Beschreibung:
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<jats:bold>Background</jats:bold>
Non-ischemic mid wall fibrosis (MWF) on cardiac magnetic resonance (CMR) has been linked to poor prognosis in patients with right ventricular (RV) dysfunction, but its link to adverse RV remodeling is unknown.
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<jats:bold>Methods</jats:bold>
The population comprised patients with RV dysfunction (EF<50%) undergoing CMR and transthoracic echo (TTE) within a 14 day (5±3) interval. Cardiac structure, function, and MWF were assessed on CMR; MWF was defined in accordance with standard criteria (mid wall or epicardial septal fibrosis). Pulmonary artery systolic pressure (PASP) was measured on echo. RV wall stress was calculated via an established formula: RV wall stress=(4π*[0.620]
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*PASP*RVESV)/(3*RV myocardial volume)
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<jats:bold>Results</jats:bold>
118 patients (65% male, 55±18yo) with RV dysfunction were studied, among whom 47% had MWF. Patients with MWF had lower RVEF (34±10 vs. 39±9%; p=0.01) but similar LVEF (40±21 vs 39±18%; p=0.7) and LV volumes (p=NS). RV wall stress was higher with MWF (26±10 vs. 19±9kPa; p<0.001) corresponding to increased RVESV (143±79 vs. 110±36ml; p=0.006), myocardial mass (60±21 vs. 53±17gm; p=0.04), and PASP (52±18 vs. 41±18 mmHg; p=0.001). MWF was associated with increased wall stress among subgroups with isolated RV (p=0.003) and concomitant LV dysfunction (p=0.02). Among RV wall stress components, MWF was independently associated with RV volume (OR=1.17 per 10 ml, [CI 1.04-1.32]; p=0.01) and PASP (OR=1.43 per 10 mmHg, [1.14-1.81]; p=0.002) but not RV mass (OR=0.91 per 10gm, [0.69-1.20]; p=0.5) [model χ
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=21; p 6-fold more common in the highest, vs. the lowest, common tertile of PASP and RV size (p<0.001; Figure).
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<jats:bold>Conclusion</jats:bold>
MWF strongly relates to increased RV wall stress. Among wall stress components, MWF was independently associated with both RV chamber dilation and afterload, supporting the concept that MWF is a generalized marker of adverse RV chamber remodeling.
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