1. Cardiovascular course 4th year - Pathophysiology
Arrhythmias
Cardiovascular course 4th year - Pathophysiology

2. Arrhythmias - Definition and Causes
Abnormal rhythm of the heart
Causes
Abnormal rhythmicity of the pacemaker (tachycardia, bradycardia)
Shift of the pacemaker to another place in the heart (junctional. Idioventricular rhythms)
Block of different parts of the conducting system (impulse conduction blocks)
Abnormal pathway of impulses transmission (WPW syndrome)
Spontaneous generation of impulses in atrias or ventricles (premature beats, paroxysmal tachycardia, fibrillation, flutter)
Ionic dysbalance (changes of depolarisation, repolarisation)

3. Mechanisms of Cardiac Arrhythmias
Mechanisms of bradycardias
Mechanisms generating tachycardias
Accelerated automaticity
Triggered activity
Re-entry

4. Abnormal Sinus Rhythms
abnormal rhythmicity of the pacemaker
Tachycardia
Bradycardia
Extrinsic causes
Intrinsic causes

5. Impulse Conduction Block
Sinoatrial block
Sinus Arrest
Atrioventricular block
block between atrias and ventricles
Interventricular block ( RBBB or LBBB)
impulses fail to reach part of the heart during heart cycle

6. Types of AV Blocks 1st degree 2nd degree block: partial block Mobitz I
3rd degree block: complete heart block

7. Right and Left Bundle Branch Blocks
Right bundle branch block (RBBB)
Left bundle branch block (LBBB)

8. Preexcitation Syndrome – Wolff-Parkinson-White
AV conduction through the accessory pathway is faster than through the AV node

9. Premature Beats - Extrasystoles
the heart beats before the time of normal contraction.
Types:
Premature atrial contraction
Premature junctional contraction
Premature ventricular contraction

10. Paroxysmal Tachycardia
rapid rhythmical discharge of impulses that spread throughout the heart
caused by re-entrant circuitry movement
Types of paroxysmal tachycardia
Paroxysmal supraventricular tachycardia (atrial, junctional)
Paroxysmal ventricular tachycardia

11. Fibrillation
results from cardiac impulses that have gone chaotically within the muscle
known as a phenomenon of re-entry:
Types:
atrial
ventricular

12. Atrial Flutter
atrial focus activates the atria at a rate of around 300 times per minute

13. A Systematic Approach to Reading the 12-lead ECG
Check these data (patient’s name, birthday, and identification number; date and time of tracing) on the ECG to make sure:
It belongs to the patient you are reviewing.
It was obtained on the day and time you requested the examination.
Review the patient’s medical history, physical and laboratory findings, diagnosis, and indication of the ECG examination. You still should review all aspects of the ECG before drawing your conclusion.
Make old tracings available for comparison. In medical practice, changes in findings over time are as important as the presence or absence of findings at any discrete moment in time.
Check heart rate.
Check rhythm:
Primary rhythm: supraventricular (sinus, atrial, junctional) or ventricular in origin.
Superimposed abnormalities (escape or premature beats).
Check heart blocks.
Check QRS axis.
Enlargement of right and left ventricle
Bundle braches blocks
Check signs of clinical abnormalities:
Right and left atrial abnormalities.
Right and left ventricular hypertrophy.
Right and left bundle branch block.
Acute myocardial infarction.
Electrolyte abnormalities.
Drug effects.
Pulmonary embolism.
Correlate the ECG findings with the patient’s clinical presentation. Treat the patient; not the waveforms.