运动时扩张型心肌病患者运动耐量及左心室功能变化研究

Assessment on exercise tolerance and changes of left ventricular function in patients with dilated cardiomyopathy during exercise

目的 探讨运动时扩张型心肌病 (DCM)患者的左心室射血功能变化以及左心室功能改变与运动量的关系。方法 2 8例DCM患者接受了症状限制性踏车负荷超声心动图检查 ,评价运动耐量、运动前和峰值运动量时的左心室收缩及舒张功能变化。结果 峰值运动量时所有超声心动图指标与运动前比较差异均无显著性意义。运动时心率和血压明显增高。运动前左室射血分数EF(2 7%± 7% )与最大运动量 [(92± 3 7)W ]之间无相关性 ,r =0 .2 9,P >0 .0 5 ;但峰值运动量时的EF(2 7%± 11% )与最大运动量之间具有相关性 ,r =0 .42 ,P <0 .0 5。在左室舒张功能方面 ,二尖瓣前向血流E峰速度无论在运动前 [(0 .77±0 .2 3 )m/s]或峰值运动量时 [(0 .87± 0 .3 1)m/s]均与最大运动量呈负相关关系 ,r =-0 .42～ -0 .70 ,P <0 .0 5。结论 DCM患者可以达到一个较高水平的运动量 ,运动前的左室EF与最大运动量无明显关系。左室收缩及舒张功能在峰值运动量时与运动前比较无明显变化。

Objective To investigate whether there is a change of left ventricular (LV) ejection fraction (EF) during exercise in patients with dilated cardiomyopathy(DCM) and whether this change could be responsible for different levels of exercise capacity in the individual patients. Methods Exercise tolerance was assessed by symptom limiting stress echocardioyraphy on a bicycle using a ramp protocol in 28 patients with DCM. LV systolic and diastolic function was evaluated at rest and at peak exercise. Results Statistically there were no significant changes of all considered echocardiographic parameters during exercise. An increase of working capacity seemed to be possible only by accelerating heart rate and an increase of blood pressure. There was no correlation between LVEF at rest 27%±7% and maximal exercise capacity (r= 0.29 , P > 0.05 ). However, there was a correlation between EF at peak exercise 27%±11% and maximal exercise capacity ( r = 0.42 , P < 0.05 ). For the diastolic parameters there was a negative correlation between the E-wave-velocity at rest [( 0.77 ± 0.23 )m/s] and the maximal loading capacity( r = -0.42 , P < 0.05 ), which increased at peak exercise [( 0.87 ± 0.31 )m/s] (r=-0.70 , P < 0.01 ).Conclusions In patients with DCM, a higher level of exercise capacity could be reached. The determination of the EF at rest showed no correlation with maximal exercise capacity. There are no changes between left ventricular function at rest and maximal exercise capacity.