Introduction to Heart Failure
Heart Failure is a clinical state (syndrome) in which the heart is unable to generate enough cardiac output to meet the metabolic demands of the body or does so at an increased filling pressure.
The common causes of Heart failure include hypertension, dilated cardiomyopathy and rheumatic heart disease.
Cardiac failure may be acute or chronic with the latter being the most frequently
encountered in the Nigerian setting because of late presentation.
Clinical features of Heart Failure
Major Diagnostic criteria:
- Paroxysmal nocturnal dyspnoea
- Orthopnoea
- Raised jugular venous pressure
- S3
- Pulmonary edema
Minor diagnostic criteria
Signs include:
- Cough productive of frothy sputum
- Leg swelling
- Abdominal swelling
The prominence of particular symptoms will depend on which side is affected
- Oedema
- Tachycardia (about 100 beats per minute)
- Displaced apex
- Abdomen: hepatomegaly, Ascites
A diagnosis of heart failure requires 2 major or I major and 2 or more minor criteria
Differential diagnoses
- Bronchial asthma
- Chronic obstructive airways disease (COAD)
- Chronic kidney disease
- Chronic liver disease
Complications of Heart Failure
- Thrombo-embolic phenomena: stroke, pulmonary embolism
- Pre-renal azotaemia
- Arrhythmias
Investigations
- Electrocardiography
- Chest radiograph
- Full Blood Count with differentials
- Echocardiography Urea, Electrolytes and Creatinine
- Fasting blood glucose
- Urine micro-analysis
Treatment objectives
- Relieve symptoms
- Treat precipitating factors
- Treat cause where feasible
- Enhance quality of life
- Prolong life
- Prevent complications
Non-drug treatment
- Bed rest
- Low salt diet
- Exercise (within limits of tolerance)
- Stop cigarette smoking
- Avoid excessive alcohol
Drug treatment for Heart Failure
Diuretics
- Furosemide 40-160 mg intravenously or orally
- Spironolactone 25 daily
- Potassium supplements: Potassium chloride 600 mg orally once, every 8-12 hours daily depending on the serum levels of potassium
Vasodilators
Angiotensin converting enzyme
inhibitors (ACEIs):
- Captopril 6.25 25 mg every 12 hours
preferably at bedtime
Or:
- Lisinopril 2.5-20 mg daily especially if there is hypertension
Cardioselective blockers (moderate to severe cardiac failure)
- Carvedilol 3.125-25 mg daily. Initially 3.125 mg once to twice daily(with food); dose increased at intervals of at least 2 weeks to 6.25 mg twice daily, then to 12.5 mg twice daily, then to 25mg twice daily; increase to highest dose tolerated, max. 25 mg twice daily in patients with severe heart failure or body weight less than 85 kg and 50 mg twice daily in patients over 85 kg
Or
- Metoprolol 25-150mg daily
Venodilators
- Nitrates
- Glyceryl trinitrate 0.3 – 1 mg sublingually and repeated as required
Ionotropes
- Digoxin: 125 250 micrograms daily (the elderly may require 62.5-125 micrograms daily)
- Dopamine 25 microgram/kg/minute
by intravenous infusion
Anticoagulants
- Warfarin: monitor INR 2-2.5
- Important in atrial fibrillation
Supportive measures
- Pacemakers for arrythmias
- Ventricular assist devices
Notable adverse drug reactions
- Digoxin: arrhythmias
- Potassium-sparing drugs: hyperkalaemia
- ACEIS: hypotension, hyperkalaemia
- Do not combine potassium supplements with potassium-sparing drugs
Precautions
The dose and infusion rate for dopamine are critical.
Low dose infusion rates will cause
excessive hypotension.
Higher infusion rates will elevate the blood pressure.
The use of P blockers, atrial natriuretic
peptide analogues and endothelin receptor antagonists should be reserved for specialist care.
Prevention
- Adequate treatment of hypertension and diabetes mellitus
- Good sanitation and personal hygiene (to prevent rheumatic fever)