Daniel Sado

Heart pumping weakness occurs progressively in all patients with Duchenne muscular dystrophy (DMD), but symptoms only occur very late in the process. Regular imaging assessments of heart function are needed to see how the heart is ‘doing’ and how well it is responding to treatment with heart drugs. Echocardiography (echo) has been the standard type of imaging used for these assessments in the UK. It is widely available but has limitations. Cardiac MRI (CMR), although less readily available and more expensive, is better able to detect tissue changes in the heart before there is any reduction of heart pump function and retains accuracy in all measures even as DMD progresses. An expert panel of cardiologists, muscle specialists and patient representatives was set up to review evidence and provide expert guidance on how to use both echo and CMR best to the benefit of patients with DMD, Becker muscular dystrophy (BMD) and females affected by DMD-gene abnormalities (‘female gene carriers’). The working group concluded that echo should remain the predominant method used in heart checks for patients with DMD in the UK. However, wider use of CMR, performed at times individualised to key decision points after about the age of 10 years, would allow earlier detection of those heart changes prompting the introduction and changes in heart therapies. Similarly, greater use of CMR could contribute to improving cardiac management of males with BMD and females with DMD-gene variations. _______________________ Objective: To provide guidance on the use of cardiac MRI (CMR) in the UK in paediatric and adult patients with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD) as well as recommendations for screening and monitoring females with dystrophin-gene variations. Specifically, to examine the ‘added value’ of CMR over echocardiography at selected time points in the assessment of individuals with or at risk of developing cardiac dystrophinopathy. Methods: Initiated by an expert working group of UK-based and US-based imaging cardiologists, neuromuscular clinicians and DMD-patient representatives, draft guidelines were created based on published evidence, current practice and expert opinion. After wider consultation with UK cardiologists, consensus was reached on the optimal use of CMR in clinical decision-making about therapy. Results and conclusions: Echocardiography should remain the predominant modality for cardiac surveillance and to guide therapy for patients with DMD in the UK. However, when tolerated, wider use of CMR at key stages in patients with DMD, older than age 10 years, and for males with BMD and females with DMD-gene variations would allow earlier detection of those with cardiac involvement and inform the earlier initiation of regimes of cardiac medications. In this way, greater use of CMR could contribute to improving cardiac health in each of these patient groups.

Aims: Heart failure with preserved ejection fraction (HFpEF) accounts for approximately half of all heart failure cases, with high levels of morbidity and mortality. However, many patients who meet diagnostic criteria for HFpEF do not have a documented diagnosis, particularly in non-White populations where conventional risk scores may underestimate risk. Our aim was to develop and validate a diagnostic prediction model to detect HFpEF based on ESC criteria, AIM-HFpEF. Methods and results: We applied natural language processing (NLP) and machine learning methods to routinely collected electronic health record (EHR) data from a tertiary centre hospital trust in London, UK, to derive the AIM-HFpEF model. We then externally validated the model and performed benchmarking against existing HFpEF prediction models (H2FPEF and HFpEF-ABA) for diagnostic power on the entire external cohort and in patients of non-White ethnicity and patients from areas of increased socioeconomic deprivation. An XGBoost model combining demographic, clinical, and echocardiogram data showed strong diagnostic performance in the derivation dataset [n = 3173, AUC = 0.88, (95% CI, 0.85–0.91)] and validation cohort [n = 5383, AUC: 0.88 (95% CI, 0.86–0.90)]. Diagnostic performance was maintained in patients of non-White ethnicity [AUC = 0.89 (95% CI, 0.85–0.93)] and patients from areas of high socioeconomic deprivation [AUC = 0.90 (95% CI, 0.85–0.95)]. In contrast, AIM-HFpEF demonstrated favourable performance relative to the H2FPEF and HFpEF-ABA models. AIM-HFpEF model probabilities were associated with an increased risk of death, hospitalization, and stroke in the external validation cohort (P < 0.001, P = 0.01, P < 0.001, respectively, for highest vs. middle tertile). Conclusion: AIM-HFpEF represents a validated equitable diagnostic model for HFpEF, which can be embedded within an EHR to allow for fully automated HFpEF detection.

