Irace L, Iarussi D, Guadagno I, De Rimini M L, Lucca P, Spadaro P, Romano A, Mansi L, Iacono A
Cardiology Medicine Institute, Medical School, II University of Naples, Italy.
Clin Cardiol. 1998 Aug;21(8):567-71. doi: 10.1002/clc.4960210807.
Left ventricular (LV) preload changes may alter exercise tolerance (ET), probably lessening activation of the Maestrini-Starling mechanism. Reduced LV filling (pre-load) during the diastolic phase, usually impaired in diabetic patients, could affect ventricular function.
To evaluate the relationship between some echocardiographic LV function indices and ET, 24 patients (age 43-75 years, mean 54 +/- 13 years, Group A) with type II diabetes mellitus (DM), not suffering from other pathologies, and for whom the ergometric stress test (EST) resulted in an early interruption because of muscular fatigue and/or dyspnea, and 14 patients (age 38-70 years, mean 53 +/- 12 years, Group B) with type II DM and maximal ergometric stress test, used as control group, were studied.
The EST was performed by increasing the load by 25 W every 2 min; its duration was used as an ET index and correlated with clinical parameters of LV function obtained with M-mode, two-dimensional, and Doppler echocardiography.
No patients in either Group A or Group B showed a high systolic blood pressure value at rest and/or an LV hypertrophy and/or an alteration of systolic functional indices. In neither group was there significant correlation between ET and duration of DM, basal heart rate, basal and max systolic blood pressure, and EF values. Linear regression analysis showed a significant correlation between Doppler parameters of the diastolic function and ET index in Group A, while there was no significant correlation in Group B.
From these data we can deduce that in absence of left systolic ventricular dysfunction the impairment of LV relaxation in DM can influence exercise tolerance, probably by limiting activation of the contractile reserve.
左心室（LV）前负荷变化可能会改变运动耐力（ET），可能会减少Maestrini - 斯塔林机制的激活。舒张期左心室充盈减少（前负荷），通常在糖尿病患者中受损，可能会影响心室功能。
为了评估一些超声心动图左心室功能指标与运动耐力之间的关系，对24例（年龄43 - 75岁，平均54±13岁，A组）患有II型糖尿病（DM）且无其他疾病的患者进行了研究，这些患者因肌肉疲劳和/或呼吸困难而导致运动负荷试验（EST）提前中断；并将14例（年龄38 - 70岁，平均53±12岁，B组）患有II型糖尿病且进行了最大运动负荷试验的患者作为对照组。
通过每2分钟将负荷增加25W来进行运动负荷试验；其持续时间用作运动耐力指标，并与通过M型、二维和多普勒超声心动图获得的左心室功能临床参数相关联。
A组和B组患者在静息时均未出现高收缩压值和/或左心室肥厚和/或收缩功能指标改变。两组中运动耐力与糖尿病病程、基础心率、基础和最大收缩压以及射血分数值之间均无显著相关性。线性回归分析显示，A组舒张功能的多普勒参数与运动耐力指标之间存在显著相关性，而B组则无显著相关性。
从这些数据我们可以推断，在不存在左心室收缩功能障碍的情况下，糖尿病患者左心室舒张功能受损可能会影响运动耐力，可能是通过限制收缩储备的激活。
