Yokoyama Y, Novitzky D, Deal M T, Snow T R
Oklahoma Transplantation Institute, Baptist Medical Center, Oklahoma City.
Cardiology. 1992;81(1):34-45. doi: 10.1159/000175773.
Reperfusion following a transient ischemic insult has been shown to result in a delayed recovery of myocardial function. A reduction in plasma triiodothyronine (T3) has been reported in these acute cardiovascular challenges. To test whether the replacement of T3 can facilitate the recovery of myocardial function following a transient regional ischemia, we investigated cardiac performance for 3 h after a 15-min, left anterior descending coronary artery occlusion in a canine model. Three groups of dogs were studied: I--control (n = 10); II--receiving T3 (0.25 micrograms/kg i.v. and 0.25 micrograms/kg/h for 3 h, n = 9), and III--receiving T3 (0.25 micrograms/kg i.v. and 0.5 micrograms/kg/h for 3 h, n = 9). Three hours following reperfusion, the T3 level in blood was significantly decreased in group I. Concomitantly, local segmental shortening was reduced from preocclusion control levels in group I (15.2 to 5.1%, p < 0.05), but recovered in both treated groups. The endsystolic elastance (Ees) and the external work (EW) efficiency (EW/PVA) in group I were depressed from preocclusion control (Ees = 95.5 +/- 0.8%; EW/PVA = 90.2 +/- 1.8%, both p < 0.05), the effective arterial elastance (Ea) and ventriculoarterial coupling (Ea/Ees) in group I were still elevated from preocclusion control (Ea = 122.5 +/- 5.1%; Ea/Ees = 128.3 +/- 5.3%, both p < 0.05). But these measures of global cardiac performance in the treated groups recovered following reperfusion, and the extent of recovery was dose dependent. These data suggest that T3 facilitates recovery of the stunned myocardium by improvement in local and global contractile function, in ventriculoarterial coupling, and in the energy efficiency.
短暂性缺血损伤后的再灌注已被证明会导致心肌功能延迟恢复。据报道，在这些急性心血管挑战中，血浆三碘甲状腺原氨酸（T3）水平会降低。为了测试补充T3是否能促进短暂性局部缺血后心肌功能的恢复，我们在犬模型中研究了左前降支冠状动脉闭塞15分钟后3小时的心脏功能。研究了三组犬：I组——对照组（n = 10）；II组——接受T3（静脉注射0.25微克/千克，持续3小时，每小时0.25微克/千克，n = 9），III组——接受T3（静脉注射0.25微克/千克，持续3小时，每小时0.5微克/千克，n = 9）。再灌注3小时后，I组血液中的T3水平显著降低。与此同时，I组局部节段缩短从闭塞前对照水平降低（从15.2%降至5.1%，p < 0.05），但在两个治疗组中均恢复。I组的收缩末期弹性（Ees）和外功（EW）效率（EW/PVA）较闭塞前对照降低（Ees = 95.5 +/- 0.8%；EW/PVA = 90.2 +/- 1.8%，均p < 0.05），I组的有效动脉弹性（Ea）和心室 - 动脉耦合（Ea/Ees）仍高于闭塞前对照（Ea = 122.5 +/- 5.1%；Ea/Ees = 128.3 +/- 5.3%，均p < 0.05）。但治疗组的这些整体心脏功能指标在再灌注后恢复，且恢复程度呈剂量依赖性。这些数据表明，T3通过改善局部和整体收缩功能、心室 - 动脉耦合以及能量效率来促进顿抑心肌的恢复。
