Causes of Heart Block & Treatment Options

By: Dr. Bradford J. Matthews

Heart block is an abnormal heart rhythm where the heart beats too slowly a condition called bradycardia. It is caused by a blockage that disrupts the communication between the upper and lower chambers of the heart. Heart block can be acquired, meaning it is the result of damage to the heart, or congenital, meaning the person is born with the condition. Heart block is measured in degrees of severity, and can be detected a number of ways. 

In this article, we’ll take a look at the causes and symptoms of heart block, how it is diagnosed and how the condition is treated.

Causes of Heart Block

In some cases, a person is born with heart block. Babies born to mothers with autoimmune conditions are at risk for heart block as the mother’s antibodies can be passed on to the fetus. Babies can also be born with congenital heart disease that results in defects within the heart. 

More commonly, heart block is acquired over time, meaning that some type of damage to the heart has caused the block. For example, a patient could have had a previous heart attack in the zone that controls the communication between the upper and lower chambers of the heart.  Hypertensive heart disease (caused by high blood pressure) can cause disruptions that progress to heart block.  Finally as people age, their conduction system ages as well, and  increased calcification can contribute to heart block. 

Overmedication can also contribute to heart block symptoms. Beta-blockers, digitalis and calcium channel blockers can damage the heart’s conduction system. People with diseases like sarcoidosis and Lenegre’s disease have an increased risk for heart block. Finally, trauma from surgery, like mitral valve replacement, can cause conduction abnormalities in the heart.

Symptoms of Heart Block

The symptoms of heart block are the same whether the condition is congenital or acquired, and the severity of the block will usually dictate the symptoms a person will experience. Lower degrees of heart block result in fewer symptoms, so some patients never know they have it. As the severity of heart block increases, so do the symptoms. Second-degree heart block sufferers are divided into two categories, Mobitz Type I and Mobitz Type II. Mobitz Type I patients may experience dizziness, fatigue, and intolerance to exercise due to the delay of the electrical impulses in the heart. Mobitz Type II patients will experience all the same symptoms, but may also have shortness of breath or fainting. With third-degree heart block, or complete heart block, there is no communication between the upper and lower chambers of the heart. Patients typically feel poorly and are at risk for a major cardiac event. Since every patient is different, it is important to undergo diagnosis and, if necessary, treatment, to prevent the progression of the condition.

How Heart Block is Diagnosed 

It is important to see a specialist right away if you experience symptoms such as fatigue, shortness of breath, or dizziness. In order to diagnose heart block, your physician should give an exam, complete with medical history, and a baseline electrocardiogram (EKG). The EKG may or may not catch the miscommunication between the upper and lower chambers of the heart, since it only takes a six-second snapshot of the heart’s rhythm. In cases where the block is not immediately detected, the physician might equip a patient with a heart monitor. Heart monitors can measure rhythms for 24 hours, 3-4 weeks or even six months, depending on what the cardiologist believes is necessary. Once the block is detected, treatment can begin.

Treating a Heart Block

The first step in treating a heart block is to examine the patient’s medication. If they are taking something that disrupts the electrical signals of the heart, taking the patient off that medication may fix the problem. Once the medication is completely metabolized, the patient’s conduction system is reevaluated. If medicine is not the issue, the physician will determine the severity of the block.  In cases where the patient has second-degree or third-degree heart block, a pacemaker is typically needed to regulate the conduction abnormalities in the heart.

If you suspect heart block or have any symptoms that concern you, please contact us immediately to make an appointment.


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