Influence of Myocardial Fibrosis on Left Ventricular Diastolic Function

OBJECTIVES: Fibrosis is a common end point of many pathological processes affecting the myocardium and may alter myocardial relaxation properties. By measuring myocardial fibrosis with cardiac magnetic resonance and diastolic function with Doppler echocardiography, we sought to define the influence of fibrosis on left ventricular diastolic function.

METHODS: Two hundred four eligible subjects from 252 consecutive subjects undergoing late postgadolinium myocardial enhancement (LGE) cardiac magnetic resonance and Doppler echocardiography were investigated.

RESULTS: Subjects with normal diastolic function exhibited no or minimal fibrosis (median LGE score, 0; interquartile range, 0 to 0). In contrast, the majority of patients with cardiomyopathy (regardless of underlying cause) had abnormal diastolic function indices and substantial fibrosis (median LGE score, 3; interquartile range, 0 to 6.25). Prevalence of LGE positivity by diastolic filling pattern was 13% in normal, 48% in impaired relaxation, 78% in pseudonormal, and 87% in restrictive filling (P<0.0001). Similarly, LGE score was significantly higher in patients with deceleration time <150 ms (P<0.012), and it progressively increased with increasing left ventricular filling pressure estimated by tissue Doppler imaging–derived E/E’ (P<0.0001). After multivariate analysis, LGE remained significantly correlated with degree of diastolic dysfunction (P=0.0001).

CONCLUSIONS: Severity of myocardial fibrosis by LGE significantly correlates with the degree of diastolic dysfunction in a broad range of cardiac conditions. Noninvasive assessment of myocardial fibrosis may provide valuable insights into the pathophysiology of left ventricular diastolic function and therapeutic response. 

PMID: pending

Posted in Magnetic Resonance Imaging and tagged , .

One Comment

  1. Every few months more keeps accumulating regarding the contribution of myocardial fibrosis to the pathogenesis of diastolic dysfunction, and specifically the use of MRI to assess these underlying myocardial changes.

    There are many interesting findings in this study, among them:

    – The authors found NO LV segments with persistent late enhancement in those subject without structural heart disease (42 out of 204,20%). This is not in keeping with other prior studies were some mid-myocardial enhancement has been reported.

    – There were 63 (31%) of subjects with normal diastolic parameters as established by the methods. The majority of these subjects (87%) had no foci of late enhancement.

    – When the patients were divided by EF, by either less or more than 50%, the statistical analysis still showed significance in the relationship between late enhancement and diastolic function.

    – One of the most interesting findings is that there was no correlation between the E/E’ and the pathologic etiology. Furthermore, in addition to the severity of fibrosis, only its location in the septum was significantly and independently associated with E/E’, again regardless of the etiology.

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