Letter by Kass regarding article, "Role of left ventricular stiffness in heart failure with normal ejection fraction".

To the Editor: In their recent study, Westermann et al1 examined detailed hemodynamics using pressure-volume analysis in patients with heart failure symptoms despite a preserved ejection fraction (HFpEF), the latter defined by an EF >50%. Their control group was individuals referred for chest discomfort without heart failure or significant coronary disease. The work represents the largest effort to date to detail rest and reserve function in HFpEF patients, and as such it is an important accomplishment. A primary conclusion was that diastolic chamber stiffening in HFpEF compromised stroke volume (because of reduced end-diastolic volume) …