PBL 7 - Heart Failure Flashcards
- Blood tests on Mr. Williams would include measurement of B-type Natriuretic peptide (BNP). Where does BNP originate and what is the significance of its blood level? (2 marks)
BNP is secreted from the ventricles when they are stretched (1 mark). Increased BNP levels in the blood indicate overstretched or enlarged ventricles (1 mark)
Explain why Mr. Williams has a raised jugular venous pressure (2 marks)
He has right heart failure (1 mark) which means his right heart cannot pump out the blood delivered to it; thus blood and pressure build up in the great veins and venous circulation (1 mark)
What imaging tests would Mr. Willams receive? (1 mark) What might the imaging tests show to confirm a diagnosis of heart failure? (2 marks)
Chest x-ray and echocardiogram (1/2mark each) echocardiogram would show a dilated, poorly contractile left ventricle. (1 mark) CXR should show heart enlargement (1 mark) and evidence of pulmonary oedema such as Kerley B lines (1 mark)
List three classes of drug which would be ‘first line’ therapy for Mr. Williams. Explain the rationale for each drug class. (3 marks)
A diuretic (1/2 mark), most likely a loop diuretic such as frusemide (1/2 mark) . This would reduce the venous blood volume and thus preload on the heart, reducing its workload (1/2 mark).
A beta blocker (1/2 mark) could be introduced as long as there is no evidence for metabolic syndrome or type II diabetes in Mr. Houseman. This would also reduce the work of the heart by reducing contractile force (1/2 mark)
An ACE inhibitor (1/2 mark) will reduce blood pressure and also reduce sodium retention; this will reduce both preload and afterload on the heart (1/2 mark). Angiotensin receptor antagonists (ARBs) may be used instead of ACE inhibitors, and will have similar effects (marks for either ACE inhibitors or ARB’s but not both) A vasodilator (1/2 mark) such as isosorbide dinitrate can be used. This lowers peripheral resistance and reduces the work of the heart (1/2 mark)
What is heart failure (2)
When the heart cannot supply enough blood to meet the metabolic demands of the body
Usually due to a reduction in stroke volume
Occurs when the heart becomes enlarged –> less ejection pressure –> lower stroke volume and increased end systolic ventricular volume
How is Heart failure diagnosed? (1) (how many minor and major)
either 2 major criteria or 1 major and 2 minor criteria.
Name 3 major and 3 minor criteria from the Framingham criteria (3)
Major = Paroxysmal nocturnal dyspnea = Weight loss 4.5kg in 5 days after treatment = Hepatojugular reflux = S3 gallop = Rales (crackles in lungs)
Minor = Nocturnal cough = Dyspnea on ordinary exertion = Pleural effusion = Tachycardia
Explain why Mr. Williams was tired, short of breath? (2)
left ventricle may be able to pump out
sufficient blood at rest, when the patient takes even mild exercise the cardiac output is
insufficient to supply the metabolic requirements of the exercising skeletal muscles.
Explain why were Mr Williams’ ankles swelled? (1)
Indicates Right heart failure. raised central venous pressure disrupting the Starling Mechanism in the systemic capillaries. worse in the evenings because it is gravitational in nature.
What is pulsus alternans and what does it indicate? (2)
alternating strong and weak pulse. It indicates left ventricular
impairment, and could be a sign that aortic stenosis or aortic valve disease is contributing
to the left heart failure.
Name 3 abnormalities you could identify in a clinical examination of someone with HF? (2)
- Small pulse volume (reduced ejection fraction)
- Elevated venous pressure
- Left ventricular enlargement
- 3rd and 4th heart sounds
- Heart murmur due to mild mitral regurgitation
What abnormalities would you see on the echocardiogram and X-ray in HF? (2)
X-ray - Heart size enlarged - Pulmonary Oegema - Interstitial oedema (kerley B-lines) ECHO - Dilated, poorly contractile left ventricle (L A dilated)
What surgical treatments could man have? (1)
Revascularisation
Valve replacement/repair
Heart transplant
What is the non-pharmacological treatment he could have and why is it given? (2)
Oxygen
Non-invasive positive pressure ventilation, dietary sodium and fluid restriction, physical activity , weight loss
What is the life expectancy of patients with HF and what do they die of? (2)
Poor - 50% 5 year mortality Ventricular arrhythmia (sudden cardiac death)
