Evaluation of left ventricular systolic asynchrony in patients with subclinical hypothyroidism

The heart was very sensitive to fluctuating thyroid hormone levels. To assess intra-left ventricular (LV) systolic asynchrony in patients with subclinical thyroid dysfunction.

Fifty patients with subclinical hypothyroidism and 40 controls were included. A diagnosis of subclinical hypothyroidism was reached with increased TSH and normal free T4. All subjects were evaluated by echocardiography. Evaluation of intra-LV systolic asynchrony was performed by tissue synchronization imaging (TSI), and four TSI parameters of systolic asynchrony were calculated. LV asynchrony was defined by these parameters.

All of the groups were similar in terms of demographic findings and conventional and Doppler echocardiograpic parameters except peak systolic velocity and early diastolic velocity. LV systolic asynchrony parameters of TSI including; standard deviation of Ts of the 12 LV segments (Ts-SD-12), maximal difference in Ts between any 2 of the 12 LV segments (Ts-12), standard deviation of TS of the 6 basal LV segments (Ts-SD-6), maximal difference in Ts between any of the 6 basal LV segments (Ts-6) were significantly lengthened in patients with subclinical hypothyroidism than controls (p <0.001, p < 0.001, p < 0.001 and p < 0.001, respectively). The prevalence of LV asynchrony was significantly higher in patients with subclinical hypothyroidism than control.

Patients with subclinical hypothyroidism present evidence of LV asynchrony by TSI. LV systolic asynchrony could be a warning sign of the early stage in cardiac systolic dysfunction in subclinical hypothyroid patients.