Page 164 - The role of advanced echocardiography in patients with ischemic heart disease - Rachid Abou

Chapter eight. LV mechanical dispersion versus LV scar burden
Similarly, a study by Haugaa et al 5, evaluated 569 patients after myocardial infarction (at least 40 days after) and demonstrated that patients with ventricular arrhythmias (n=15; ventricular tachycardia and sudden death) showed more prolonged LV MD than their counterparts (63 ± 25ms vs. 42 ± 17ms).5 On multivariable analysis, both studies reported that LV MD was independently associated with the endpoint. We report a relative lower event rate (n=14; n=3 ICD therapy, n=11 death) and slightly lower value of LV MD when compared to the aforementioned studies.5,26 This can be explained by differences in study populations: while the present study includes patients with STEMI treated with primary PCI, the other studies included more heterogeneous populations (STEMI and non-STEMI) that received different therapies (not all of them received PCI) and with different follow-up time.
In the present study, LV MD provided the highest accuracy for predicting the endpoint followed by LV GLS and CMR derived parameters. In contrast, LVEF showed poor discrimination to identify patients at risk for events. As early detection of myocardial fibrosis possibly leads to early identification of patients at risk for adverse events, LV MD by 2D STE appears to be a promising marker of LV fibrosis and outcome.
Study limitations
The current study was retrospective in nature and the data was generated from a single centre. T1 mapping techniques were not applied in this study cohort and therefore the association between reactive fibrosis and ventricular arrhythmias could not be evaluated. Furthermore, CMR was performed relatively early after STEMI when compared to transthoracic echocardiography. Therefore, LV MD may improve due to functional recovery in a later stage. In addition, the measurements of LV MD may not be generalizable for all vendors and the cut-off value of LV MD provided in this study may not be applicable in other study populations. Finally, the number of events during follow up were relatively small. Data on specific cause of death was not available. Further studies including larger sample size are needed.
Conclusions
LV MD is correlated with total scar burden, infarct core and border zone. In addition, patients with prolonged LV MD showed higher rates of all-cause mortality and ICD therapy. Finally, LV MD provided the highest predictive value for the combined endpoint of all-cause mortality and ICD therapy when compared to other parameters.
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