Heart Failure Flashcards
Define Heart failure
Hf can be defined as LV or global ventricular dysfunction often with signs of congestion.
Explain systolic Hf
The main issue is with LV contractility and ejection resulting is decreased cardiac output. Reduced co, high preload due to elevated end-diastolic volume, elevated SVR (afterload)
Explain diastolic Hf
.Hf with preserved ejection fraction. Ventricles are stiff and cannot relax during diastole resulting in rising volume and pressure within the LA and pulmonary vasculature resulting in congestion.
What is ejection fraction?
The amount of blood pumped in a sing beat, relative to available blood for that beat (preload)
What is a normal EF?
. 60-80%
What does low CO cause?, in the discussion of the neurohormonal changes
Low CO causes SNS and RAAS stimulation which over time results in ventricular remodelling.
This results in increased preload, increased after load and decreased contractility
-what is a major consequence of unceasingly increased preload?
- Pulmonary congestion, resulting in impaired gas exchange. V/q MIs match, decreased lung compliance etc.
What are the 4 mechanisms of Heart failure
Cardio-renal(Na/h2o retention), cardiocirculatory (decreased pump abitiy), neurohormonal (cardiac remodelling), biomechanical.
Define valvular stenosis
Mechanical obstruction of blood flow resulting in decreased co, increased myocardial workload from stiffening of valves -
Define valve regurgitation
Leaflets of valve do not seal when closing, his causes back-flow of blood.
Define the cardiorenal mechanism of HF
Disease related to excessive retention of sodium and water secondary to diminished renal perfusion.
Basis for diuretic use
Define the cardiocirculatory mechanism of HF
Decreased LV contractility resulting in decreased CO.
Basis for the use of inotropic drugs
Define the biomechanical mechanism of HF
Biomechanical mechanism is neurohormonal in origin but eventually neurohormonal changes result in cardiac remodelling.
