Systolic time intervals in hyperthyroidism.

PEPI (pre-ejection period index), QS2I (total electromechanical systolic index), LVETI (left ventricular ejection time index), and PEP/LVET ratio were measured in 35 thyrotoxic patients. None of the patients had clinical evidence of heart disease nor received drugs which might have affected the systolic time intervals. the hyperthyroid subjects showed significant shortening of PEPI and significant reduction of PEP/LVET, which returned within normal limits when the patients became euthyroid during treatment. No correlation could be found between T3, T4, FTI and PEPI or PEP/LVET. However, serial measurements indicated that the fall toward the normal range of PEPI parallelled that of T3; the latter is considered the most important index of thyroid function. Our study suggests that PEPI and PEP/LVET ratio may be of great usefulness in detecting hemodynamic alterations in subjects with uncomplicated hyperthyroidism. Moreover, these methods may facilitate the diagnosis in unusual types of hyperthyroidism occurring in the absence of clinical signs of toxicosis. In addition, PEPI and PEP/LVET appear to be useful in detecting T3 toxicosis. Finally, serial controls of PEPI could represent a useful index to monitor the response to therapy.