Morace G, Alcidi L, Fantini F
Clinica Medica II, Università degli Studi di Firenze.
G Ital Cardiol. 1989 Feb;19(2):97-103.
Using an electric circuit model, made of two segments formed of sections that behave electrically as subendocardial and subepicardial cells, we simulated myocardial ischemia in one of the two segments. The changes in the ST segment and in the T wave were obtained respectively by diminishing the intercellular potential from -90 mV to -60 mV and by shortening or prolonging the duration of action potentials. In order to simulate acute subendocardial, subepicardial and transmural ischemia, the potentials of the internal section, the outer section, and of both sections were diminished respectively. The ST segment appeared depressed both in the segment involved and in the undamaged one in subendocardial ischemia. In subepicardial ischemia it appeared elevated in the segment involved and was normal in the undamaged one. In transmural ischemia it was elevated in the segment with reduced potential and it was depressed in the undamaged segment. The depression of the ST segment in the undamaged part, both in subendocardial ischemia and in transmural ischemia, depends on the imbalance of the central point and therefore the whole subendocardial layer behaves electrically as if it really were ischemic. The T-wave changes in acute ischemia are in keeping with those of the ST segment.
利用一个由两段组成的电路模型，这两段由电行为类似于心内膜下细胞和心外膜下细胞的部分构成，我们模拟了两段中的一段心肌缺血情况。ST段和T波的变化分别通过将细胞间电位从-90mV降至-60mV以及缩短或延长动作电位持续时间来获得。为了模拟急性心内膜下、心外膜下和透壁性缺血，分别降低内部部分、外部部分以及两部分的电位。在心内膜下缺血时，受累节段和未受损节段的ST段均出现压低。在心外膜下缺血时，受累节段的ST段抬高，未受损节段正常。在透壁性缺血时，电位降低节段的ST段抬高，未受损节段的ST段压低。在心内膜下缺血和透壁性缺血时，未受损部分ST段的压低取决于中心点的失衡，因此整个心内膜下层的电行为就好像它真的缺血一样。急性缺血时的T波变化与ST段的变化一致。
