What is a Heart Block?

A heart block is an abnormal rhythm of the heart. In this case, the heart beats too slowly. This is called bradycardia. Heart block occurs when electrical signals that tell the heart to contract are prevented from passing between the upper and lower chambers of the heart, also known as the atria and ventricles. Because of this, heart block is also referred to as “atrioventricular block,” or AV block.

Types of Heart Block

There are several types of heart block that can occur within the heart’s electrical system. Some take place in the upper part of the heart, at the sinoatrial (SA) node, while others take place in the lower part of the heart, at the atrioventricular (AV) node. Patients may also experience heart block along the conductive tissue of the ventricles.

Medical providers categorize types of heart block in the following ways:

First-degree heart block: Electrical impulses are slowed as they pass through the heart, but they all reach the ventricles. Some medications may cause this condition. Symptoms or problems are rare in first-degree heart block and typically no treatment is needed.

Second-degree heart block, Type I: In this type of heart block, electrical impulses are slowed until the heart skips a beat. It occurs most often in a deeply relaxed state of during sleep. Symptoms with this condition are rare, though it sometimes can cause dizziness.

Second-degree heart block, Type II: This condition is rarer than Type 1, and more serious. Here, some of the impulses don’t reach the ventricles. Doctors will recommend a pacemaker to treat Type II second-degree heart block.

Third-degree heart block: This is also called complete heart block. It occurs when none of the electrical impulses reach the ventricles. Patients with complete heart block usually receive a permanent pacemaker to treat it.

Bundle branch block: In a bundle branch block, impulses are slowed or blocked in the tissue of one of the ventricles.

Heart Block Symptoms

Heart block is characterized by a range of symptoms, from chest pain to fatigue. The heart blockage symptoms patients experience will vary depending on the type of heart block they have. For example, a patient with first-degree heart block may not experience any symptoms at all, while a patient with second-degree heart block can have nausea and dizziness. Third-degree heart block patients can experience heart palpitations and even go into cardiac arrest. Below is a complete list of signs of heart blockage.

First-degree heart block

• Likely no symptoms at all

Second-degree heart block

• Chest pain
• Shortness of breath
• Feeling that your heart skips a beat
• Nausea
• Dizziness
• Fainting
• Fatigue

 Third-degree heart block

• Irregular heart beat
• Heart palpitations
• Cardiac arrest
• Dizziness
• Fainting
• Sudden, sever fatigue

Heart Block Causes and Risk Factors

Heart block is caused by damage to the cardiac fibers that transmit electrical impulses between the chambers of the heart, causing an irregular heartbeat. Some people are born with heart block, while others develop it as the result of contracting Lyme disease.

Anyone is at risk for heart block, but it is most common in older adults. This is usually because other heart conditions are present and scarring to the heart tissue has occurred. Medical conditions that contribute to heart block risk include:

• Recent heart surgery
• Cardiomyopathy
• Coronary thrombosis
• Inflammation of the heart muscle (myocarditis)
• Inflammation of the heart valves (endocarditis)
• Hyperthyroidism
• High potassium

Heart Block Diagnosis and Treatment

Doctors consider a number of factors when diagnosing heart block, in addition to conducting exams. The patient’s medical history, as well as alcohol and tobacco use, all play a role. An electrocardiogram (EKG) will be used to monitor the electrical activity of the patient’s heart, and the patient may be asked to wear a monitor called a Holter monitor to track the heart’s rhythm.

Heart blockage treatment often depends on treating the underlying cause of the heart block. In some instances, a change in medication is all that’s needed. When the underlying cause is heart disease, lifestyle changes such as increasing exercise, eating a healthier diet and quitting smoking can alleviate the issue. In other cases, a pacemaker will need to be implanted in the patient’s chest. This is a device the size of a credit card that signals the heart to beat regularly. A pacemaker procedure is considered a minor surgery.

Learn More about Heart Block at Baptist Health

Successfully treating heart block is just one example of how the medical professionals at Baptist Health are leading the way in total heart care. Talk with your provider about Heart Care treatment at Baptist Health.