Question 236#

Which one of the following clinical signs would best indicate severe aortic stenosis? 

A. Valvular gradient of less than 30 mmHg

Correct Answer B:

Questions may sometimes refer to a soft A2 rather than a soft S2 (second heart sound), specifically mentioning the aortic component.

Aortic stenosis:

• Features of severe aortic stenosis:
• Narrow pulse pressure
• Slow rising pulse
• Delayed ESM
• Soft/absent S2
• S4
• Thrill
• Duration of murmur
• Left ventricular hypertrophy or failure

Causes of aortic stenosis:

• Degenerative calcification (most common cause in older patients > 65 years)
• Bicuspid aortic valve (most common cause in younger patients < 65 years)
• William's syndrome (supravalvular aortic stenosis)
• Post-rheumatic disease
• Subvalvular: HOCM 

Management:

• If asymptomatic then observe the patient is general rule
• If symptomatic then valve replacement
• If asymptomatic but valvular gradient > 50 mmHg and with features such as left ventricular systolic dysfunction then consider surgery
• Balloon valvuloplasty is limited to patients with critical aortic stenosis who are not fit for valve replacement 

Question 237#

You review a 60-year-old man who had a drug-eluding stent inserted 6 months ago for ischaemic heart disease. His current medication includes aspirin, clopidogrel, atorvastatin, ramipril and bisoprolol. He has developed an inguinal hernia and is keen for surgical repair. The cardiologists plan was to continue clopidogrel for 12 months following stent insertion.

What is the most appropriate course of action? 

A. Stop clopidogrel the day before the operation

Correct Answer D:

The AHA/ACC/SCAI/ACS/ADA published recommendations in 2007 stressed the importance of 12 months of dual antiplatelet therapy after placement of a drug-eluting stent (DES).

Clopidogrel:

Clopidogrel is an antiplatelet agent used in the management of cardiovascular disease. It was previously used when aspirin was not tolerated or contraindicated but there are now a number of conditions for which clopidogrel is used in addition to aspirin, for example in patients with an acute coronary syndrome. Following the 2010 NICE technology appraisal clopidogrel is also now first-line in patients following an ischaemic stroke and in patients with peripheral arterial disease.

Mechanism:

• Inhibits ADP binding to its platelet receptor

Interactions:

• Concurrent use of proton pump inhibitors (PPIs) may make clopidogrel less effective (MHRA July 2009)
• This advice was updated by the MHRA in April 2010, evidence seems inconsistent but omeprazole and esomeprazole still cause for concern. Other PPIs such as lansoprazole should be OK

Question 238#

A 55-year-old man is admitted with central chest pain. His ECG shows ST depression in the inferior leads and the chest pain requires intravenous morphine to settle. Past medical history includes a thrombolysed myocardial infarction 2 years ago, asthma and type 2 diabetes mellitus. Treatment with aspirin, clopidogrel and unfractionated heparin is commenced.

Which one of the following factors should determine if an intravenous glycoprotein IIb/IIIa receptor antagonist is to be given?

A. High GRACE (Global Registry of Acute Cardiac Events) risk score + whether a percutaneous coronary intervention is to be performed

Correct Answer A:
Acute coronary syndrome: management:

NICE produced guidelines in 2010 on the management of unstable angina and non-ST elevation myocardial infarction (NSTEMI). They advocate managing patients based on the early risk assessment using a recognized scoring system such as GRACE (Global Registry of Acute Cardiac Events) to calculate a predicted 6 month mortality.

All patients should receive:

• Aspirin 300mg
• Nitrates or morphine to relieve chest pain if required 

Whilst it is common that non-hypoxic patients receive oxygen therapy there is little evidence to support this approach. The 2008 British Thoracic Society oxygen therapy guidelines advise not giving oxygen unless the patient is hypoxic. 

Antithrombin:

• Treatment. Fondaparinux should be offered to patients who are not at a high risk of bleeding and who are not having angiography within the next 24 hours. If angiography is likely within 24 hours or a patients creatinine is > 265 μmol/l unfractionated heparin should be given. 

Clopidogrel:

• 300mg should be given to patients with a predicted 6 month mortality of more than 1.5% or patients who may undergo percutaneous coronary intervention within 24 hours of admission to hospital. Clopidogrel should be continued for 12 months. 

Intravenous glycoprotein IIb/IIIa receptor antagonists (eptifibatide or tirofiban):

• Should be given to patients who have an intermediate or higher risk of adverse cardiovascular events (predicted 6 month mortality above 3.0%), and who are scheduled to undergo angiography within 96 hours of hospital admission. 

Coronary angiography:

• Should be considered within 96 hours of first admission to hospital to patients who have a predicted 6-month mortality above 3.0%. It should also be performed as soon as possible in patients who are clinically unstable.

The table below summaries the mechanism of action of drugs commonly used in the management of acute coronary syndrome:

Question 239#

A 13-year-old girl presents with palpitations, fatigue and dyspnoea. She has had symptoms for around a year. There is no history of syncope or chest pain. On examination she has a pan-systolic murmur associated with giant V waves in the jugular venous pulse. Auscultation of the chest is unremarkable. A resting ECG is normal but a 24 hour tape shows a short burst of supraventricular tachycardia.

What is the most likely diagnosis?

A. Atrial septal defect

Correct Answer E:

Ebstein's anomaly:

Ebstein's anomaly is a congenital heart defect characterized by low insertion of the tricuspid valve resulting in a large atrium and small ventricle. It is sometimes referred to as 'atrialization' of the right ventricle.

Associations:

• Tricuspid incompetence (pan-systolic murmur, giant V waves in JVP)
• Wolff-Parkinson White syndrome

Ebstein's anomaly may be caused by exposure to lithium in-utero. 

Question 240#

You review a 24-year-old woman who has recently been diagnosed as having long QT syndrome type I (LQTS1). You are discussing the need to avoid certain drugs and other aggravating factors.

Which one of the following should be avoided if possible?

A. Methotrexate

Correct Answer B:

Long QT syndrome:

Long QT syndrome (LQTS) is an inherited condition associated with delayed repolarization of the ventricles. It is important to recognise as it may lead to ventricular tachycardia and can therefore cause collapse/sudden death.

The most common variants of LQTS (LQT1 & LQT2) are caused by defects in the alpha subunit of the slow delayed rectifier potassium channel. A normal corrected QT interval is less than 430 ms in males and 450 ms in females.

Causes of a prolonged QT interval:

 

Features:

• May be picked up on routine ECG or following family screening
• Long QT1 - usually associated with exertional syncope, often swimming
• Long QT2 - often associated with syncope occurring following emotional stress, exercise or auditory stimuli
• Long QT3 - events often occur at night or at rest
• Sudden cardiac death 

Management:

• Avoid drugs which prolong the QT interval and other precipitants if appropriate (e.g. Strenuous exercise)
• Beta-blockers***
• Implantable cardioverter defibrillators in high risk cases 

*The usual mechanism by which drugs prolong the QT interval is blockage of potassium channels.

**A non-sedating antihistamine and classic cause of prolonged QT in a patient, especially if also taking P450 enzyme inhibitor, e.g. Patient with a cold takes terfenadine and erythromycin at the same time.

***Note sotalol may exacerbate long QT syndrome.