Casella G, Pavesi P C, Di Niro M, Medda M, Rubboli A, Lezha M, Sangiorgio P, Bracchetti D
Servizio di Cardiologia, Ospedale Magglore, Bologna.
G Ital Cardiol. 1996 Dec;26(12):1401-13.
The significance of exercise-induced ST segment depression is well known while limited data are available on the clinical/prognostic power of ST depression occurring only during recovery. Aim of the study was to clarify the clinical/prognostic value of "recovery only" ST depression in stable patients late from myocardial infarction (AMI) and to determine whether the addition of recovery data to exercise parameters improves the interpretation of exercise test.
From a population of 766 consecutive patients (mean age: 57.2 +/- 8.6 yrs.; male: 89%) who underwent a Bruce Treadmill test at least 1 year after a Q wave AMI and whose exercise data were prospectively entered in the database of our Institution, 4 different Groups were identified: 1) 99 patients with a negative exercise test; 2) 53 patients with "exercise only" ST depression; 3) 140 patients with "exercise and recovery" ST depression; 4) 31 patients with "recovery only" ST depression. The main clinical and exercise data and a cardiac follow-up (average mean length: 1530 +/- 600 day) were evaluated by one-way analysis of variance, Bonferroni T-test, chi-square, relative risk (RR) with 95% confidence intervals (CI), Kaplan-Meler method and log-rank.
Baseline clinical parameters were similar in the 4 Groups except for older age in Group 3 compared to Group 2 (< 0.05) and higher prevalence of anterior AMI in Group 4 compared to others (= 0.004). Patients with exercise and recovery ST depression or with "recovery only" ST depression had significantly less exercise tolerance than patients with negative exercise test or "exercise only" ST depression [exercise duration (< 0.05, Group 1 vs. 3, vs. 4; Group 2 vs. 3), peak rate pressure product (< 0.05), maximal heart rate (< 0.05; Group 1 vs. 2; vs. 3; vs. 4)]. Exercise-induced ST depression was higher and angina was significantly more frequent in patients with exercise and recovery ST depression as well as an high Mark's risk score (< 0.001). Only patients with exercise and recovery ST depression demonstrated significantly higher risk of overall mortality (RR: 1.35, CI: 1.04-1.74), unstable angina (RR: 1.34, CI: 1.09-1.65) or revascularisation procedures (RR: 1.51, CI: 1.25-1.83). Relative risk of patients with "recovery only" ST depression was similar to that of subjects with "exercise only" ST depression.
In stable patients with old Q wave AMI, "recovery only" ST depression is rate, but does represent a true sign of ischemia. It could be associated with indirect indexes of worse ventricular function. The prognostical power of "recovery only" ST depression is mild, although similar to that of "exercise only" ST depression. Moreover the presence of ST depression not only during exercise but also during the recovery phase identifies patients with more severe prognosis. Therefore the inclusion of findings from the recovery phase in the analysis of the exercise test could increase the predictive power of the test itself.
运动诱发的ST段压低的意义已广为人知，而仅在恢复过程中出现的ST段压低的临床/预后价值的数据有限。本研究的目的是阐明“仅恢复期”ST段压低在心肌梗死（AMI）后晚期稳定患者中的临床/预后价值，并确定将恢复数据添加到运动参数中是否能改善运动试验的解读。
在766例连续患者（平均年龄：57.2±8.6岁；男性：89%）中，这些患者在Q波AMI至少1年后接受了Bruce平板运动试验，且其运动数据被前瞻性地录入我们机构的数据库，据此确定了4个不同的组：1）99例运动试验阴性的患者；2）53例“仅运动期”ST段压低的患者；3）140例“运动期和恢复期”ST段压低的患者；4）31例“仅恢复期”ST段压低的患者。通过单因素方差分析、Bonferroni t检验、卡方检验、95%置信区间（CI）的相对风险（RR）、Kaplan - Meler方法和对数秩检验对主要临床和运动数据以及心脏随访（平均长度：1530±600天）进行评估。
4组患者的基线临床参数相似，除了3组患者的年龄比2组大（<0.05），4组患者前壁AMI的患病率高于其他组（=0.004）。有运动期和恢复期ST段压低或“仅恢复期”ST段压低的患者的运动耐量明显低于运动试验阴性或“仅运动期”ST段压低的患者[运动持续时间（<0.05，1组与3组、4组相比；2组与3组相比）、峰值心率血压乘积（<0.05）、最大心率（<0.05；1组与2组、3组、4组相比）]。运动诱发的ST段压低在有运动期和恢复期ST段压低的患者中更高，心绞痛也明显更频繁，且Mark风险评分较高（<0.001）。只有有运动期和恢复期ST段压低的患者显示出总体死亡率（RR：1.35，CI：1.04 - 1.74）、不稳定型心绞痛（RR：1.34，CI：1.09 - 1.65）或血运重建手术（RR：1.51，CI：1.25 - 1.83）的风险显著更高。“仅恢复期”ST段压低患者的相对风险与“仅运动期”ST段压低患者的相似。
在陈旧性Q波AMI的稳定患者中，“仅恢复期”ST段压低发生率低，但确实代表了真正的缺血迹象。它可能与心室功能较差的间接指标有关。“仅恢复期”ST段压低的预后价值较小，尽管与“仅运动期”ST段压低相似。此外，不仅在运动期间而且在恢复阶段出现ST段压低可识别出预后更严重的患者。因此，将恢复阶段的结果纳入运动试验分析中可提高试验本身的预测能力。
