Lecture 6: Cardiac Arrythmia Flashcards
What causes the P wave, QRS complex and T wave?
P - spread of atrial depolarisation
QRS - depolarisation of the ventricles
T - repolarisation of the ventricles
What is ion transport involved in?
Excitability Contraction Secretion Activation of 2nd messengers Regulation of transcription Regulation of fluid volume
The L-type Calicum channel has ____ transmembrane domains and at least ______ axillary subunits.
4
1 or 2
What is Cardiac Arrhythmia?
A disorder of rate, rhythm, origin or conduction of impulses within the heart
What can cause arrhythmia?
Hypoxia/Ischemia Excessive autonomic discharge Drugs Electrolyte imbalance Mutations in ion channels or heart muscle
What are the 2 main properties of the heart?
Excitation
Contraction
What are some examples of abnormalities in impulse formation?
Sinus brachycardia/tachycardia
Ectopic Pacemakers
What are some examples of abnormalities in impulse conduction?
AV block
Slowed conduction with re-entry
What is Long QT syndrome?
An autosomal dominant or acquired condition characterised by prolongation of the QT interval
What causes Long QT syndrome?
Most commonly caused by mutations in the phase 0 Na channels or K channels in phase 3 (repol phase)
How does myocardial Ischemia/hypoxia cause arrhythmia?
Increases the level of circulating and local catecholamines which increases the risk of arrhythmia
Hypoxia ___________ sensitivity of the L-type calcium channel to β-adrenergic stimulation
Increases sensitivity
