BNP + Brugada + Buerger

Question 1

What is B-type natriuretic peptide?

Answer 1

B-type natriuretic peptide (BNP) is a hormone produced mainly by the left ventricular myocardium in response to strain

Question 2

What other causes of high BNP levels are there?

Answer 2

• Heart failure is the most obvious cause of raised BNP levels
• Any cause of left ventricular dysfunction such as myocardial ischaemia or valvular disease may raise levels
• Raised levels may also be seen due to reduced excretion in patients with chronic kidney disease
• Factors which reduce BNP levels include treatment with ACE inhibitors, angiotensin-2 receptor blockers and diuretics

Question 3

What are the effects of BNP?

Answer 3

Effects of BNP

• vasodilator
• diuretic and natriuretic
• suppresses both sympathetic tone and the renin-angiotensin-aldosterone system

Question 4

What are the clinical uses of BNP?

Answer 4

1. Diagnosing patients with acute dyspnoea

• a low concentration of BNP(< 100pg/ml) makes a diagnosis of heart failure unlikely, but raised levels should prompt further investigation to confirm the diagnosis
• NICE currently recommends BNP as a helpful test to rule out a diagnosis of heart failure

2. Prognosis in patients with chronic heart failure

• initial evidence suggests BNP is an extremely useful marker of prognosis
• Guiding treatment in patients with chronic heart failure
• effective treatment lowers BNP levels

3. Screening for cardiac dysfunction

• not currently recommended for population screening

Question 5

What are the indications of beta blockers?

Answer 5

Indications

• angina
• post-myocardial infarction
• heart failure: beta-blockers were previously avoided in heart failure but there is now strong evidence that certain beta-blockers improve both symptoms and mortality
• arrhythmias: beta-blockers have now replaced digoxin as the rate-control drug of choice in atrial fibrillation
• hypertension: the role of beta-blockers has diminished in recent years due to a lack of evidence in terms of reducing stroke and myocardial infarction.
• thyrotoxicosis
• migraine prophylaxis
• anxiety

Question 6

What are the side effects of beta blockers?

Answer 6

1. Bronchospasm
2. Cold peripheries
3. Fatigue
4. Sleep disturbances, including nightmares
5. Erectile dysfunction

Question 7

What are contra-indications for beta blockers?

Answer 7

1. uncontrolled heart failure
2. asthma
3. sick sinus syndrome
4. concurrent verapamil use: may precipitate severe bradycardia

Question 8

What is bivalirudin?

Answer 8

Bivalirudin is a reversible direct thrombin inhibitor used as an anticoagulant in the management of acute coronary syndrome

Question 9

What is brugada syndrome?

Answer 9

• Form of inherited cardiovascular disease with may present with sudden cardiac death
• Autosomal dominant
• Prevalence of 1:5,000-10,00
• More common in Asians.

Question 10

What is the pathophysiology of brugada syndrome?

Answer 10

• large number of variants
• 20-40% of cases: mutation in the SCN5A gene which encodes the myocardial sodium ion channel protein

Question 11

What are ECG changes in brugada syndrome?

Answer 11

1. Convex ST segment elevation > 2mm in > 1 of V1-V3 followed by a negative T wave
2. Partial right bundle branch block
3. ECG changes may be more apparent following the administration of flecainide or ajmaline (investigation of choice in suspected cases of Brugada syndrome)

Management:

• implantable cardioverter-defibrillator

Question 12

What is Buerger’s disease?

Answer 12

Buerger’s disease (also known as thromboangiitis obliterans) is a small and medium vessel vasculitis that is strongly associated with smoking

Features

• extremity ischaemia
• intermittent claudication
• ischaemic ulcers
• superficial thrombophlebitis
• Raynaud’s phenomenon