gated blood pool single-photon emission computed tomography (GBPS) with low-dose dobutamine (LDD) stress test, performed on a single-photon emission computed tomography (SPECT) camera equipped with cadmium-zinc-telluride (CZT) solid-state detectors, in assessing of left ventricle (LV) contractile reserve in patients with ischemic cardiomyopathy (ICM). METHODS: A total of 52 patients (age 59 ± 7.2 years, 47 men and 5 women) with ICM and a control group of 10 patients without obstructive coronary artery lesion underwent GBPS and transthoracic echocardiography (TTE) at rest and during LDD stress test (5, 10, 15 µg/kg/min). The duration of each GBPS step was 5 min. Stress-induced changes in LV ejection fraction (ΔLVEF), peak ejection rate, LV volumes, and mechanical dyssynchrony (phase histogram standard deviation, phase histogram bandwidth and entropy) obtained with GBPS were estimated. RESULTS: All GBPS indices except end-diastolic volume showed significant dynamics during stress test in both groups. The majority of parameters in ICM patients showed significant changes at a dobutamine dose of 10 µg/kg/min as compared to the rest study. Seventeen percent of ICM patients, but none from the control group, showed a decrease in LVEF during stress, accompanied by a significant increase in entropy. The intra- and inter-observer reproducibility was excellent for both rest and stress studies. There was a moderate correlation (r = 0.5, p = 0.01) between GBPS and TTE, with a mean difference value of - 1.7 (95% confidence interval - 9.8; 6.4; p = 0.06) in ΔLVEF. CONCLUSION: Low-dose dobutamine stress GBPS performed with high-efficiency CZT-SPECT cameras can be performed for evaluating stress-induced changes in LV contractility and dyssynchrony with lower acquisition time. A dobutamine dose of 10 µg/kg/min can potentially suffice to detect stress-induced changes in patients with ICM during GBPS. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04508608 (August 7, 2020).

[18F-FDG-PET/CT AS A TOOL FOR DIAGNOSIS AND FOLLOW-UP OF INFLAMMATORY DISEASES OF LARGE BLOOD VESSELS].

INTRODUCTION: Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET) / Computed Tomography (FDG-PET/CT) is a well-established functional-anatomical imaging technique mostly used in oncology. In addition, it was found to have an important role in the diagnosis and follow-up of large vessel vasculitis mainly when combined with computed tomography angiography. Large vessel vasculitis is a disease mainly affecting large blood vessels and has two major groups: Takayasu arteritis (TA) and Giant cell arteritis (GCA). GCA is usually accompanied by polymyalgia rheumatica (PMR).

[IS MYOCARDIAL PERFUSION IMAGING INTERPRETATION HARDER WITH X-RAY BEAM HARDENING ARTIFACT?]

INTRODUCTION: Myocardial perfusion imaging (MPI) is a well-established imaging modality for the diagnosis of coronary artery disease and for prognostication. In recent years, the management of heart failure has developed tremendously including implantation of defibrillators for prevention of malignant tachyarrhythmias and resynchronizing therapy for the improvement of clinical symptoms and left ventricular function. Cardiac magnetic resonance and computed tomography are imaging modalities that are negatively affected by the presence of metallic devices. MPI is a hybrid study combining computed tomography for attenuation correction and nuclear imaging. This case shows that a metal device has no effect on the interpretation of MPI.

Effect of proton pump inhibitors on Rubidium-82 gastric uptake using positron emission tomography myocardial perfusion imaging.

BACKGROUND: Rb-82 positron emission tomography (PET) myocardial perfusion imaging (MPI) is a robust tool for the evaluation of coronary artery disease (CAD). However, gastric uptake and spillover can be seen in 10% of Rb-82 PET MPI studies, commonly affecting the inferior wall, and can preclude the accurate identification of myocardial ischemia. We sought to understand the relationship between Rb-82 gastric uptake and the use of proton pump inhibitors (PPI). METHODS: 600 consecutive patients who presented for a clinically indicated Rb-82 PET MPI study were prospectively enrolled. In addition to the clinical history, PPI use was ascertained (medication, dose, frequency and duration of use, and time of last dose). Patients were categorized as PPI and non-PPI users. Rb-82 uptake in the gastrium, myocardium, and liver were measured at rest. Absolute uptake values and gastric:hepatic ratios were compared in PPI and non-PPI users. RESULT: Of 600 enrolled patients, 181 (30.2%) patients were using PPI. The gastric Rb-82 uptake in PPI users was 23% higher than non-PPI users (146 ± 52 kBq/cc vs 119 ± 40 kBq/cc, respectively; P < 0.001). The resting gastric:hepatic Rb-82 uptake ratio was also 23% higher in PPI vs non-PPI users (2.7 ± 1.0 vs 2.2 ± 0.8, respectively; P < 0.001). CONCLUSION: The gastric uptake of Rb-82 appears to be greater in patients actively using PPI and may identify a group who might be at greater risk of non-diagnostic Rb-82 PET MPI.

Strategies for Minimizing Occupational Radiation Exposure in Cardiac Imaging.

