Recumbent Ergometer vs Treadmill Cardiopulmonary Exercise Test in HFpEF: Implications for Chronotropic Response and Exercise Capacity.

BACKGROUND: Cardiopulmonary exercise testing (CPET) can identify mechanisms of exercise intolerance in heart failure with preserved ejection fraction (HFpEF), but exercise modalities with differing body positions (eg, recumbent ergometer, treadmill) are broadly used. In this study, we aimed to determine whether body position affects CPET parameters in patients with HFpEF. METHODS: Subjects with stable HFpEF (n = 23) underwent noninvasive treadmill CPET, followed by an invasive recumbent-cycle ergometer CPET within 3 months. A comparison group undergoing similar studies included healthy subjects (n = 5) and subjects with pulmonary arterial hypertension (n = 6). RESULTS: The peak oxygen consumption (VO2peak) and peak heart rate were significantly lower in the recumbent vs the upright position (10.1 vs 13.1 mL/kg/min [Δ-3 mL/kg/min]; P < 0.001; and 95 vs 113 bpm [Δ-18 bpm]; P < 0.001, respectively). No significant differences were found in the minute ventilation to carbon dioxide production ratio, end-tidal pressure of carbon dioxide or respiratory exchange ratio. A similar pattern was observed in the comparison groups. CONCLUSIONS: Compared to recumbent ergometer, treadmill CPET revealed higher VO2peak and peak heart rate response. When determining chronotropic incompetence to adjust beta-blocker administration in HFpEF, body position should be taken into account.