Using exercise testing to prognosticate patients with heart failure. Which parameter should we measure?

Peak oxygen consumption, as measured by direct gas exchange analysis during exercise testing, is well established as a powerful and independent predictor of risk for death among patients with chronic, but stable, heart failure. Although there is still some debate about whether peak oxygen consumption should be indexed against a predicted value and what the best cut-off point may be, most authorities agree that peak oxygen consumption is such a powerful predictor of outcome that it routinely should be incorporated into the evaluation of all ambulatory heart transplant candidates. A few recent studies have demonstrated that a hyperventilatory response to exercise, as measured by the VE/VCO2 slope, also may be a powerful and independent predictor of death; however, more large studies, with large numbers of end-points, will be needed before this measure can deservedly take a place alongside peak oxygen consumption as a primary component of the heart failure staging process.