Clinical InvestigationCardiac Output and Cardiopulmonary Responses to Exercise in Heart Failure: Application of a New Bio-Reactance Device
Section snippets
Subjects
This was a retrospective analysis of clinical data obtained from 36 consecutive subjects referred to a private cardiology clinic for CPX testing for evaluation of dyspnea. All patients provided consent for the use of their data in the analysis. Twenty-three of the subjects had heart failure (18 with low ejection fraction [EF], 5 with normal EF) and 13 were ultimately diagnosed as normal (normal EF, dyspnea based on noncardiac factors). Demographic and clinical characteristics of the subjects
Exercise Test Responses
Exercise test responses are summarized in Table 2. For the overall group, the mean maximal perceived exertion was 7.8 ± 1.7 (range 5–10), and the mean peak respiratory exchange ratio was 1.12 ± 0.09 (range 0.87–1.28), suggesting that maximal effort was achieved by most patients. Among CHF patients, the mean maximal heart rate of 103 ± 24 beats/min (range 76–140) was lower than that expected for age (61% of predicted), reflecting the fact that many patients were limited by symptoms associated
Discussion
Cardiac output is a fundamental measure for the assessment of cardiac performance; its measurement has been widely used to quantify the presence and degree of cardiovascular disease and response to various interventions. CHF, in particular, is characterized by a reduction in cardiac output at rest and an impaired cardiac output response to exercise; measures of both resting and exercise cardiac output have been shown to be important prognostic markers in CHF.2, 25, 26, 27 Clinically, the
Summary
The present findings provide face validity to the noninvasive measurement of cardiac output in response to exercise using a novel device based on bioreactance technology. Estimates of cardiac output and ventricular performance concurred with previous studies using direct Fick measures in patients with CHF. We also explored the interactions between CPX and cardiac output responses to exercise in patients with CHF, and observed that the noninvasive device provided insight on interactions between
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Cited by (46)
Noninvasive Assessment of Cardiac Output in Advanced Heart Failure and Heart Transplant Candidates Using the Bioreactance Method
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2016, Wilderness and Environmental MedicineCitation Excerpt :We used a noninvasive CO monitor (NICOM) to take continuous measurements of stroke volume and cardiac output during all exercise tests at simulated altitude (Cheetah Medical Systems, Newton, MA). This technology, although typically used in a critical care setting, has been validated in 1 study in which results suggest the NICOM provides face validity for measuring cardiac performance during exercise in patients with heart failure.40 The NICOM uses bioreactance, or phase shifts in pulsatile flow, to continuously capture hemodynamic signals.
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2014, Revista Espanola de Anestesiologia y ReanimacionBioimpedance and bioreactance methods for monitoring cardiac output
2014, Best Practice and Research: Clinical AnaesthesiologyCardiopulmonary and noninvasive hemodynamic responses to exercise predict outcomes in heart failure
2013, Journal of Cardiac FailureCitation Excerpt :In addition, the relationship between peak VO2 and peak cardiac index that we observed (r = 0.73; P < .001; Fig. 1) is similar to that of previous studies using noninvasive estimates of cardiac hemodynamics,19–21 providing an additional measure of validity with the use of the Physioflow device. Many studies over the years have shown that the degree of impairment in the cardiac output response to exercise reflects the severity of HF; in addition to studies using direct measures of cardiac output, several recent studies used impedance cardiography.6,10,19,21 For more than 2 decades, peak VO2 has been widely used as a valuable prognostic marker in patients with HF because it is generally thought to closely reflect cardiac output and thus cardiac reserve with exercise.4,22
Supported in part by a grant from Cheetah Medical Inc, Wilmington, DE.