Each one of the following is associated with left axis deviation on ECG, except:
Correct Answer C:
ECG: axis deviation: Causes of left axis deviation (LAD):
Causes of right axis deviation (RAD):
*In the majority of cases, or in a question without qualification, Wolff-Parkinson-White syndrome is associated with left axis deviation.
NICE have produced guidelines on the management of non-ST elevation myocardial infarction (NSTEMI) in which they recommend an approach to treatment based on risk assessment.
What cut off do they recommend for the use of coronary angiography within 96 hours in patients with a NSTEMI?
Correct Answer E:
NICE NSTEMI/unstable angina guidelines are based on 6 month mortality risk:
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:
Which one of the following is least associated with prolongation of the PR interval?
Correct Answer B:
Causes of a prolonged PR interval:
A prolonged PR interval may also be seen in athletes.
*Hyperkalaemia can rarely cause a prolonged PR interval, but this is a much less common association than hypokalaemia.
A 64-year-old man who is known to have ischaemic heart disease is due to start a chemotherapy regime which includes doxorubicin. His cardiologist wants to accurately assess his left ventricular function as he is concerned the doxorubicin may damage his myocardium.
Which one of the following is the most accurate method to determine his left ventricular function?
Correct Answer D:
Cardiac imaging: non-invasive techniques excluding echocardiography:
The ability to image the heart using non-invasive techniques such as MRI, CT and radionuclides has evolved rapidly over recent years.
Nuclear imaging:
These techniques use radiotracers which are extracted by normal myocardium. Examples include:
The primary role of SPECT is to assess myocardial perfusion and myocardial viability. Two sets of images are usually acquired. First the myocardium at rest followed by images of the myocardium during stress (either exercise or following adenosine / dipyridamole). By comparing the rest with stress images any areas of ischaemia can classified as reversible or fixed (e.g. Following a myocardial infarction). Cardiac PET is predominately a research tool at the current time.
Multigated Acquisition (MUGA) scan:
Cardiac Computed Tomography (CT):
Cardiac CT is useful for assessing suspected ischaemic heart disease, using two main methods:
Cardiac MRI:
Cardiac MRI (commonly termed CMR) has become the gold standard for providing structural images of the heart.
It is particularly useful when assessing congenital heart disease, determining right and left ventricular mass and differentiating forms of cardiomyopathy. Myocardial perfusion can also be assessed following the administration of gadolinium. Currently CMR provides limited data on the extent of coronary artery disease.
Your next patient is a 74-year-old woman who is known to have type 2 diabetes mellitus. Her blood pressure has been borderline for a number of weeks now but you have decided she would benefit from treatment. Her latest blood pressure is 146/88 mmHg, HbA1c is 7.5% and her BMI is 25 kg/m2.
What is the most appropriate drug to prescribe?
Hypertension in diabetics - ACE-inhibitors are first-line regardless of age.
Diabetes mellitus: hypertension management:
Hypertension is an added cardiovascular risk factor for diabetics and should therefore by actively looked for and treated. It is also a risk factor for the development of diabetic nephropathy.
Selected points:
*Increase insulin sensitivity and can therefore theoretically cause hypoglycaemia - rarely clinically relevant.
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