Cardiac involvement in idiopathic inflammatory myopathies (IIM) purports to worse clinical outcomes and therefore early identification is important. Research has focused on blood biomarkers and basic investigations such as electrocardiography and echocardiography, which have the advantage of wide availability and low cost but are limited in their sensitivity. Imaging the myocardium to directly look for inflammation and scarring has therefore been explored, with a number of new methods for doing this gaining wider research and clinical availability. Cardiovascular magnetic resonance (CMR) with contemporary multiparametric mapping techniques and late gadolinium enhancement imaging, is an extremely valuable and increasingly used non-invasive imaging modality for the diagnosis of myocarditis. The recently updated CMR based Lake Louise Criteria for the diagnosis of myocarditis incorporate the newer T1 and T2 mapping techniques which have greatly improved the diagnostic accuracy of IIM myocarditis.¹⁸F-FDG-PET/CT is a well-utilised imaging modality in the diagnosis of malignancies in IIM which also has a role for the diagnosis of myocarditis in multiple systemic inflammatory diseases. Endomyocardial biopsy however remains the gold standard technique for the diagnosis of myocarditis and is necessary for the diagnosis of specific cases of myocarditis. This article provides an overview of the important tests and imaging modalities which clinicians should consider when faced with an IIM patient with potential myocarditis.

Background: Coronary angiography and viability testing are the cornerstones of diagnosing and managing ischemic cardiomyopathy. At present, no single test serves both needs. Coronary wave intensity analysis interrogates both contractility and microvascular physiology of the subtended myocardium and therefore has the potential to fulfil the goal of completely assessing coronary physiology and myocardial viability in a single procedure. We hypothesized that coronary wave intensity analysis measured during coronary angiography would predict viability with a similar accuracy to late-gadolinium–enhanced cardiac magnetic resonance imaging. Methods: Patients with a left ventricular ejection fraction ≤40% and extensive coronary disease were enrolled. Coronary wave intensity analysis was assessed during cardiac catheterization at rest, during adenosine-induced hyperemia, and during low-dose dobutamine stress using a dual pressure-Doppler sensing coronary guidewire. Scar burden was assessed with cardiac magnetic resonance imaging. Regional left ventricular function was assessed at baseline and 6-month follow-up after optimization of medical-therapy±revascularization, using transthoracic echocardiography. The primary outcome was myocardial viability, determined by the retrospective observation of functional recovery. Results: Forty participants underwent baseline physiology, cardiac magnetic resonance imaging, and echocardiography, and 30 had echocardiography at 6 months; 21/42 territories were viable on follow-up echocardiography. Resting backward compression wave energy was significantly greater in viable than in nonviable territories (−5240±3772 versus −1873±1605 W m ⁻² s ⁻¹ , P P =0.649); a threshold of −2500 W m ⁻² s ⁻¹ had 86% sensitivity and 76% specificity. Conclusions: Backward compression wave energy has accuracy similar to that of late-gadolinium–enhanced cardiac magnetic resonance imaging in the prediction of viability. Coronary wave intensity analysis has the potential to streamline the management of ischemic cardiomyopathy, in a manner analogous to the effect of fractional flow reserve on the management of stable angina.

