cardiology: Arrythmias Flashcards
What is torsades de pointes?
A rare arrhythmia associated with long QT interval. It can turn into venticular fibrillation and then death.
What can cause long QT syndrome?
Congenital Antiarrhythmic medication (amioderone, sotalol) tricyclics antipsychotics erythromycin chlorquine electolyte abnormalitis (HYPOcalcaemia, HYPOkalaemia, HYPOmagnesaemia) Myocarditis Hypothermia Subarachnoid haemorrhage
How do you treat torsades de pointes?
IV magnesium sulphate
What is an abnormal QT in a heart beat of 60bpm?
More than 440 ms in males
More that 460 in females
As the rate increases what happens to the QT syndrome?
It decreases
How do youc alcuklate Qtc?
Bezetts formula
QT(ms)/Square root (RR/1)
What does lobg Qt actually mean in terms of heart cells?
Some of the heart cells take an abnormally long time to repolarise. This can happen due to ion abnormali for example dysfunction of L Type calcium channels
What should the P R interval be?
120 - 200ms (3 - 5 small squares)
Wahat do you do if you find first degreee heart block on an ECG of a patient who is otherwise well?
Nothing - probably a normal variant
What kind of drug is amioderone?
Class III antiarrythmic agent used in the treatment of atrial, nodal and ventircular tachycardias
Its main mechaism of action is by clocking pottassium channels which inhibits repolarisation and prologs the action potential. It also has some other effects such as blocking sodium channels
What do you need to monitor in all patients on amioderone?
TFTs
LFTs
every 6 months
What do you need to test in all patients prior to treatment with amioderone?
TFT
LFT
U and E
CXR
What isthe half life of amioderone?
20 - 100 days
Why do you give amioderone into central veins?
It causes thrombophlebitis
what are some of the main adverse effects of amioderone?
Thyroid dysfunction
Pulmonary fibrosis
Liver fibrosis
Long Qt
