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second-degree atrioventricular block

ICD-10 Codes

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Description

Second-Degree Atrioventricular (AV) Block: An Overview

Second-degree AV block, also known as second-degree heart block, is a type of heart condition characterized by the intermittent disruption of electrical signals between the atria and ventricles of the heart. This condition occurs when some, but not all, of the electrical impulses from the atria fail to reach the ventricles, resulting in an irregular heartbeat.

Causes and Symptoms

The exact cause of second-degree AV block is often unknown, but it can be related to various factors such as:

  • Aging
  • High blood pressure
  • Heart valve problems
  • Previous heart surgery or injury

Symptoms of second-degree AV block may include: * Missed beats or palpitations * Lightheadedness or dizziness * Syncope (fainting) * Shortness of breath * Chest pain or discomfort

Types and Severity

There are two types of second-degree AV block: Type I and Type II. Type I is characterized by a gradual delay in the electrical impulses, while Type II involves a complete interruption of the impulses.

Type II second-degree AV block is more serious and may warrant a pacemaker implantation to regulate the heartbeat.

Diagnosis

The presence of second-degree AV block is diagnosed when one or more (but not all) of the atrial impulses fail to conduct to the ventricles due to impaired conduction in the His-Purkinje system. This condition can be detected through various tests, including electrocardiograms (ECGs), echocardiograms, and cardiac stress tests.

Treatment

Treatment for second-degree AV block depends on the severity of the condition and may include:

  • Medications to regulate heart rhythm
  • Pacemaker implantation in severe cases
  • Lifestyle modifications such as regular exercise, a balanced diet, and stress management

It is essential to consult with a healthcare professional for proper diagnosis and treatment.

References: [2] Second-degree atrioventricular (AV) block, or second-degree heart block, is a disorder characterized by disturbance, delay, or interruption of atrial impulse ... [4] Heart block is a condition in which the electrical wiring system of the heart does not work properly. Second-degree heart block causes a missed heartbeat ... [9] Second-degree heart block is a condition in which the impulses from the atria occasionally fail to reach the ventricles.

Additional Characteristics

  • irregular heartbeat
  • shortness of breath
  • Second-degree AV block
  • intermittent disruption of electrical signals between the atria and ventricles
  • missed beats or palpitations
  • lightheadedness or dizziness
  • syncope (fainting)
  • chest pain or discomfort
  • Type I: gradual delay in electrical impulses
  • Type II: complete interruption of impulses
  • pacemaker implantation to regulate heartbeat
  • medications to regulate heart rhythm

Signs and Symptoms

Symptoms of Second-Degree Atrioventricular Block

Second-degree atrioventricular (AV) block can manifest in various ways, depending on the severity and type of blockage. Some common symptoms include:

  • Lightheadedness: Patients may experience a feeling of dizziness or lightheadedness due to inadequate blood flow to the brain.
  • Syncope: In severe cases, second-degree AV block can lead to fainting spells (syncope) when the heart fails to pump enough blood to meet the body's needs.
  • Chest pain: Some individuals may experience chest pain or discomfort due to reduced blood flow to the heart muscle.
  • Dizziness: Dizziness is another common symptom, which can be caused by a sudden drop in blood pressure.
  • Feeling faint: Patients may feel like they

Diagnostic Tests

Diagnostic Tests for Second-Degree Atrioventricular Block

Second-degree atrioventricular (AV) block can be diagnosed using various tests, which help identify the presence and type of block. Here are some diagnostic tests used to diagnose second-degree AV block:

  • Electrocardiography (ECG): This is a non-invasive test that uses soft electrodes placed on the skin to record the electrical activity of the heart. ECG can identify the presence and type of second-degree AV block, including Mobitz I and Mobitz II types [2][3].
  • Electrophysiologic testing: This test is sometimes done to confirm the diagnosis of second-degree AV block, especially in cases where the ECG findings are unclear or inconclusive. Electrophysiologic testing involves inserting catheters into the heart to record its electrical activity [1].
  • Imaging tests: Imaging tests such as CT scans or MRIs can be used to identify issues with the heart's structure that may be contributing to the second-degree AV block. These tests can also help rule out other conditions that may be causing similar symptoms [7][8].
  • Blood tests: Blood tests are not typically used to diagnose second-degree AV block, but they may be ordered to rule out other conditions or to assess the overall health of the patient.
  • Treadmill exercise stress testing: This test can be used to identify the development of atrioventricular block in the presence of ischemia [8].

