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 μg/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 mmHg (P < 0.001). Distance walked in 6 min increased from 217 ± 58 to 319 ± 51.6 m; and mitral valve area from 0.63 ± 0.01 to 1.43 ± 0.26 cm2 (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.