Page 140 - The role of advanced echocardiography in patients with ischemic heart disease - Rachid Abou

Chapter seven. LVMD in STEMI and prognosis
angiotensin converting enzyme inhibitor/angiotensin receptor blocker, β-blockers, heart rate at discharge, wall motion score index, mitral regurgitation ≥2, left ventricular ejection fraction, indexed left ventricular mass and left ventricular global longitudinal strain.
The incremental prognostic value of left ventricular mechanical dispersion
A baseline model consisting of age, hypertension, diabetes mellitus, previous myocardial infarction, QRS duration, multi-vessel disease, TIMI flow ≥2, Killip class ≥2, peak troponin levels, eGFR, body mass index, usage of ACEi/ARBs and β-blockers, heart rate at discharge, WMSI, significant mitral regurgitation, LVEF, indexed LV mass and LV GLS was constructed. To determine the incremental value of LVMD over clinical and conventional echocardiographic parameters, global χ2 values were calculated using Cox regression model. The inclusion of LVMD in the multivariable analysis resulted in a significant increment of model discrimination power (∆χ2 = + 21, ∆log likelihood ratio = -11; p<0.001 and p=0.001, respectively) to a model containing clinical and conventional echocardiographic parameters (Table 4).
Intra- and interobserver reproducibility
Intra- and interobserver reproducibility for LVMD measurements were excellent with an ICC of 0.854 (95% confidence interval 0.671 to 0.935) and an interclass correlation coefficient of 0.938 (95% confidence interval 0.866 to 0.972 ).
DISCUSSION
The main findings of the present study can be summarized as follows: in a large contemporary STEMI population treated with primary PCI, increasing age, diabetes mellitus, LAD as culprit vessel, impaired LV GLS and lower discharge heart rate were independently associated with prolonged LVMD. Whereas, TIMI flow <2 and usage of ACEi/ARBs were independently associated with shorter LVMD after STEMI. In addition, patients with prolonged LVMD after STEMI experienced worse long-term outcome compared to patients with shorter LVMD. Finally, LVMD had incremental prognostic value over clinical and conventional echocardiographic parameters.
Independent correlates of left ventricular mechanical dispersion
LVMD reflects regional heterogeneity in myocardial contraction throughout the cardiac cycle. It has been suggested that increasing fibrosis may be a major determinant of prolonged LVMD. In patients with hypertrophic cardiomyopathy, an increase in LVMD has been correlated with the presence of fibrosis as evaluated by late gadolinium
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