• Nicolas Villarraga, Brit Warner, Eric J Bruhn, Shane M Hammer, Thomas G Bissen, Thomas P Olson, and Joshua R Smith.
• Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN.
• Chest. 2023 Jun 1; 163 (6): 149215051492-1505.

BackgroundIt is unknown if pulmonary alterations in heart failure with preserved ejection fraction (HFpEF) impact respiratory mechanics during exercise.Research QuestionAre the operating lung volumes, work of breathing (Wb), and power of breathing (Pb) abnormal in patients with HFpEF during exercise?Study Design And MethodsPatients with HFpEF (n = 8; median age, 71 years [interquartile range (IQR), 66-80 years]) and control participants (n = 9; median age, 68 years [IQR, 64-74 years]) performed incremental cycling to volitional exhaustion. Esophageal pressure, end-expiratory lung volume (EELV), inspiratory lung volume (EILV), and ventilatory variables were compared at similar absolute (30 and 50 L/min) and relative (45% of peak, 70% of peak, and 100% of peak) minute ventilation (V.E) during exercise.ResultsDuring exercise, EELVs were not different between patients with HFpEF and control participants (P > .13 for all). EILVs were lower in patients with HFpEF than control participants at 45% and 70% V.E peak (P < .03 for all). Dynamic lung compliance was lower in patients with HFpEF than control participants at 30 L/min, 50 L/min, 45% V.E peak, and 100% V.E peak (P < .04 for all). Compared with control participants, patients with HFpEF showed higher total Wb and Pb at 30 L/min (Wb: median, 1.08 J/L [IQR, 0.93-1.82 J/L] vs 0.52 J/L [IQR, 0.43-0.71 J/L]; Pb: median, 36 J/min [IQR, 30-59 J/min] vs 17 J/min [IQR, 11-23 J/min] and 50 L/min; Wb: median, 1.40 J/L [IQR, 1.27-1.68 J/L] vs 0.90 J/L [IQR, 0.74-1.05 J/L]; Pb: median, 73 J/min [IQR, 60-83 J/min] vs 45 J/min [IQR, 33-63 J/min]; P < .01 for all). At 30 and 50 L/min, inspiratory and expiratory resistive Wb and Pb were higher in patients with HFpEF than control participants (P < .04 for all). Total Wb was higher for patients with HFpEF than control participants at 45% of V.E peak (P = .02). Total Pb was higher for control participants than patients with HFpEF at 100% V.E peak because of higher inspiratory resistive Pb (P < .04 for both).InterpretationThese data demonstrate the HFpEF syndrome is associated with pulmonary alterations eliciting a greater Pb during exercise resulting from greater inspiratory and expiratory resistive Pb.Copyright © 2022 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

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