Baseline Longitudinal Strain Predicts Recovery of Left Ventricular Ejection Fraction in Hospitalized Patients With Nonischemic Cardiomyopathy

Abstract

Background Heart failure ( HF ) with "recovered" ejection fraction ( HF rec EF ) is an emerging phenotype, but no tools exist to predict ejection fraction ( EF ) recovery in acute HF . We hypothesized that indices of baseline cardiac structure and function predict HF rec EF in nonischemic cardiomyopathy and reduced EF . Methods and Results We identified a nonischemic cardiomyopathy cohort with EF <40% during the first HF hospitalization (n=166). We performed speckle-tracking echocardiography to measure longitudinal, circumferential, and radial strain, and the average of these measures (myocardial systolic performance). HF rec EF was defined as follow-up EF ≥40% and ≥10% improvement from baseline EF . Fifty-nine patients (36%) achieved HF rec EF (baseline EF 26±7%; follow-up EF 51±7%) within a median of 135 (interquartile range 58-239) days after the first HF hospitalization. Baseline demographics, biomarker profiles, and comorbid conditions (except lower chronic kidney disease in HF rec EF ) were similar between HF rec EF and persistent reduced- EF groups. HF rec EF patients had smaller baseline left ventricular end-systolic dimension (3.6 versus 4.8 cm; P<0.01), higher baseline myocardial systolic performance (9.2% versus 8.1%; P=0.02), and improved survival (adjusted hazard ratio 0.27, 95% confidence interval 0.11, 0.62). We found a significant interaction between baseline left ventricular end-systolic dimension and absolute longitudinal strain. Among patients with left ventricular end-systolic dimension >4.35 cm, higher absolute longitudinal strain (≥8%) was associated with HF rec EF (unadjusted odds ratio=3.9, 95% CI )confidence interval 1.2, 12.8). Incorporation of baseline indices of cardiac mechanics with clinical variables resulted in a predictive model for HF rec EF with c-statistic=0.85. Conclusions Factors associated with achieving HF rec EF were specific to cardiac structure and indices of cardiac mechanics. Higher baseline absolute longitudinal strain is associated with HF rec EF among nonischemic cardiomyopathy patients with reduced EF and larger left ventricular dimensions.

Keywords: echocardiography; heart failure with recovered ejection fraction; longitudinal strain; nonischemic heart failure; recovery.

Figure 1

Kaplan‐Meier survival curve of 166 participants.

Figure 2

Importance of longitudinal strain and left ventricular end‐systolic dimension on recovery of left ventricular ejection fraction. A, Rate of recovery among 166 NICM participants, with low and high defined at the median and associated strain curves. B, Odds ratio for recovery among participants with high LS compared with low LS dichotomized by high and low LVESD. C, Example of LS strain curve in a patient with large LV dimension (high LVESD) and low LS who does not recover (HFrEF). D, Example of LS strain curve in a patient with large LV dimension and high LS who does recover (HFrecEF). Low LS is defined as <8, high LS as ≥8; low LVESD is defined as ≤4.35 cm, high as >4.35 cm; HFrecEF is defined as follow‐up LVEF ≥40% and ≥10% absolute improvement in LVEF from baseline to follow‐up, assessed within 18 months of the index hospitalization. Persistent HFrEF is defined as follow‐up LVEF <40% and no improvement or worsening of LVEF from baseline. EF indicates ejection fraction; LS, longitudinal strain; LVESD, left ventricular end‐systolic dimension; NICM, nonischemic cardiomyopathy.