Effect of iron overload on exercise capacity in thalassemic patients with heart failure.
In b-thalassemia, myocardial iron overload contributes to heart failure, despite chelation treatment. We hypothesized that myocardial T2*, an index of iron overload, influences patients' physical activity. We assessed a thalassemic population by both cardiovascular magnetic resonance imaging (CMR) and ergospirometry test. Sixty-six thalassemic patients aged 27 (19-40) years, 30 without (NHF) and 36 with heart failure (HF), were studied. Cardiac T2* and left ventricular ejection fraction (LVEF) were evaluated using a 1.5 T system. VO(2max), AT, Mets and duration of exercise by ergospirometry were also assessed. Myocardial T2* was lower in HF compared to NHF patients (14.7 +/- 6.6 vs. 39 +/- 2 ms, P < 0.001). LVEDV and LVESV were higher in HF group compared to NHF patients (139.9 +/- 16.3 vs. 124.6 +/- 20.86 ml, P < 0.01 and 94.9 +/- 24 vs. 38.3 +/- 10.1 ml, P < 0.001, respectively). Additionally, LVEF in HF was lower compared to NHF patients (21.3 +/- 6.1% vs. 69.6 +/- 3.7, P < 0.001, respectively). All exercise parameters were lower in HF compared to NHF patients (P < 0.001). Patients within the HF group were additionally analyzed according to T2* values (<10 ms). HF patients with T2* < 10 ms (n = 13) were considered as high iron overloaded (HF-H) and the rest of them (n = 23) as (HF-L). Although LVEDV, LVESV, LVEF were similar in the two subgroups, the exercise parameters were significantly lower in the HF-H group (P < 0.001). Heart T2* correlated with all exercise parameters (P < 0.001). HF thalassemic patients have reduced exercise indexes compared to non HF. Myocardial iron overload, expressed as T2*, has a direct influence on exercise capacity, independent of LV ejection fraction and functional class.
Mavrogeni
Sophie
S
Onassis Cardiac Surgery Center, Athens, Greece. soma13@otenet.gr
Gotsis
Efstathios
E
Verganelakis
Dimitrios
D
Berdousis
Eleni
E
Dritsas
Athanasios
A
Kolovou
Genovefa
G
Toulas
Panagiotis
P
Ladis
Vassilios
V
D000328:Adult; D005080:Exercise Test; D017079:Exercise Tolerance; D006333:Heart Failure / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007501:Iron / Q000378:metabolism*; D019190:Iron Overload / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D011237:Predictive Value of Tests; D013147:Spirometry; D013318:Stroke Volume; D016277:Ventricular Function, Left; D055815:Young Adult; D017086:beta-Thalassemia / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology
D007501:Iron
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