It's worth noting that routine imaging is not required for initial evaluation of second-degree AV block, and electrophysiologic testing is usually reserved for cases where the diagnosis is unclear or inconclusive.

References: [1] - Not available in context [2] - 2. Jun 28, 2022 — Diagnosis. Electrocardiography (ECG) is employed to identify the presence and type of second-degree AV block. [3] - 3. Aug 11, 2022 — On an ECG, Mobitz type II can be identified by the presence of intermittent, non-conducted P waves without progressive prolongation of the PR interval. [7] - 7. Imaging tests, such as CT scan or MRI, which allow doctors to identify issues with the heart's structure or to rule out other conditions. [8] - 8. Jul 25, 2021 — Treadmill exercise stress testing can be used to identify the development of atrioventricular block in the presence of ischemia.

Additional Diagnostic Tests

  • Blood tests
  • Imaging tests
  • Electrocardiography (ECG)
  • Electrophysiologic testing
  • Treadmill exercise stress testing

Treatment

Treatment Options for Second-Degree Atrioventricular (AV) Block

Second-degree AV block can be treated with medication to increase heart rate and stabilize the heartbeat. The goal of drug treatment is to alleviate symptoms and prevent further complications.

  • Medicines to Increase Heart Rate: In some cases, medications such as at

Recommended Medications

💊 Drug information is sourced from ChEBI (Chemical Entities of Biological Interest) database. Always consult with a healthcare professional before starting any medication. Click on any medication name for detailed information.

Differential Diagnosis

Differential Diagnosis of Second-Degree Atrioventricular (AV) Block

Second-degree AV block, also known as Mobitz II or Wenkebach AV block, is a type of heart condition where some but not all atrial impulses are conducted to the ventricles. The differential diagnosis of second-degree AV block involves identifying other conditions that may present with similar symptoms.

Conditions to Consider:

  • Atrial fibrillation: Atrial fibrillation can sometimes be mistaken for second-degree AV block, especially if the ventricular rate is slow and regular (2).
  • Blocked premature atrial impulses: Blocked premature atrial impulses can simulate second-degree AV block by causing some but not all atrial impulses to be conducted to the ventricles (6).
  • Anterior myocardial infarction: Anterior MI can sometimes present with similar ECG changes as second-degree AV block, making differential diagnosis challenging (3).
  • Rheumatic fever: Rheumatic fever can cause heart block and other cardiac abnormalities that may resemble second-degree AV block (3).

Key Features to Distinguish Second-Degree AV Block:

  • Mobitz type II second-degree AV block is always pathologic, occurring at the His bundle in 25% of patients and in the bundle branches in the rest (4).
  • Second-degree AV block must be differentiated from different abnormal and irregular cardiac rhythms such as atrial fibrillation with slow ventricular rate (5).

Clinical Presentation:

People with second-degree or third-degree heart block may experience fainting, tiredness, and shortness of breath (8). It is essential to consider these symptoms when evaluating patients for differential diagnosis.

References:

  • [1] Congenital heart block · Sinoatrial exit block · Nonconducted premature atrial contractions. Differential Diagnoses.
  • [2] Atrial fibrillation with a slow heart rate may indicate second-degree AV block.
  • [3] Differential Diagnosis · Anterior MI · Rheumatic fever · Myocarditis · Lyme disease · Lenegre's disease · Lev's disease · SLE · Systemic sclerosis ...
  • [4] Mobitz type II second-degree AV block is always pathologic; the block occurs at the His bundle in 25% of patients and in the bundle branches in the rest.
  • [5] Second degree AV block must be differentiated from different abnormal and irregular cardiac rhythms as atrial fibrillation with slow ventricular ...
  • [6] DIFFERENTIAL DIAGNOSIS OF SECOND-DEGREE AV BLOCK​​ Second-degree AV block may be simulated by blocked premature atrial impulses (see Chapter 14).
  • [7] Also known as a Mobitz I or Wenkebach AV block; Disturbance of atrial impulse conducting through the AV node; Considered more benign than ...
  • [8] People with second-degree or third-degree heart block may experience fainting, tiredness and shortness of breath.
  • [9] Observations on second degree atrioventricular block, including new criteria for the differential diagnosis between type I and type II block. Am J Cardiol ...

Additional Differential Diagnoses

Additional Information

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IAO_0000115
An atrioventricular block that is characterized by progressive prolongation of the PR interval on consecutive beats followed by a blocked P wave on electrocardiogram or intermittently non-conducted P waves not preceded by PR changes on electrocardiogram caused by a conduction block between the atria and the ventricles through the atrioventricular node.
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