Subendocardial Involvement as an Underrecognized Cardiac MRI Phenotype in Myocarditis

Cardiac MRI in infarct-like myocarditis: transmural extension of late gadolinium enhancement is associated with worse outcomes

OBJECTIVES

To assess the prognostic value of cardiac MRI (CMR) parameters for the occurrence of major adverse cardiac events (MACE) in patients with infarct-like myocarditis.

METHODS

In this retrospective single-center study, patients with CMR-confirmed acute myocarditis with infarct-like presentation were identified (2007-2020). Functional and structural parameters were analyzed including late gadolinium enhancement (LGE). The primary endpoint was the occurrence of MACE up to 5 years after discharge.

RESULTS

In total, 130 patients (mean age, 40 ± 19 years; 97 men, 75%) with infarct-like myocarditis were included. CMR was conducted a median of 3 days (interquartile range [IQR], 1-5) after symptom onset. MACE occurred in 18/130 patients (14%) during a median follow-up of 19.3 months (IQR, 4.5-53). The median extent of LGE was 7% (IQR, 4-10). LGE affected the subepicardium in 111/130 patients (85%), the midwall in 45/130 patients (35%), and both the subepicardium and midwall in 27/130 patients (21%). Transmural extension of non-ischemic LGE lesions was observed in 15/130 patients (12%) and septal LGE in 42/130 patients (32%). In univariable Cox regression analysis, a significant association was found between the occurrence of MACE and both, quantified LGE extent and transmural LGE pattern. In multivariable analysis, transmural extension of LGE was an independent predictor for MACE (hazard ratio, 6.34; 95% confidence interval: 2.29-17.49; p < 0.001). Patients with the transmural extension of LGE had a shorter event-free time on Kaplan-Meier analysis (log-rank p < 0.001).

CONCLUSIONS

MACE occurred in 14% of patients with infarct-like myocarditis during follow-up. A transmural extension of non-ischemic LGE was associated with a worse long-term prognosis.

CRITICAL RELEVANCE STATEMENT

CMR-based assessment of transmural extension of non-ischemic LGE holds the potential to serve as an easily assessable marker for risk stratification in patients with infarct-like myocarditis.

KEY POINTS

The prognostic value of CMR was studied in patients with infarct-like myocarditis. The extent of LGE and transmural extension were linked to adverse cardiac events. Transmural non-ischemic LGE can serve as an easily assessable prognostic marker.

Leukocytoclastic Vasculitis-Associated Myocarditis as an Extraintestinal Manifestation of Crohn's Disease

Cardiac extraintestinal manifestations (EIMs) of Crohn's disease (CD) are uncommon. They include pericarditis, myocarditis, and arrhythmias; however, distinguishing these from alternative causes including medication-related adverse effects is often challenging. Leukocytoclastic vasculitis is another uncommon EIM of CD that may present with systemic involvement. We present a rare case of myocarditis associated with leukocytoclastic vasculitis occurring as EIMs of CD. The myocarditis proved refractory to standard therapy and biologics targeting underlying gut inflammation. She developed an inflammatory cardiomyopathy and symptoms consistent with heart failure with preserved ejection fraction. Anakinra was tried, but despite the initial response, it should be used cautiously in patients with CD.

Phenotyping of giant cell myocarditis versus cardiac sarcoidosis using cardiovascular magnetic resonance

BACKGROUND

Giant cell myocarditis (GCM) and cardiac sarcoidosis (CS) are rare inflammatory diseases of the myocardium with poor prognosis. Little is known about the cardiovascular magnetic resonance (CMR) appearance of GCM and the methods ability to distinguish the two rare entities from one another.

METHODS

We assessed a total of 40 patients with endomyocardial biopsy-proven GCM (n = 14) and CS (n = 26) concerning their clinical and CMR appearance in a blinded manner.

RESULTS

Patients with GCM and CS were of similar median age (55 vs 56 years), and a male predominance was observed in both groups. In GCM, median levels of troponin T (313 vs 31 ng/L, p < 0.001), and natriuretic peptides (6560 vs 676 pg/mL, p < 0.001) were higher than in CS, and the clinical outcome worse (p = 0.04). On CMR imaging, the observed alterations of left and right ventricular (LV/RV) dimensions and function were similar. GCM showed multifocal LV late gadolinium enhancement (LGE) with a similar longitudinal, circumferential, and radial distribution as in CS, including suggested signature imaging biomarkers of CS like the "hook sign" (71% vs 77%, p = 0.702). The median LV LGE enhanced volume was 17% and 22% in GCM and CS (p = 0.150), respectively. The number of RV segments with pathologically increased T2 signal and/or LGE were most extensive in GCM.

