Aims: to examine biomechanical and neuroautonomic adaptation to blood volume displacement induced by tilt-test in patients with previous inferoapical/inferolateral (IA-IL) or basal/apical septal (BS-AS) myocardial infarction (MI). Methods: Twenty-four patients with heart failure (HF) and previous IA-IL MI and thirty patients with HF and previous BS-AS MI were enrolled. All patients underwent head-up tilt-test, radionuclide ventricular function monitoring (VEST), sympatho-vagal balance evaluation and chronotropic 25 dose isoproterenol infusion test (CD₂₅). Physiopathological reactions to stress-tests were assessed in both groups. Follow-up lasted 36 months. Results: IA-IL patients showed lower stroke volume (SV), cardiac output (CO) and left ventricle ejection fraction (LVEF) compared to BS-AS. End-diastolic volume decreased in IA-IL group (F=3.1, p=0.043) more than in BS-AS group during tilt-test. The time-trend of end-systolic volume, SV, CO, LVEF and peak-filling rate were similar in the two groups. Norepinephrine (IA-IL supine→tilting 499.5 [SD:28.8]→719.3 [SD:41.5] pg/ml vs BS-AS supine→tilting 533.9 [SD:33.3]→768.8 [SD:47.9] pg/ml; p<0.001) and epinephrine plasma concentrations (IA-IL supine→ tilting 125.7 [SD:9.8]→193.7 [SD:9.6] pg/ml vs BS-AS supine→ tilting 118.8 [SD:8.9]→191.7 [SD:10.2] pg/ml; p<0.001) increased in both groups. Low-to-high frequencies ratio significantly increased in IA-IL and decreased in BS-AS patients. CD25 was similar in IA-IL and BS-AS patients (IA-IL=4.6 [SD:0.94], BS-AS=5.0 [SD:1.06] µg; p=0.79). CD₂₅ predicted all-cause mortality (hazard ratio 1.48, 95% confidence interval 1.32-1.67; p<0.0001) after adjusting for age/heart rate. Conclusions: Patients with ischemic HF show abnormal biomechanical adaptation to volume displacement and compensatory sympathetic overdrive. The association of reduced β-adrenergic sensitivity and sympathetic denervation in such patients warrants for careful therapeutic choices.

中文翻译：

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缺血性扩张型心肌病急性血容量移位的生物力学和神经自主适应：CD25测试的预测价值。

目的：检查对先前下根尖/下外侧（IA-IL）或基底/根尖间隔（BS-AS）心肌梗死（MI）的患者进行倾斜测试所引起的血容量位移的生物力学和神经自主适应性。方法：招募了24例心力衰竭（HF）和先前的IA-IL MI患者以及30例HF和先前的BS-AS MI患者。所有患者均接受平视前倾试验，放射性核素心室功能监测（VEST），交感迷走平衡评估和变时性25剂量异丙肾上腺素输注试验（CD ₂₅）。两组均评估了对压力测试的生理病理反应。随访持续了36个月。结果：与BS-AS相比，IA-IL患者的中风量（SV），心输出量（CO）和左心室射血分数（LVEF）更低。在倾斜测试期间，IA-IL组的舒张末期容积减少（F = 3.1，p = 0.043）比BS-AS组更大。两组的收缩末期，SV，CO，LVEF和峰填充率的时间趋势相似。去甲肾上腺素（IA-IL仰卧位→倾斜499.5 [SD：28.8]→719.3 [SD：41.5] pg / ml vs BS-AS仰卧位533.9 [SD：33.3]→768.8 [SD：47.9] pg / ml; p < 0.001）和肾上腺素血浆浓度（IA-IL仰卧位→倾斜125.7 [SD：9.8]→193.7 [SD：9.6] pg / ml vs BS-AS仰卧位→倾斜118.8 [SD：8.9]→191.7 [SD：10.2] pg /ml；p<0.001）在两组中均增加。IA-IL中的低频比明显增加，而BS-AS患者则降低。IA-IL和BS-AS患者的CD25相似（IA-IL = 4.6 [SD：0.94]，BS-AS = 5.0 [SD：1.06] µg； p = 0.79）。光盘调整年龄/心率后，有_25位预测的全因死亡率（危险比1.48，95％置信区间1.32-1.67； p <0.0001）。结论：缺血性HF患者对体积移位和代偿性交感神经超速表现出异常的生物力学适应性。这类患者中β-肾上腺素敏感性降低和交感神经支配减少的相关性，需要慎重的治疗选择。