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Arrhythmia
The heart is a pump with four chambers that "beat" to an electrical impulse. A normal beat is called sinus rhythm and starts in the right atria moving to the atrioventricular node, then to all parts of the ventricles. This exact path must be followed for the heart to work properly as a pump.
Any time the electrical impulses change, the heart experiences an abnormal rhythm and pumps less effectively. In most people, arrhythmias are minor. But for certain people, it can be dangerous and requires treatment. If you have existing heart problems, arrhythmias can be a serious matter.
Minor arrhythmias can be caused by excessive alcohol, smoking, caffeine, stress, or exercise. The most common cause is heart disease, particularly coronary artery disease, abnormal heart valve function, and heart failure.
"What constitutes a normal heart rate is based upon each person's health status, age, and stress level," says James Martin, MD, UI Heart and Vascular Center cardiologist. "Normal ranges from 50 to 100 beats per minute at rest and awake. Obviously, faster rates can be normal during exercise. Slower rates may occur during sleep. However, when rates deviate from normal and are associated with heart disease, symptoms may occur.
"The best way to address questions about heart symptoms is to consult with your physician."
Tachycardia
A fast heart rate (more than 100 times per minute) is called tachycardia. A fast heart beat can cause palpitations, dizziness, lightheadedness, or fainting. Rapid heart beating limited to the ventricles can be life threatening. The most serious is ventricular fibrillation where the lower chambers quiver and the heart can't pump blood. Using emergency electrical shock treatment, both ventricular tachycardia and ventricular fibrillation can be returned to normal sinus rhythm. An implantable cardioverter defibrillator can correct a rapid heart beat.
Bradycardia
A heart rate of less than 50 beats per minute is bradycardia. Slow heart rate can cause many of the same symptoms as tachycardia – fatigue, dizziness, lightheadedness, fainting. An artificial pacemaker may be implanted to help maintain a regular heart beat.
Risk factors
- Age
Heart muscle electrical functions slow with age
- Genetics
An inherited heart abnormality may affect your heart's function
- Coronary artery disease, other heart problems, and previous heart surgery
This includes narrowed arteries, previous heart attack, abnormal valves, and cardiomyopathy
- Thyroid problems
Released hormones can speed your metabolism causing an irregular heart beat
- Drugs
This includes over-the-counter cough and cold medicines with pseudoephedrine and appetite suppressants, as well as illegal drugs including cocaine and marijuana
- Obesity
- Diabetes
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