title: Multivariate Criteria Most Accurately Distinguish Cardiac from Noncardiac Causes of Dyspnea.
abstract: Cardiopulmonary exercise testing provides oxygen pulse as a continuous measure of stroke volume, which is superior to other stress-testing methods in which systolic function is measured at baseline and at peak stress. However, the optimal peak oxygen pulse criterion for distinguishing cardiac from noncardiac causes of exercise limitation is unknown. In comparing several peak oxygen pulse criteria against the clinical standard of cardiopulmonary exercise testing, we retrospectively studied 54 consecutive patients referred for cardiopulmonary exercise testing. These exercise tests included measurement of oxygen consumption, carbon dioxide production, breathing reserve, arterial blood gases at baseline and at peak stress, exercise electrocardiogram, heart rate, and blood pressure response. Results were blindly interpreted and patients were categorized as members either of our Cardiac Group (abnormal result secondary to cardiac causes of exercise limitation) or of our Noncardiac Group (normal or abnormal result secondary to any noncardiac cause of exercise limitation). The accuracy of the peak oxygen pulse criteria ranged from 50% for univariate criterion (≤15 mL/beat), to 61% for oxygen pulse curve pattern, to 63% for bivariate criterion (≤15 mL/beat for men, ≤10 mL/beat for women), to as high as 81% for a multivariate criterion. All multivariate criteria outperformed oxygen pulse curve pattern, univariate, and bivariate criteria. This is the first study to evaluate the optimal peak oxygen pulse criterion for differentiating cardiac from noncardiac causes of exercise limitation. Multivariate criteria (especially a criterion incorporating age, sex, height, and weight) should be used preferentially, as opposed to the commonly used univariate and bivariate criteria.
authors.forename: Mirza Nubair
authors.initials: MN
authors.lastname: Ahmad
authors.forename: Syed Hasan
authors.initials: SH
authors.lastname: Yusuf
authors.forename: Rafath
authors.initials: R
authors.lastname: Ullah
authors.forename: Mirza Mujadil
authors.initials: MM
authors.lastname: Ahmad
authors.forename: Mary K
authors.initials: MK
authors.lastname: Ellis
authors.forename: Haroon
authors.initials: H
authors.lastname: Yousaf
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Paterick
authors.forename: Khawaja Afzal
authors.initials: KA
authors.lastname: Ammar
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001784:Blood Gas Analysis; D001794:Blood Pressure; D001827:Body Height; D001835:Body Weight; D004417:Dyspnea / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006331:Heart Diseases / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015999:Multivariate Analysis; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012119:Respiration; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013318:Stroke Volume
keywords: Exercise test; forced expiratory volume; heart diseases/diagnosis; lung diseases/diagnosis; oxygen consumption; oxygen pulse; respiration; retrospective studies; stress test, cardiopulmonary