Cardiopulmonary Exercise Testing with Echocardiography to Identify Mechanisms of Unexplained Dyspnea

Pieter Martens, Lieven Herbots, Philippe Timmermans, Frederik H. Verbrugge, Paul Dendale, Barry A. Borlaug, Jan Verwerft

Research output: Contribution to journalArticlepeer-review


Little data is available about the pathophysiological mechanisms of unexplained dyspnea and their clinical meaning. Consecutive patients with unexplained dyspnea underwent prospective standardized cardiopulmonary exercise testing with echocardiography (CPETecho). Patients were grouped as having normal exercise capacity (peak VO2 > 80% with respiratory exchange [RER] > 1.05), reduced exercise capacity (peak VO2 ≤ 80% with RER > 1.05), or a submaximal exercise test (RER ≤ 1.05). From 307 patients, 144 (47%) had normal and 116 (38%) reduced exercise capacity, and 47 (15%) had a submaximal exercise test. Patients with reduced versus normal exercise capacity had significantly more mechanisms for unexplained dyspnea (2.3±1.0 vs 1.5±1.0, respectively; p<0.001). Exercise PH (42%), low heart rate reserve (51%), low stroke volume reserve (38%), low diastolic reserve (18%), and peripheral muscle limitation (17%) were most common. Patients with more mechanisms for dyspnea displayed poorer peak VO2 and had an increased risk for cardiovascular hospitalization (p=0.002). Patients with unexplained dyspnea display multiple coexisting mechanisms for exercise intolerance, which relate to the severity of exercise limitation and risk of subsequent cardiovascular hospitalizations.

Original languageEnglish (US)
Pages (from-to)116-130
Number of pages15
JournalJournal of cardiovascular translational research
Issue number1
StatePublished - Feb 2022


  • Cardiopulmonary exercise testing
  • Dyspnea
  • Exercise-induced pulmonary hypertension
  • Heart failure
  • Pathophysiology

ASJC Scopus subject areas

  • Molecular Medicine
  • Genetics
  • Pharmaceutical Science
  • Cardiology and Cardiovascular Medicine
  • Genetics(clinical)


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