What can we learn from pulmonary function testing in heart failure?

Pulmonary diseases frequently coexist in heart failure (HF), thus posing diagnostic and therapeutic challenges to cardiologists evaluating patients with overlapping symptoms and implementing recommended HF treatments. There is a growing body of evidence suggesting that pulmonary function testing might provide useful information for the best management of these patients. The availability of portable devices, allowing the measurement of spirometry and lung diffusion capacity for carbon monoxide outside of hospital-based pulmonary lung function laboratories, provides an opportunity for a more widespread use of these measures in the cardiology community, but their interpretation can be challenging. In this work, after a brief review of the methodologies, we discuss the interpretation of pulmonary function testing in patients with HF alone or associated with pulmonary diseases, and its contribution in differentiating cardiac and pulmonary symptoms and preventing acute cardiac decompensation. In addition, we examined recent evidence suggesting how the use of pulmonary function testing may provide independent prognostic information in HF patients with and without pulmonary disorders, and help therapeutic decisions to fill the treatment gap that still exists in HF patients with concomitant pulmonary diseases.