Left Ventricular Diastolic Dyssynchrony in Post-Myocardial Infarction Patients: Does It Predict Future Left Ventricular Remodeling?

Left ventricular (LV) remodeling is well-known complication after myocardial infarction (MI) and numerous studies have emphasized the clinical importance of ventricular remod-eling. 1-4) In these literatures, progressive LV dilatation and decreased LV ejection fraction were major determinants in future development of heart failure and long term survival. That is why early recognition of patients at risk for LV remodeling after MI has vital importance and identification of the predictive markers for developing ventricular remodeling is clinically meaningful. While the clinical importance of LV mechanical dyssyn-chrony is mainly described in heart failure patients, 5-7) its significance in patients with MI was less well established. Actually , ventricular dyssynchrony is not uncommon in post-MI patients even with narrow QRS complexes. 8)9) Zhang et al. 8) and Fahmy Elnoamany et al. 9) noted LV systolic dyssynchrony early after MI in 69.8% and 77.5% of the patients and it was mainly determined by the initial infarct size. After that, various parameters from tissue Doppler imaging and speckle-tracking technique have been used for detecting regional contraction and relaxation abnormalities and LV systolic and diastolic dyssynchrony early after MI. Several studies demonstrated that LV systolic dyssynchrony in post-MI patients is closely related with future LV remodeling 10-13) and poor prognosis. 14)15) Mollema et al. 10) showed that patients with more extensive LV dyssynchrony at baseline have larger LV end sys-tolic volume after 6 months of follow up and increased risk of LV remodeling. Similar results were showed by Zhang et al. ejection fraction in the remodeling group. On the other hand, information on the role of LV diastolic dyssynchrony in post-MI patients is limited and only a few studies examined the clinical implication. In earlier studies, the prevalence of dia-stolic dyssynchrony was not significantly different in post-MI patients compared with control group. 8)9) In a study from Zhang et al., 11) both standard deviation (SD) of time to peak myocardial contraction represents LV systolic dyssynchrony and SD of time to peak early relaxation (Te-SD) represents LV diastolic dyssynchrony at baseline were significantly higher in patients who experienced LV remodeling after 1 year with the marginal statistical significance of Te-SD (p = 0.048). However , in multivariate analysis to identify independent predictor of 1 year LV remodeling, Te-SD did not predict LV remodel-ing. In the article published in this issue of the Journal of Car-diovascular Ultrasound titled " Diastolic dyssynchrony in acute ST segment elevation myocardial infarction …