Usefulness of pulsed tissue Doppler for the assessment of left ventricular myocardial function in overt hypothyroidism.

BACKGROUND

The aim of this study was to assess the role of tissue Doppler (TD) in the identification of left ventricular (LV) myocardial regionl abnormalities in overt hypothyroidism.

METHODS

Fourteen women with newly diagnosed, never treated overt hypothyroidism and 14 healthy women, matched for age, underwent standard echocardiography and pulsed TD, by placing the sample volume at the basal posterior septum and lateral mitral annulus, in the apical 4-chamber view. The myocardial systolic (SM) and diastolic velocities (Em, Am and their ratio) and time intervals (relaxation time [RTm], pre-contraction time [PCTm], contraction time) were measured.

RESULTS

The two groups were comparable for body surface area, blood pressure and heart rate. At standard echocardiography, patients with overt hypothyroidism had a significantly greater septal thickness and LV mass index, a longer LV pre-ejection period (PEP), deceleration time and isovolumic relaxation time (IVRT) and a lower E peak velocity and E/A ratio. TD showed a significantly longer PCTm and RTm and a lower Em and Em/Am ratio of both the septum and mitral annulus in overt hypothyroidism. The ratio of the standard Doppler E to Em of the mitral annulus was 5.5 +/- 1.2 in controls and 5.3 +/- 1.7 in overt hypothyroidism (p = NS). In the overall population, PEP, IVRT, PCTm and RTm were correlated negatively with FT3 and FT4, and positively with thyroid-stimulating hormone. After adjusting for age, body surface area and heart rate in separate multivariate analyses, the associations of TD PCTm with the thyroid hormones and thyroid-stimulating hormone were greater than the homologous associations of standard Doppler PEP.

CONCLUSIONS

Standard echocardiography confirms itself as a satisfactory diagnostic technique for the identification of LV global dysfunction in overt hypothyroidism. Pulsed TD may be useful to determine the severity of LV myocardial dysfunction in relation to the degree of hormonal impairment.