A harmless early extra heartbeat and a chaotic, racing, potentially lethal heart rhythm are obviously two different things. Yet, both fit the medical definition of an arrhythmia.
Arrhythmia simply means an irregular heartbeat. However, arrhythmia conditions vary depending on which part of the heart the arrhythmia originates, symptoms you feel, treatments — if any — you need and the damage it can do to your health.
“The majority of arrhythmias are non-life threatening,” says Dr. Bruce Koplan, a cardiovascular medicine specialist at Brigham and Women’s Hospital in Boston. Still, he says, “For a patient it’s a very scary thing to think that you have an arrhythmia.”
An important role for physicians is to help patients understand what type of arrhythmia they have and the associated risks, Koplan says. If you see a cardiologist for a possible arrhythmia, he or she will explain your options and work with you to make treatment decisions.
[See: 6 Signs You’re Having a Heart Attack.]
Heart Chambers, Valves and Electrical System
Arrhythmias are often grouped by where they occur, so it’s helpful to know basic heart anatomy.
The heart muscle has four chambers. The two top chambers are the left and right atrium (or the atria). Blood circulates back from the rest of the body through the veins into the atria.
The two bottom chambers are the left and right ventricles. The ventricles pump oxygen-rich blood away from the heart and into the body through arteries.
Heart valves keep blood moving in the right direction. The mitral and tricuspid valves direct blood flow from the atria to the ventricles. The aortic and pulmonary valves direct blood flow out of the ventricles.
The PQRSTs of EKGs
The heart’s electrical impulses control heart contractions. Electrical signals start in the sinoatrial node at the top of the right atrium. The SA node is known as the heart’s natural pacemaker.
An electrocardiogram, or EKG, records the strength and timing of electrical signals traveling through your heart. The EKG tracing shows five basic waves: P, Q, R, S and T. The P wave represents atrial contractions. The QRS complex corresponds to ventricular contractions. The T wave represents the moment where the heart relaxes before the next contraction.
With normal heart rhythms, these PQRST patterns look orderly, regular and evenly spaced on EKG tracings. With arrhythmias, by contrast, waves can be missing, irregular, unevenly spaced or quivering. By evaluating your symptoms and EGK patterns, cardiologists — or in some cases, emergency medical technicians — can determine your specific type of arrhythmia.
In general, a slow heart rate is called a bradyarrhythmia. A fast heart rate is a tachyarrhythmia. Here are some arrhythmias of concern:
Supraventricular Arrhythmias
Fast heart rates that start above the ventricles are called supraventricular tachycardia. Atrial fibrillation and atrial flutter are types of supraventricular arrhythmias.
Atrial Fibrillation (AFib)
Atrial fibrillation is one of the most common arrhythmias. As you get older, your risk for developing AFib rises. Dizziness, palpitations, shortness of breath with exercise, fatigue and chest pains are some symptoms. With AFib, small blood clots can form in the heart and potentially migrate to the brain, raising the risk of stroke. Heart failure is another possible complication of AFib if the heart is unable to pump blood well enough to meet the body’s needs.
Even for people who don’t have symptoms, AFib comes with increased stroke risk, emphasizes Dr. Vivek Reddy, director of the cardiac arrhythmia service at Mount Sinai Health System in New York. People with AFib should be on blood thinner medication, he says, unless they’re at risk for bleeding. Increasingly, a procedure called catheter ablation is used to treat AFib. If AFib leads to persistent bradyarrhythmia with symptoms, a pacemaker may be recommended.
Atrial Flutter
Atrial flutter also occurs in the atrium, but it’s a more regular rhythm than atrial fibrillation. People with heart failure, heart valve abnormalities or a heart attack history are among those at increased risk for this abnormally fast heart rhythm. Atrial fibrillation treatments are similar, but not identical, to those for AFib. A procedure called electrical cardioversion may stop atrial flutter by using an electrical current to shock the heart back to normal sinus rhythm.
Paroxysmal Supraventricular Tachycardia (PSVT)
An extremely rapid heart rate that starts and ends suddenly is called paroxysmal supraventricular tachycardia. With PSVT, the heart rate ranges from about 150 to 250 beats per minute. (A normal heart rate is about 60 to 100 beats per minute.) Certain medications increase the risk for PSVT. For some people, consuming caffeine, alcohol or illicit drugs can increase their PSVT risk. Heart palpitations, chest tightness, shortness of breath, a sensation of anxiety and fainting are possible symptoms. Many people with PSVT require no treatment. However, a heart evaluation may reveal an underlying cause that will respond to medications or cardiac procedures.
