Heslinga J W, Allaart C P, Westerhof N
Laboratory for Physiology, Institute for Cardiovascular Research Vrije Universiteit Amsterdam, The Netherlands.
Eur J Morphol. 1996;34(1):55-62. doi: 10.1076/ejom.34.1.55.13160.
The intramyocardial pressure (IMP) plays a role in the interaction between heart contraction and coronary flow. In order to measure IMP we developed the isolated perfused papillary muscle. The papillary muscle was suspended in a muscle bath with oxygenated Tyrode's solution. Perfusion with Tyrode's solution took place via the septal artery. Diastolic intramyocardial pressure was measured with micropipettes with a tipdiameter of 3 to 4 microns in combination with the servo-null technique. After an equilibration period of at least a half hour where the muscle was perfused with a perfusion pressure of 40 cmH2O and stimulated with 0.2 Hz the IMP measurements started. Pressure changes resulting from changes in perfusion pressure and injection of ink via the pipette made it possible to distinguish between interstitial and vascular localization. No leakage along the shaft of the pipette to the outside was found. Perfusion caused interstitial edema in the muscle so that the cross-sectional area (CSA) of myocytes relative to total muscle CSA decreased from 71% in non-perfused muscle to 51% in perfused muscle. Interstitial edema increased approximately from 10% to 30%. The amount of edema was reduced by rapid pacing (3.3 Hz) as judged from decreased muscle diameter and a lower IMP. It is concluded that reliable IMP measurements can be made in the isolated papillary muscle and that increased filling of the interstitium increases its pressure.
心肌内压（IMP）在心脏收缩与冠脉血流的相互作用中发挥作用。为了测量IMP，我们开发了离体灌注乳头肌。乳头肌悬浮于含有氧合台氏液的肌肉浴中。通过间隔动脉用台氏液进行灌注。舒张期心肌内压采用尖端直径为3至4微米的微量移液器结合伺服零位技术进行测量。在至少半小时的平衡期后，以40 cmH₂O的灌注压力对肌肉进行灌注，并以0.2 Hz的频率进行刺激，然后开始IMP测量。灌注压力变化和通过移液器注入墨水所导致的压力变化使得区分间质和血管定位成为可能。未发现移液器杆向外部的渗漏情况。灌注导致肌肉出现间质水肿，使得心肌细胞的横截面积（CSA）相对于总肌肉CSA从未灌注肌肉中的71%降至灌注肌肉中的51%。间质水肿大约从10%增加到30%。根据肌肉直径减小和IMP降低判断，快速起搏（3.3 Hz）可减少水肿量。得出的结论是，在离体乳头肌中可以进行可靠的IMP测量，并且间质充盈增加会使其压力升高。
