Oscillatory hyperventilation in severe congestive heart failure secondary to idiopathic dilated cardiomyopathy or to ischemic cardiomyopathy

Thirty-one subjects with chronic congestive heart failure (CHF) were separated into 3 groups according to ventilatory patterns during graded exercise: Group 1-oscillators (n = 6); group 2—intermediate oscillators (n = 14); and group 3—nonoscillators (n = 11). Group 1 patients showed cyclic fluctuations in minute ventilation (change of 30 to 40 liters/min) and arterial P02 (change of 38.0 ± 4.1 mm Hg) and PCO 2 (change of 11 ± 2.8 mm Hg). The nadir in arterial PO 2 occurred at times when wasted ventilatory effort was maximal. The amplitude of ventilatory oscillations in group 1 patients increased in the transition from rest to light exercise and damped with heavy exercise. There was no evidence of alveolar hypoventilatlon at the nadirs of minute ventilation; arterial PCO 2 was always 40 mm Hg or less. Substantial hyperventilation (ventilatory equivalent for C02 twice normal) occurred with maximal minute ventilation in group 1 patients. Oscillatory hyperventilation correlated with severity of CHF. Maximal oxygen uptake was significantly lower in group 1 (11.7 ± 1.1 ml/kg/min) than group 3 (17.9 ± 1.8 mi/kg/min) (p