Mark Dunlap, M.D.
Professor, Cardiology
Case Western Reserve University School of Medicine
“POTS and reverse-POTS in HF: recognizing and managing inadequate preload reserve”.
Conventional wisdom holds that the major pathway leading to decompensation in patients with heart failure (HF) occurs via fluid retention leading to elevated filling pressures and acute HF. However, the observation that most patients do not gain weight prior to an episode of acute HF suggests that fluid redistribution rather than accumulation is the more likely mechanism leading to elevated filling pressure. Studies in animals and humans suggest that these mechanisms are mediated by activation of the sympathetic nervous system (SNS) and can occur both chronically (days to weeks) or more rapidly (minutes to hours).
The SNS also plays an important in regulating preload in health (eg. orthostatic stress) and disease (eg. HF). Preload reserve refers to increased blood flow to the heart that augments stroke volume and cardiac output during exertion. Multiple mechanisms are involved, the most important of which lie outside the heart, including intact cardiovascular reflexes and a healthy venous system. Failure of preload reserve mechanisms can lead to exertional fatigue and dyspnea, symptoms that are common in patients with HF.
This talk will present data showing that SNS activity mediated by splanchnic nerves can lead to fluid redistribution, elevated filling pressures and acute HF in patients with chronic HF. Preliminary studies in humans also suggest that therapies aimed at ablating these influences may be beneficial in patients with HF to mitigate against these redistribution mechanisms. I also will discuss how abnormalities in preload reserve may contribute to signs and symptoms in many patients with HF.
Friday April 19, 2024, 11:00AM-12:00PM, LIB-110
University of North Texas Health Science Center
Fort Worth, Texas