Idioventricular rhythm: Difference between revisions
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==Overview== | ==Overview== | ||
Normally, the SA node is responsible for triggering each heart beat that results in ventricular contraction. However, if the ventricle does not receive triggering signals at a rate high enough, the ventricular myocardium itself becomes the pacemaker or produces escape beats. This is called idioventricular rhythm. | Normally, the [[SA node]] is responsible for triggering each heart beat that results in ventricular contraction. However, if the [[ventricle]] does not receive triggering signals at a rate high enough, the ventricular myocardium itself becomes the pacemaker or produces escape beats. This is called idioventricular rhythm. | ||
==Pathophysiology== | ==Pathophysiology== | ||
Idioventricular rhythm originates in the ventricular area and the depolarization wave spreads either partially through the electrical conduction system or completely via direct cell-to-cell transmission. | *Idioventricular rhythm originates in the ventricular area and the depolarization wave spreads either partially through the electrical conduction system or completely via direct cell-to-cell transmission. | ||
*Idioventricular rhythm can occur as any of the following mechanisms : | |||
** an escape rhythm | |||
** an increased automaticity of a single ventricular ectopic pacemaker. This increased automaticity may lead to rates that are faster than the intrinsic rate of the upper pacemakers. | |||
* The intrinsic rate in idioventricular rhythm is most commonly between 30 and 50 BPM, but the rhythm can be anywhere from 20 to 50 BPM. | |||
* The idioventricular complexes will have the morphological characteristics of the ventricular escape complex, two ventricular escape complexes, two ventricular escape complexes with associated AV dissociation or ectopic ventricular complexes.<ref name="isbn0-7637-2246-4">{{cite book |author=Miller, Geoffrey P.; Garcia, Tomas B. |authorlink= |editor= |others= |title=Arrhythmia recognition: the art of interpretation |edition= |language= |publisher=Jones and Bartlett Publishers |location=Boston |year=2004 |origyear= |pages= |quote= |isbn=0-7637-2246-4 |oclc= |doi= |url= |accessdate=}}</ref> | |||
==Causes== | ==Causes== | ||
| Line 252: | Line 257: | ||
| 1-2 bpm | | 1-2 bpm | ||
| Ventricle | | Ventricle | ||
| | | Usually associated with [[AV-dissociation]] | ||
|- | |- | ||
! [[Idioventricular rhythm]] | ! [[Idioventricular rhythm]] | ||
| Line 259: | Line 264: | ||
| Usually 20-50 bpm | | Usually 20-50 bpm | ||
| Ventricle | | Ventricle | ||
| | | Usually associated with [[AV-dissociation]] | ||
|- | |- | ||
! [[Accelerated Idioventricular Rhythm]] | ! [[Accelerated Idioventricular Rhythm]] | ||
| Line 266: | Line 271: | ||
| 50-110 bpm | | 50-110 bpm | ||
| Ventricle | | Ventricle | ||
| [[AV-dissociation]] | | Usually associated with [[AV-dissociation]] | ||
|- | |- | ||
! [[Ventricular Tachycardia]] | ! [[Ventricular Tachycardia]] | ||
Latest revision as of 18:21, 3 September 2013
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mahmoud Sakr, M.D. [2]
Synonyms and keywords: IVR
Overview
Normally, the SA node is responsible for triggering each heart beat that results in ventricular contraction. However, if the ventricle does not receive triggering signals at a rate high enough, the ventricular myocardium itself becomes the pacemaker or produces escape beats. This is called idioventricular rhythm.
Pathophysiology
- Idioventricular rhythm originates in the ventricular area and the depolarization wave spreads either partially through the electrical conduction system or completely via direct cell-to-cell transmission.
- Idioventricular rhythm can occur as any of the following mechanisms :
- an escape rhythm
- an increased automaticity of a single ventricular ectopic pacemaker. This increased automaticity may lead to rates that are faster than the intrinsic rate of the upper pacemakers.
- The intrinsic rate in idioventricular rhythm is most commonly between 30 and 50 BPM, but the rhythm can be anywhere from 20 to 50 BPM.
- The idioventricular complexes will have the morphological characteristics of the ventricular escape complex, two ventricular escape complexes, two ventricular escape complexes with associated AV dissociation or ectopic ventricular complexes.[1]
Causes
Life Threatening Causes
Idioventricular rhythm is a life-threatening condition and must be treated as such irrespective of the causes. Life-threatening conditions can result in death or permanent disability within 24 hours if left untreated.
Common Causes
- Acute rheumatic fever
- Amiodarone
- Beta-blockers
- Calcium channel blockers
- Cardiomyopathy
- Congestive heart failure
- Diabetic ketoacidosis
- Digoxin
- Hyperkalemia
- Hypermagnesemia
- Hypertensive heart disease
- Hypothermia
- NSTEMI
- Organophosphate poisoning
- Severe brain injury
Causes by Organ System
Causes in Alphabetical Order
Differentiating Idioventricular Rhythm from other Diseases
Below is a table to illustrate some of the similarities and disparities between different ventricular arrhythmias.
| example | regularity | ventricular frequency | origin | AV-dissociation | |||
|---|---|---|---|---|---|---|---|
| Wide complex (QRS>0.12) | |||||||
| Ventricular escape beat(s) |  [2]
|
Irregular | 1-2 bpm | Ventricle | Usually associated with AV-dissociation | ||
| Idioventricular rhythm |  [3]
|
Regular (mostly) | Usually 20-50 bpm | Ventricle | Usually associated with AV-dissociation | ||
| Accelerated Idioventricular Rhythm | 
|
Regular (mostly) | 50-110 bpm | Ventricle | Usually associated with AV-dissociation | ||
| Ventricular Tachycardia | 
|
Regular (mostly) if monomorphic | 110-250 bpm | Ventricle | AV-dissociation | ||
| Ventricular Fibrillation | 
|
Irregular | 400-600 bpm | Ventricle | AV-dissociation | ||
| Ventricular Flutter | 
|
Regular | 150-300 bpm | Ventricle | AV-dissociation | ||
| Torsade de Pointes | 
|
Irregular | 150-300 bpm | Ventricle | AV-dissociation | ||
References
- ↑ Miller, Geoffrey P.; Garcia, Tomas B. (2004). Arrhythmia recognition: the art of interpretation. Boston: Jones and Bartlett Publishers. ISBN 0-7637-2246-4.
- ↑ "ECG ¡V A Pictorial Primer".
- ↑ "www.learnekgs.com".