Cardiology Teaching Package
A Beginners Guide to Normal Heart Function, Sinus Rhythm & Common Cardiac Arrhythmias
Causes of Atrial Flutter
- Idiopathic
- Cor Pulmonale
- Ischaemic heart disease
- Cardiomyopathy
- Systemic Hypertension
- Thyrotoxicosis
- Valvular heart disease
- Congenital heart disease
Atrial flutter often presents at a rate of 150 bpm on admission. This means that every second flutter wave is depolarising the AV node, but the first wave is blocked due to the "refractory period" (This is known as "atrial flutter with 2:1 block"). Once under control the rate tends to come down in a ratio to 300.
For example:
| Ratio | Rate |
|---|---|
| Atrial flutter with 2:1 block | 150 |
| Atrial flutter with 3:1 block | 100 |
| Atrial flutter with 4:1 block | 75 |
| Atrial flutter with 5:1 block | 60 |
