Preclinical cardiac dysfunction in transfusion-dependent children and young adults detected with low-dose dobutamine stress echocardiography.
Transfusion-dependent (TD) patients develop cardiac iron overload that will eventually lead to cardiac pump failure. Low-dose dobutamine stress echocardiography may complement resting echocardiography and identify preclinical myocardial dysfunction caused by early cardiac hemosiderosis. Twenty-six iron-overloaded TD patients had stress echocardiography with 5 microg/kg per minute of dobutamine. Indexed left ventricular (LV) mass, LV dimensions, meridional wall stress, and cardiac index were significantly increased. TD patients had similar LV shortening fraction by M-mode (40.5% +/- 5.6% vs 39.4% +/- 4.5%) but had a lower mean LV ejection fraction (53.3% +/- 3.9% vs 46.8% +/- 6.9%, P < .002) and a subnormal increase in cardiac index during dobutamine stress (35% +/- 20% vs 11% +/- 16%, P < .0001). Impairment in LV relaxation was demonstrated by a prolonged isovolumetric relaxation time (0.060 +/- 0.005 vs 0.088 +/- 0.019 seconds, P < .0001), increased peak mitral E wave, and abnormal E/A ratio. Asymptomatic TD patients demonstrate decreased systolic functional reserve and abnormal left ventricular relaxation that may be caused by cardiac hemosiderosis. Low-dose dobutamine stress echocardiography may be useful for detecting and following cardiac dysfunction in patients at risk for cardiac hemosiderosis.
Suarez
W A
WA
Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
Snyder
S A
SA
Berman
B B
BB
Brittenham
G M
GM
Patel
C R
CR
D000293:Adolescent; D000328:Adult; D009202:Cardiomyopathies / Q000150:complications / Q000000981:diagnostic imaging*; D002316:Cardiotonic Agents; D002648:Child; D003971:Diastole; D004280:Dobutamine; D017707:Erythrocyte Transfusion; D005080:Exercise Test; D005260:Female; D006439:Hemodynamics; D006486:Hemosiderosis / Q000150:complications* / Q000209:etiology; D006801:Humans; D008297:Male; D013599:Systole; D014463:Ultrasonography; D018754:Ventricular Dysfunction / Q000150:complications / Q000000981:diagnostic imaging*
D002316:Cardiotonic Agents; D004280:Dobutamine