Goebbels U, Myers J, Dziekan G, Muller P, Kuhn M, Ratte R, Dubach P
Cardiology Division, Kantonsspital, Chur, Switzerland.
Chest. 1998 May;113(5):1387-93. doi: 10.1378/chest.113.5.1387.
Exercise training is recommended after myocardial infarction (MI) or bypass surgery in order to improve exercise tolerance. In some patients, the decrement in exercise capacity secondary to deconditioning and the left ventricular stunning associated with MI or coronary artery bypass graft (CABG) spontaneously improves after the event. However, the impact of the status of the left ventricle on these improvements is unknown.
Sixty-seven patients 1 month after MI or CABG were randomized to a training (n=34; age, 59+/-7 years) or a control group (n=33; age, 55+/-6 years). Forty-two patients had an ejection fraction >50% (22 in the training group and 20 in the control group), and 25 patients had an ejection fraction <40% (12 in the exercise group and 13 in the control group). After stabilization for approximately 1 month after the event, patients in the exercise group underwent 8 weeks of twice daily exercise at a residential rehabilitation center, while control patients received usual care. Initially and after 8 weeks, patients in both groups underwent maximal exercise testing with gas exchange and lactate analysis.
Exercise training increased peak oxygen consumption (VO2) only in the reduced ejection fraction group (19.4+/-3.0 to 23.9+/-4.8 mL/kg/min; p<0.05); the exercise group with normal ventricular function did not change significantly. Changes in VO2 at the lactate threshold paralleled those of peak VO2 for both groups. Conversely, control patients with normal ventricular function increased peak VO2 spontaneously (20.8+/-3.9 to 24.8+/-3.5 mL/kg/min; p<0.01), whereas control patients with reduced ventricular function did not improve peak VO2.
These data suggest that patients with depressed left ventricular function strongly benefit from rehabilitation, whereas most patients with preserved left ventricular function following MI or CABG tend to improve spontaneously 1 to 3 months after the event.
心肌梗死（MI）或搭桥手术后建议进行运动训练以提高运动耐量。在一些患者中，因失健状态继发的运动能力下降以及与MI或冠状动脉搭桥术（CABG）相关的左心室顿抑在事件发生后会自发改善。然而，左心室状态对这些改善的影响尚不清楚。
67例MI或CABG术后1个月的患者被随机分为训练组（n = 34；年龄59±7岁）或对照组（n = 33；年龄55±6岁）。42例患者射血分数>50%（训练组22例，对照组20例），25例患者射血分数<40%（运动组12例，对照组13例）。事件发生后稳定约1个月后，运动组患者在住院康复中心每天进行2次运动，持续8周，而对照组患者接受常规护理。两组患者在初始时和8周后均进行了气体交换和乳酸分析的最大运动测试。
运动训练仅在射血分数降低组增加了峰值耗氧量（VO2）（从19.4±3.0增至23.9±4.8 mL/kg/min；p<0.05）；心室功能正常的运动组无显著变化。两组在乳酸阈值时VO2的变化与峰值VO2的变化平行。相反，心室功能正常的对照组患者峰值VO2自发增加（从20.8±3.9增至24.8±3.5 mL/kg/min；p<0.01），而心室功能降低的对照组患者峰值VO2未改善。
这些数据表明，左心室功能低下的患者从康复中获益显著，而大多数MI或CABG后左心室功能保留的患者在事件发生后1至3个月往往会自发改善。
