2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

Aim This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy i...

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary

Writing Committee Members 3

Myocardial fibrosis, either focal or diffuse, is a common feature of many cardiac diseases and is associated with a poor prognosis for major adverse cardiovascular events. Although histological analysis remains the gold standard for confirming the presence of myocardial fibrosis, endomyocardial biopsy is invasive, has sampling errors, and is not practical in the routine clinical setting. Cardiac imaging modalities offer noninvasive surrogate biomarkers not only for fibrosis but also for myocardial edema and infiltration to varying degrees, and have important roles in the diagnosis and management of cardiac diseases. This review summarizes important pathophysiological features in the development of commonly encountered cardiac diseases, and the principles, advantages, and disadvantages of various cardiac imaging modalities (echocardiography, single-photon emission computer tomography, positron emission tomography, multidetector computer tomography, and cardiac magnetic resonance) for myocardial tissue characterization, with an emphasis on imaging focal and diffuse myocardial fibrosis.

Myocardial Tissue Characterization and Fibrosis by Imaging

Hypertrophic Cardiomyopathy (HCM) confers a 4–5 %/year-risk for sudden cardiac death. Intramyocardial fibrosis (IF) is associated with this risk. The gold standard of IF visualization is cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE–CMR). In view of a number of CMR-limitations the hypothesis of this study was that late enhanced multi-slice computed tomography (leMDCT) enables demonstration of late enhancement (LE) indicating IF. In a prospective single-center validation study leMDCT research-scans were exclusively performed for IF-imaging in HCM-patients not including non-invasive coronary angiography during first-pass (64-slice; 80 kV; Iopromide, 150 mL, injected 7 min before scanning). Applying a 17-segment-polar-map short cardiac axis views (multiplanar reformations; 5 mm slice thickness) were analysed in order to exclude/detect, localize and measure LE practicing the manual quantification method if present. Finally, leMDCT and LGE–CMR data were unblinded for intermodal correlation. We included n = 24 patients consecutively (64.0 ± 14.5 years of age). LE was demonstrated by LGE–CMR in n = 14/24 patients (prevalence 58 %). Patient- and segment-based sensitivity in leMDCT was 100 and 68 %, respectively. In leMDCT tissue density of LE was 142 ± 51 versus 89.9 ± 19.3 HU in remote myocardium (p < 0.001). Signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) appeared to be 7.3 ± 3.3 and 2.3 ± 1, respectively. Sizing of LE-area gave 2.2 ± 1.4 cm2 in leMDCT versus 2.9 ± 2.4 cm2 in LGE–CMR (r = 0.93). Intra-/interobserver variability was assessed with an accuracy of 0.36 cm2 (r = 0.91) and 0.47 cm2 (r = 0.82), respectively. In consecutive HCM patients leMDCT can reliably detect intramyocardial fibrosis marked by LE. In view of a comparatively low SNR and CNR leMDCT may alternatively be applied in case of CMR contraindications.

C. Gierloff

Papers

Hypertrophic cardiomyopathy in cardiac CT: a validation study on the detection of intramyocardial fibrosis in consecutive patients