PURPOSE OF REVIEW: Radiation safety has been at the center of interest of both researchers and healthcare institutions. This review will summarize and shed light on the various techniques adapted to reduce staff exposure to ionizing radiation (IR) in the field of cardiac imaging. RECENT FINDINGS: In the last years, with the advance of awareness and the development of new technologies, there have been several tools and techniques adapted. The breakthrough of several technologies to lower radiation dose and shorten the duration of diagnostic tests associated with IR, the use of protection devices by staff members, and mostly the awareness of exposure to IR are the hallmark of these advances. Using all these measures has led to a significant decrease in staff exposure to IR. Reducing staff exposure to meet the "As Low As Reasonably Achievable" principle is feasible. This review introduces the most important strategies applied in cardiac imaging.

Conduction abnormalities during dipyridamole stress testing.

Pharmacological stress tests using dipyridamole are considered to be safe. However, cases of atrioventricular (AV) block have been reported. We retrospectively analyzed ECG at baseline and during dipyridamole stress tests of 2010 consecutive patients (patients with second or third degree AV block were excluded). At baseline, 350 (17.4%) patients had conduction abnormalities. Following dipyridamole infusion 16 patients (0.8%) developed a transient change in AV conduction (15 patients) and or sinus arrest (1 patient). Compared to patients without baseline conduction abnormalities, patients with any conduction abnormalities at baseline were at a higher risk for the development of AV block after dipyridamole infusion [0.3% vs 3.14%, respectively; P < .0001].

Cardiovascular Imaging in Women.

Multimodality cardiovascular imaging is a cornerstone diagnostic tool in the diagnosis, risk stratification, and management of cardiovascular diseases, whether those involving the coronary tree, myocardial, or pericardial diseases in general and particularly in women. This manuscript aims to shed some light and summarize the very features of cardiovascular disease in women, explore their unique characteristics and discuss the role of cardiovascular imaging in ischemic heart disease and cardiomyopathies. The role of four imaging modalities will be discussed including nuclear medicine, echocardiography, noninvasive coronary angiography, and cardiac magnetic resonance.

Transesophageal echocardiography and computerized tomography angiography mismatch in left atrial appendage thrombus evaluation.

BACKGROUND: Transesophageal echocardiography (TEE) is the gold standard test for the diagnosis of left atrial appendage (LAA) thrombus. Nonetheless, computerized tomography angiography (CTA) is readily used to exclude LAA thrombus before pulmonary vein isolation (PVI) and LAA closure procedures. We aimed to assess the comparability of LAA thrombus diagnosis using chest CTA scans in patients with atrial fibrillation who underwent TEE. METHODS: Retrospective collection of consecutive patients with atrial fibrillation who underwent TEE and chest CTA within 30 days and had evidence of spontaneous echo contrast (SEC) or LAA thrombus on TEE. Clinical, demographic, and echo data were collected. Prospective analysis of the CTA for evidence of LAA thrombus in the same group of patients was performed. We compared the findings of the two modalities. RESULTS: Out of 1550 patients with atrial fibrillation who underwent TEE examinations in the study period, 63 patients underwent TEE within 30 days of a chest CTA scan. Twenty-three patients had LAA thrombus and 40 had some degree of SEC according to TEE. On CTA, 11 were interpreted as positive with a high level of suspicion for the presence of an LAA thrombus. Six patients (26.1%) had LAA thrombus according to both CT and TEE. Therefore, low concordance was found between test results (chi-squared continuity correction = 5.5, df  = 1, and P -value = 0.01902). CONCLUSION: The discrepancy between CTA and TEE results suggests these examinations might be more suitable as complementary examinations to exclude LAA thrombus.

Identifying left ventricular dysfunction using prospective electrocardiogram-triggered coronary computed tomography angiography.

PURPOSE: Coronary computed tomography angiography (CCTA) is an important non-invasive tool for the assessment of coronary artery disease and the delivery of information incremental to coronary anatomy. CCTA measured left ventricular (LV) mid-diastolic volume (LVMDV) and LV mass (LVMass) have important prognostic information but the utility of prospectively ECG-triggered CCTA to predict reduced left ventricular ejection fraction (LVEF) is unknown. The objective of this study was to determine if indexed LVMDV (LVMDVi) and the LVMDV:LVMass ratio on CCTA can identify patients with reduced LVEF. MATERIALS/METHODS: 8179 patients with prospectively ECG-triggered CCTA between November 2014 and December 2019 were reviewed. A subset derivation cohort of 4352 healthy patients was used to define normal LVMDVi and LVMDV:LVMass. Sex-specific thresholds were tested in a validation cohort of 1783 patients, excluded from the derivation cohort, with cardiac disease and known LVEF. The operating characteristics for 1 SD above the mean were tested for the identification of abnormal LVEF, LVEF≤35 â€‹% and ≤30 â€‹%. RESULTS: The derivation cohort had a mean LVMDVi of 61.0 â€‹± â€‹13.7 â€‹mL/m2 and LVMDV:LVMass of 1.11 â€‹± â€‹0.24 â€‹mL/g. LVMDVi and LVMDV:LVMass were both higher in patients with reduced LVEF than those with normal LVEF (98.8 â€‹± â€‹40.8 â€‹mL/m2 vs. 63.3 â€‹± â€‹19.7 â€‹mL/m2, p â€‹< â€‹0.001, and 1.32 â€‹± â€‹0.44 â€‹mL/g vs. 1.05 â€‹± â€‹0.28 â€‹mL/g, p â€‹< â€‹0.001). Both mean LVMDVi and LVMDV:LVMass increased with the severity of LVEF reduction. Sex-specific LVMDVi thresholds were 79 â€‹% and 80 â€‹% specific for identifying abnormal LVEF in females (LVMDVi â€‹≥ â€‹69.9 â€‹mL/m2) and males (LVMDVi â€‹≥ â€‹78.8 â€‹mL/m2), respectively. LVMDV:LVMass thresholds had high specificity (87 â€‹%) in both females (LVMDVi:LVMass â€‹≥ â€‹1.39 â€‹mL/g) and males (LVMDVi:LVMass â€‹≥ â€‹1.30 â€‹mL/g). CONCLUSION: Our study provides reference thresholds for LVMDVi and LVMDV:LVMass on prospectively ECG-triggered CCTA, which may identify patients who require further LV function assessment.

