{
  "id": 4881046,
  "title": "Sympathetic activation and the force-frequency relationship in heart failure with reduced ejection fraction",
  "url": "https://urgent.news/2026/09/01/sympathetic-activation-and-the-force-frequency-relationship-in-heart",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-01T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.08.24.746885v1?rss=1"
  },
  "original_language": "en",
  "account": "In a study of individuals with heart failure with reduced ejection fraction (HFrEF), researchers discovered a complex relationship between heart rate and sympathetic activation. The investigation involved 157 HFrEF patients and 55 healthy controls, with participants undergoing an incremental pacing protocol. As heart rate increased from 50 to 140 beats per minute, researchers measured the force-frequency relationship (FFR) using echocardiography, along with cardiac output, total peripheral resistance, and blood pressure variability.\n\nAs heart rate increased, both groups experienced an increase in left ventricular contractility and cardiac output until reaching the peak of the FFR, after which these values declined. Interestingly, total peripheral resistance, blood pressure variability, and sympathetic nerve activity (measured via microneurography) all decreased at the peak of the FHR, and then increased beyond this point. These relationships were evident in both groups, but more pronounced in those with HFrEF.\n\nThe study concluded that there exists a bidirectional relationship between heart rate and sympathetic activation in individuals with HFrEF. The nadir of sympathetic tone occurs at the peak of the FFR, and both excessively low and high heart rates coincide with greater sympathetic activation. These findings suggest that optimal heart rate targets for individuals with HFrEF are likely to be individualized.",
  "summary": "Background Limited heart rate rise contributes to reduced exercise tolerance for people who have heart failure with reduced ejection fraction (HFrEF), yet rate-adaptive pacing does not improve functional capacity due to an attenuated force-frequency relationship (FFR). How the FFR relates to total peripheral resistance and sympathetic tone in HFrEF is unknown. Methods In a prospective,…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}