Which of the following is responsible for the rapid depolarisation phase of the myocardial action potential?
Correct Answer A:
Electrical activity of the heart:
NB: Cardiac muscle remains contracted 10-15 times longer than skeletal muscle.
Which one of the following types of hyperlipidaemia are eruptive xanthoma most commonly associated with?
Hyperlipidaemia: xanthomata:
Characteristic xanthomata seen in hyperlipidaemia:
Palmar xanthoma:
Eruptive xanthoma are due to high triglyceride levels and present as multiple red/yellow vesicles on the extensor surfaces (e.g. elbows, knees).
Causes of eruptive xanthoma:
Tendon xanthoma, tuberous xanthoma, xanthelasma:
Xanthelasma are also seen without lipid abnormalities.
Management of xanthelasma, options include:
Which of the following statements concerning the third heart sound is correct?
Correct Answer B:
A third heart sound is often heard in left ventricular failure and constrictive pericarditis.
Heart sounds:
The first heart sound (S1) is caused by closure of the mitral and tricuspid valves whilst the second heart sound (S2) is due to aortic and pulmonary valve closure.
S1:
S2:
S3:
S4:
A 14-year-old boy is admitted with palpitations and is noted to have a long QT interval. His only past medical history is deafness.
What is the likely diagnosis?
Correct Answer C:
Jervell-Lange-Nielsen syndrome is associated with profound deafness and a prolonged QT interval.
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.
Features:
Management:
*The usual mechanism by which drugs prolong the QT interval is blockage of potassium channels. See the link for more details
**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
Which of the following congenital heart defects may progress to Eisenmenger's syndrome?
Although patients with tetralogy of Fallot have, by definition, a ventricular septal defect they do not go on to develop Eisenmenger's syndrome.
Eisenmenger's syndrome:
Describes the reversal of a left to right shunt in a congenital heart defect due to pulmonary hypertension.
Associated with:
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