Diffuse myocardial fibrosis in hypertrophic cardiomyopathy can be identified by cardiovascular magnetic resonance, and is associated with left ventricular diastolic dysfunction

Abstract

BackgroundThe presence of myocardial fibrosis is associated with worse clinical outcomes in hypertrophic cardiomyopathy (HCM). Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) sequences can detect regional, but not diffuse myocardial fibrosis. Post-contrast T1 mapping is an emerging CMR technique that may enable the non-invasive evaluation of diffuse myocardial fibrosis in HCM. The purpose of this study was to non-invasively detect and quantify diffuse myocardial fibrosis in HCM with CMR and examine its relationship to diastolic performance.MethodsWe performed CMR on 76 patients - 51 with asymmetric septal hypertrophy due to HCM and 25 healthy controls. Left ventricular (LV) morphology, function and distribution of regional myocardial fibrosis were evaluated with cine imaging and LGE. A CMR T1 mapping sequence determined the post-contrast myocardial T1 time as an index of diffuse myocardial fibrosis. Diastolic function was assessed by transthoracic echocardiography.ResultsRegional myocardial fibrosis was observed in 84% of the HCM group. Post-contrast myocardial T1 time was significantly shorter in patients with HCM compared to controls, consistent with diffuse myocardial fibrosis (498 ± 80 ms vs. 561 ± 47 ms, p < 0.001). In HCM patients, post-contrast myocardial T1 time correlated with mean E/e’ (r = −0.48, p < 0.001).ConclusionsPatients with HCM have shorter post-contrast myocardial T1 times, consistent with diffuse myocardial fibrosis, which correlate with estimated LV filling pressure, suggesting a mechanistic link between diffuse myocardial fibrosis and abnormal diastolic function in HCM.

Investigation of Global and Regional Myocardial Mechanics With 3-Dimensional Speckle Tracking Echocardiography and Relations to Hypertrophy and Fibrosis in Hypertrophic Cardiomyopathy

“…On the other hand, myocardial fibrosis also seems to be associated with worse cardiac performance. [14][15][16] Some studies have underscored that this finding is likely to do with segmental or regional dysfunction associated with the fibrosis, 12,17 but other data suggest that fibrosis may not predict all of the LV contractile heterogeneity in HCM. 18 Heterogeneous myocardial hypertrophy and fibrosis, both characteristic of HCM, are probably responsible for global and regional abnormalities of LV myocardial mechanics, whose quantitative assessment is challenging by conventional cardiovascular imaging techniques.…”

Evaluating the Utility of Circulating Biomarkers of Collagen Synthesis in Hypertrophic Cardiomyopathy

“…Late-gadolinium enhancement (LGE) sequences can identify regions of dense replacement fibrosis in most patients with HCM, and its presence is associated with a worse prognosis. 13 More recently, postcontrast T 1 mapping, a technique shown to correlate with histopathologic findings, 14 has been used to quantify diffuse patterns of interstitial myocardial fibrosis in several cardiac disease states, [15][16][17] including HCM, 18 and that lower T 1 times, suggestive of more diffuse myocardial fibrosis, have correlated with higher LV filling pressures. 18 In the present study, we sought to evaluate in HCM patients the relationship between peripheral markers of collagen turnover and CMR-derived measures of myocardial fibrosis, echocardiographic indices of diastolic performance, and invasively determined hemodynamic indices.…”

Diffuse Ventricular Fibrosis Measured by T 1 Mapping on Cardiac MRI Predicts Success of Catheter Ablation for Atrial Fibrillation

“…5,20 Diastolic dysfunction and LA stiffness as assessed on echocardiography have been associated with an increase in recurrent AF after catheter ablation. 21 In the present study, shortening of the postcontrast ventricular T 1 time representative of tissue fibrosis may result in diastolic dysfunction, increased LA pressure and chronic atrial stretch, and fibrosis with the consequence of recurrent AF after catheter ablation.…”