Instantaneous pressure-volume relationship of right atrium during isovolumic contraction in canine heart.

摘要: We studied the contraction of right atrium in an excised cross-circulated heart preparation. Atrial volume and instantaneous atrial pressure were measured a water-filled balloon fitted spontaneously contracting atrium. The relation to was analyzed by collecting data from multiple isovolumic contractions with different volumes but at identical time points cycle. found be quasi-linear during most systole diastole. A linear regression formula P(t) = K(t)[V- VD(t)] therefore data. K(t) VD(t) are slope axis intercept pressure-volume plane, respectively. When beat regular sinus rhythm no inotropic intervention. increased decreased diastole, whereas average value K 13 +/- 1.7 (SE) mmHg . kg ml-1 end diastole 33 0.02 systole. VD 0.303 0.017 ml kg-1 0.212 .025 Enhancement contractility epinephrine or Ca2+ significantly systole, it did not affect either