Strain, Strain Rate, and the Force Frequency Relationship in Patients with and without Heart Failure

Background: The aim of this study was to examine the effect of heart rate (HR) on indices of deformation in adults with and without heart failure (HF) who underwent simultaneous high-fidelity catheterization of the left ventricle to describe the force-frequency relationship. Methods: Right atrial pacing to control HR and high-fidelity recordings of left ventricular (LV) pressure were used to inscribe the force-frequency relationship. Simultaneous two-dimensional echocardiographic imaging was acquired for speckle-tracking analysis. Results: Thirteen patients with normal LV function and 12 with systolic HF (LV ejection fraction, 31 +/- 13%) were studied. Patients with HF had depressed isovolumic contractility and impaired longitudinal strain and strain rate. HR-dependent increases in LV+dP/dt(max), the force-frequency relationship, was demonstrated in both groups (normal LV function, baseline to 100 beats/min: 1,335 +/- 296 to 1,564 +/- 320 mm Hg/sec, P < .0001; HF, baseline to 100 beats/min: 970 +/- 207 to 1,083 +/- 233 mm Hg/sec, P < .01). Longitudinal strain decreased significantly (normal LV function, baseline to 100 beats/min: 18.0 +/- 3.5% to 10.8 +/- 6.0%, P < .001; HF: 9.4 +/- 4.1% to 7.5 +/- 3.4%, P < .01). The decrease in longitudinal strain was related to a decrease in LV end-diastolic dimensions. Strain rate did not change with right atrial pacing. Conclusions: Despite the inotropic effect of increasing HR, longitudinal strain decreases in parallel with stroke volume as load-dependent indices of ejection. Strain rate did not reflect the modest HR-related changes in contractility; on the other hand, the use of strain rate for quantitative stress imaging is also less likely to be confounded by chronotropic responses. (J Am Soc Echocardiogr 2012;25:341-8.)