Second-degree heart block is a type of heart rhythm disorder. There are two types of second degree heart block — Mobitz type 1 and Mobitz type 2. Mobitz type 2 heart block occurs when the electrical impulses between the atria and the ventricles are intermittent.

There are four chambers in the heart, with two on the top and two on the bottom. The top chambers are called atria, and the bottom chambers are called ventricles. When the heart beats, an electrical impulse travels through the atria to tell them to contract and send blood to the ventricles.

This article will look at what Mobitz type 2 heart block is and whether it is dangerous. It will also discuss the causes, symptoms, and treatment of this condition.

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If a person has a second degree heart block, the electrical impulses that tell the heart to contract may not reach the ventricles. When the electrical impulses become disrupted, the heart may skip a beat. This leads to an abnormal heart rhythm.

Healthcare professionals can categorize second degree heart block into two types:

  • Mobitz type 1: In this type, the signals become slower between the beats. This can cause the heart to skip a beat. A person is unlikely to experience symptoms.
  • Mobitz type 2: In this type, the electrical signals intermittently reach the ventricles. This can often progress to third degree heart block. A person may experience symptoms with this type of heart block.

When a person has a Mobitz type 2 heart block, their heart skips beats in an irregular pattern. The body cannot typically handle this irregular pattern, and a person is likely to experience symptoms as a result. The outlook usually depends on the cause.

Mobitz type 2 heart block is more likely to develop into third degree heart block, which can lead to a heart attack.

The symptoms of Mobitz type 2 heart block can be different for each person, but they usually include:

Some people are born with heart block. When this occurs, the condition is called congenital heart block. It may happen due to a condition that the mother experienced during pregnancy or because a person was born with another heart condition.

Usually, heart block develops as a person ages, and the wires that connect the atria and the ventricles develop fibrosis.

Coronary artery disease appears to be among the most common causes of heart block.

However, a 2022 article notes that Mobitz type 2 heart block can also occur due to:

  • autoimmune conditions, such as lupus
  • inflammatory conditions, such as Lyme disease, rheumatic fever, or myocarditis
  • hyperkalemia, which is when the potassium levels in the blood are too high
  • electrolyte imbalances
  • sarcoidosis, which is a growth of tiny granulomas in the body
  • amyloidosis, which is a rare disease that happens when a type of protein called amyloid builds up in the organs

It can also develop after a person undergoes heart surgery or takes the following medications:

The treatment for a second degree heart block depends on its cause and severity. For Mobitz type 2 heart block, healthcare professionals may recommend a pacemaker.

If a person has Mobitz type 1 heart block, they may not require any treatment. If medications are causing the heart block, a doctor will reduce or discontinue these medications.

There are different ways to diagnose Mobitz type 2 heart block. The most common is an EKG.

This test records the electrical activity of the heart and can reveal irregularities in its rhythm. It can help doctors determine the severity of the heart block.

Healthcare professionals may also look at a person’s medical history, including any procedures they have recently undergone and any medication they may be taking.

Without treatment, Mobitz type 2 heart block can lead to various complications, such as:

Heart block can also increase the risk of sudden cardiac arrest.

Prevention typically focuses on managing any risk factors.

People should regularly discuss their medications with a doctor to ensure that they are not increasing their risk of developing a heart block.

People with a heart block should aim to lead a heart-healthy lifestyle to minimize their risk of complications. This involves exercising for at least 2.5 hours per week and monitoring blood pressure.

Other steps that people can take include:

Learn about foods to eat and avoid to promote heart health.

Untreated Mobitz type 2 heart block can lead to serious problems, such as heart failure. If people notice symptoms of second degree heart block, they should contact a doctor.

People should seek immediate medical attention and call 911 if they or someone around them experiences the following symptoms:

  • extreme tiredness without a clear cause
  • fainting
  • loss of consciousness
  • dizziness
  • chest pain
  • shortness of breath

Mobitz type 2 heart block is a condition in which the electrical impulses from the atria are sometimes not able to reach the ventricles.

This can cause an irregular heartbeat, resulting in dizziness, fainting, the sensation of a skipped heartbeat, chest pain, nausea, difficulty breathing, and fatigue.

Anyone who develops symptoms of cardiac arrest will require emergency medical care.