Abstract 16785: Exercise Oscillatory Ventilation is Associated with Abnormal Exercise Hemodynamics in Systolic Heart Failure
Background: Exercise oscillatory ventilation (EOV) is a non-invasive parameter that potently predicts outcomes in systolic heart failure (HF). However, previous studies have not directly measured physiologic variables during exercise that are thought to contribute to EOV. We therefore assessed the relationship between EOV and prolonged circulatory time (depressed cardiac index [CI]) hyperventilation to the apnea threshold (reduced PaCO2 and increased pH), and pulmonary congestion (increased PCWP) during exercise.
Methods: 56 patients with systolic HF (age 59 ± 2 yrs, left ventricular ejection fraction 30 ± 1%, peak VO2 12 ± 1 ml/kg/min, mean ± SEM) and 19 age and gender-matched controls were studied with incremental cardiopulmonary exercise testing (CPET) and invasive hemodynamic monitoring. Simultaneous Fick cardiac outputs, cardiac filling pressures, arterial blood gases, and respiratory gas exchange parameters were measured at one-minute intervals during 6 min of exercise. EOV was defined as >= 3 consecutive regular oscillations in ventilation (VE), with VE oscillation amplitude >= 30% of average VE.
Results: EOV was detected in 45% of HF patients and in no controls. The HF with EOV group did not differ from the HF without EOV group in age, gender, BMI, LVEF, or etiology of HF. Univariate predictors of EOV included higher exercise right atrial pressure, PCWP, pulmonary vascular resistance, and pH and lower CI (figure), but not PaCO2 or PaO2. Multivariate logistic regression identified low exercise CI as the strongest predictor of EOV. Within the EOV group, cumulative CI (Sum CI over 6 min) was inversely related to EOV cycle length (R=-0.65) and mean amplitude (R=-0.57), both P<0.001.
Conclusions: EOV in systolic HF is more closely related to impaired CI and elevated filling pressures during exercise than it is to low PaCO2. Recognition of EOV during CPET, particularly with long cycle length and high amplitude, may in turn signal hemodynamic compromise in HF patients.
- © 2010 by American Heart Association, Inc.