Tissue Doppler and strain rate imaging detect improvement of myocardial function in iron deficient patients with congestive heart failure after iron replacement therapy.

Background: Iron deficiency may contribute to diminished exercise tolerance in patients with congestive heart failure (CHF) even in absence of anemia. The aim of this study was to evaluate the effect of correction of iron deficiency on functional capacity and myocardial function in patients with CHF.

Methods: We studied 40 patients with ejection fraction <40%, hemoglobin% >12 g/dL, serum ferritin <100 ug/L, and transferrin saturation <20%. Patients received 200 mg weekly doses of iron dextran complex until serum ferritin level was between 200 and 300 ug/L or transferrin saturation level was between 30% and 40%. Transthoracic echocardiogram, tissue Doppler imaging, peak systolic strain rate, and 6 minute walk test were performed before iron therapy and at 12-week follow up. Peak early diastolic myocardial tissue velocity (E'), peak late diastolic myocardial tissue velocity (A'), and peak systolic myocardial tissue velocity (S') were measured.

Results: There was a significant improvement of New York Heart Association functional class (3.0 ± 0.4 vs. 2.1 ± 0.3, P < 0.05) and 6minutes walk distance (322 ± 104 vs. 377 ± 76, P < 0.01) from rest to follow up, respectively. Ejection fraction did not change significantly (32 ± 8% vs. 34 ± 9%, respectively). There was a significant improvement of S'-wave (3.0 ± 0.8 cm/sec vs. 6.0 ± 1.2 cm/sec, P < 0.05), E/E' ratio (22 ± 3 vs. 13 ± 3, P < 0.05), and peak systolic strain rate (-0.72 ± 0.11/s vs. -1.09 ± 0.37/s, P < 0.05) from baseline to follow-up, respectively.

Conclusion: Correction of iron deficiency improves functional class and walking distance in nonanemic iron deficient patients with systolic heart failure. Tissue Doppler and strain rate demonstrated a significant improvement of diastolic and systolic function after therapy despite lack of improvement of ejection fraction. (Echocardiography 2012;29:13-18).