The heart’s primary function is to pump an adequate supply of oxygen-rich blood throughout the body. When your heart cannot circulate enough oxygenated blood, it may disrupt your body’s functions. Various factors trigger heart failure, one being arrhythmia (irregular heartbeat). With an irregular heartbeat, your heart may beat too slowly, too fast, or irregularly compared to the normal rates.
When your heart beats too slowly, you likely have bradycardia. Bradycardia is a common condition in older adults due to the wear and tear of the heart’s electrical system.
But how is a slow heartbeat related to heart failure? This article explores how a slow heartbeat can lead to heart failure. You’ll also learn about various causes of bradycardia, symptoms, and preventive measures.
What Is a Slow Heartbeat?
A slow heartbeat (bradycardia) is an arrhythmia where a heart beats less than 60 bpm in a minute, resting or active. A regular heart rate should range between 60 and 100 times per minute.
Other forms of abnormal heart rhythms include Atrial Fibrillation (AFib or AF), which causes an irregular and abnormally fast heartbeat.
Bradycardia is not always a life-threatening condition. A slow heartbeat can be expected from healthy young people and athletes.
For example, healthy young adults and athletes might have a resting heart rate between 40 and 60 bpm. But does that mean the slow heart rate threatens their lives?
Luckily not. For such individuals, their heart muscles are strong, thanks to good health and exercise, and can pump plenty of oxygen-rich blood with each heartbeat.
It’s also common for young individuals and adults to have a slow heartbeat during deep sleep. That’s because heart muscles have relaxed, resulting in slower breathing and heart rate.
A slow heartbeat becomes a serious concern when the heart cannot pump enough oxygenated blood that the body requires.
When bradycardia gets to that level, it may hinder your brain and various body organs from getting adequate oxygen. As a result, patients may experience:
- Dizziness or lightheadedness
- Fatigue
- Shortness of breath
- Confusion or memory problems
- Fainting
- Weakness
- Getting tired quickly during physical activities
When such symptoms arise, it’s advisable to visit a health provider for a diagnosis. Critical complications such as heart failure, cardiac arrest, chest pains, kidney failure, or high blood pressure may arise if a slow heartbeat is left untreated.
What Is Heart Failure?
Heart failure develops when your heart fails to pump blood to body parts as it should.
For your body to be functional, it requires an adequate supply of oxygen and nutrients. Your blood is responsible for supplying oxygen and nutrients. In the case of heart failure, insufficient blood fails to circulate the amount of oxygen and nutrients your body needs.
According to the CDC, about 6.2 million U.S. adults have heart failure. When diagnosed with heart failure, it’s advisable to seek the help of a family or friend who will help you through. Unfortunately, heart failure is a progressive condition that usually doesn’t have a cure.
Common symptoms of heart failure include:
- Fatigue
- Weakness
- Swelling of legs
- Irregular heartbeat
- Swelling of the abdomen
- Nausea
- Loss of appetite
- Shortness of breath
- Persistent coughing
- Rapid weight gain
- Exercise intolerance
Heart failure can either be acute or chronic. Acute heart failure is short-term, and symptoms will disappear at some point.
For chronic heart failure, the condition is ongoing and doesn’t improve over time. That said, patients with chronic heart failure can manage the disease through medication and healthy lifestyle changes.
A slow heartbeat is usually associated with old age. However, it can affect people of all ages and gender. People with the following risk factors have higher chances of suffering from bradycardia:
- High blood pressure
- Smoking
- Heavy use of alcohol
- Stress and anxiety
- Illegal drug use
How Does a Slow Heartbeat Lead to Heart Failure?
The heart relies on electrical impulses to start a heartbeat. The Sinoatrial (SA) node, located at the top of your heart’s right atrium, is responsible for generating these impulses. When the SA node functions correctly, it provides impulses for starting heartbeats so your heart can pump blood correctly.
In a normal heartbeat, the SA node sends an electric impulse to the atrioventricular (AV) node. From the AV node, the impulse passes through the His-Purkinje system (HPS) to the heart’s muscle cells, leading to the contraction of ventricles.
A series of electrical impulses from the SA to AV nodes and through the HPS instigate contractions, responsible for pumping blood from your heart to the rest of the body.
