What is it?
You might never have heard of the word bradycardia before, but based upon the ‘cardia’ part of the name, you might guess that it has something to do with your heart. You’re correct, but what exactly does it mean? Is it a serious issue? Is it something that requires treatment? Should you be worried about trying to prevent it?
Bradycardia is when your heart beats at a slower than average rate. For adults, a regular heart rate is between 60 – 100 beats per minute, so this means that your heart rate would be less than 60. To understand how this happens, let’s take a moment to look at how the electrical circuitry of your heart works. Your heart has four chambers with two atria on top and two ventricles on the bottom. Your blood enters your heart via the right atrium, passes through the right ventricle before being sent to the lungs. Here, it gets rid of carbon dioxide and picks up oxygen. It returns to your heart via the left atria and ends up in the left ventricle. From here, it’s propelled to the rest of the body. The trigger that causes your heart to pump so it can complete this process numerous times a minute is an electrical current that originates in the sinus node that sits in the tissue of your right atrium. This is your heart’s natural pacemaker and controls the rate. After the electrical impulse starts in the sinus node, it travels across both atria, which causes them to contract and push your blood into your ventricles. The electrical impulse then reaches the atrioventricular (AV) node, which is situated right near the middle of your heart. This signals the start of the contraction of your ventricles. The signal then reaches the bundle of His, which slows the signal down just enough that the ventricles have time to finish filling with the blood. At this point, the nerve fibers split with one half going down to the right ventricle and the other half going to the left. The signal continues down these paths to complete the transmission, which finishes the contraction of the ventricles and pumps blood to your lungs and body. Bradycardia occurs as the result of this electrical current slowing down or becoming blocked.
Bradycardia can result from damage to the heart tissue caused by aging, heart disease, heart attack, congenital heart defect, infection of the heart tissue, underactive thyroid, imbalance of chemicals within your body, sleep apnea, inflammatory diseases or certain medications. For individuals, who are very athletic or young adults, it’s not uncommon for them to have a resting heart rate that is lower than 60 beats per minute—this isn’t considered a health problem. If the dysfunction starts with the sinus node, it can be the result of electrical impulses that are slower than usual, pauses in/failure to send a signal at a regular rate, or a blockage in the signal that doesn’t allow the atria to contract. Sometimes, the message is unable to get past the AV node, which is known as heart block. There are three main types. First-degree heart block is when the signal stills reach the ventricles, but is just slow. It’s the mildest form and rarely requires treatment. Second-degree is when not all of the electrical signals reach the ventricles, which means that if you look on an electrocardiogram (EKG), it seems like there is an absent beat. The heart rate is usually slower and irregular when compared to a regular heart rate. Third-degree, or complete heart block, is when none of the electrical impulses are reaching the ventricles resulting in slow and unreliable electrical impulses to control the rate of the ventricles. Third-degree heart block is a life-threatening emergency.
Symptoms don’t depend on the type and include near-fainting/fainting, dizziness, lightheadedness, fatigue, shortness of breath, chest pain, confusion, memory problems, or getting tired quickly during physical activity. Some things can increase your risk of developing bradycardia, such as aging, having heart disease, having heart damage from a heart attack, having high blood pressure, smoking, heavy alcohol use, recreational drug use, psychological stress, or anxiety. The complications of bradycardia are frequent fainting, heart failure (your heart can’t pump enough blood to your body), and sudden cardiac arrest/death. This is why if you have any symptoms of bradycardia, it’s essential to be seen by your doctor. If you’re having difficulty breathing, feel faint or have chest pain that lasts more than a few minutes, call 911.
Many different tests can be used to evaluate your heart. The first is an EKG because it provides a snapshot of what’s going on with your heart. The only downside is that unless you’re in the middle of a bradycardic episode, your bradycardia won’t be visible on the EKG. To get a more thorough look, your doctor might want you to wear a Holter monitor, which records your heart’s activity for about 24 – 48 hours. During the time that you’re wearing the device, you’ll need to keep a log of how you feel, like if you have any symptoms and when they occurred. A different type of monitor, an event monitor, is worn for several weeks and when you feel any symptoms, you push a button that records what your heart is doing during that moment. Another test is the tilt table test, which is used to see if you get dizzy upon standing from a seated or reclining position. Your doctor might also recommend an exercise test, which uses a treadmill or stationary bike to see if your heart rate increases appropriately in response to physical exertion.
The treatment for bradycardia depends on where the electrical conduction problem originates from and the severity of your symptoms. If there are any underlying disorders, like hypothyroidism or sleep apnea, it’s vital to treat them. If you’re taking medications that can contribute to the development of bradycardia, your doctor will recommend switching to another that doesn’t have the same side effect or lowering the dose of the medication that you’re currently on. If these treatments don’t improve your bradycardia, then you’re going to need a pacemaker. A pacemaker is a small, battery-operated device that is put under your skin near your collarbone. Some wires come from it and are placed through veins into your heart. The tiny electrodes at the end of the wires are attached to your heart tissue, which allows the pacemaker to monitor your heart’s rate and generate an electrical impulse when necessary to help your heart to beat more regularly.
The best way to prevent bradycardia is to prevent heart disease. You can do this by exercising regularly and eating a diet that is low in salt, fat, and sugar while being high in fruits, vegetables, and whole grains. It’s essential to keep your blood pressure and cholesterol under control, which will be much easier if you’re a healthy weight and living a healthy lifestyle. It’s vital not to smoke or use recreational drugs. If you do drink alcohol, do not exceed the recommended amount of only 1 drink per day for all women and men over 65 and 2 drinks per day for men under 65. Managing stress is also key to decreasing your risk of bradycardia. If you already have bradycardia, be sure to follow the treatment plan you and your doctor discussed, including taking all of your medication as directed. If you do experience any changes, it’s necessary to inform your doctor.
Bradycardia can be a mild, annoying little feeling in your chest. Or, it can be a life-threatening condition. In either scenario, it’s critical to get it addressed. If you have any questions or concerns about bradycardia, please speak with your doctor. If you would like more information, please visit the American Heart Association’s Bradycardia page at https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia–slow-heart-rate