Correlations between high sensitive troponin I and acute myocarditis extent in cardiac magnetic resonance imaging.

PURPOSE: To assess the correlation between high sensitive troponin I (HsTnI) levels and myocardial damage on cardiac magnetic resonance (CMR) represented by late gadolinium enhancement (LGE) percentage in patients diagnosed with myocarditis. METHODS: Retrospective analysis of consecutive patients who underwent CMR following a suspected diagnosis of acute myocarditis, comparing CMR findings viewed as LGE percentage and HsTnI levels. RESULTS: Between February 2016 and December 2021, 101 patients underwent CMR for suspected myocarditis in Rambam Medical Center. Seventy-six (75.2%) patients with a documented diagnosis of acute myocarditis in the medical records based on clinical history and lab work were included in the final analysis. The median age was 30 years [interquartile range (IQR) 22,42] and 62 patients (81.6%) were male. Thirty-four patients (44.7%) had a history of fever and 26 (34.2%) had upper respiratory tract symptoms. The median maximal HsTnI was 3935 ng/l (1165,10 380) and the median C-reactive protein (CRP) was 7.97 mg/l (2.35,19.28). The median LGE percentage was 4.65% (2.6,8.5) and ventricular ejection fraction 60% (56.00,64.75).Linear association was found between LGE (%) and maximal HsTnI (ng/l) value with r  = 0.49 ( P  < 0.001). After including only patients in whom the CMR was performed within 5 days of the maximal HsTnI the correlation improved to r  = 0.67 ( P  < 0.001). CONCLUSIONS: HsTnI is an indicator for myocardial damage extent resulting from inflammation in patients with acute myocarditis.

Coronary computed tomography angiography in the evaluation of acute chest pain in patients with elevated high sensitive cardiac troponin I (hs-cTn) level.

Aims CCTA is a well-established and safe imaging modality for the diagnosis of CAD and is gate keeping for invasive coronary angiography (ICA). We aimed to examine CCTA performance in patients presenting with ACP and dynamic hs-cTn elevation compatible with MI but not exceeding 7 folds of the URL. We also examined the performance of GRACE and PTP consortium scores in this population of patients.

Computed tomography measured epicardial adipose tissue and psoas muscle attenuation: new biomarkers to predict major adverse cardiac events and mortality in patients with heart disease and critically ill patients. Part II: Psoas muscle area and density.

Sarcopenia is a syndrome characterised by loss of skeletal muscle mass, loss of muscle quality, and reduced muscle strength, resulting in low performance. Sarcopenia has been associated with increased mortality and complications after medical interventions. In daily clinical practice, sarcopenia is assessed by clinical assessment of muscle strength and performance tests and muscle mass quantification by dual-energy X-ray absorptio-metry (DXA) or bioelectrical impedance analysis (BIA). Assessment of the skeletal muscle quantity and quality obtained by abdominal computed tomography (CT) has gained interest in the medical community, as abdominal CT is performed for various medical reasons, and quantification of the psoas and skeletal muscle can be performed without additional radiation load and dye administration. The definitions of CT-derived skeletal muscle mass quantification are briefly reviewed: psoas muscle area (PMA), skeletal muscle area (SMA), and transverse psoas muscle thickness (TPMT). We explain how CT attenuation coefficient filters are used to determine PMA and SMA, resulting in the psoas muscle index (PMI) and skeletal muscle index (SMI), respectively, after indexation to body habitus. Psoas muscle density (PMD), a biomarker for skeletal muscle quality, can be assessed by measuring the psoas muscle CT attenuation coefficient, expressed in Hounsfield units. The concept of low-density muscle (LDM) is explained. Finally, we review the medical literature on PMI and PMD as predictors of adverse outcomes in patients undergoing trauma or elective major surgery, transplantation, and in patients with cardiovascular and internal disease. PMI and PMD are promising new biomarkers predicting adverse outcomes after medical interventions.