Heart Failure Flashcards
General cause
Anything which impairs the pump function
Epidemiological info:
Global incidence and prevalence
Mortality rate
Incidence 2/1000
Prev: 23M Globally
Mortality: 50% after 5 years
Main causes of HF
IHD
Dilated cardiomyopathy
Hypertension
Main causes of HF cause what?
Systolic failure
Other causes of HF
A VICAR
Arrhythmia Valve disease Infection Congenital Abuse of substances RHF
Basic pathophysiology behind HF
Heart begins to fail > Change to heart and peripheral vasc. system in response to haemodynamic changes > mechanisms become overwhelmed
Why does the heart have to undergo structural/functional changes when failing?
To compensate and maintain CO and peripheral perfusion
Describe maintenance of CO in the intact heart in early HF
failure > reduction of blood volume ejected > increased volume after systole > stretched myocardial fibres > maintains myocardial contraction
Describe maintenance of CO in the presence of mild myocardial depression
CO maintained by increased venous pressure ergo increased diastolic volume
Proportion of blood ejected with each heart beat reduced
Sinus tachycardia increases HR which maintains CO
Describe maintenance of CO in severe myocardial dysfunction
CO only maintained by large venous pressure and/or marked sinus tachycardia
Increased venous pressure = dyspnoea due to accumulation of interstitial and alveolar fluid, ascites + hepatic enlargement
What happens to blood distribution in very severe HF?
Redistributed to brain, kidneys and heart
Deleterious effects of sympathetic nervous system activation in HF
Activates baroreceptors to compensate but also increases neuro-hormonal activation and myocycte apoptosis
Releases ANP/BNP/C-type peptide
Symptoms of HF
External dyspnoea Orthopnoea PND Fatigue Oedema Palpitations
Signs of HF
Cardiomegaly 3/4th heart sounds Increased JVP Hypotension Pleaural effusion Peripheral oedema Ascites
