Relationship of Myocardial Strain by 2D Speckle Tracking Echocardiography and Coronary Flow Reserve by Magnetic Resonance Imaging in Patients with Heart Failure with Preserved Ejection Fraction

Introduction: A recent study demonstrated that myocardial strain assessed by 2D speckle tracking echocardiography (2D-STE) is significantly reduced in heart failure with preserved ejection fraction (HFpEF). Phase contrast (PC) cine magnetic resonance (MR) imaging allows for non-invasive and accurate evaluation of microcirculation of myocardium, namely coronary flow reserve (CFR). Hypothesis: We hypothesized that both myocardial strain by 2D STE and CFR by PC cine MRI are substantially reduced in patients with HFpEF in comparison those without and myocardial strain by 2D-STE is correlated with CFR by PC cine MRI. Methods: We studied 20 HFpEF patients (mean age: 72 ± 6 years) and 18 controls (mean age: 66 ± 13 years). Assessment of myocardial strain was performed in three directions, radial strain (RS); circumferential strain (CS); longitudinal strain (LS). By using 1.5T MR scanner and 32 channel cardiac coils, breath-hold PC cine MR images of coronary sinus (CS) were obtained to assess the blood flow of CS both at rest and during adenosine triphosphate (ATP) infusion. CFR was calculated as CS blood flow during ATP infusion divided by CS blood flow at rest. Impairment of CFR was defined as Results: In patients with HFpEF, myocardial strains were significantly decreased in comparison to control subjects (RS: 28.5 ± 11.2 vs 38.9 ± 14.6, p=0.018; CS: -17.6 ± 3.8 vs -21.0 ± 5.5, p=0.029; LS: -15.7 ± 3.7 vs -18.6 ± 2.5, p=0.007). Furthermore, median CFR was Conclusions: In patients HFpEF, both myocardial strain by 2D-STE and CFR by PC cine MRI were significantly reduced in comparison to controls. CS by 2D-STE showed significant correlation with CFR by PC cine MRI. The results in the current study indicated that the dysfunction of left ventricular microcirculation might play an important role for the decreased CS strain by 2D-STE in patients with HFpEF.