The aim of this paper was the evaluation of the control of breathing and respiratory patterns in patients with congestive heart failure (CHF) and its relation with the genesis of dyspnoea. Forty seven patients were studied with CHF, with a mean age of 60.9±12.5 years and compared them with 35 age-matched controls, free of cardiopulmonary diseases. The evaluation included: (a) measurements of lung function using the helium dilution method; (b) determination of occlusion pressure (P0.1) at rest; (c) noninvasive breathing pattern at rest assessed by means of respiratory inductive plethysmography (RIP); (d) CO2 re-breathing test with the simultaneous recording of ventilation, P0.1 and dyspnoea perception using a visual analogue scale. A mild restrictive ventilatory defect was found in CHF patients, together with an abnormal breathing pattern at rest defined by a significant increase in respiratory frequency and a decrease in tidal volume, when compared with the control group. However, the mean pulmonary ventilation at rest did not differ between the two groups whereas the baseline P0.1 was higher in CHF, (median 1.6; range 2.00 cmH2O), than in controls (median 1.20; range 1.00 cmH2O), (P<0.001). The slope of the ventilatory response to hypercapnia was significantly lower in CHF patients, (median 0.93; range 1.95 l/min per mmHgCO2), than in controls (median 1.30; range 1.29), (P<0.006). However, the slope of P0.1, was similar in both groups, whereas the slope of dyspnoea perception was higher in CHF but not statistically significant. In conclusion, despite having a higher central drive at rest the CHF patients responded to hypercapnia with a slope of P0.1 similar to that of controls, however, the ventilatory response was lower and not generally accompanied by a higher sensation of dyspnoea. These findings do not favour an inappropriate increase in ventilation as a major cause of dyspnoea in CHF patients. Copyright (C) 1999 Elsevier Science Ireland Ltd.
- Inspiratory occlusion pressure
- Left ventricular failure
- Pulmonary congestion
- Respiratory inductive plethysmography
- Ventilatory response to hypercapnia