Presence of lobeline-like sensations in exercising patients with left ventricular dysfunction

Since there is evidence that lobeline-induced sensations, associated with discomfort in the mouth, throat and chest arise by stimulating juxtapulmonary or J receptors, we were interested in investigating if similar sensations are felt by patients with left ventricular dysfunction (LVD) in whom a natural stimulation of these receptors would occur by transient interstitial oedema or during augmentation of the stimulus, by increased pulmonary blood flow during exercise. Threshold doses of lobeline produced three or more respiratory sensations simultaneously in 9 out of 10 patients, which was greater than the response of the controls (P < 0.01). With mild exercise, a greater number of patients (7) than controls (1) reported feeling two or more sensations (P < 0.01); in fact half the controls did not express a respiratory sensation with equivalent exercise (P < 0.05). The predominant lobeline-like sensations reported by patients with exercise were a feeling of heat or burning and pressure in the throat or chest (P < 0.05). The presence of cough in three patients and in none of the controls was noteworthy. The mean latency with which sensations appeared during exercise in patients (4.4 +/- 0.3 min) was almost half that in controls (7.4 +/- 0.2 min) (P < 0.005). Since, respiratory sensations in response to lobeline and exercise were intensified in patients compared to controls and since both lobeline and exercise-induced sensations were similar (P < 0.05), we speculate that a common origin exists. Despite important caveats, that we discuss, in our view these respiratory sensations and cough arise from stimulation of J receptors.