慢性心臟衰竭患者在漸增式運動測試中之心肺反應

Cardiopulmonary Response to Incremental Exercise Testing in Chronic Heart Failure Patients

由於慢性心衰竭患者在運動中會出現呼吸困難及容易疲乏等現象，影響運動表現。本研究的目的即在比較慢性心衰竭患者與無心血管疾病之正常人在運動能力、動態攝氣量、自主之最大盡力運動時之吐氣氣流限制及換氣反應值的差異，並分析慢性心衰竭患者與正常人運動能力差異的因素。由醫師轉介之18位慢性心衰竭患者（14位男性，4位女性，平均年齡63±13歲），NYHA功能分級介於第二至第三級，平均左心室射出率為34.9±3.4%，是為病患組，16位健康受試者（11位男性，5位女性，平均年齡58±8歲）為對照之正常組。所有受試者均接受身體組成、活動與飲食量表，以及生活品質問卷之量測和自主最大盡力之最大運動測試，用運動測試最初3分鐘每口換氣之氣體資料，以攝氣量時問常數分析受試者之動態攝氧量，並於測試停止時立即接受以負壓吐氣法接受吐氣氣流限制測試。以Mann-Whitney U Test 檢測兩組各參數之差異，並以Spearman Correlation Test分析影響慢性心衰竭．患者運動能力的相關因子。慢性心衰竭患者與正常組相較，在自主最大盡力運動時之攝氣量、心率和氧脈皆明顯較低（p＜0.05），攝氣量時問常數則較高（p＜0.05）。慢性心衰竭患者在最大盡力運動時的潮氣量和潮氣量與吸氣時間比等明顯為低 （ p <0.05 ） ，然而吐氣末二氧化碳分壓和換氣反應值則較高（p＜0.05）。吐氣氣流限制方面，兩組則無顯著差異。相關性分析中，發現慢性心衰竭患者最大盡力時攝氣量與換氣反應值或攝氧量時問常數值問具有顯著負相關，其 r 值分別為-0.60（p=0.009）和-0.51（p=0.042）。慢性心衰竭患者之最大運動能力和最大運動量時之平均氣流均較正常為低，換氣反應值則較高，還有明顯攝氣量延遲增加的現象。此外，運動能力與攝氣量時間常數及換氣反應值間有明顯負相關。

Patients with chronic heart failure (CHF) often suffer from dyspnea and fatigue, thus limit their exercise capacity. The purpose of the study was to compare the differences in voluntary exhaustion exercise capacity, 02 consumption (V02) on-kinetics in early stage of exercise, expiratory flow limitation, and ventilatory response (VE/VC02) at voluntary exhaustion exercise between CHF patients and normal subjects, and to investigate the correlation between maximal exercise capacity and these variables of interest. Eighteen patients with CHF (14 men and 4 women, age averaged 63±13 yrs), and 16 normal subjects (11 men and 5 women with average age of 58±8 yrs) served as subjects of the study. The patients had an average of LVEF of 34.9±3.4% and in NYHA class II to III. All subjects received a voluntary exhaustion cardiopulmonary exercise test, body composition test, questionnaires of physical activity and diet-calories intake, and expiratory flow limitation test by negative expiratory pressure immediately after the exercise test. Breath-by-breath gas data of the fist three minutes of the exercise test were analysed to study the V02 time constant in early stage of exercise. Mann-Whitney U test was used to make group comparisons and Spearman correlation test to investigate the relationship between exercise capacity and those related variables in CHF group. Significantly lower values in maximal V02, heart rate, and oxygen pulse but higher V02 time constant were found in CHF patients (p<0.05). As to pulmonary function at maximal exercise, the tidal volume, ratio of tidal volume and inspiratory time were lower, while the end-tidal CO2 partial pressure and VE/VCO2 were higher in patient group (p<0.05). No difference in expiratory flow limitation between groups was found. In addition, a moderate negative correction was found between peak V02 and VE/VCO2 (r=-0.60, p=0.009), as well as with VU2 time constant (r=-0.51, p=0.042) in CHF group. CHF patients have lower values in exercise capacity that may be related to higher VE/VCO2 and V02 time constant.