This is a sample of our (approximately) 7 page long Arrhythmias notes, which we sell as part of the Cardiology Notes collection, a MBChB (hons) (1st) package written at University Of Leicester in 2014 that contains (approximately) 27 pages of notes across 8 different documents.
The original file is a 'Word (Docx)' whilst this sample is a 'PDF' representation of said file. This means that the formatting here may have errors. The original document you'll receive on purchase should have more polished formatting.
The following is a plain text extract of the PDF sample above, taken from our Cardiology Notes. This text version has had its formatting removed so pay attention to its contents alone rather than its presentation. The version you download will have its original formatting intact and so will be much prettier to look at.
Arrhythmias Bracdycardias = 100bpm
- SVT - arise from atria of atrioventricular junction
- VT - arise from ventricles Sinus arrhythmia
- Inspiration = decreased parasympathetic tone = Increased HR
- Expiration = Increased parasympathetic tone = decreased HR Causes regularly irregular pulse Mechanism of arrhythmia production
- Accelerated automaticity o Increased frequency of pacemaker potentials due to
Increased slope of depolarization
- Triggered activity o Myocardial damage can cause oscillations of the transmembrane potential at the end of an action potential o These oscillations may reach threshold triggering another AP o E.g atrial tachycardia from digoxin toxicity or ventricular arrhythmia in long QT syndrome
- Re-entry loops o Occurs when a ring of excitable cardiac tissue surround an inexcitable core e.g scar tissue o Can cause episodes of tachycardia e.g paroxysmal tachycardia
2 causes o Failure of impulse formation i.e sinus bradycardia o Failure of impulse conduction from atria to ventricles i.e AV block
Causes o Extrinsic (i.e outside factors affecting normal node)
B blockers o Intrinsic (i.e node disease)
Ischaemia/infarction o 'Sick sinus' syndrome
Usually caused by fibrosis of SA node
Can lead to tachy-brady syndrome
- Treat underlying cause
- Temp/permanent pacing
- Warfarin for tachy-brady syndrome
Block in AV node or bundle of His = AV block Block lower in conduction system = bundle branch block
AV block has 3 forms 1) 1st degree AV block (heart block) a. Prolongation of PR interval > 5 small squares b. Every P wave is followed by QRS i.e delayed conduction 2) 2nd degree AV block (heart block) a. Some P waves conduct, some don't 2 types a) Mobitz type 1/Wenckebach a. Almost always a disease of the AV node b. Progressive prolongation of PR interval until a P wave fails to conduct b) Mobitz type 2/Hay a. Almost always a disease of the distal conduction system (purkinje/his) b. Every 2nd or 3rd P wave fails to conduct, therefore absent QRS complex (2:1/3:1) c. PR interval is normal and consistent and most P waves followed by QRS d. Can progress without warning to complete heart block - needs pacemaker. May be caused by MI 3) 3rd degree/complete AV block a. All atrial activity fails to conduct to ventricles
****************************End Of Sample*****************************
Buy the full version of these notes or essay plans and more in our Cardiology Notes.