If the SA node isn’t working properly – a condition called sinus bradycardia – it generates slower electrical impulses that lead to slower heartbeats.
Patients with mild sinus bradycardia may not experience any symptoms. However, if untreated for a long time, sinus bradycardia may develop serious conditions such as heart failure.
Sinoatrial Node Failure
The heart has a brilliant way of replacing the SA node with the atrioventricular node if the SA fails to generate electrical impulses. In such a situation, there is no communication or relay of electrical impulses from the SA to the AV node.
When electrical impulses begin in the AV node, the condition is called junctional bradycardia.
The AV node is an alternative pacemaker to generate electrical signals for contracting the heart. With junctional bradycardia, the AV node generates impulses that will only reach the ventricles.
For a sufficient blood supply to your body, your ventricles (the two lower heart chambers) need to work hand in hand with your atria (the two upper heart chambers). Ventricles rely on the atria’s contraction to help fill up with blood so they can pump sufficient blood to the body.
Junctional bradycardia means your ventricles do all the heavy lifting because the SA node on your right atria is not functional. However, the AV node doesn’t generate enough impulses to pump enough blood to your body.
Atrioventricular Block
Atrioventricular block (heart block) can also slow the heartbeat when the heart’s conduction pathways become dysfunctional. With an AV block, the electrical impulses in the heart can’t travel from the atria to the ventricles.
The three forms of the atrioventricular block are:
- First Degree – Electrical impulses from the upper chamber reach the lower chamber. However, the transmission of impulses is slower than usual.
- Second Degree – A few electrical impulses from the upper chamber reaches the lower chamber. This leads to palpitations, thus failure to pump enough blood to the body.
- Third Degree – No electrical impulses from the upper chamber make it to the lower chamber. When this happens, the AV node controls the heartbeat at a slower rate.
When the SA and AV nodes fail to work together, they result in a slow heart rate. And a slow heart rate won’t pump adequate blood carrying oxygen and nutrients throughout your body, resulting in heart failure.
Other risk factors that may result in a slow heartbeat include:
- A complication as a result of heart surgery
- Congenital heart disease (a heart disease present at birth)
- Heart tissue infection
- Hypothyroidism
- Damage resulting from heart disease or heart attack
- Inflammatory diseases like lupus or rheumatic fever
- Obstructive sleep apnea
- Electrolyte imbalance in your blood, such as calcium or potassium
- Hypoxia
- Wear and tear of heart tissues due to aging
How To Measure Your Heart Rate
You can use your resting heart rate to determine your heart’s health. Luckily, you don’t have to visit your health provider to do so. Take your pulse when sitting or lying to measure your resting heart rate. Ensure to stay calm and relaxed to get an accurate figure.
You can take your pulse without a hassle by touching different locations on your body. Some of the best areas that are easy to count your pulse from include:
- Wrist
- Side of your neck
- Top of your feet
- Inside of your elbow
Press any of these locations with two fingers and find where your pulse is easy to feel. Please avoid using your thumb since it has its pulse and might interfere with the counting.
After locating your pulse, set a stopwatch and count the number of beats over 60 seconds.
You have a regular heart rate if your heartbeat ranges between 60 and 100 bpm. If your heartbeat rate is below 60 bpm, you have bradycardia.
The good news is that bradycardia might not be a serious health condition, especially if you’re young, healthy, and athletic. However, it’s advisable to visit your doctor to know the cause of bradycardia and possible health risks.
Final Thoughts
Slow heartbeat (bradycardia) is an arrhythmia that can lead to serious complications such as heart failure if left untreated. Bradycardia causes the heart to beat more slowly than the normal 60 to 100 bpm rate.
In the case of bradycardia, the resting heart rate may range between 40 and 60 bpm. A slow heartbeat means the heart supplies less blood than the body requires. Insufficient blood carries less oxygen and nutrients, disrupting the normal functioning of your body.
Kate Macmorn
Communications Director
Kate is the communications director for the American Medical Resource Institute, where they’ve trained over a million healthcare professionals to study for, earn and maintain life support certifications that allow them to better respond to cardiac emergencies. When not in the office, you can find Kate practicing her tennis skills. She also frequents live music venues and is always looking for her next creative hobby.