Heart block in adults

Each heartbeat originates in the heart’s upper right chamber (atrium) at the sinus node, a bundle of specialized cells that act as the heart’s natural pacemaker. When it beats, an electrical signal travels from the upper chambers to the lower ones, which causes the heart to contract and pump blood. Heart block disrupts this normal rhythm.

What is heart block

Heart block is a problem with the heart’s electrical system that causes our heart to beat too slowly (bradycardia). This condition is also called atrioventricular (AV) block.

If heart block occurs, the electrical signal from the AV node to the ventricles that controls our heartbeat is partially or completely blocked.

Degrees of heart block in adults

Heart block can be first, second, or third degree, depending on the disturbance in the electrical signal.

First degree heart block. In this case, the electrical impulse still reaches the ventricles, but travels through the AV node more slowly than usual.

Second degree heart block. It falls into two categories:

• type I, also called Mobitz I block or Wenckebach’s AV block – a less serious form of second-degree heart block, the electrical signal on its way to the ventricles becomes slower and slower;
• type II, aka Mobitz II block – in this case, some electrical signals do not reach the ventricles at all, the heartbeat may be slower than usual.

Third degree heart block. In this embodiment, the electrical signal from the atria to the ventricles is completely blocked. To compensate for this, part of the ventricles acts as a pacemaker, producing electrical signals. These signals cause the heart to pump blood, but much more slowly than usual.

Causes of heart block in adults

The most common cause of heart block is a heart attack. Other causes include heart disease, problems with the structure of the heart (due to defects) and rheumatism. Blockade can also be caused by injury during open heart surgery, as a side effect of certain medications or exposure to toxins.

Heart block may be congenital, but this is a rare pathology. The risk of heart block increases with age and in the presence of heart disease.

First-degree heart block is common in well-trained athletes, teenagers, young adults, and people with a highly active vagus nerve.

Symptoms of heart block in adults

First-degree heart block often causes no symptoms. It can be detected during a routine ECG. The heart rate and rhythm in this case is usually normal.

Symptoms of second and third degree heart block include:

• dizziness;
• fainting;
• chest pain;
• fatigue;
• shortness of breath

The symptoms of third degree heart block are more intense due to the low heart rate.

Treatment of heart block in adults

Treatment for heart block depends on what causes it, how severe it is, and what symptoms it causes.

Diagnostics

First, the cardiologist will review the patient’s medical history and ask questions about your general health, diet and activity level, as well as family medical history. In addition, he will ask about the medications the patient is taking, as well as bad habits.

The doctor will then listen to the heart and check for a pulse, signs of heart failure such as fluid retention in the legs and feet.

In addition, to diagnose heart block, use:

• ECG – it will show the heart rate and rhythm, as well as the timing of electrical signals as they pass through the heart;
• a Holter monitor is a portable ECG that is attached to the patient’s body and records heart activity from 24 to 48 hours;
• event monitor – another type of portable ECG that is worn for a long period, while the device records the activity of the heart at a certain time, and not constantly;
• electrophysiological study – this test uses thin flexible wires (catheters) that are placed on the surface of the heart to record its electrical activity.

Modern treatments

If a patient has first-degree heart block, they probably won’t need treatment.

If it is second-degree heart block and there are symptoms, a pacemaker may be needed.

Third-degree heart block is often first discovered during an emergency. Treatment almost always involves a pacemaker.

Prevention of heart block in adults at home

Blockade prevention is the treatment of any diseases that can cause it and the maintenance of a healthy lifestyle, which includes:

• proper nutrition;
• physical activity;
• rejection of bad habits.

Popular questions and answers

Answered questions about heart block cardiologist Stanislav Snihovsky.