A 34-year-old woman is admitted to the Emergency Department following a collapse. An ECG shows a polymorphicventricular tachycardia.
Which one of the following is not associated with an increased risk ofdeveloping torsade de pointes?
Correct Answer C: Hypocalcaemia, not hypercalcaemia, causes prolongation of the QT interval and hence may predispose to the development of torsade de pointes.
Long QT syndrome:
Long QT syndrome (LQTS) is an inherited condition associated with delayed repolarization of the ventricles. It is important to recognize 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:
Management:
The usual mechanism by which drugs prolong the QT interval is blockage of potassium channels.
A non-sedating antihistamine is 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.
A 54-year-old man is admitted to the Emergency Department with a 15 minute history of crushing central chestpain.
Which one of the following rises first following a myocardial infarction?
Correct Answer E: Myoglobin rises first following a myocardial infarction. Interpretation of the various cardiac enzymes has now largely been superceded by the introduction of troponin T and I. Questions still however commonly appear in the MRCP.
Key points for the exam:
Cardiac enzymes and protein markers:
A 17-year-old girl is brought into resuscitation in cardiac arrest. On admission she is in asystole and attempts to resuscitate are unsuccessful. She collapsed whilst competing in a 1,500m race at college. The only past medical of note was asthma for which she occasionally used a salbutamol inhaler. There is no relevant family history.
What is the most likely underlying cause of death?
Correct Answer B: HOCM is the most common cause of sudden cardiac death in the young.
Hypertrophic obstructive cardiomyopathy (HOCM) is a more common cause of sudden cardiac death than arrhythmogenic right ventricular dysplasia (ARVD). Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a form of inherited cardiac disease which is also associated with sudden cardiac death. It is inherited in an autosomal dominant fashion and has a prevalence of around 1:10,000. Brugada syndrome is a form of inherited cardiovascular disease which again may present with sudden cardiac death. It is inherited in an autosomal dominant fashion and has an estimated prevalence of 1:5,000-10,000. Brugada syndrome is more common in Asians.
HOCM features:
Hypertrophic obstructive cardiomyopathy (HOCM) is an autosomal dominant disorder of muscle tissue caused by defects in the genes encoding contractile proteins. The estimated prevalence is 1 in 500.
Associations:
Echo - mnemonic - MR SAM ASH:
ECG:
A 54-year-old male with no past medical history is found to be in atrial fibrillation during a consultation regardinga sprained ankle. He reports no history of palpitations or dyspnoea. After discussing treatment options he electsnot to be cardioverted. According to the latest European Society of Cardiology guidelines, if the patient remains in chronic atrial fibrillation what is the most suitable treatment to offer?
Correct Answer A: Young man with AF, no TIA or risk factors, no treatment is now preferred to aspirin.
The European Society of Cardiology guidelines suggest that 'no treatment is preferred to aspirin' for low risk patients such as this man.
Atrial fibrillation: Anticoagulation: The European Society of Cardiology published updated guidelines on the management of atrial fibrillation in 2012. They suggest using the CHA2DS2-VASc score to determine the most appropriate anticoagulation strategy.
This scoring system superceded the CHADS2score.
The table below shows a suggested anticoagulation strategy* based on the score:
*the wording in the guidelines ('is preferred to') can be slightly confusing. It basically means that, say for a score of 0, whilst aspirin is an acceptable management option the weight of the clinical evidence would support no treatment instead.
A 54-year-old man is admitted following a myocardial infarction associated with ST elevation. He is treated with thrombolysis and does not undergo angioplasty.
What advice should he be given regarding driving?
Correct Answer D: DVLA advice post MI - cannot drive for 4 weeks.
DVLA: cardiovascular disorders:
The guidelines below relate to car/motorcycle use unless specifically stated. For obvious reasons, the rules relating to drivers of heavy goods vehicles tend to be much stricter Specific rules:
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