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.

Patterns of Oxygen Pulse Curve in Response to Incremental Exercise in Patients with Chronic Obstructive Pulmonary Disease – An Observational Study

“…However, another study reported that flattening of the O 2 P curve during exercise can only be used to detect extensive but not mild myocardial ischemia 6 . Moreover, a study on multivariate criteria in diagnosing cardiac causes of exercise limitation found that the O 2 P curve flattening pattern was not superior to predicted O 2 P% 4 . Despite these inconsistent clinical implications of O 2 P curve flattening, 16.6% of patients with COPD have ischemic heart disease 34 , which enhances the importance of this pattern.…”

“…Reduced O 2 P with a plateau, or decreasing pattern 4 , 5 when approaching peak exercise has been attributed to cardiac dysfunction or myocardial ischemia in patients with cardiac impairment. Although the relationship between a flattened O 2 P curve and severity of myocardial ischemia is not linear 6 , O 2 P remains an indicator of training effect 7 , and a prognosticator of heart failure 8 – 11 and primary pulmonary hypertension 12 .…”

“…Although the relationship between a flattened O 2 P curve and severity of myocardial ischemia is not linear 6 , O 2 P remains an indicator of training effect 7 , and a prognosticator of heart failure 8 – 11 and primary pulmonary hypertension 12 . Recently, three patterns of O 2 P curve have been reported, two of which include plateaus or decreases which are thought to be related to cardiac dysfunction 4 . Moreover, an O 2 P value ≤80% of the predicted value has been reported to be non-specific for low stroke volume, because anemia, carboxyhemoglobinemia, poor blood oxygenation in the lung, right to left shunt, and low peripheral oxygen extraction have been associated with low O 2 P 3 .…”

The Impact of Oxygen Pulse and Its Curve Patterns on Male Patients with Heart Failure, Chronic Obstructive Pulmonary Disease, and Healthy Controls—Ejection Fractions, Related Factors and Outcomes

“…In addition, O 2 P curve pattern (O 2 PCP) is the trajectory of O 2 P during exercise, and therefore represents continuous monitoring of O 2 P. O 2 PCP is different in patients with obstructive airway disease and heart disease [ 7 ]. However, three types of O 2 PCP have been reported in patients with dyspnea [ 17 ] and COPD: plateau (P), decreasing (D), and increasing (I) types [ 18 ]. Furthermore, the P and D types are signs of cardiac dysfunction or myocardial ischemia in subjects with various heart diseases [ 17 , 19 , 20 ], and their presence should prompt additional cardiovascular work-up [ 19 , 20 ].…”

Influence of extracellular volume fraction on peak exercise oxygen pulse following thoracic radiotherapy

“…The peak oxygen pulse is an expression of peak VO 2 that by its nature corrects for HR and when further corrected for age, sex, and anthropometrics can differentiate cardiac from noncardiac causes of exercise intolerance [ 31 , 32 ]. The findings of the current study have implications, as the peak O 2 pulse is associated with risk for sudden cardiac death, fatal coronary heart disease, CVD, and all-cause mortality [ 33 – 35 ].…”