Conduction system of the<unk>  Sinus rhythm with acute inferior infarction complicated by Type I AV<unk>  manifest in the form of 5:4 Wenckebach periods; R-P/P-R reciprocity. Sinus rhythm (rate = 100/min) with 3:2 and 2:1 Type II AV<unk> ; right bundle branch<unk>  Sinus tachycardia with complete AV<unk>  and resulting junctional escape Following the path of the electrical signals, the places where conduction can be<unk> ed give rise to different kinds of<unk> s: Location Name Within the sinoatrial node (SA node or Sinus node), where the<unk> 's signals originate Sinoatrial nodal<unk> s (often abbreviated "SA nodal<unk> " or "SA<unk> ", sometimes written "Sinuatrial<unk> ") Within the atrioventricular node (AV node) Atrioventricular<unk>  (often abbreviated "AV nodal<unk> ", "AV<unk> " or AVB). At and below the bundle of His Intra-Hisian<unk> s and Infra-Hisian<unk> s respectively. Within the left or right bundle branches Bundle branch<unk> s. Within the fascicles of the left bundle branch "Fascicular<unk> " or hemiblocks. SA and AV node<unk> s are each divided into three degrees, with second degree<unk> s being divided into two types (written either "type I or II" or "type 1 or 2"). In an SA<unk> , the electrical impulse is delayed or<unk> ed on the way to the atria, thus delaying atrial depolarization. By contrast, an AV<unk>  occurs in the AV node and delays ventricular depolarization. The term "Wenckebach<unk> " is also used for some<unk> s, and can refer to a second degree type I<unk>  in either the SA node or the AV node, however the ECG features of the two are quite distinctly different. SA nodal<unk> s SA<unk> s rarely give severe symptoms, because even if an individual had complete<unk>  at this level of the conduction system (which is uncommon), the secondary pacemaker of the<unk>  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. However SA<unk>  is capable of causing problematic symptoms even so, and may also hint at conduction issues elsewhere in the<unk> , and therefore SA<unk> s are - despite their lower level of life-threatening risk - still "the most common indication for pacemaker implantation in the US". Types of SA nodal<unk> s include: * SA node Wenckebach (Mobitz I) * SA node Mobitz II * SA node exit<unk>  In addition to the above<unk> s, 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<unk>  and SA node suppression is that in SA node<unk>  an electrical impulse is generated by the SA node that doesn't make the atria contract. 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. AV nodal<unk> s There are three basic types of AV nodal<unk> : * First-degree AV<unk>  * Second-degree AV<unk>  * Type I second-degree AV<unk>  (Mobitz I), also known as a Wenckebach<unk>  * Type 2 second-degree AV<unk>  (Mobitz II) - due to a<unk>  in or below the bundle of His * Third-degree AV<unk>  (complete<unk>  Infra-Hisian<unk>  Infra-Hisian<unk>  is that of the distal conduction system. Types of infra-Hisian<unk>  include: * Type 2 second degree<unk>  (Mobitz II) –a type of AV<unk>  due to a<unk>  within or below the bundle of His * Left anterior fascicular<unk>  * Left posterior fascicular<unk>  * Right bundle branch<unk>  Of these types of infra-Hisian<unk> , Mobitz II<unk>  is considered most important because of the possible progression to complete<unk> .
Heart block
Torsades de pointes
Sinus arrhythmia
Angina
Angina 
Atrial fibrillation
Carditis
Broken heart