A novel cardiac output response to stress test developed to improve diagnosis and monitoring of heart failure in primary care.

AIMS: Primary care physicians lack access to an objective cardiac function test. This study for the first time describes a novel cardiac output response to stress (CORS) test developed to improve diagnosis and monitoring of heart failure in primary care and investigates its reproducibility. METHODS AND RESULTS: Prospective observational study recruited 32 consecutive primary care patients (age, 63 ± 9 years; female, n = 18). Cardiac output was measured continuously using the bioreactance method in supine and standing positions and during two 3 min stages of a step-exercise protocol (10 and 15 steps per minute) using a 15 cm height bench. The CORS test was performed on two occasions, i.e. Test 1 and Test 2. There was no significant difference between repeated measures of cardiac output and stroke volume at supine standing and Stage 1 and Stage 2 step exercises (all P > 0.3). There was a significant positive relationship between Test 1 and Test 2 cardiac outputs (r = 0.92, P = 0.01 with coefficient of variation of 7.1%). The mean difference in cardiac output (with upper and lower limits of agreement) between Test 1 and Test 2 was 0.1 (-1.9 to 2.1) L/min, combining supine, standing, and step-exercise data. CONCLUSIONS: The CORS, as a novel test for objective evaluation of cardiac function, demonstrates acceptable reproducibility and can potentially be implemented in primary care.Funding: This study was funded by the UK Medical Research Council Confidence in Concept Scheme grant to Dr Jakovljevic (Grant No BH161161). Dr Jakovljevic’s is supported by the UK Research Councils’ Newcastle Centre for Ageing and Vitality (Grant No L016354). The views expressed are those of the authors and not necessarily those of the Medical Research Council. The funders of the study had no role in study design or in data collection, analysis, or interpretation