Background: Global longitudinal strain (GLS) and global circumferential strain (GCS) have been shown to be impaired in heart failure with preserved ejection fraction. We sought to assess whether treating patients with heart failure with preserved ejection fraction with sacubitril/valsartan would significantly improve GLS and GCS compared with valsartan alone. Methods and Results: PARAMOUNT (Prospective Comparison of ARNI With ARB on Management of Heart Failure With Preserved Ejection Fraction Trial) was a phase II, randomized, parallel-group, double-blind multicenter trial in 301 patients with New York Heart Association functional class II–III heart failure, a left ventricular ejection fraction of 45%, and an N-terminal pro-B-type natriuretic peptide of ≥400 pg/mL. Participants were randomly assigned (1:1) to sacubitril/valsartan titrated to 200 mg twice daily or valsartan titrated to 160 mg twice daily for 36 weeks. We assessed changes in the GLS and the GCS from baseline to 36 weeks, adjusting for baseline value, in patients with sufficient imaging quality for 2-dimensitonal speckle tracking analysis at both timepoints (n = 60 sacubitril/valsartan, n = 75 valsartan only). GCS was significantly improved at 36 weeks in the sacubitril/valsartan group when compared with the valsartan group (Δ4.42%, 95% confidence interval [CI] 0.67–8.17, P =.021), with no significant difference observed in GLS (Δ0.25%, 95% CI, –1.19 to 1.70, P =.73). Patients with a history of hospitalization for heart failure had a differentially greater improvement in GCS when treated with sacubitril/valsartan. Conclusions: In patients with heart failure with preserved ejection fraction, sacubitril/valsartan improved GCS but not GLS when compared with valsartan during a 36-week period. This trial is registered at ClinicalTrials.gov, NCT00887588.