Hello and welcome to the zero to finals podcast.

My name is Tom and in this episode I'm going to be talking to you about atrial fibrillation.

And if you want to follow along with written notes on this topic,

you can follow along at zero to finals.com slash a.f,

or in the cardiology section of the zero to finals medicine book. So let's get straight into it.

Let's start with some basic pathophysiology. Normally the sinoatrial node, which is found in the right

atrium, produces organized electrical activity that coordinates the contraction of the atria in the

heart. Atrial fibrillation is where the contraction of the atria is uncoordinated, rapid and irregular.

And this is due to disorganize electroactivity that overrides the normal organized activity of the sinoatrial node.

An ECG will show absence of P waves, and this reflects the lack of

coordinated atrial electrical activity. This disorganized electrical activity in the atria also leads

to irregular conduction of electrical impulses to the ventricles, and this results in irregularly irregular ventricular contractions,

tachycardia, which means a fast heart rate, heart failure due to poor filling of the

ventricles during diastole when the heart is relaxed, and an increased risk of stroke.

When the activity of the atria is chaotic, there's a tendency for

blood to collect in the atria and form blood clots. And these clots can become emboly and travel to the

brain and block the cerebral arteries causing an ischemic stroke. And this is what causes the

increased risk of stroke in atrial fibrillation.

So how do patients with AF present?

Well, patients are often asymptomatic and atrial fibrillation is incidentally picked up when attending the doctor or the nurse for other reasons.

They can present with symptoms, which can be palpitations, shortness of breath,

syncope with dizziness or fainting,

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