CONCLUSIONS

The CMR appearance of both GCM and CS is highly similar, making the differentiation between the two rare entities solely based on CMR challenging. This stands in contrast to the clinical appearance, which seems to be more severe in GCM.

Cardiac magnetic resonance in giant cell myocarditis: a matched comparison with cardiac sarcoidosis

AIMS

Giant cell myocarditis (GCM) is an inflammatory cardiomyopathy akin to cardiac sarcoidosis (CS). We decided to study the findings of GCM on cardiac magnetic resonance (CMR) imaging and to compare GCM with CS.

METHODS AND RESULTS

CMR studies of 18 GCM patients were analyzed and compared with 18 CS controls matched for age, sex, left ventricular (LV) ejection fraction and presenting cardiac manifestations. The analysts were blinded to clinical data. On admission, the duration of symptoms (median) was 0.2 months in GCM vs. 2.4 months in CS (P = 0.002), cardiac troponin T was elevated (>50 ng/L) in 16/17 patients with GCM and in 2/16 with CS (P < 0.001), their respective median plasma B-type natriuretic propeptides measuring 4488 ng/L and 1223 ng/L (P = 0.011). On CMR imaging, LV diastolic volume was smaller in GCM (177 ± 32 mL vs. 211 ± 58 mL, P = 0.014) without other volumetric or wall thickness measurements differing between the groups. Every GCM patient had multifocal late gadolinium enhancement (LGE) in a distribution indistinguishable from CS both longitudinally, circumferentially, and radially across the LV segments. LGE mass averaged 17.4 ± 6.3% of LV mass in GCM vs 25.0 ± 13.4% in CS (P = 0.037). Involvement of insertion points extending across the septum into the right ventricular wall, the "hook sign" of CS, was present in 53% of GCM and 50% of CS.

CONCLUSION

In GCM, CMR findings are qualitatively indistinguishable from CS despite myocardial inflammation being clinically more acute and injurious. When matched for LV dysfunction and presenting features, LV size and LGE mass are smaller in GCM.

Effectiveness of levosimendan and role of cardiac magnetic resonance in cardiogenic shock due to COVID-19 related lymphocytic myocarditis in the course of viral sepsis

COVID-19 and sepsis pose great challenges to clinicians and growing evidence is demonstrating links between the two conditions. Both can be complicated by acute heart failure. The use of levosimendan in patients with ventricular dysfunction during COVID-19 infection and sepsis has very little evidence. A 46-year-old, hypertensive and obese patient was admitted for severe left ventricular failure and shock during sepsis following a COVID-19 infection. The patient was treated first with norepinephrine, which was partially effective, then with the addition of levosimendan as a continuous 24 hours infusion. Vital signs and echocardiographic systolic performance indices, such as FE, SVi, CI, dP/dT, TAPSE, and tricuspid S-wave velocity, as well as diastolic function, were recorded at access, 12 and 24 hours. After initiation of levosimendan, a rapid improvement in vital signs and systolic and diastolic performance indices was observed, not depending on changes in preload, afterload, and inflammatory status. Blood cultures were negative for the presence of bacteria, thus defining the picture of likely viral sepsis. Cardiac magnetic resonance was determinant, showing a picture of myocarditis sustained by immune processes rather than direct viral injury, which was confirmed by endomyocardial biopsy. In conclusion, this case highlights the efficacy of levosimendan in acute heart failure complicated by shock due to COVID-19-related myocarditis and concomitant sepsis and confirms cardiac magnetic resonance as the gold standard for the diagnosis of myocardial inflammatory disease. To the best of our knowledge, this is the first documented case of effective use of levosimendan in this context.

Detection of myocardial fibrosis: Where we stand

Myocardial fibrosis, resulting from the disturbance of extracellular matrix homeostasis in response to different insults, is a common and important pathological remodeling process that is associated with adverse clinical outcomes, including arrhythmia, heart failure, or even sudden cardiac death. Over the past decades, multiple non-invasive detection methods have been developed. Laboratory biomarkers can aid in both detection and risk stratification by reflecting cellular and even molecular changes in fibrotic processes, yet more evidence that validates their detection accuracy is still warranted. Different non-invasive imaging techniques have been demonstrated to not only detect myocardial fibrosis but also provide information on prognosis and management. Cardiovascular magnetic resonance (CMR) is considered as the gold standard imaging technique to non-invasively identify and quantify myocardial fibrosis with its natural ability for tissue characterization. This review summarizes the current understanding of the non-invasive detection methods of myocardial fibrosis, with the focus on different techniques and clinical applications of CMR.