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Mobitz 1 vs. Mobitz 2: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on February 10, 2024
Mobitz 1 is a type of heart block with progressive lengthening of the PR interval before a beat is dropped. Mobitz 2 is a type of heart block where dropped beats occur without a change in the preceding PR interval.

Key Differences

Mobitz 1, also known as Wenckebach phenomenon, is characterized by a progressive elongation of the PR interval on the electrocardiogram (ECG) until a beat is dropped. In contrast, Mobitz 2 heart block shows dropped beats that are not preceded by a change in the PR interval length.
In Mobitz 1, the atrioventricular (AV) node is typically affected, reflecting a less serious condition. Mobitz 2, however, often indicates a more serious issue involving the His-Purkinje system.
Mobitz 1 is generally considered a more benign and stable form of heart block and often does not require aggressive treatment. Conversely, Mobitz 2 can be more unpredictable and is often treated with a pacemaker due to its potential to progress to complete heart block.
The ECG pattern in Mobitz 1 shows a gradually increasing delay in the AV conduction until a beat is missed. In Mobitz 2, the ECG typically shows a sudden drop of a QRS complex without prior lengthening of the PR interval.
Mobitz 1 can sometimes be seen in healthy individuals, especially during sleep or in athletes. Mobitz 2, on the other hand, is rarely a normal finding and usually indicates underlying heart disease.

Comparison Chart

ECG Pattern

Progressive PR interval lengthening before a beat drop.
Constant PR interval before a sudden beat drop.

Affected Area

Typically the AV node.
Usually the His-Purkinje system.


Generally less serious, often seen in healthy individuals.
More serious, usually indicates underlying heart disease.


Often managed without a pacemaker.
Frequently requires pacemaker implantation.


More stable and predictable.
Can be unpredictable, may progress to complete heart block.

Mobitz 1 and Mobitz 2 Definitions

Mobitz 1

A benign form of second-degree heart block.
Despite being diagnosed with Mobitz 1, he required no immediate intervention.

Mobitz 2

Not typically seen in healthy individuals.
Mobitz 2 is rarely a finding in asymptomatic, healthy people.

Mobitz 1

Usually does not require a pacemaker.
The cardiologist decided against a pacemaker for his Mobitz 1 condition.

Mobitz 2

A type of heart block with consistent PR intervals followed by dropped beats.
His ECG revealed Mobitz 2, with several beats missing without prior PR interval changes.

Mobitz 1

A progressive heart block characterized by increasing PR interval duration.
The patient's ECG showed Mobitz 1, with the PR interval getting longer with each beat.

Mobitz 2

Can unpredictably progress to complete heart block.
Given the unpredictable nature of his Mobitz 2, close monitoring was essential.

Mobitz 1

Often transient and can be seen in healthy individuals.
Her Mobitz 1 resolved on its own, as is common in many healthy young people.

Mobitz 2

More serious than Mobitz 1, often indicating underlying heart pathology.
The diagnosis of Mobitz 2 led to further investigations for underlying cardiac issues.

Mobitz 1

Less likely to progress to more severe heart block.
Given his Mobitz 1 diagnosis, the risk of developing complete heart block was low.

Mobitz 2

Frequently treated with pacemaker implantation.
Due to her Mobitz 2, she was scheduled for a pacemaker implantation.


How is Mobitz 1 treated?

Often managed without intervention, but depends on symptoms.

Is Mobitz 1 serious?

It's generally less serious and often benign.

How is Mobitz 2 treated?

Usually with a pacemaker due to the risk of progression.

Is Mobitz 2 found in healthy individuals?

Rarely, it usually indicates underlying pathology.

What is Mobitz 1?

A type of second-degree heart block with progressive PR interval elongation.

What is Mobitz 2?

A heart block with consistent PR intervals and sudden beat drops.

Can Mobitz 1 resolve on its own?

Yes, especially in young and healthy individuals.

Is a pacemaker always needed for Mobitz 2?

Often, due to the risk of progression to complete heart block.

Is Mobitz 2 serious?

Yes, it's more serious and can indicate heart disease.

Can exercise cause Mobitz 1?

Yes, it can appear transiently in athletes.

Can Mobitz 1 progress to Mobitz 2?

It's uncommon, as they typically affect different parts of the heart.

Is Mobitz 2 reversible?

It's less likely to be reversible compared to Mobitz 1.

Are symptoms of Mobitz 2 different from Mobitz 1?

Symptoms can be more severe in Mobitz 2, like dizziness or fainting.

How is Mobitz 2 diagnosed?

By ECG showing consistent PR intervals with dropped beats.

Is Mobitz 1 seen in children?

Rarely, it's more common in adults.

Is Mobitz 2 a congenital condition?

It's not typically congenital and often indicates acquired heart disease.

Can stress cause Mobitz 1?

Stress isn't a typical cause, but can exacerbate underlying heart conditions.

Are there symptoms specific to Mobitz 1?

Symptoms are rare; it's often asymptomatic.

Can medications cause Mobitz 1?

Some medications can affect heart conduction and lead to Mobitz 1.

How is Mobitz 1 diagnosed?

Through an ECG showing progressive PR interval lengthening.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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