A heart block denotes a disease in the electrical system of the heart. This is opposed to coronary artery disease, which is disease of the blood vessels of the heart. While coronary artery disease can cause angina (chest pain) or myocardial infarction (heart attack), heart block can cause lightheadedness, syncope (passing out), and palpitations. The normal electrical conduction in the heart allows the impulse that is generated by the SA node of the heart to be propagated to (and stimulate) the myocardium (muscle of the heart). ... The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. ... Coronary heart disease (CHD), also called coronary artery disease (CAD) and atherosclerotic heart disease, is the end result of the accumulation of atheromatous plaques within the walls of the arteries that supply the myocardium (the muscle of the heart). ... Angina pectoris (Latin for chest constriction) is the result of a lack of oxygen supply to the heart muscle, due to a reduced blood flow around the hearts blood vessels. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... Syncope can also mean fainting (in medicine). ... A palpitation is an abnormal, rapid beating of the heart, brought on by overexertion, disease or drugs. ...

Types of heart block

A heart block can be a blockage at any level of the electrical conduction system of the heart. Blocks that occur within the sinoatrial node (SA node) are described as SA nodal blocks. Blocks that occur within the atrioventricular node (AV node) are described as AV nodal blocks. Blocks that occur below the AV node are known as infra-Hisian blocks (named after the bundle of His). Clinically speaking, most of the important heart blocks are AV nodal blocks and infrahisian blocks. The normal electrical conduction in the heart allows the impulse that is generated by the SA node of the heart to be propagated to (and stimulate) the myocardium (muscle of the heart). ... The sinoatrial node (abbreviated SA node, also called the sinus node) is the impulse generating (pacemaker) tissue located in the right atrium of the heart. ... The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ...

Types of SA nodal blocks

The SA nodal blocks rarely give symptoms. This is because if an individual had complete block at this level of the conduction system (which is uncommon), the secondary pacemaker of the heart would be at the AV node, which would fire at 40 to 60 beats a minute, which is enough to retain consciousness in the resting state. Consciousness is a quality of the mind generally regarded to comprise qualities such as subjectivity, self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and ones environment. ...

Types of SA nodal blocks include:

• SA node Wenckebach (Mobitz I)
• SA node Mobitz II
• SA node exit block

In addition to the above blocks, the SA node can be suppressed by any other arrhythmia that reaches it. This includes retrograde conduction from the ventricles, ectopic atrial beats, atrial fibrillation, and atrial flutter.

The difference between SA node block and SA node suppression is that in SA node block an electrical impulse is generated by the SA node that doesn't conduct to the ventricles. In SA node suppression, on the other hand, the SA node doesn't generate an electrical impulse because it is reset by the electrical impulse that enters the SA node.

Types of AV nodal blocks

There are four basic types of AV nodal block:

• First degree heart block
• Second degree heart block
  • Type 1 second degree heart block (Mobitz I) (also known as Wenckeback phenomenon)
• Third degree heart block (Complete heart block)

First degree heart block is a disease of the electrical conduction system of the heart. ... Second degree heart block is a disease of the electrical conduction system of the heart. ... Third degree heart block, also known as complete heart block, is a disease of the electrical system of the heart, in which the impulse generated in the top half of the heart (typically the SA node in the right atrium) does not propagate to the left or right ventricles. ...

Types of infrahisian block

Infrahisian block describes block of the distal conduction system. Types of infrahisian block include:

• Type 2 second degree heart block (Mobitz II)
• Left bundle branch block
  • Left anterior hemiblock
  • Left posterior hemiblock
• Right bundle branch block

Of these types of infrahisian block, Mobitz II heart block is considered most important because of the possible progression to complete heart block. Bundle branch block refers to a disorder of the hearts electrical conducting system. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ...

Related topics

• Electrical conduction system of the heart
  • Sinoatrial node (SA node)
  • Atrioventricular node (AV node)
• First degree heart block
• Second degree heart block
• Trifascicular heart block
• Third degree heart block (Complete heart block)
• Left bundle branch block
  • Left anterior hemiblock
  • Left posterior hemiblock
• Right bundle branch block
• Lev's disease

The normal electrical conduction in the heart allows the impulse that is generated by the SA node of the heart to be propagated to (and stimulate) the myocardium (muscle of the heart). ... The sinoatrial node (abbreviated SA node, also called the sinus node) is the impulse generating (pacemaker) tissue located in the right atrium of the heart. ... The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ... First degree heart block is a disease of the electrical conduction system of the heart. ... Second degree heart block is a disease of the electrical conduction system of the heart. ... Trifascicular heart block is the triad of first degree heart block, right bundle branch block, and either left anterior or left posterior heart block seen on an electrocardiogram (EKG). ... Third degree heart block, also known as complete heart block, is a disease of the electrical system of the heart, in which the impulse generated in the top half of the heart (typically the SA node in the right atrium) does not propagate to the left or right ventricles. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ...

External links

• "heartblock.blogspot.com - Living with Heart Block and a Pacemaker"