From impaired pumping or filling to SNS and RAAS activation — and why briefly-helpful compensation becomes a harmful self-reinforcing loop.
In systolic dysfunction, ventricular contraction weakens and stroke volume may fall. In diastolic dysfunction, the ventricle is stiff or relaxes poorly, so it needs higher pressure to fill. Either path raises filling pressures. When effective forward flow falls, the sympathetic nervous system and RAAS activate.
The vicious cycle
The body reads reduced effective circulation as a threat, so it retains salt and water and constricts vessels. This supports pressure briefly, but chronically it increases vasoconstriction, Na⁺/water retention, cardiac workload, and remodeling — worsening congestion and afterload in a self-reinforcing loop.
“Wet” — congestion
“Cold” — hypoperfusion
Nursing role
Trend the findings, not a single value. Rising weight + worsening orthopnea + more edema + falling urine output + dropping BP together are far more concerning than any one sign. A severe patient can be both wet and cold.
Common misconception
“Fluid retention happens only because the patient drinks too much.” False. Neurohormonal sodium/water retention is a core HF mechanism; intake can worsen it but is not the only cause.
Check answer
Why is chronic RAAS activation harmful?
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