This document summarizes cardiac arrhythmias. It defines normal and abnormal heart rates as bradyarrhythmias below 60 bpm and tachyarrhythmias above 100 bpm. Specific arrhythmias are classified by their heart rates, such as simple tachycardia ranging from 100-150 bpm. Potential causes include hypertension, hyperthyroidism, ischemia, hypokalemia, and medications like digitalis. Symptoms can include palpitations, skipped heartbeats, chest pain, and flutters. The electrophysiology and phases of the cardiac action potential are also outlined.

1. CARDIAC ARRHYTHMIAS
Normal Heart Rate is 60-100 bpm
Every Heartbeat should originate from SA node,
Velocity should be normal,
Impulse conduction should originate from conduction
pathway.
Brady Arrhythmia(less than 60bpm) Tachy Arrhythmia(Greater than 100bpm)
Mild Bradycardia 60-40bpm Simple Tachycardia 100-150bpm
Moderate Bradycardia 40-20bpm Paroxysmal Tachycardia 150-250bpm
Severe Bradycardia 20 & less bpm Atrial Flutter 250-350bpm
Atrial Fibrillation 350 & above

2. Causes:
 Hypertension.
 Hyperthyroidism.
 Ischeamia & Hypoxia.
 Hypokalemia.
 Acidosis & Alkalosis.
 Patients on Digatalis therapy
 Overstretching of
myocardial contractile
fibres.
Symptoms:
 Palpitations.
 Skipping of Heart beat.
 Poor O2 supply.
 Chest pain.
 Flutters.

5. • Action Potential is divided to 5 phases:
Phase 0/Rapid Depolarisation
Phase 1/Partial Repolarisation
Phase 2/Plateau/ Maintained Depolarisation
Phase 3/Rapid Repolarisation
Phase 4/Diastolic Depolarisation

6. Electrophysiology of Cardiac Rhythm

7. • The normal electrocardiogram (ECG).
• The P wave results from activation
(depolarisation of the atria).
• The PR interval isisoelectric as the activation
wavefront proceeds slowly through
theatrioventricular node.
• The QRS complex reflects activation of
theventricles and is large compared to the P wave
because of the much greater mass of the
ventricular myocardium, and brief, reflecting
extremely rapid conduction in the H is–Purkinje
system.
• The T wave represents ventricular repolarisation.

10. Mechanism of Arrhythmias

11. Types of Arrhythmias

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