The left side of the heart fails, for many reasons:
- Restrictive (haemochromatosis, pericardial disease)
- Ischaemic (MI)
- Congestive (volume overload of teventricle from valvular insufficiencies)
- Hypertrophic (longstanding HTN)
This reduces the stroke volume, and hence the cardiac output.
Cardiac output = stroke volume x heart rateSV affected by preload, afterload and myocardial contractility. The Frank-Starling Curve has an effect here.
Exertional dyspnoea
Fatigue
PND
Orthopnoea
Vague "not feeling right"
Clinical Findings
- Increased sympathetic activity to attempt to maintain cardiac output = sweating, tachypnoea, tachycardia
- Loud P2, presence of S3 and S4
- Raised diastolic pressure --> narrowed pulse pressure
- Ascites
- Ankle oedema
Investigations
BNP
<100 microgram /mL - unlikely CHF
100 - 500 = may be CHF
500 - most consistent with CHF
CXR
Upper lobe diversion
Peri-bronchial cuffing
Kerley B lines
White interlobular fissures
Pleural effusion
Air bronchogram
Airspace opacification
Cardiomegaly - cardiac ratio > 0.5 on PA film
Echo
Look for evidence of ischaemia and poor contractility
Management Options
Decrease Pre-load: Salt and water restriction
Reduce caffeine, alcohol and smoking
Diuretics - get euvolemia, then titrate to lowest possible dose.
Improve contractility: Inotropes
Reduce afterload: Vasodilators
Improve Mortality:
- ACE inhibitors eg. ramipril - NNT 26. Titrate up
- Angiotensin receptor blockers if ACE intolerant.
- Beta blockers eg. metoprolol
- Consider aldosterone agonists like spironolactone NNT 10 or eplerenone NNT 34
End of Life
There is no cure - consider end of life options early. Involve palliative care if needed.
Grading
Class I
No limitations, ordinary physical activity does not cause undue fatigue, dyspnoea or palpitations (asymptomatic LV dysfunction). 5% 1 year mortality.
Class II
Slight limitation of physical activity, ordinary physical activity results in fatigue, palpitation, dyspnoea, or angina (Mild CHF). 10% 1 year mortality.
Class III
Marked limitation of physical activity. Less than ordinary physical activity causes symptoms (moderate CHF). 20% 1 year mortality.
Class IV
Unable to carry on any physical activity without discomfort. Symptoms of CHF present at rest (severe CHF). 50% 1 year mortality.
References
http://www.cemfoamed.co.uk/portfolio/agm-conference/
http://learning.bmj.com/learning/module-intro/chronic-heart-failure.html?moduleId=10051928&searchTerm=%E2%80%9Cheart%20failure%E2%80%9D&page=1&locale=en_GB
http://lifeinthefastlane.com/frank-starling-curve-physiology-bscc/
http://calgaryguide.ucalgary.ca/left-heart-failure-pathogenesis/
http://foam4gp.com/2014/10/23/chronic-heart-failure/
