1Herzzentrum der Universität zu Köln Klinik III für Innere Medizin Köln, Deutschland; 2Uniklinik Köln Institut für diagnostische und interventionelle Radiologie Köln, Deutschland; 3Universitätsklinikum Köln Klinik III für Innere Medizin - Experimentelle Kardiologie Köln, Deutschland; 4Universitätsklinikum Tübingen Kardiopathologie Tübingen, Deutschland
Background
Myocarditis is an inflammatory cardiac disease that may be due to viral infection or is mediated by non-infectious immune processes. There is tremendous variation in the clinical presentation of patients with respect to symptoms, laboratory and instrumental findings, as well as functional or hemodynamic compromise. Endomyocardial biopsy (EMB) is still considered the diagnostic gold standard for myocarditis with the consequence that patients can be treated by immunosuppression when cardiac infections are excluded. However, in the past decades, cardiac magnetic resonance (CMR) has established itself as a non-invasive diagnostic tool, reducing the demand for EMB. Thus, we sought to characterise the remaining benefit of the invasive procedure in myocarditis patients by analysing immediate diagnostic and therapeutic consequences resulting from EMB.
Methods
In this retrospective single-centre study, data of all patients presenting with (peri-) myocarditis between 01/2016 and 06/2023 at our tertiary care centre were included, and the impact of myocardial biopsy on diagnostic and treatment strategy were described.
Results
A total of 150 consecutive patients (36.7 ± 15.5 years, 77.3% male) were included in this study. In 44/150 patients (29%) EMB was performed, most frequently in the subgroup of patients with EF <30% (21/26, 80.7%). In 11/44 patients, EMB had direct therapeutic consequence and led to the initiation of immunosuppressive therapy. This was the case exclusively in patients with at least one of the following three risk factors (28/44): (i) LV-EF <30%, (ii) presence of severe arrhythmias (VF, VT, high grade AV-block), or (iii) underlying autoimmune disease (11/28, 39.3% vs. 0/16, 0% in patients with none of these risk factors; p=0.003). With respect to patients presenting with recurrent myocarditis (n=10), EMB had therapeutic consequence in none of the cases.
Conclusions
Due to a high therapeutic yield (39.3%) for initiation of immunosuppressive therapy in non-infectious myocarditis, performing EMB should be considered in all high-risk patients. For patients without clinical risk factors there was limited benefit in performing EMB, even in cases of recurrent or relapsing myocarditis.