Lele S S, Macfarlane D, Morrison S, Thomson H, Khafagi F, Frenneaux M
Department of Cardiology, Royal Brisbane Hospital, Australia.
Eur Heart J. 1996 Feb;17(2):204-12. doi: 10.1093/oxfordjournals.eurheartj.a014836.
To test the hypothesis that diastolic filling abnormalities are an important cause of exercise limitation in some patients with coronary artery disease we assessed the factors limiting exercise capacity in a group of patients with coronary artery disease in whom exercise limitation was greater than expected from the degree of resting left ventricular systolic dysfunction.
We assessed the relationship between exercise capacity (maximal oxygen consumption) during erect cycle ergometry, heart rate, radionuclide indices of left ventricular systolic function (ejection fraction) and diastolic filling (peak filling rate, and time to peak filling) during semi-erect cycle ergometry in 20 patients (15 male, five female) who were aged 42-72 years (mean 61 years) and had angiographically proven coronary artery disease and evidence of reversible myocardial ischaemia on thallium scintigraphy. All patients exhibited marked exercise limitation (maximal oxygen consumption 8.7- 22.4 ml.min-1.kg-1--mean 15.9 ml.kg-1.min-1, which was 61.1 +/- 16% of age and gender predicted maximum) due to breathlessness or fatigue rather than angina, in spite of a mean ejection fraction for the group of 46.5% (range 30-67%). We also compared the diastolic filling characteristics of these patients during exercise with 10 healthy controls (age 38-66, mean 58 years; eight male, two female). Comparing diastolic filling characteristics, peak filling rate was higher and time to peak filling shorter both at rest and at peak exercise in controls than patients (peak filling rate 3.1 +/- 0.5 vs 2.2 +/- 0.9 EDV.s-1, P = 0.01 at rest and 8.3 +/- 0.8 vs 5.2 +/- 1.9 EDV.s-1, P < 0.0001 on exercise; time to peak filling 115.2 +/- 29.8 vs 228.9 +/- 71.7 ms, P < 0.0001 at rest and 52.8 +/- 16.2 vs 139.6 +/- 44.8 ms, P < 0.0001 on exercise respectively). On univariate analysis in the patients studied, maximal oxygen consumption was correlated with peak heart rate (r = 0.45 P = 0.04), peak exercise time to peak filling (r = -0.85 P < 0.0001), peak exercise peak filling time rate (r = 0.51 P = 0.019), and the relative increase in cardiac output i.e. cardiac output peak/cardiac output rest (r = 0.58, P = 0.008). There was no correlation between maximal oxygen consumption and resting indices of diastolic filling (peak filling rate and time to peak filling) or with resting or peak exercise ejection fraction. On multiple regression analysis, only peak exercise time to peak filling was significantly related to maximal oxygen consumption.
We have observed a strong correlation between exercise capacity and indices of exercise left ventricular diastolic filling, and have confirmed previous studies showing a poor correlation with resting and exercise indices of systolic function and resting diastolic filling, in patients with coronary artery disease.
为验证舒张期充盈异常是某些冠心病患者运动受限的重要原因这一假说，我们评估了一组冠心病患者运动能力受限的因素，这些患者的运动受限程度超过了根据静息左心室收缩功能障碍程度所预期的范围。
我们评估了20例患者（15例男性，5例女性）在直立式自行车测力计运动期间的运动能力（最大耗氧量）、心率，以及在半直立式自行车测力计运动期间左心室收缩功能（射血分数）和舒张期充盈（峰值充盈率和达到峰值充盈的时间）的放射性核素指标。这些患者年龄在42 - 72岁（平均61岁），经血管造影证实患有冠心病，并且铊闪烁显像显示有可逆性心肌缺血。尽管该组患者的平均射血分数为46.5%（范围30 - 67%），但所有患者均因呼吸急促或疲劳而非心绞痛表现出明显的运动受限（最大耗氧量为8.7 - 22.4 ml·min⁻¹·kg⁻¹，平均15.9 ml·kg⁻¹·min⁻¹，为年龄和性别预测最大值的61.1±16%）。我们还将这些患者运动期间的舒张期充盈特征与10名健康对照者（年龄38 - 66岁，平均58岁；8例男性，2例女性）进行了比较。比较舒张期充盈特征发现，对照组在静息和运动峰值时的峰值充盈率均高于患者，达到峰值充盈的时间短于患者（静息时峰值充盈率3.1±0.5 vs 2.2±0.9 EDV·s⁻¹，P = 0.01；运动时8.3±0.8 vs 5.2±1.9 EDV·s⁻¹，P < 0.0001；静息时达到峰值充盈的时间115.2±29.8 vs 228.9±71.7 ms，P < 0.0001；运动时52.8±16.2 vs 139.6±44.8 ms，P < 0.0001）。在所研究的患者中进行单因素分析时，最大耗氧量与峰值心率（r = 0.45，P = 0.04）、运动峰值时达到峰值充盈的时间（r = -0.85，P < 0.0001）、运动峰值时的峰值充盈时间率（r = 0.51，P = 0.019）以及心输出量的相对增加即心输出量峰值/静息心输出量（r = 0.58，P = 0.008）相关。最大耗氧量与舒张期充盈的静息指标（峰值充盈率和达到峰值充盈的时间）或与静息或运动峰值时的射血分数均无相关性。在多元回归分析中，只有运动峰值时达到峰值充盈的时间与最大耗氧量显著相关。
我们观察到运动能力与运动时左心室舒张期充盈指标之间存在很强的相关性，并证实了先前的研究结果，即在冠心病患者中，运动能力与收缩功能的静息和运动指标以及静息舒张期充盈指标的相关性较差。
