Idioventricular rhythm
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
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 escape rhythm. 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 an escape rhythm, or as 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.
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
- Cardiomyopathy
- Diabetic ketoacidosis
- Digoxin
- Hypothermia
- NSTEMI
- Organophosphate poisoning
- Severe brain injury
Causes by Organ System
| Cardiovascular | No underlying causes |
| Chemical/Poisoning | No underlying causes |
| Dental | No underlying causes |
| Dermatologic | No underlying causes |
| Drug Side Effect | No underlying causes |
| Ear Nose Throat | No underlying causes |
| Endocrine | No underlying causes |
| Environmental | No underlying causes |
| Gastroenterologic | No underlying causes |
| Genetic | No underlying causes |
| Hematologic | No underlying causes |
| Iatrogenic | No underlying causes |
| Infectious Disease | No underlying causes |
| Musculoskeletal/Orthopedic | No underlying causes |
| Neurologic | No underlying causes |
| Nutritional/Metabolic | No underlying causes |
| Obstetric/Gynecologic | No underlying causes |
| Oncologic | No underlying causes |
| Ophthalmologic | No underlying causes |
| Overdose/Toxicity | No underlying causes |
| Psychiatric | No underlying causes |
| Pulmonary | No underlying causes |
| Renal/Electrolyte | No underlying causes |
| Rheumatology/Immunology/Allergy | No underlying causes |
| Sexual | No underlying causes |
| Trauma | No underlying causes |
| Urologic | No underlying causes |
| Miscellaneous | No underlying causes |
Causes in Alphabetical Order
- Acute myocardial infarction
- Brugada syndrome
- Cardiomyopathy
- Commotio cordis
- Digoxin
- Electric shock
- Hypothermia
- Ibutilide
- Idiopathic
- Myocardial ischemia
- Reperfusion arrhythmia
Differentiating Idioventricular Rhythm from other Diseases
Below is a Venn diagram to illustrate some of the similarities and disparities between different ventricular escape rhythms.
