Assessment of right ventricular sympathetic dysfunction in patients with arrhythmogenic right ventricular cardiomyopathy: An 123I-metaiodobenzylguanidine SPECT/CT study

Abstract

Purpose. The purpose of the study was to evaluate a novel approach for the quantification of right ventricular sympathetic dysfunction in patients diagnosed with ARVC/D through stateof-the-art functional SPECT/CT hybrid imaging. Methods. Sympathetic innervation of the heart was assessed using 123 I-MIBG-SPECT/CT in 17 patients diagnosed with ARVC according to the modified task force criteria, and in 10 patients diagnosed with idiopathic ventricular fibrillation (IVF). The 123 I-MIBG-uptake in the left (LV) and right ventricle (RV) was evaluated separately based on anatomic information derived from the CT scan, and compared to the uptake in the mediastinum (M). Results. There was a significant difference in the LV/M ratio between the ARVC/D and the IVF groups (3.2 ± 0.5 vs. 3.9 ± 0.8, P = 0.014), with a cutoff value of 3.41 (77% sensitivity, 80% specificity, AUC 0.78). There was a highly significant difference in the mean RV/M ratios between both groups (1.6 ± 0.3 vs. 2.0 ± 0.2, P = 0.001), with optimal cutoff for discrimination at 1.86 (88% sensitivity, 90% specificity, AUC 0.93). Conclusion. Employing state-of-the-art functional SPECT/CT hybrid imaging, we could reliably assess and quantify right and left ventricular sympathetic innervation. The RV/M ratio was significantly lower in patients diagnosed with ARVC/D and provided sensitive and specific discrimination between patients with ARVC/D and IVF patients. (J Nucl Cardiol 2018) Electronic supplementary material The online version of this article (

Excess TGF-β1 Drives Cardiac Mesenchymal Stromal Cells to a Pro-Fibrotic Commitment in Arrhythmogenic Cardiomyopathy

“…Intense physical exercise is both associated with activation of β adrenergic signaling and leads to excessive mechanical stretching of the heart. The areas affected by myocardial replacement in the ACM heart show reduced reuptake of norepinephrine that promotes stimulation of adrenergic receptors [ 31 ]. The norepinephrine treatment induces cardiac fibrosis and TGFB1 gene expression in rats’ ventricular endocardium [ 32 , 33 ].…”

Comparison of metabolic and functional parameters using cardiac 18F-FDG-PET in early to mid-adulthood male and female mice

“…Estimates for myocardial viability were calculated from static images as a percentage of the left ventricular surface area and automated volume measurements with QPS ® (Cedars-Sinai, Los Angeles, CA, USA) using a normative database, as described previously [11,22]. Left ventricular function parameters: EDV, ESV, the SV, and the EF, were calculated from ECG-gated images using QGS ® (Cedars-Sinai, Los Angeles, CA, USA), as described previously [10,12].…”

Fibrosis in Arrhythmogenic Cardiomyopathy: The Phantom Thread in the Fibro-Adipose Tissue

“…It has been reported that sympathetic dysinnervation characterize both the left (Wichter et al, 1994;Paul et al, 2011) and the RVs (Todica et al, 2018) of ACM patients: the areas affected by myocardial replacement show reduced reuptake of norepinephrine leading to chronic stimulation of adrenergic receptors, which in turn has been related to cardiac fibrosis. The norepinephrine treatment induces cardiac fibrosis promoting a series of events, such as CM death and collagen and transforming growth factor beta 1 (TGFβ1) gene expression in rats' ventricular endocardium (Bhambi and Eghbali, 1991;Castaldi et al, 2014).…”