Tokmakova Mariya P, Marinov Blagoi I, Manukov Ivan H, Djurdjev Atanas B, Kostianev Stefan S, Iluchev Dimitar H
Clinic of Cardiology, Medical University, Plovdiv, Bulgaria.
Folia Med (Plovdiv). 2007;49(3-4):26-31.
The VE-VO2 relationship during graded exercise has an inflection point beyond the ventilatory anaerobic threshold (VAT) termed the respiratory compensation point (RCP). Metabolic variables analyzed at the level of VAT and RCP may contribute to the better understanding of such limiting symptoms in chronic heart failure (CHF) patients as dyspnea and early fatigue. The AIM of the present study was to analyze the RCP during symptom limited ramp exercise testing in CHF patients.
Forty six CHF patients (II and III NYHA functional class; age = 51 +/- 9 years, LVEF% = 35% +/- 6%; mean +/- SD) and 20 matched controls performed graded cardiopulmonary exercise test on a cycle ergometer.
The duration and productivity of RCP (delta(x) = peak(x) - VAT(x)) in patients were significantly (p < 0.001) reduced compared to healthy subjects: delta duration = 3.0 +/- 1.2 vs 4.3 +/- 1.5 min, delta watts = 24.3 +/- 11.5 vs. 39.4 +/- 11.5, delta VO2/kg (ml.kg-1 x min-1) = 3.8 +/- 1.3 vs 8.8 +/- 2.3. An important characteristic of this phase was the higher subjective cost of physical effort assessed by Borg scale and Watts/Borg ratio (Borg peak = 9.9 +/- 0.4 vs. 6.0 +/- 1.2; p < 0.001, Watts/Borg peak = 9.2 +/- 2.3 vs 23.9 +/- 6.4, p < 0.001). The relative hyperventilation of patients on the basis of the watt exercise can be seen in the values of derivative index V (ml x min-1 x watt-1) 478 +/- 59 vs 568 +/- 118; (p < 0.001) in controls and patients, respectively.
The impaired efficiency of oxygen delivery systems in patients with CHF is what causes the appearance of early limiting symptoms. Duration and productivity of respiratory compensation phase in CHF patients are considerably reduced compared to controls.
分级运动期间的VE-VO2关系在通气无氧阈（VAT）之外有一个拐点，称为呼吸补偿点（RCP）。在VAT和RCP水平分析代谢变量可能有助于更好地理解慢性心力衰竭（CHF）患者的呼吸困难和早期疲劳等限制症状。本研究的目的是分析CHF患者症状受限的斜坡运动试验期间的RCP。
46例CHF患者（纽约心脏协会II级和III级功能分级；年龄=51±9岁，左心室射血分数%=35%±6%；均值±标准差）和20名匹配的对照者在自行车测力计上进行分级心肺运动试验。
与健康受试者相比，患者RCP的持续时间和产能（δ(x)=峰值(x)-VAT(x)）显著降低（p<0.001）：δ持续时间=3.0±1.2分钟对4.3±1.5分钟，δ瓦特数=24.3±11.5对39.4±11.5，δVO2/kg（毫升·千克-1·分钟-1）=3.8±1.3对8.8±2.3。该阶段的一个重要特征是通过Borg量表和瓦特/Borg比率评估的主观体力消耗更高（Borg峰值=9.9±0.4对6.0±1.2；p<0.001，瓦特/Borg峰值=9.2±2.3对23.9±6.4，p<0.001）。根据瓦特运动，患者的相对过度通气可分别在导数指数V（毫升·分钟-1·瓦特-1）的值中看出，对照组为478±59，患者组为568±118；（p<0.001）。
CHF患者氧输送系统效率受损是早期限制症状出现的原因。与对照组相比，CHF患者呼吸补偿阶段的持续时间和产能显著降低。
