Arterial baroreflex control of heart rate in young and older adults and in patients with heart failure with preserved ejection fraction

• Published in: Physiology (Bethesda, Md.) Md.), 2023-05, Vol.38 (S1)
• Main Authors: Bunsawat, Kanokwan, Holwerda, Seth, Alpenglow, Jeremy, Broxterman, Ryan, Francisco, Michael, Craig, Jesse, Iacovelli, Jarred, Weavil, Joshua, Iannetta, Danilo, Inglis, Erin, Tuday, Eric, Harrison, Jonathan, Ma, Christy, Ryan, John, Wray, D. Walter
• Format: Article
• Language: English
• ISSN: 1548-9213; 1548-9221
• DOI: 10.1152/physiol.2023.38.S1.5731195

Abstract only Background: The arterial baroreflex (ABR) plays an important role in evoking appropriate cardiovascular adjustments in response to perturbations such as exercise. The ABR control of heart rate (HR) becomes attenuated with advancing age and in a variety of patient populations, but limited information is available in patients with heart failure with preserved ejection fraction (HFpEF). The present study tested the hypothesis that the ABR control of HR is attenuated to a greater extent in patients with HFpEF compared to older and young controls. Methods: Six patients with HFpEF (71±6 years; 35.3±6.6 kg/m2), 4 older controls (68±4 years; 25.1±3.4 kg/m2), and 7 young controls (27±4 years; 26.6±3.9 kg/m2) underwent sequential bolus infusions of sodium nitroprusside (50-100 μg) and phenylephrine (150 μg) (modified Oxford technique) to provoke acute hypotension (“BP falls”) and hypertension (“BP rises”), respectively. Cardiac baroreflex gain was quantified as the weighted linear regression slope between the R-R interval and systolic blood pressure (BP). Results: Compared to young controls (10.7±3.4 ms/mmHg), overall cardiac baroreflex gain was reduced in older controls (3.4±1.6 ms/mmHg) and patients with HFpEF (2.1±1.8 ms/mmHg) (p0.05); however, responses in patients with HFpEF were attenuated compared to young controls 10.7±5.8 ms/mmHg) (p