Comparing the findings and diagnostic sensitivity of cardiovascular magnetic resonance in biopsy confirmed acute myocarditis with infarct-like vs. heart failure presentation

Abstract

Background Cardiovascular magnetic resonance (CMR) is considered the reference imaging modality in providing a non-invasive diagnosis of acute myocarditis (AM), as it allows for the detection of myocardial injury associated with AM. However, the diagnostic sensitivity and pattern of CMR findings appear to differ according to clinical presentation. Methods This is a retrospective cross-sectional study. Consecutive adult patients presenting to a single tertiary centre in South Africa between August 2017 and January 2022 with AM confirmed on endomyocardial biopsy (EMB) were enrolled. Patients with infarct-like symptoms, defined as those presenting primarily with chest pain syndrome with associated ST-T wave changes on electrocardiogram, or heart failure (HF) symptoms, defined as clinical signs and symptoms of HF without significant chest discomfort, were compared using contrasted CMR and parametric techniques with EMB confirmation of AM as diagnostic gold standard. Results Forty-one patients were identified including 23 (56%) with infarct-like symptoms and 18 (44%) with HF symptoms. On CMR, the infarct-like group had significantly higher ejection fractions of both ventricles (LVEF 55.3 ± 15.3% vs. 34.4 ± 13.5%, p < 0.001; RVEF 57.3 ± 10.9% vs. 42.9 ± 18.2%, p = 0.008), without significant differences in end diastolic volumes (LVEDVI 82.7 ± 30.3 ml/m2 vs. 103.4 ± 35.9 ml/m2, p = 0.06; RVEDVI 73.7 ± 22.1 ml/m2 vs. 83.9 ± 29.9 ml/m2, p = 0.25). Myocardial oedema was detected more frequently on T2-weighted imaging (91.3% vs. 61.1%, p = 0.03) and in more myocardial segments [3.0 (IQR 2.0–4.0) vs. 1.0 (IQR 0–1.0), p = 0.003] in the infarct-like group. Despite the absence of a significant statistical difference in the prevalence of late gadolinium enhancement (LGE) between the two groups (95.7% vs. 72.2%, p = 0.07), the infarct-like group had LGE detectable in significantly more ventricular segments [4.5 (IQR 2.3–6.0) vs. 2.0 (IQR 0–3.3), p = 0.02] and in a different distribution. The sensitivity of the original Lake Louise Criteria (LLC) was 91.3% in infarct-like patients and 55.6% in HF patients. When the updated LLC, which included the use of parametric myocardial mapping techniques, were applied, the sensitivity improved to 95.7% and 72.2% respectively. Conclusion The pattern of CMR findings and its diagnostic sensitivity appears to differ in AM patients presenting with infarct-like and HF symptoms. Although the sensitivity of the LLC improved with the addition of parametric mapping in the HF group, it remained lower than that of the infarct-like group, and suggests that EMB should be considered earlier in the course of patients with clinically suspected AM presenting with HF.

Infarct-like versus Non-Infarct-like Clinical Presentation of Acute Myocarditis: Comparison of Cardiac Magnetic Resonance (CMR) Findings

“…This mechanism is also able to justify, in part, the different locations of the signal alterations found in the two study samples; the "non-infarct-like" form showed, in our study, a significantly greater distribution of edema (p = 0.0308) and a significantly greater extent of edema and LGE at the level of the lateral (p = 0.0405 and p = 6.91 × 10 −4 , respectively) and inferior segments (edema p = 0.045) of the LV, particularly in the midsegment (p = 0.0076). The infero-lateral middle (basal) wall of the LV is, in fact, described as the site commonly affected by the phlogistic process, and it is the one in direct contact with the pericardium, accounting for its frequent involvement in AM caused by cardiotropic viruses (PVB19), as mentioned previously [2,5,12,21,25,26]. This localization of tissue damage in relation to PVB19 infection was described by Mahrholdt et al in association with an "infarct-like" presentation of AM [19].…”

“…The sample size of the study is small, reflecting the activity of a single hospital center; however, it is of the order of magnitude overlapping with that of some recent studies [1,15,25]. The CMR diagnosis was confirmed by clinical diagnosis in all enrolled patients, however, without biopsy.…”

“…The new LLC, updated in 2018, redefined imaging diagnosis according to the combined presence of a T1 criterion (presence of LGE or increased T1 mapping or extracellular volume values) and a T2 criterion (hyperintensity in T2 weighted STIR or increased T2 mapping values). These changes have significantly improved both the specificity and diagnostic accuracy of the LLC, especially in patients who do not present with infarct-like symptoms [25]. Unfortunately, in our hospital, the CMR mapping technique was not available at the time of the study.…”

Advancing Precision Medicine in Myocarditis: Current Status and Future Perspectives in Endomyocardial Biopsy-Based Diagnostics and Therapeutic Approaches

“…It is based on the Lake Louise Criteria (LLC) including T1 and T2 mapping and has been shown to assess severe inflammation and fibrosis [15]. However, the diagnostic power of CMR is limited because CMR is unable to detect the underlying etiology of myocarditis, particularly the presence of viral infections and transcriptional activity and the quality and intensity of inflammation cannot be accurately detected [11,16,17]. Therefore, no therapeutic decision can be made based on imaging alone [18].…”

SARS-CoV-2-Induced Myocarditis: A State-of-the-Art Review

“…Several studies have suggested the substantial role of non-invasive cardiac magnetic resonance imaging (CMRI), which is the reference standard for diagnosis, bypassing the risks associated with cardiac biopsies. With the use of cardiac MRIs, regions of myocarditis have been observed to closely correlate with regions of abnormal signal [13][14][15][16]. The current recommendations are proposed on the basis of consensus emerging from the position statement that invasive studies such as endomyocardial biopsies (EMBs) should be performed only if there is a good overall prognosis for patients with mild acute dilated cardiomyopathy, even if these subjects are potentially at risk of worsening clinical conditions.…”