Early symptom-relief after valvulotomy in mitral stenosis indicates role of lobeline-sensitive intrapulmonary receptors.

Respiratory sensations of eight patients with mitral stenosis in response to i.v. lobeline and 6-min walk before percutaneous mitral valvulotomy (PMV) were 'being short of breath', pressure in chest, tracheo-bronchial irritation, a desire to cough, persistent dry cough, chest pain and were qualitatively similar amongst 75% (P=0.005) of the patients. A week after PMV lobeline evoked similar sensations but the threshold dose decreased from 32.4+/-3.8 to 24.1+/-3.2 microg/kg (P=0.001) and pulmonary artery wedge pressure (PAwP), signifying reduction in pulmonary congestion, from 23.1+/-1.4 to 14.3+/-3.4 mm Hg (P<0.001). Distance walked in 6 min increased from 217+/-58 to 319+/-51.6m; and mitral valve area from 0.63+/-0.01 to 1.43+/-0.26 cm(2) (P<0.001). A fall in lobeline-sensation threshold dose indicated reduction in pulmonary congestion and stimulus to juxtapulmonary/J (or pulmonary C fibre) receptors which suggests that they had contributed to the respiratory and viscerosomatic symptoms seen before PMV.