Parameter Normal values Hyperthyroidism Hypothyroidism Blood volume (% of normal value) 100 105.5 84.5 Heart rate (bpm) 72–84 88–130 60–80 Cardiac output (L/min) 4.0–6.0 > 7.0 < 4.5 Systemic vascular resistance (dyn·sec/cm-5) 1500–1700 700–1200 2100–2700 Left ventricular ejection fraction (%) > 50 > 65 60 Isovolumic relaxation time (msec) 60–80 25–40 > 80

[Reprinted with permission from Klein I, Ojamaa K 2001 Thyroid hormone and the cardiovascular system. N Engl J Med 344:501–509. Copyright © 2001 Massachusetts Medical Society.]