Quarterly Focus Issue: Heart Failure
Clinical Research
Oscillatory Breathing and Exercise Gas Exchange Abnormalities Prognosticate Early Mortality and Morbidity in Heart Failure

https://doi.org/10.1016/j.jacc.2009.10.075Get rights and content
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Objectives

The goal of this study was to identify better predictors of early death in patients with chronic left ventricular heart failure (CHF). Potential predictors, derived from cardiopulmonary exercise testing, were compared with other commonly used cardiovascular measurements.

Background

The prediction of early death in patients with CHF remains challenging.

Methods

Five hundred eight patients with CHF due to systolic dysfunction underwent resting cardiovascular measurements, 6-min walking tests, and cardiopulmonary exercise testing. The peak oxygen uptake (V̇o2), peak oxygen pulse, anaerobic threshold, ratio of ventilation to carbon dioxide output (V̇e/V̇co2), slope of V̇eversus V̇co2, and presence or absence of a distinctive oscillatory breathing pattern (OB) were ascertained. Outcomes were 6-month mortality and morbidity, the latter a sum of cardiac hospitalizations and deaths.

Results

The single best predictor of mortality was an elevated lowest V̇e/V̇co2(≥155% predicted). Adding OB on the basis of stepwise regression (optimal 2-predictor model), the odds ratio for mortality increased from 9.4 to 38.9 (p < 0.001). The slope of V̇eversus V̇co2slope, peak V̇o2, peak oxygen pulse, and anaerobic threshold combined with OB were also strong predictors. OB also increased the odds ratio 2- to 3-fold for each of these (p < 0.01). Kaplan-Meier survival curves and area under the receiver-operating characteristic curve confirmed that lowest V̇e/V̇co2and OB were superior. For morbidity, elevated lowest V̇e/V̇co2or lower peak V̇o2with OB were the best predictors. No nonexercise measurements discriminated mortality and morbidity.

Conclusions

Cardiopulmonary exercise testing parameters are powerful prognosticators of early mortality and morbidity in patients with CHF, especially the optimal 2-predictor model of a combination of elevated lowest V̇e/V̇co2and OB.

Key Words

heart failure
cardiopulmonary exercise testing
oscillatory breathing
early death
gas exchange

Abbreviations and Acronyms

AT
anaerobic threshold
AUC
area under the receiver-operating characteristic curve
BVP
biventricular pacing
CHF
chronic heart failure
CPX
cardiopulmonary exercise testing
CRT
cardiac resynchronization therapy
OB
oscillatory breathing pattern
OR
odds ratio
%pred
percent of predicted value
co2
carbon dioxide output per minute (0°C, 760 mm Hg, dry)
e
minute ventilation (body temperature, ambient atmospheric pressure, saturated with water vapor)
o2
oxygen uptake per minute (0°C, 760 mm Hg, dry)

Cited by (0)

The 3 investigators from Harbor-UCLA Medical Center served as the core laboratory for analysis of the exercise physiology of left ventricular heart failure due to systolic dysfunction used in 2 St. Jude Medical (St. Paul, Minnesota) clinical trials (Resynchronization for Hemodynamic Treatment for Heart Failure Management and Cardiac Resynchronization Therapy in Patients With Heart Failure and Narrow QRS Complexes). All authors received funding from St. Jude Medical. However, this study does not have any direct financial support from St. Jude Medical.