Invasive coronary angiography and non-invasive viability testing are the cornerstones of diagnosing and managing ischemic left ventricular dysfunction. At present there is no single test which serves both needs but, if developed, could revolutionise investigation of this condition. Coronary wave intensity analysis (cWIA) interrogates both contractility and microvascular physiology of the subtended myocardium [1,2] and therefore has the potential to fulfil this goal. We hypothesized that cWIA measured during coronary angiography would predict functional recovery with a similar accuracy to late gadolinium enhanced cardiac magnetic resonance imaging (LGE-CMR). Patients with a left ventricular ejection fraction ≤40% and extensive coronary disease were enrolled. cWIA, fractional flow reserve and microvascular resistance were assessed with a simultaneous coronary Doppler and pressure-sensing guidewire during cardiac catheterization at rest, during hyperaemia and during low-dose dobutamine stress. Viability was assessed using LGE-CMR. Regional left ventricular function was assessed at baseline and 6-month follow up after optimization of medical therapy +/− revascularization, using transthoracic echocardiography. The primary outcome was regional functional recovery. Forty participants underwent baseline physiology, LGE-CMR and thirty had echocardiography at baseline and 6 months; 21/42 territories demonstrated functional recovery. Resting backward compression wave energy was significantly greater in recovering than non-recovering territories (−5240±3772 vs. −1873±1605 W m^–2 s^–1, p=0.099, Figure 1), and had comparable diagnostic accuracy to CMR (area under the curve 0.812 vs. 0.757, p=0.649, Figure 2); a threshold of −2500 W mm^–2 s^–1 had 86% sensitivity and 76% specificity at predicting recovery. Backward expansion wave energy did not predict recovery. FFR was numerically higher in recovering territories (0.81±0.17 vs. 0.71±0.16, p=0.058), whilst hyperaemic microvascular resistance did not differentiate recovering from non-recovering territories (1.97±0.73 vs. 2.29±1.00, p=0.287). The likelihood of functional recovery was similar in revascularised and non-revascularised territories (15/29 vs. 6/13 respectively, p=0.739). Low-dose dobutamine stress increased the energy of all waves, but did not improve the accuracy of cWIA in predicting recovery. In a regression model, resting backward compression wave energy and optimization of medical therapy predicted functional recovery; fractional flow reserve and hyperemic microvascular resistance did not. Backward compression wave energy has similar accuracy to LGE-CMR in the prediction of functional recovery. cWIA has the potential to revolutionise the management of ischaemic left ventricular dysfunction, in a manner analogous to the effect of fractional flow reserve on the management of stable angina. Type of funding sources: Foundation. Main funding source(s): The British Heart Foundation Clinical Research Training Fellowship Figure 1 Figure 2

Differentiating exudative from transudative effusions is clinically important and is currently performed via biochemical analysis of invasively obtained samples using Light’s criteria. Diagnostic performance is however limited. Biochemical composition can be measured with T1 mapping using cardiovascular magnetic resonance (CMR) and hence may offer diagnostic utility for assessment of effusions. A phantom consisting of serially diluted human albumin solutions (25–200 g/L) was constructed and scanned at 1.5 T to derive the relationship between fluid T1 values and fluid albumin concentration. Native T1 values of pleural and pericardial effusions from 86 patients undergoing clinical CMR studies retrospectively analysed at four tertiary centres. Effusions were classified using Light’s criteria where biochemical data was available (n = 55) or clinically in decompensated heart failure patients with presumed transudative effusions (n = 31). Fluid T1 and protein values were inversely correlated both in the phantom (r = −0.992) and clinical samples (r = −0.663, P < 0.0001). T1 values were lower in exudative compared to transudative pleural (3252 ± 207 ms vs. 3596 ± 213 ms, P < 0.0001) and pericardial (2749 ± 373 ms vs. 3337 ± 245 ms, P < 0.0001) effusions. The diagnostic accuracy of T1 mapping for detecting transudates was very good for pleural and excellent for pericardial effusions, respectively [area under the curve 0.88, (95% CI 0.764–0.996), P = 0.001, 79% sensitivity, 89% specificity, and 0.93, (95% CI 0.855–1.000), P < 0.0001, 95% sensitivity; 81% specificity]. Native T1 values of effusions measured using CMR correlate well with protein concentrations and may be helpful for discriminating between transudates and exudates. This may help focus the requirement for invasive diagnostic sampling, avoiding unnecessary intervention in patients with unequivocal transudative effusions.

Dear Editor, Paediatric multisystem inflammatory syndrome temporally associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PIMS-TS) is an increasingly recognized entity, with features of both Kawasaki disease and toxic shock syndrome. There have been multiple reports of this syndrome in the paediatric population [ 1, 2]. We describe an adult male presenting with features suggestive of Kawasaki disease after recently confirmed infection with SARS-CoV-2.