New echocardiographic findings correlate with intramyocardial inflammation in endomyocardial biopsies of patients with acute myocarditis and inflammatory cardiomyopathy

Abstract

Background: The diagnosis of acute myocarditis (AMC) and inflammatory cardiomyopathy (DCMi) can be difficult. Speckle tracking echocardiography with accurate assessments of regional contractility could have an outstanding importance for the diagnosis.

Methods and results: N = 25 patients with clinically diagnosed AMC who underwent endomyocardial biopsies (EMBs) were studied prospectively. Speckle tracking imaging was examined at the beginning and during a mean follow-up period of 6.2 months. In the acute phase patients had markedly decreased left ventricular (LV) systolic function (mean LV ejection fraction (LVEF) 40.4 ± 10.3%). At follow-up in n = 8 patients, inflammation persists, correlating with a significantly reduced fractional shortening (FS, 21.5 ± 6.0%) in contrast to those without inflammation in EMB (FS 32.1 ± 7.1%, P < 0.05). All AMC patients showed a reduction in global systolic longitudinal strain (LS, -8.36 ± -3.47%) and strain rate (LSR, 0.53 ± 0.29 1/s). At follow-up, LS and LRS were significantly lower in patients with inflammation, in contrast to patients without inflammation (-9.4 ± 1.4 versus -16.8 ± 2.0%, P < 0.0001; 0.78 ± 0.4 versus 1.3 ± 0.3 1/s). LSR and LS correlate significantly with lymphocytic infiltrates (for CD3 r = 0.7, P < 0.0001, and LFA-1 r = 0.8, P < 0.0001).

Conclusion: Speckle tracking echocardiography is a useful adjunctive assisting tool for evaluation over the course of intramyocardial inflammation in patients with AMC and DCMi.

Figure 1

Quantitative analysis of global longitudinal strain (in %) in AMC at baseline and at followup in patients with inflammation (n = 8) in EMB and without inflammation (n = 17) at followup. Columns represent mean ± standard deviation with *P < 0.05.

Figure 2

Analysis of global longitudinal strain (in %) correlated with inflammation in EMB. (a) Correlation between global longitudinal strain and CD3 positive T-lymphocytes. (b) Correlation between global longitudinal strain and LFA-1 positive lymphocytes. (c) Correlation between global longitudinal strain and Mac-1 positive cells used as marker for macrophages and (d) correlation between global longitudinal strain and HLA-1 expression.

Figure 3

Representative images of EMBs: (a) HE staining of samples from patients with acute myocarditis at baseline, (b) immunohistochemical staining of extremely increased CD3 positive T-lymphocytes in acute myocarditis at baseline, (c) immunohistochemical staining of CD3 positive T-lymphocytes in patients without inflammation at followup, and (d) increased CD3 positive T-lymphocytes in patients with proof of inflammation at followup (magnification 200×).

Figure 4

Representative strain imaging by speckle tracking imaging in (a) patients with inflammation in EMB specimens at followup in a 4-chamber view, (b) 2-chamber view, (c) patients without EMB inflammation in a 4-chamber view, (d) 2-chamber view.