What are the different types of heart rhythm problems?

One of the most common heart dysrhythmias/arrhythmias (abnormal rhythms) is premature ventricular beats, or PVCs. PVCs are just what they sound like: the ventricles beat sooner than they should. This means that the ventricle is contracting and pumping out blood before the atrium above it has completely pumped its blood volume into the ventricle. Most of the time, PVCs are harmless. In fact, almost everyone has them at one time or another. However, if PVCs occur too frequently (more than several times per minute), the heart is unable to pump an adequate volume of blood to the body, which can cause symptoms such as weakness, fatigue, palpitations, or low blood pressure.

Other types of rhythm problems can have similar effects. Problems may occur when the heart beats too fast, too slow, or with an irregular rhythm. But whether the heart is beating too fast, too slow, or too irregularly, the effects are often the same as one or more of those described above. Some additional examples of rhythm problems include:

• Atrial fibrillation -- occurs when the atria beat irregularly and too fast
• Ventricular fibrillation -- occurs when the ventricles beat irregularly and too fast
• Bradycardia -- occurs when the heart beats too slow
• Tachycardia -- occurs when the heart beats too fast
• Heart block -- occurs when the electrical signal is delayed or blocked after leaving the sinoatrial (SA) node. There are several types of heart blocks, and each one has a distinctive electrocardiogram (ECG) tracing.