Expected changes in heart rate occur during physical activity, stress or excitement, and sleep.
The prevalence of atrial and ventricular arrhythmias tends to increase with age, even when there's no clear sign of coronary heart disease.Acquired heart disease --- such as damage caused to the heart muscle by a heart attack --- is the most important factor making a person prone to arrhythmias. Scarring or abnormal tissue deposits can cause bradycardia by interfering with the work of the sinus node or overall AV conduction. Likewise, they can cause tachycardia (originating in either the atria or ventricles) by causing cells to fire abnormally or by creating islands of electrically inert tissue. (Impulses circulate in a reentrant fashion around these areas.)
If you have heart disease, your healthcare team is likely monitoring your heart rhythm with regular EKGs (electrocardiograms). But arrhythmias that occur infrequently may not be detected. Also, not all arrhythmias cause detectable symptoms, so be sure to tell your healthcare professionals about any unusual symptoms such as fainting (syncope), difficulty breathing, fatigue, or a “flopping,” fluttering or thumping feeling in your chest.
Certain congenital conditions from birth may make a person prone to arrhythmias. For example, an incompletely developed conduction system can cause chronic heart block and bradycardia. People born with extra conduction pathways, either near the AV node or bridging the atria and ventricles, are prone to reentrant supraventricular tachycardias.Many chemical agents may cause arrhythmias, sometimes with serious consequences. Known factors include high or low blood and tissue concentrations of a variety of minerals, such as potassium, magnesium and calcium. These play a vital role in starting and conducting normal impulses in the heart. Addictive substances, especially alcohol, cigarettes and recreational drugs, can provoke arrhythmias, as can various cardiac medications. Even drugs used to treat an arrhythmia may cause another arrhythmia.
Risk factors for atrial fibrillation
Atrial fibrillation (AFib or AF) can develop in people who have heart failure or have had a heart attack. It's also found in people with heart valve disease, an inflamed heart muscle or lining (endocarditis) or recent heart surgery. Atrial fibrillation is common in persons with hypertension or diabetes. Sometimes it's related to congenital heart defects. A problem with your lungs can also affect your heart. That's why AFib often appears in people with chronic lung disease, pulmonary embolism, emphysema and asthma.
Gender and age also affect the odds of developing AFib and its severity. Men are slightly more likely than women to develop AFib, but women diagnosed with it carry a longer-term risk of premature death. Older people are somewhat more likely to have AFib than younger people. Other factors that affect risk are thyroid disorders, diabetes, high blood pressure, excessive alcohol consumption and cigarette or stimulant drug use (including caffeine).
Manage your risk factors
Just having an arrhythmia increases your risk of heart attack, cardiac arrest and stroke (View an animation of arrhythmia). Work with your healthcare team and follow their instructions to control other risk factors:
- Reduce high blood pressure
- Control cholesterol levels
- Lose excess weight
- Eat a heart-healthy diet
- Avoid tobacco smoke
- Enjoy regular physical activity
This content was last reviewed on 05/30/2012.