Dyspnea
The origin of dyspnea in HF is probably multifactorial. The most important mechanism is pulmonary congestion with accumulation of interstitial or intra-alveolar fluid, which activates juxtacapillary J receptors, which in turn stimulate the rapid, shallow breathing characteristic of cardiac dyspnea.
Other factors that contribute to dyspnea on exertion include reductions in pulmonary compliance.