文章基本信息

标题：Cardiopulmonary Exercise Testing-Based Algorithm and Its Usefulness in Clinical Cardiology
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作者：Ahmad, Mirza Nubair ; Yusuf, Syed Hasan ; Ullah, Rafath 等
期刊名称：Journal of Patient-Centered Research and Reviews
电子版ISSN：2330-0698
出版年度：2015
卷号：2
期号：4
页码：204-205
出版社：Aurora Health Care
摘要：Background: Only cardiopulmonary exercise (CPX) testing provides information on the ability of the cardiovascular system to meet the body’s metabolic demands in terms of oxygen consumption (VO2) and carbon dioxide production (VCO2). However, CPX testing is underutilized by cardiologists due to complex diagnostic algorithms involving up to 30 variables as well as lack of validation studies. In addition, CPX also provides oxygen (O2) pulse as a continuous measure of stroke volume, which is its superiority to other stress modalities in which systolic function is measured at peak stress and rest. In the literature, it has been recommended that a composite criterion (combining peak O2 pulse with O2 pulse curve pattern) should be used to assess the cardiac function. Furthermore, the operating test characteristics and optimal cutoff of O2 pulse for distinguishing cardiac from noncardiac causes of exercise limitation also are unknown. Purpose: We tested whether a 6-variable algorithm would discriminate cardiac from noncardiac causes of dyspnea when compared with comprehensive CPX testing to promote its use by cardiologists. We also tested several cutoff points along with the composite criterion against the clinical standard to define the optimal O2 pulse cutoff point. Methods: Consecutive patients (n = 54) referred for dyspnea underwent CPX test consisting of pulmonary (VO2, VCO2, 22 additional variables and invasive measurement of lactate and blood gases at peak and baseline) and cardiac (exercise ECG, heart rate and blood pressure response) components as well as medical record evaluation. Patients were categorized as normal or abnormal by an experienced pulmonologist. Abnormal patients were further categorized according to cause of dyspnea (cardiac, pulmonary, deconditioning, poor effort and miscellaneous). Subsequently, the 6-variable algorithm was applied by a cardiologist blinded to all of the information from CPX tests, and the patients were categorized similarly. The 6 variables used were peak O2 uptake, peak respiratory exchange ratio, O2 pulse, heart rate reserve, breathing reserve (1 – [peak ventilation (VE) / maximal voluntary ventilation]) and ventilatory efficiency (VE/VCO2). Seven O2 pulse reference cutoff points included nongender-based (< 15 ml/beat), gender-based (< 15 ml/beat for males and < 10 ml/beat for females) and < 80% of O2 pulse based on five different definitions of predicted VO2 max. The optimal cutoff obtained was then used to create the composite criterion. For the purpose of evaluating this composite criterion, the study population was recategorized as: noncardiac group (n = 18), normal patients according to the composite criterion;
关键词：cardiopulmonary exercise testing; oxygen pulse; dyspnea; metabolics