Effect of L-thyroxine replacement in patients with hypothyroidism on serum T4, TSH, and cardiac contractility as measured by the PEP as a function of LVET. Contractility increased (as demonstrated by a fall in PEP/LVET) in a dose-dependent fashion.
Adapted from: Crowley WF Jr, Ridgway EC, Bough EW, et al. Noninvasive evaluation of cardiac function in hypothyroidism. Response to gradual thyroxine replacement. N Engl J Med 1977; 296:1.