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 PO2 (change of 38.0 +/- 4.1 mm Hg) and PCO2 (change of 11 +/- 2.8 mm Hg). The nadir in arterial PO2 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 hypoventilation at the nadirs of minute ventilation; arterial PCO2 was always 40 mm Hg or less. Substantial hyperventilation (ventilatory equivalent for CO2 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 ml/kg/min) (p less than 0.05). Oscillatory hyperventilation during exercise may accompany severe CHF and compounds the inadequate delivery of oxygen by the failing heart.
D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000503:physiopathology*; D003327:Coronary Disease / Q000150:complications / Q000503:physiopathology*; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D006985:Hyperventilation / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D011659:Pulmonary Gas Exchange