Wolff-Parkinson-White Syndrome
Wolff-Parkinson-White syndrome is a special type of PSVT that children are born with. In WPW, an extra electrical pathway in the heart causes a rapid heart rate. In rare cases, WPW can be life-threatening if a particularly rapid heart rate leads to cardiac arrest.
[See: The 12 Best Diets for Your Heart.]
Ventricular Arrhythmias
With irregular rhythms that originate in the ventricles, treatments may involve medication, catheter procedures like cardiac ablation and, in some cases, devices such as pacemakers or implantable cardioverter defibrillators or ICDs. Ventricular tachycardia and ventricular fibrillation are two extremely serious arrhythmias.
Ventricular Tachycardia (V-tach)
Ventricular tachycardias are fast heartbeats coming from the bottom chambers of the heart. “They oftentimes, but not always, occur in people that have had heart disease (such as) a heart attack in the past or heart failure,” Reddy says. When scar tissue develops on the heart, for instance after a heart attack, tachycardia circuits can develop. Chest pain, dizziness, shortness of breath and fainting are symptoms.
Ventricular tachycardia is dangerous and can lead to cardiac arrest. Antiarrhythmic medications are prescribed to prevent V-tach. For patients who have them, ICD implants detect abnormal heartbeats and if needed, send electrical shocks to the heart to return the heart rhythm to normal.
Ventricular Fibrillation (V-fib)
V-fib is considered the most serious heart arrhythmia. Rather than beating regularly to pump out blood, the ventricles of the heart quiver ineffectively. Sustained V-fib is a medical emergency requiring immediate lifesaving treatments such as cardiopulmonary resuscitation, or CPR, and defibrillation to shock the heart back into normal rhythm. A weakened heart muscle, or cardiomyopathy, ongoing or previous heart attacks and certain genetic conditions put people at higher risk for V-fib. Treatments address the underlying heart condition and also include medications to help prevent future episodes. Doctors may recommend an ICD device for patients who’ve experienced V-fib.
Premature Ventricular Contractions (PVCs)
Premature ventricular contractions are early, extra heartbeats that start in the ventricles. Symptoms can include a fluttering or pounding sensation in the chest. Many people have PVCs, which are usually considered harmless, unless they also have risk factors such as heart disease or heart failure. In some cases, people in otherwise good health who have frequent PVCs can reduce or eliminate them with lifestyle changes such as cutting caffeine, alcohol and tobacco use. Cardiologists can evaluate PVCs to determine whether they pose a serious health problem.
Sick Sinus Syndrome
When the heart’s natural pacemaker, the SA node or sinus node, becomes diseased, it can cause a slow heart rate (bradycardia) that produces symptoms such as being easily fatigued, lightheadedness, fainting and shortness of breath. Sick sinus syndrome may also be accompanied by episodes of AFib and fast heart rate (tachycardia). A permanent pacemaker is the standard treatment for sick sinus syndrome.
Long Q-T Syndrome (LQTS)
Long Q-T syndrome refers to a specific part of the EKG pattern called the “Q-T interval.” That’s the space between the beginning of the Q wave and the end of the T wave on the EKG tracing. A prolonged Q-T interval means the heart is taking longer to contract and recover before the next contraction. This rare type of arrhythmia is usually hereditary. If untreated, it can lead to an extremely dangerous form of ventricular tachycardia called torsade de pointes.
Sudden Cardiac Arrest
In some cases, ICDs are advised for patients with severe heart disease, although they do not have an arrhythmia yet. “If you have a lot of scar tissue in the heart — even if you don’t have any arrhythmia at all — you still have a risk of sudden death and that falls under the arrhythmia category,” says Dr. Joseph H. Levine, director of the Arrhythmia & Pacemaker Center at St. Francis Hospital in Long Island, New York. “Those people have an arrhythmia potential.” He says studies that he and other researchers have conducted “have shown that in some of the high-risk patients, you may actually need an implantable defibrillator for prevention.”
[See: 12 Medical Emergencies You Need to Address Right Away.]
Understanding Arrhythmia
People often have misunderstandings about arrhythmias and their implications. “The first misconception is that all arrhythmias are abnormal,” Levine says. “The majority of people who have irregular heartbeats are normal. The second misconception is you have to live as an invalid for the rest of your life if you have arrhythmia. And the third is you have a death sentence because you have arrhythmia. There are so many ways to treat it that you want to make sure you go to the right place to get the right advice.”
Irregular heartbeats come in many varieties, Reddy points out. “There are arrhythmias that have really minimal significance and nothing needs to be done with them,” he says. “And there are others that are highly significant and can be quite emergent and require emergent management.”
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Types of Arrhythmias originally appeared on usnews.com
