Many things can cause your heart to speed up or feel like it skips a beat. Stress, anxiety, and even diet can all cause the occasional extra beat, skip, or flutter. Most of the time, these irregular heartbeats, or arrhythmias, are relatively brief and perfectly harmless. But if they happen frequently or are associated with significant symptoms, they could be a sign of a more serious or even life-threatening condition. In this article, we’re going to uncover what causes an irregular heartbeat and discuss the risks of having one as well as available treatment options.
What Causes Arrhythmia?
The heart muscle has four chambers—two upper and two lower—all of which are involved in controlling blood flow. The upper chambers of the heart are called the atria, and the two lower chambers are called the ventricles. Each heartbeat begins with electrical impulses produced in the upper right chamber of the heart, in a group of cells called the sinus node, also known as the heart’s natural pacemaker.
After the electrical impulses move across the atria, they reach the atrioventricular (AV) node, where they’re slowed down to give the ventricles time to fill with blood. The impulses then cause the ventricles to contract, which sends the blood out to the lungs and the rest of the body. However, if something happens to disrupt this process, the heart rhythm becomes abnormal and arrhythmia occurs.
Risk factors for an arrhythmia include:
- High blood pressure
- Heart disease
- Scarring from a heart attack
- Hypo- or hyperthyroidism
- Sleep apnea
- Excessive caffeine or alcohol
- Certain supplements or medications
- Abnormalities of heart structure
- Electrolyte imbalances
Types of Arrhythmia
Although there are many different types of arrhythmias, each is classified based on whether it originates in the atria or ventricles and whether it involves a slow heartbeat (bradycardia) or a fast heartbeat (tachycardia). While a resting heart rate below 60 beats a minute is generally considered bradycardia, a resting heart rate above 100 beats a minute is generally considered tachycardia.
However, unlike tachycardia, bradycardia can be considered a normal variant in physically fit individuals, whose hearts are capable of pumping adequate supplies of blood at rates less than 60 beats a minute at rest.
But bradycardia may also be the result of certain medical conditions. And the two most common causes are:
- Sick sinus syndrome: If the sinus node isn’t working properly, bradycardia, tachycardia, or a combination of the two may result. Sick sinus syndrome is most commonly seen in older adults.
- Heart block: If electrical impulses are blocked at any point on their way to the ventricles, heart block may occur. Bradycardia caused by heart block can be the result of a congenital abnormality, old age, or scarring from a heart attack.
There are several different types of tachycardia as well. However, unlike bradycardia, tachycardias are classified based on whether they originate in the atria or ventricles. Tachycardias that begin in the atria include:
- Atrial fibrillation: This is the most common form of arrhythmia and occurs when the electrical impulses in the atria become chaotic. Sometimes atrial fibrillation will spontaneously correct itself, but some episodes may require medical intervention. Left untreated, this type of arrhythmia can lead to serious complications, including heart failure and stroke.
- Atrial flutter: Although atrial flutter is similar to atrial fibrillation and can cause complications of its own, the electrical impulses seen with this condition are not as chaotic as those seen with atrial fibrillation.
Tachycardias that begin in the ventricles include:
- Ventricular tachycardia: This type of tachycardia involves a rapid but regular heart rate that prevents the ventricles from filling and contracting adequately and thus supplying the body with enough blood. If left untreated, ventricular tachycardia can lead to ventricular fibrillation.
- Ventricular fibrillation: If the electrical impulses within the ventricles become erratic, the ventricles can begin to quiver (fibrillate) instead of contract. Ventricular fibrillation is considered the most serious type of abnormal rhythm and can lead to cardiac arrest and death within minutes if not reversed.
- Long QT syndrome: Like ventricular fibrillation, long QT syndrome causes rapid, chaotic heartbeats and may lead to episodes of fainting, seizures, or even sudden death. This type of tachycardia can be caused by congenital anomalies or medications that prolong the QT interval—the section on an electrocardiogram (EKG) that indicates the time it takes for the heart to contract and recover.
Not everyone with an arrhythmia experiences symptoms, and even if symptoms are present, they’re not necessarily a sign of a serious medical condition. That being said, symptoms of arrhythmias may be severe and may include:
- Chest fluttering
- Slow or rapid heartbeat
- Shortness of breath
- Chest pain
If you’re experiencing an arrhythmia without symptoms, you may not even know you have the condition unless it’s found during a routine medical exam. But if you are having symptoms, your health care provider will likely speak with you about your medical history, conduct a physical exam, and perform a variety of tests designed to evaluate the heart. These include:
- EKG: This noninvasive procedure is used to evaluate the electrical activity of the heart.
- Holter monitor: This wearable EKG is used to monitor the activity of the heart continuously for 24 to 48 hours.
- Echocardiogram: This noninvasive ultrasound uses sound waves to evaluate the heart’s structure and motion.
- Tilt table test: This test uses changes in body angle to evaluate differences in heart rate and blood pressure.
- Electrophysiology (EP) study: An EP study is an invasive procedure that uses a catheter equipped with an electrode to measure electrical activity within the heart. Because the catheter is placed within the heart itself, an EP study can determine where an arrhythmia is originating and what might be causing it.
If you’ve been diagnosed with arrhythmia, treatment will depend on your symptoms. If symptoms are relatively mild and benign, no treatment may be recommended. However, serious arrhythmias that cause significant symptoms or that may lead to life-threatening complications will require treatment.
In cases involving bradycardia, patients are often offered pacemaker implantation. This device, which is usually implanted under the skin near the collarbone, uses electrodes to send out electrical impulses, which stimulate a regular rhythm when the heart rate becomes too slow or the heart stops.
By contrast, treatments for tachycardia are more varied and may include:
- Vagal maneuvers: Arrhythmias that arise in the upper half of the heart can often be stopped by performing certain maneuvers that stimulate the vagus nerve. For example, holding your breath and straining, coughing, and submerging your face in ice water may all help slow down a fast heart rate.
- Medication: Many types of tachycardia can be helped by medications designed to prevent abnormal heart rhythms and control heart rate. And in people with atrial fibrillation, blood thinners may also be prescribed to prevent the formation of blood clots.
- Electrical cardioversion: This type of procedure is often used in people with both atrial fibrillation and atrial flutter. Unlike defibrillation, which uses strong shocks to normalize heart rhythm in patients with life-threatening arrhythmias, cardioversion is an elective procedure that employs milder shocks to correct irregular heart rhythms. Cardioversion can also be performed using medications, but electrical cardioversion works much faster and is the method normally used.
- Catheter ablation: This procedure is often performed after an EP study has identified what section of the heart is causing the arrhythmia. During an ablation, electrodes are used to deliver heat, cold, or radiofrequency energy to the affected tissue. Once these areas are damaged, they can no longer conduct electrical impulses and are unable to disrupt the heart’s rhythm.
- Maze procedure: In people who don’t respond to other forms of therapy, a maze procedure may be performed. This heart surgery involves the use of incisions, temperature, or energy to create a maze of scar tissue that directs electrical impulses to the ventricles via a controlled pathway.
Whether you have a mild form of arrhythmia that can be alleviated by simply limiting caffeine consumption or a more serious type that requires surgery, there are many techniques available that can help you take control of your heart health. So if you’re experiencing symptoms, don’t hesitate to speak with your health care provider. They can help you find the treatment plan that’s right for you.