Have you ever experienced occasional, irregular heartbeats or palpitations that feel like your heart is fluttering or racing? They last briefly and seem harmless, so you aren’t especially worried. You figure it was caused by your stressful day at work or drinking too many beers and smoking too many cigarettes at your friend’s party last night.
Heart rhythm problems (arrhythmias) occur when the electrical impulses in your heart become uncoordinated, causing your heart to beat too fast, too slow, or irregularly. Most of these arrhythmias are common. During a 24-hour period, about one-fifth of healthy adults are likely to have irregular heart rhythms, causing a premature or temporary pause in heartbeat so fleeting that the overall heart rate or rhythm is not greatly affected.
But if the episodes begin to occur more frequently and are accompanied by symptoms such as dizziness, fainting, shortness of breath, chest pain, trouble sleeping, or confusion and memory problems, it’s time to seek medical evaluation and advice. Failure to do so could lead to life-threatening complications, such as a heart attack or stroke, which early detection could prevent.
Arrhythmias that last longer may cause the heart rate to be too slow or too fast. A normal heartbeat is 60 to 100 beats per minute. Tachycardia is a fast heart rate of more than 100 beats per minute. Bradycardia is a slow heart rate of less than 60 beats per minute. Both types can cause the heart’s normal rhythm to be erratic.
What causes arrhythmia?
Your heart is made up of four chambers – two upper chambers (atria) and two lower chambers (ventricles). The rhythm of your heart is controlled by the sinoatrial node, or SA node, an area of specialized cells. Normally, the SA node produces a steady pace of regular electrical impulses.
When the SA node does not function properly, rapid, disorganized electrical signals can make the atria act erratically, causing your heart to beat too fast, too slow, or irregularly. The atria are then less able to effectively pump blood to the ventricles and on to the rest of the body. This SA node abnormality can cause unusual heart rhythms (arrhythmias) that can generally be seen on an electrocardiogram, or EKG.
In “sick sinus syndrome,” the sinus node is bombarded with electrical impulses and is unable to efficiently direct these impulses to the hearts’ two lower ventricles. “A person with SSS may have heart rhythms that are too fast, too slow, punctuated by long pauses, or an alternating combination of all of these rhythm problems,” says internist J. Edward DeBoard, M.D., an HMSA participating provider. “It may be necessary to convert the patient’s abnormal heart rhythm to a normal rhythm through cardioversion. In this brief procedure, an electrical shock is delivered to the heart.”