Arrhythmias are irregular heartbeats that can occur when the electrical impulses that coordinate your heartbeats are not functioning properly. This can cause the heart to beat too fast (tachycardia), too slow (bradycardia), or erratically. Arrhythmias can be harmless or life-threatening, depending on their type and severity. Causes of Arrhythmias Arrhythmias can arise from a variety