Histological findings
We compared histological findings in patients with TCM with findings in
patients who had ICM or DCM. We found distinct differences in the
presence of T cells, which were strongly associated with ICM (0.2 cells
in high power field (HPF) in TCM vs. 1.1 cells in HPF in ICM vs. 0.27
cells in HPF in DCM; overall p < 0.0001) (Figure 2A). The
presence of CD 68 positive macrophages was not significantly more
frequent in patients with TCM compared with DCM, but less frequent
compared with patients with ICM (0.45 cells in HPF in TCM vs. 0.47 cells
in HPF in DCM vs. 1.1 cells in HPF in ICM; overall p < 0.0001)
(Figure 2B).
Figure 2: Comparison of
Biopsies.
(A) CD3+ T cells and (B) CD68+macrophages as well as (C) immunohistological score of myocardial
fibrosis (trichrome staining), and (D) anti–cleaved caspase 3 are
compared in myocardial biopsy samples from patients with
tachycardia-induced cardiomyopathy (TCM), inflammatory cardiomyopathy
(ICM), and dilated cardiomyopathy (DCM).
***: p-value < 0.001 compared to TCM; ns: not significant
compared to TCM
In patients with TCM, MHC-II (anti–major histocompatibility complex
class II) expression was similar to that in patients with ICM and
significantly enhanced compared with DCM (38.9 % in TCM vs. 54.4% in
ICM vs. 4.1% in DCM; overall p < 0.0001) (Figure 3).
Figure 3: MHC-II
(anti–major histocompatibility complex class II) expression
TCM: tachycardia-induced cardiomyopathy; ICM: inflammatory
cardiomyopathy; DCM: dilated cardiomyopathy; ***: p-value <
0.001 compared to TCM
Patients with TCM had a moderately increased degree of fibrosis which
was slightly higher in patients with DCM and ICM (fibrosis score [0 to
4]: 1.6 in TCM vs. 2.1 in ICM vs. 1.9 in DCM; severe fibrosis: 6.7 %
in TCM vs. 8.9 % in ICM vs. 17.6 % in DCM; overall p=0.45) (Figure
2C).
Apoptosis and cell death are essential issues in HF. The presence of
cleaved caspase 3, a specific indicator for apoptosis, was lowest in the
DCM (48 % cells in HPF in TCM vs. 50 % cells in HPF in ICM vs. 42 %
cells in HPF in DCM; overall p < 0.0001). Notably, despite the
excellent recovery potential of TCM, the marker of apoptosis in patients
with TCM was elevated o a similar degree compared to those with ICM
(Figure 2D).