[The diastolic pressure-volume relationship of the left ventricle--evaluation of XXXX isovolumetric contracting left ventricle].

@entity235 @entity1169 @entity591 @entity63
Isovolumetrically contracting left ventricle of the anesthetized @entity235 was used to evaluate the end-diastolic pressure-volume relationship [LVEDP (P)-LVEDV (V) relationship (curve)] following changes in heart rate, @entity63 and administration of beta-adrenergic blocking drug. At the same time, relaxation indices were also obtained. Initial left ventricular volume was set at the end-diastolic pressure of 2.0 mmHg. Comparison of each parameters after intervention was done when each initial left ventricular volume was increased by 10 ml. With increase in heart rate, LVEDP increased significantly from 5.1 +/- 2.1 to 14.0 +/- 2.2 mmHg (at 160 bpm, p less than 0.02, vs 100 bpm) and to 24.0 +/- 1.0 mmHg (at 180 bpm, vs p less than 0.001, vs 100 bpm). Regional @entity63 also increased LVEDP significantly from 6.4 +/- 1.4 mmHg to 12.8 +/- 4.1 mmHg (after 30 min, p less than 0.01, vs control) and to 14.1 +/- 4.7 mmHg (after 45 min, p less than 0.01, vs control). However, global @entity63 produced by decreasing coronary perfusion pressure to 50 mmHg, or administration of @entity1169 (1.0 mg/kg) brought about no significant changes in LVEDP. Among the relaxation indices, peak negative dp/dt decreased significantly following global @entity63 , regional @entity63 and administration of @entity1169 (from 1101 +/- 131 to 733 +/- 49 mmHg/sec, p less than 0.01, from 888 +/- 425 to 268 +/- 94 mmHg/sec after 45 min, p less than 0.01 and from 562 +/- 160 to 291 +/- 100 mmHg/sec, p less than 0.01, respectively). On the other hand, time constant (T) of the left ventricular pressure fall was prolonged significantly following regional @entity63 from 44.7 +/- 5.2 to 72.0 +/- 8.6 msec (after 30 min, p less than 0.001) and 95.4 +/- 26.0 msec (after 30 min, p less than 0.001) and 95.4 +/- 26.0 msec (after 45 min, p less than 0.001). Therefore, it is concluded that LV diastolic compliance decreases by @entity591 (160 and 180 bpm) and regional @entity63 , while the changes of the relaxation indices were not necessarily parallel to those of the LV compliance.
