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Cardiovascular Ultrasound

, 8:15

First Online: 23 April 2010Received: 14 December 2009Accepted: 23 April 2010


BackgroundStructural myocardial abnormalities have been extensively documented in hypothyroidism. Experimental studies in animal models have also shown involvement of thyroid hormones in gene expression of myocardial collagen. This study was planned to investigate the ability of ultrasonic tissue characterization, as evaluated by integrated backscatter IBS, to early identify myocardial involvement in thyroid dysfunction.

Patients and MethodsWe studied 15 patients with hyperthyroidism HYPER, 8 patients with hypothyroidism HYPO, 14 patients with subclinical hypothyroidism SCH and 19 normal N subjects, who had normal LV systolic function. After treatment, 10 HYPER, 6 HYPO, and 8 SCH patients were reevaluated. IBS images were obtained and analyzed in parasternal short axis papillary muscle level view, at left ventricular LV posterior wall. The following IBS variables were analyzed: 1 the corrected coefficient CC of IBS, obtained by dividing IBS intensity by IBS intensity measured in a rubber phantom, using the same equipment adjustments, at the same depth; 2 cardiac cyclic variation CV of IBS - peak-to-peak difference between maximal and minimal values of IBS during cardiac cycle; 3 cardiac cyclic variation index CVI of IBS - percentual relationship between the cyclic variation CV and the mean value of IBS intensity.

ResultsCC of IBS was significantly larger p < 0.05 in HYPER 1.57 ± 0.6 and HYPO 1.53 ± 0.3 as compared to SCH 1.32 ± 0.3 or N 1.15 ± 0.27. The CV dB HYPO: 7.5 ± 2.4; SCH: 8.2 ± 3.1; HYPER: 8.2 ± 2.0 and the CVI HYPO: 35.6 ± 19.7%; SCH: 34.7 ± 17.5%; HYPER: 37.8 ± 11.6% were not significantly different in patients with thyroid dysfunction as compared to N 7.0 ± 2.0 and 44.5 ± 15.1%.

ConclusionsCC of IBS was able to differentiate cardiac involvement in patients with overt HYPO and HYPER who had normal LV systolic function. These early myocardial structural abnormalities were partially reversed by drug therapy in HYPER group. On the other hand, although mean IBS intensity tended to be slightly larger in patients with SCH as compared to N, this difference was not statistical significant.

Electronic supplementary materialThe online version of this article doi:10.1186-1476-7120-8-15 contains supplementary material, which is available to authorized users.

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Autor: Minna MD Romano - Léa MZ Maciel - Oswaldo C Almeida-Filho - Antonio Pazin-Filho - André Schmidt - Benedito C Maciel


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