Numerous studies have reported a significant diagnostic as well as a prognostic role of LV strain in the assessment of LV mechanics in various study populations [
10,
11], including patients with heart failure with preserved ejection fraction, coronary artery disease, diabetes mellitus, hypertensive heart disease, hypertrophic cardiomyopathy, and arrhythmia [
1‐
7]. Recently, CMR-FT strain analysis was shown to be accurate in the detection of myocardial dysfunction and as well useful as a predictor of major adverse cardiac events in ischemic or non-ischemic cardiomyopathy [
18], with the advantage of utilizing simple bSSFP cine sequences [
15‐
19,
33,
34]. However, notwithstanding the multitude of published papers assessing the clinical usefulness of strain, there is a notable lack of in-vivo validation studies [
35]. Whether CMR-FT LV strain represents a valid tool to assess the cardiac mechanics of the myocardium, and how this varies under different inotropic states, is still unclear. In this work, we could show a role of CMR LV strain as a surrogate of classic hemodynamic parameters such as CI, CPO, and a load-independent parameter of cardiac contractility such as Ees, which are established parameters to describe the hydraulic and mechanical role of the heart as a pump [
22,
24]. Previous in vivo studies concentrated on the role of 2D and 3D speckle tracking echocardiography (STE) [
35]. The main validation studies analysed the correlation of STE with the sonomicrometry technique in open-chest large animal models, showing an overall good agreement of the two techniques [
35]. Similarly to our study, Weidemann et al. showed the ability of strain as well as strain rate to reflect swine LV-contractility under different inotropic states and independently of heart rate [
36]. The invasively measured Ees, the slope of the end-systolic pressure–volume relationship, is a relatively load-independent parameter describing the LV inotropic state [
24]. A recent study by Seeman et al. established a reliable method to assess Ees via CMR imaging [
25]. In the current work, we showed a moderate to good correlation between both GLS, GCS, and Ees. The accuracy of GLS in reflecting Ees improved when indexing for wall stress. In line with our data, Yotti et al [
8] showed a moderate correlation between echocardiographic assessed GCS and invasive pressure–volume catheterization data, while on the opposite, GLS correlated poorly. The authors highlighted how the GCS measurements, as opposed to the GLS, did not change in patients with aortic stenosis or hypertension. They hypothesized this could be related to a lower load-dependency [
8] of the first in comparison to the latter ones, but the different methodology of strain assessment in comparison to our study is probably playing a role as well.