The role of cardiopulmonary exercise testing in the investigation of complex unexplained breathlessness

Introduction: Cardiopulmonary exercise testing (CPET) is a non-invasive dynamic assessment its9 use is well-established in pre-operative risk assessment. We present our experiences using CPET for investigating patients with complex unexplained breathlessness (CUB). Methods: A prospective analysis of the investigations required to diagnose patients attending a CUB clinic at Royal Free Hospital between Nov 2015-Aug 2016. CUB clinic is designed for patients that have already undergone non-diagnostic tests in primary care and failed a trial of therapies with persistent symptoms Results: 34 patients attended CUB clinic. To date, diagnoses have been reached for 30 patients (table 1). Conventional tests alone (echocardiogram, lung function, sleep study) only heralded a final diagnosis in 7 patients. 25 patients also underwent CPET and this was considered instrumental in determining the final diagnosis in 23 of these patients. 20 patients had normal ‘conventional’ tests and in these cases, CPET was able to conclude the final diagnosis (physical deconditioning or dysfunctional breathing) in 95% (n=19) Conclusion: CPET is a valuable investigation in patients with complex unexplained breathlessness. In our case series, without CPET we would not have made a final diagnosis in u003e66% of patients. We identified that deconditioning and dysfunctional breathing are common underlying causes of CUB and that CPET appears effective at diagnosing these patients.