References: Buller et al, 1990
Buller NP, Poole-Wilson PA
Mechanism of the increased ventilatory response to exercise in patients with
chronic heart failure
Heart 1990; 63; p.281-283.
The National Heart and Lung Institute and National Heart Hospital, London, UK.
Minute ventilation, respiratory rate, and metabolic gas exchange were measured
continuously during maximal symptom limited treadmill exercise in 30 patients
with stable chronic heart failure. The ventilatory response to exercise was
assessed by calculation of the slope of the relation between minute ventilation
and rate of carbon dioxide production. There was a close correlation between the
severity of heart failure, determined as the maximal rate ofoxygen consumption,
and the ventilatory response to exercise. Reanalysis ofthe data after correction
for ventilation of anatomical dead space did not significantly weaken the
correlation but reduced the slope of the relation by approximately one third.
These results show that the increased ventilatory response to exercise in
patients with chronic heart failure is largely caused by mechanisms other than
increased ventilation of anatomical dead space. This finding supports the
concept that a significant pulmonary ventilation/perfusion mismatch develops in
patients with chronic heart failure and suggests that the magnitude of this
abnormality is directly related to the severity of chronic heart failure.