Abstract
The aim of this study is to estimate myocardial parameters with three different approaches daring control and postischemia (myocardial stunning). After the dogs were appropriately anesthetized, incubated and ventilated, their hearts were exposed via a left thoracotomy through the fifth intercostal space. Regional ventricular stunning was induced by a 10-minute occlusion of the left anterior descending (LAD) coronary artery. Left ventricular (LV) and aortic blood pressures were measured with catheter-tip pressure transducers. Ultrasonic dimension crystals and self-devised force transducers were used to register changes in segment length and myocardial force in LAD and circumflex (CFX) coronary artery regions, respectively. Results showed that end-systolic elastance estimated in all the experiment dogs became less in stunned region than control. Also, the resting segment length and dead segment length were found to be elongated during reperfusion, despite of the full recovery of blood supply. It is concluded that: 1) After a 10-minute LAD occlusion, contractility in the insulted region remains depressed, which may explain the mechanical dysfunction in stunned myocardium. 2) Creep phenomenon in passive diastole is demonstrated, due to stanning, by the elongated resting length. And, 3) the direct subtraction method, first submitted in the current study, shows its potential for future research in assessing myocardial parameters.
| Original language | American English |
|---|---|
| Pages (from-to) | 9-16 |
| Number of pages | 8 |
| Journal | Chinese Journal of Medical and Biological Engineering |
| Volume | 17 |
| Issue number | 1 |
| State | Published - 1997 |
| Externally published | Yes |
ASJC Scopus subject areas
- Biophysics
Keywords
- Contractility
- Creep Phenomenon
- Elastance
- Left Ventricle
- Myocardial Stunning
- Postischemia
- Resting Length