238 - Heart Failure Flashcards
what causes heart failure?
- damage to heart muscle by ischaemia, infection, toxins, intrinsic cardiomyopathies
- increased afterload - HTN, valvular heart disease, COPD, pulm HTN
- Incr demand - thyrotoxicosis, anemia, pagets
- tachycardia - AF
how can left and right heart failure be described and what is it called when both exist?
- L - decr cardiac output causing pulm congestion
- R- congestion of peripheral tissues (cor pulmonale)
- congestive heart failure - R failure 2ndry to L failure causing pulm HTN
what are the signs and symptoms of Left ventricular failure?
- fatigue
- resp symptoms - cough, dyspnoea, paroxysmal nocturnal dyspnoea, orthopnoea, nocturia, pink frothy sputum
- chest pain and palpitations
- displaced apex beat (stretched ventricle)
- tachycardia
- S3/S4 gallop rhythm - s3 (early diastole rapid ventricular filling) s4 (atrial systole reduced wall compliance
- lung crackles - incr pulm P
what are the signs and symptoms of right heart failure?
- fatigue, weight loss and anorexia - gut congestion
- peripheral oedema
- incr JVP
- hepatomegaly, ascites
- s3/S4 gallop rhythm
describe systolic failure?
- decreased ejection - INSUFFICIENT CONTRACTION
- LV systolic dysfunction on echo
- caused by ischaemia, myocarditis, cardiomyopathy
describe diastolic failure?
- impaired filling - INSUFFICIENT RELAXATION - incr filling pressures
- preserved LV systolic function on echo
- caused by fibrosis, abnormal Ca handling (ischaemia, DM,HTN), compression of heart (tamponade, constrictive pericarditis)
what might an ECG show with heart failure?
- LV hypertrophy - L axis deviation, large QRS laterally
* AF
what might CXR show with heart failure?
6 signs
- 1 - cardiomegaly
- 2 - Pleural effusion
- 3 - Defined Lobar Divisions
- 4 - Kerley B (Interlobular) lines - horizontal lines near peripheries
- 5 - Bat wing shadowing in alveolar space
- 6 - Upper zone vessel enlargement - pulm venous HTN
what marker can be used to help diagnose heart failure?
*BNP - B type natriuretic peptide - produced by ventricular myocytes in response to wall stress
what might an echocardiogram show in heart failure?
- dilated ventricles
- reduced ventricular contractibility
- valvular disease
- apical thrombus
- mechanical dysnchrony between chambers
how should acute LV failure be managed?
- maximise lung function -sit up and give O2
- reduce distress - diamorphine and metoclopramide to counter N+V
- reduce preload - furosemide - venodilation
- reduce afterload - nitrates
what should be given long term for heart failure?
- symptom relief - diuretics and digoxin
* long term - ACE-I and Beta blocker first then add ARB (losartan), aldosterone antagonist (spironolactone) and nitrate
how do thiazides work?
*block na/cl transporter in distal convoluted tubule leading to decr reabsorption. can cause hyponatraemia, hypokalaemia and incr H loss (metabolic alkalosis)
how do loop diuretics like furosemide work?
*inhibits na and cl reabsorp in thick asecding loop and prevents hypertonic renal medula. Can cause hypokaalemia, metabolic alkalosis, hyponatraemia, hypomagnesaemia, deafness
how does digoxin work?
*inhibits membrane NA/K ATPase by inhibiting K binding > incr CA intacellularly > increased cardiax contractility. ALso slows HR and AV node conductance/refactory period. Can cause GI distrurbances and hypokalaemia, arrythmias and heart block
