Arrhythmia
Has your heart ever skipped a beat? Sometimes it really does if you have an arrhythmia. An arrhythmia is any disorder of your heart rate or rhythm. It means that your heart beats too quickly, too slowly or with an irregular pattern. When the heart beats faster than normal, it is called tachycardia. When the heart beats too slowly, it is called bradycardia.
Many factors can affect your heart's rhythm, such as having had a heart attack, blood chemistry imbalances or abnormal hormone levels. Some substances or medicines may also cause arrhythmias.
Symptoms of arrhythmias include
- Fast or slow heart beat
- Skipping beats
- Lightheadedness, dizziness
- Chest pain
- Shortness of breath
- Paleness
- Sweating
Your doctor can run tests to find out if you have an arrhythmia. Treatment to restore a normal heart rhythm may include medicines, an implantable cardioverter-defibrillator (ICD) or a pacemaker.
What's a normal heartbeat?
When your heart beats, the electrical impulses that cause it to contract must follow a precise pathway through your heart. Any interruption in these impulses can cause an arrhythmia.
Before learning about what can cause an arrhythmia, first consider what should happen during a normal heartbeat.
Your heart is divided into four hollow chambers. Divided top to bottom, the chambers on each half of your heart form two adjoining pumps with an upper chamber (atrium) and a lower chamber (ventricle).
During a heartbeat, the smaller, less muscular atria contract and fill the relaxed ventricles with blood. This contraction starts when the sinus node - a small group of cells in your right atrium - sends an electrical impulse causing your right and left atria to contract.
The impulse then travels to the atrioventricular node, located at the center of your heart and which lies on the pathway between your atria and your ventricles. From here, the signal exits the atrioventricular node and travels through your ventricles, causing them to contract and discharge blood throughout your body.
In a healthy heart, this process usually goes smoothly, resulting in a normal resting heart rate of 60 to 100 beats a minute. Athletes at rest commonly have a heart rate less than 60 beats a minute because their hearts are so efficient.
