Acute and chronic hypothyroidism are associated with similar left ventricular diastolic dysfunction relative to the euthyroid state: results of doppler echocardiographic comparisons.

BACKGROUND

How the duration of hypothyroidism affects left ventricular diastolic function is not well-characterized.

AIM

We sought to compare left ventricular diastolic function in acutely vs chronically hypothyroid patients vs euthyroid controls, and within individuals while on vs off T4.

SUBJECTS AND METHODS

We prospectively performed such comparisons measuring pulsed-wave and color M-mode Doppler echocardiographic variables: early or late mitral peak velocities (E wave or A wave, respectively), E wave/A wave ratio, E wave deceleration time, isovolumic relaxation time (IVRT), mitral flow propagation velocity (Vp), E wave/Vp ratio. Subjects comprised the acute HYPO group, 10 patients undergoing T4 withdrawal ≥ 6 months post-primary treatment for differentiated thyroid cancer (DTC); the chronic HYPO group, 23 treatment-naïve Hashimoto thyroiditis patients; and 21 healthy euthyroid controls. Subjects were adults aged ≤ 60 yr, predominantly female, with sinus rhythm; exclusion criteria were cardiovascular or thyroid disorder besides DTC (Hashimoto thyroiditis) in acute (chronic) HYPO patients or medication (besides thyroid hormone) affecting cardiac or thyroid function.

RESULTS

Mean IVRT was significantly delayed and mean Vp, significantly slowed in both HYPO groups vs controls (p<0.0005), but did not differ between HYPO groups. These variables also were significantly impaired (p<0.05) within individuals when off vs on T4 (no.=8 acute, 10 chronic HYPO patients). Both HYPO groups had elevated mean E wave/Vp ratios vs controls, but the elevation reached significance (p<0.05) only in the larger chronic HYPO group.

CONCLUSIONS

Left ventricular diastolic dysfunction is largely similar in acutely or chronically hypothyroid patients off T4 vs healthy controls or the same patients on T4.