DEPRESSED LEFT-VENTRICULAR SYSTOLIC EJECTION FORCE IN HYPOTHYROIDISM

Experimental hypothyroidism is associated with depressed myocardial contractile function, possibly due to alterations in contractile protein isoforms.1,2 Abnormal systolic performance has been demonstrated in humans with severe, primary hypothyroidism; replacement of thyroid hormone leads to normalization of systolic time intervals in these patients.3 Recently, a new Doppler method of noninvasively determining left ventricular (LV) ejection force was described.4 Using Newton's second law of motion, force may be derived from the product of the mass and acceleration of blood ejected out the aortic valve. This study tests the hypothesis that this new noninvasive method can detect subtle changes in LV systolic function in patients with primary hypothyroidism. © 1990.