A 60-year-old man is admitted following an acute coronary syndrome. He receives aspirin, clopidogrel, nitrates and morphine. His 6-month risk score is high and percutaneous coronary intervention is planned. He is therefore given intravenous tirofiban.
What is the mechanism of action of this drug?
Correct Answer D:
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:
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:
A 65-year-old female is admitted with a suspected infective exacerbation of chronic obstructive pulmonary disease. On examination she is dyspnoeic with a blood pressure of 112/68 mmHg. Electrocardiogram shows an irregular, narrow-complex tachycardia with a rate of 130 bpm. At least three different P wave morphologies are seen. A diagnosis of multifocal tachycardia is suspected.
What is the most appropriate management?
Correct Answer C:
Multifocal atrial tachycardia:
Multifocal atrial tachycardia (MAT) may be defined as a irregular cardiac rhythm caused by at least three different sites in the atria, which may be demonstrated by morphologically distinctive P waves. It is more common in elderly patients with chronic lung disease, for example COPD.
Management:
Which one of the following treatments is not appropriate in the management of Wolff-Parkinson White?
Correct Answer A:
Verapamil and digoxin should be avoided in patients with Wolff-Parkinson White as they may precipitate VT or VF.
Wolff-Parkinson White:
Wolff-Parkinson White (WPW) syndrome is caused by a congenital accessory conducting pathway between the atria and ventricles leading to a atrioventricular re-entry tachycardia (AVRT). As the accessory pathway does not slow conduction AF can degenerate rapidly to VF.
Possible ECG features include :
Differentiating between type A and type B:
Associations of WPW:
*In the majority of cases, or in a question without qualification, Wolff-Parkinson-White syndrome is associated with left axis deviation.
**Sotalol should be avoided if there is coexistent atrial fibrillation as prolonging the refractory period at the AV node may increase the rate of transmission through the accessory pathway, increasing the ventricular rate and potentially deteriorating into ventricular fibrillation.
A 65-year-old man is discharged from hospital following a thrombolysed ST-elevation myocardial infarction. Other than a history of depression he has no past medical history of note. His stay on the coronary care unit was complicated by the development of dyspnoea and an echo show a reduced left ventricular ejection fraction. The patient was not given clopidogrel during his hospital admission. Other than standard treatment with an ACE inhibitor, beta-blocker, aspirin and statin, what other type of drug should he be taking?
An aldosterone antagonist is recommended by current NICE guidelines as the patient has a reduced left ventricular ejection fraction. If clopidogrel was given during the first 24 hours then it should be continued for the next 4 weeks.
Myocardial infarction: secondary prevention:
NICE produced guidelines on the management of patients following a myocardial infarction (MI) in 2007. Some key points are listed below.
All patients should be offered the following drugs:
Aldosterone antagonists:
*This can be calculated using scoring systems such as GRACE.
A 62-year-old man who had a mechanical mitral valve replacement four years ago is reviewed.
What long term antithrombotic therapy is he likely to be taking?
Correct Answer E:
Prosthetic heart valves - antithrombotic therapy:
Prosthetic heart valves:
The most common valves which need replacing are the aortic and mitral valve. There are two main options for replacement: biological (bioprosthetic) or mechanical.
Following the 2008 NICE guidelines for prophylaxis of endocarditis antibiotics are no longer recommended for common procedures such as dental work.
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