Evaluation of left ventricular diastolic function in IgE-mediated anaphylaxis in dogs

Depressed left ventricular (LV) systolic function remains controversial in patients with anaphylaxis and anaphylactic animal models. However, LV diastolic function has not yet been investigated in either patients or animal models. Therefore, we assessed LV diastolic and systolic function in IgE-mediated anaphylaxis in dogs. Seven dogs sensitized to Ascaris suum antigen were studied. An aqueous extract of Ascaris suum antigen was administered over 30 s into the systemic circulation to induce anaphylaxis. To assess LV function, the time constant of the fall of isovolumic LV pressure (T), as an index of LV diastolic function, and the maximum rate of rise of LV pressure (dP/dtmax), as an index of LV systolic function, were measured for a period of 120 min after antigen challenge. T was prolonged during the period of 5 to 15 min; however, changes in T were not significantly different from prechallenge values. LV d}/dtmax significantly decreased to 0.49 +/- 0.12 times the prechallenge value 5 min after antigen challenge, and significantly increased during the period from 30 to 120 min. However, these changes in dP/dtmax almost paralleled the changes in LV end-diastolic pressure, indicating that left ventricular systolic function was relatively well preserved. In conclusion, LV diastolic function, i.e., isovolumic relaxation, is little impaired in anaphylaxis, and LV systolic function is relatively well preserved during the early stage following the onset of anaphylaxis.