Heart Failure Flashcards
Cause of Heart Failure
- Hypertension
- IHD
- Alcohol
- Cardiomyopathy
- Valvular
- Pericardial causes
How does HF effect Venous return
- Myocardial failure leads to reduction of blood ejected with each beat + increase in volume remaining after systole
- Increased diastolic volume stretches myocardial fibres (increased force of contraction) - compensation mechanism
- Myocardium eventually fails and can’t be compensated for
How does HF effect Afterload
After load - resistance against which LV contracts (increase decreases CO)
As volume of blood ejected increases, after load increases which exacerbates problem
How does HF effect Myocardial contractility
- HF activates sympathetic NS via baroreceptors - maintains CO
- Chronic sympathetic activation causes myocyte apoptosis even if there is temporary increase in contractility
Acute Decompensated CHF vs AHF
Generally effects <70 vs 71-76
Male vs Female dominance
LVEF < 40% vs LVEF> 40%
How is LVSD commonly caused
IHD, VHD and hypertension
What is diastolic heart failure
Heart Failure where stiffness in Lv increases and compliance decreases - impaired LV diastolic filling so decreased CO
Symptoms of HF
- Dyspnoea
- Fatigue
- Tachycardia
- Cardiomegaly
- Pleural effusion
- Fourth heart sounds
- Ascites
How is HF investigated in blood tests
- Full blood count, thyroid function, cardiac enzymes
How is Hf diagnosed
Echocardiography
How does an electrocardiogram help with AF
Identifies Ischaemia, hypertension
CXR in HF diagnosis
Looks for pulmonary congestion
What two systems are involved in the heart failure syndrome
- Sympathetic system
- RAAS
- Inflammation
How does the sympathetic system lead to HF
- Increased NE released from cardiac cells
- SHort-term increase of CO
- B-receptor transduction is altered
- Progressive myocardial dysfunction
- HF
How does the RAAS system cause HF
- Increase in venous pressure occurs when ventricles fail cause retention of Na and water and accumulation in interstitium
- Reduced CO causes reduced renal perfusion
- RAAS activated
- RAAS causes more salt and water retention
- Increased ANP to antagonise salt retention
How is RAAS system treated in patients with HF
- Given Neprilysin inhibitor (sacubitril) which stops angiotensin II -> AT-II (1) - NO VASOCONSTRICTION OR RETENTION
- Causes production of AT-II (2) which is vasodilatory
Non-specific symptoms of HF
- SOB
- Fatigue
- Ankle swelling
Specific signs of HF
- JVP
- S3
- Displaced apex beat
What is the NYHA classification
Class I: No Limitation (asymptomatic)
Class II: Slight Limitation (mild HF)
Class III: Marked Limitation (moderate HF)
Class IV: Inability to carry out any physical activity without discomfort (sever HF)
Stages of HF
1, High risk
- Asymptomatic
- Symptomatic HF
- End-stage HF
Causes of acute decompensation of CHF
- NSAIDS
- treatment noncompliance
- Excess alcohol
- Obesity
- Uncorrected high BP
Complications of ADCHF
- Renal dysfunction
- Rhythm disturbances
- Hepatic dysfunction
- DVT
Why are diuretics (thiazides) given in AF
Promotes renal excretion of Na and water by blocking Na/Cl co-transporters (will cure oedema and dyspnoea)
How does ACEI (angiotensin-converting enzyme inhibitors) help with AF
1, Reduce mortality
2. Less Effective in blacks
Name an aldosterone antagonist
Spironolactone