This document discusses atrial fibrillation (AF), a common heart condition where the upper chambers of the heart beat irregularly and too fast. AF can be caused by conditions like heart disease, hypertension, or hyperthyroidism. It occurs when chaotic electrical signals in the atria beat irregularly instead of in a coordinated pattern. Left untreated, AF can lead to heart failure or stroke by reducing cardiac output and allowing blood clots to form. The document classifies AF by duration and discusses its characteristic ECG findings and potential clinical symptoms like fatigue, dizziness, and palpitations.

1. ATRIAL FIBRILLATION
Introduction, Pathogenesis
and clinical features
Roll no-19099

2. Introduction
• Atrial fibrillation is characterized by disorganized,
rapid and irregular atrial activation with loss of atrial
contraction and with an irregular ventricular rate that
is determined by AV nodal conduction.
• AF is a major public health disorder with prevalence
that increases with age and about 95% of AF patients
above 60 years of age.

3. Causes of AF
• Coronary artery disease.
• Valvular heart disease.
• Hypertension
• Sinoatrial disease
• Hyperthyroidism
• Alcohol
• Cardiomyopathy
• Congenital Heart disease

4. Contd…
• Chest Infection
• Pulmonary embolism
• Pericardial disease
• Idiopathic(Lone atrial Fibrillation)

5. Pathophysiology
A normal heart beat
starts with an electric
signal from SA node.
This signal passes
through both atrium
causing them to
contract.
Then the signal passes
to the ventricles through
AV node causing them
to contract.

6. • In ATRIAL FIBRILLATION chaotic electrical signals
cause the atria to beat irregularly and fast and the
ventricles beat faster than normal .
• Episodes of AF are initiated by rapid bursts of ectopic
beats arising from conducting tissue in the sleeves of
atrial muscle that extend into the pulmonary veins.
• Some patients have initiating foci in other locations
which are more common with those having severe
underlying cardiac disease.

7. PAROXYSMAL TERMINATES
SPONTANEOUSLY IN
LESS THAN 7 DAYS
PERSISTENT SUSTAINED GREATER
THAN 7 DAYS AND
RARELY TERMINATES
SPONTANEOUSLY
PERMANENT CARDIOVERSION HAS
FAILED OR THE
RESTORATION OF
SINUS RHYTHM IS NO
LONGER POSSIBLE
Classification

8. • Paroxysmal AF becomes permanent for many
patients as the underlying disease progresses.
• This is due to electric remodelling of atrial cells.
• When AF persists for several months structural
remodelling also occurs leading to atrial fibrosis and
dilatation that predispose to permanent AF.

9. ECG Findings
• Since the atria beat rapidly but in an uncoordinated
and ineffective manner , the ventricles are also
activated irregularly at a rate determined by
conduction through AV node.
• This produces characteristic irregularly irregular
pulse.

10. •No P waves
•Irregular fibrillation waves
•Irregular QRS complex

11. Clinical Features
• General Fatigue
• Dizziness
• Shortness of Breath
• Weakness
• Palpitation
• Light Headedness
• Syncope

12. Complications of AF
Heart Failure-
 AF especially if not controlled may weaken the heart
and lead to heart failure due to loss of atrial
contraction at the end of diastole leading to reduced
Cardiac output.
AF is present in upto 50% of patients with heart
failure.

13. Stroke
• In AF the atria are not contracting as a single unit.
• As a result blood becomes more stagnant and leads to
formation of clots.
• This clot can travel from your heart to brain where it
might cause a stroke.
• The risk of stroke in AF depends upon age (Higher
age means higher risk), h/o high BP, DM , Previous
stroke.