For medical students

1. Heart failure

2. defn
• A clinical syndrome that develops when the heart can not maintain
adequate out put, or can do so only at the expense of elevated
ventricular filling pressures

3. causes
• All forms of heart diseases can lead to heart failure

4. pathophysiology
• Cardiac out put ( C.O) is determined by preload ( the volume and
pressure of blood in the ventricles at the end of diastole-the force
that stretches the myocardium) and afterload ( the volume and
pressure of blood in the ventricles during systole- the resistence at
which blood is pumped against) and myocardial contractility

5. • HF is due to low C.O, Low C.O causes neurohumoral activation (RAAS)
• RAAS causes vasoconstriction,vasoconstriction increases afterload,
increased afterload raises BP and cardiac work, this results in myocyte
death / myocardial fibrosis which causes heart failure
• RAAS also causes sodium and water retention, this increases
intravascular volume, and this results in hypertension and increased
cardiac work which causes myocyte death/myocardial fibrosis ,and
eventually heart failure

6. Types of HF
• LHF
• RHF
• BVHF

7. Diastolic dysfunction and systolic dysfunction
• Its due to impaired myocardial contraction ( systolic dysfunction) and
due to poor ventricular filling ( diastolic dysfunction)
• Diastolic dysfunction is caused by a stiff non compliant ventricle and
is commonly found in patients with Left ventricular hypertrophy

8. High out put failure
• There is increased demand for C.O
• Its HF due to excessively high C.O caused by
• Arterio-venous shunting
• Beri-beri
• Sevre anaemia
• thyrotoxicosis

9. Acute and chronic heart failure
• Compensated HF: condition of those with impaired cardiac function
in whom adaptive changes have prevented the development of overt
heart failure
• Overt or acute HF may be precipitated by
• MI
• Infection
• Atrial Fibrillation
• Inappropriate reduction of treatment

10. • Drugs with negative inotropic effects ( beta blockers), fluid retaining
properties (NSAIDs, Sterroids)
• Pulmonary embolism
• High cardiac out put condition : pregnancy, thyrotoxicosis, anemia
• IV fluid overload

11. Clinical features
• Left heart failure: central cyanosis, easy fatiguebility, orthopnea,
paroxysmal nocturnal dyspnoe (PND), basal crepitations
• Right heart failure : raised JVP, tender hepatomegaly, ascites, bilateral
pitting pedal oedema
• BVHF: combition of s/s of LHF and RHF above

12. complications
• Renal failure- due to reduced C.O, diuretics, ACEIs, ARBs
• Electrolyte imbalances:
• Hypokalaemia from diuretic therapy
• Hyperkalaemia due to ACEIs and Mineralocorticoids and antagonists
eg spironolactone
• Hyponatraemia: due to severe HF and is a poor prognostic sign.It may
be caused by diuretic therapy, fluid retention due to raised ADH
secretion

13. • Impaired liver function due to hepatic venous congestion and poor
areterial perfusion causing jaundice, abnormal liver function tests,
reduced clotting factors
• Thrombo-embolism: DVT,PE due to low C.O and immobility
• Arrhythmias: due to electrolyte imblances

14. invest
• BNP
• ECG/ ECHO
• Ues
• CXR
FBC

15. treatment
• Diuretics: furosemide plus slow k or furosemide plus spironolactone
• ACEIs eg enalapril
• ARBs eg Lorsataan
• Digoxin : for rate control and A.Fibrillation