The document discusses several types of cardiac arrhythmias including:
1. Extra-systoles which can be supraventricular or ventricular.
2. Atrial flutter and fibrillation.
3. Bradycardias, blocks, and tachycardias which have specific classifications and characteristics.
The mechanisms of arrhythmias are described as being either due to reentry of electrical impulses, abnormal automaticity, or conduction abnormalities. Specific conditions must be met for the reentry mechanism, and abnormal automaticity can arise from reduced membrane potentials self-propagating electrical activity.