Bigeminal rhythm: Difference between revisions
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==Overview== | ==Overview== | ||
Bigeminy is a type of [[cardiac arrhythmia]] in which abnormal heart beats occur every other concurrent beat. The abnormal heart beat can originate from the [[atrium]], [[AV node]] or the [[ventricle]]. A typical example is bigeminal rhythm resulting from | Bigeminy is a type of [[cardiac arrhythmia]] in which abnormal heart beats occur every other concurrent beat. The abnormal heart beat can originate from the [[atrium]], [[AV node]] or the [[ventricle]]. A typical example is bigeminal rhythm resulting from [[premature ventricular contraction|premature ventricular contractions/complexes]] (PVC). Following the PVC there is a pause and then the normal beat returns, only to be followed by another PVC. The continuation of this pairing of beats is an example of bigeminy. Other forms of abnormal beats include [[PAC]], escape beats and [[parasystole]].<ref name="pmid17086032">{{cite journal| author=Henry SA, Makaryus AN, Loewinger L, Boal B| title=The great escape: junctional escape-capture bigeminy. | journal=Am J Geriatr Cardiol | year= 2006 | volume= 15 | issue= 6 | pages= 377-8 | pmid=17086032 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17086032 }} </ref> | ||
==Classification== | ==Classification== | ||
Revision as of 15:50, 23 August 2013
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rim Halaby, M.D. [2]
Synonyms and keywords: Bigeminy, bigeminal beat
Overview
Bigeminy is a type of cardiac arrhythmia in which abnormal heart beats occur every other concurrent beat. The abnormal heart beat can originate from the atrium, AV node or the ventricle. A typical example is bigeminal rhythm resulting from premature ventricular contractions/complexes (PVC). Following the PVC there is a pause and then the normal beat returns, only to be followed by another PVC. The continuation of this pairing of beats is an example of bigeminy. Other forms of abnormal beats include PAC, escape beats and parasystole.[1]
Classification
- Atrial bigeminy
- Junctional bigeminy
- Ventricular bigeminy
- Concealed bigeminy
- Escape capture bigeminy[2]
Pathophysiology
Several mechanisms can be involved in the creation of a bigeminal rhythm, such as:
- Ectopic firing of electrical impulses
- Abnormalities in electrical impulse generation
- Abnormalities in electrical impulse conduction[2]
Differential Diagnosis
Trigeminal and Quadrigeminal Rhythms
TIf every other beat is abnormal, you can describe the rhythm as bigeminal. If every third beat is abnormal, it is trigeminal; every fourth would be quadrigeminal. Typically, if every fifth or more beat is abnormal, the abnormal beat would be termed occasional.
| Bigeminal premature ventricular contractions | Normal, PVC, Normal, PVC... |
| Trigeminal premature ventricular contractions | Normal, Normal, PVC, Normal, Normal, PVC... |
| Quadrageminal premature ventricular contractions | Normal, Normal, Normal, PVC; Normal, Normal, Normal, PVC... |
| Occasional escape complexes | Normal, Normal, Normal, Normal, Pause, Escape... |
Couplets and Triplets
Bigeminy is contrasted with couplets, which are paired abnormal beats. If these concurrent beats number three, they are called triplets and are considered as a brief run of non-sustained Ventricular tachycardia or NS-VT.
| Bigeminal premature ventricular contractions | Normal, PVC, Normal, PVC... |
| Bigeminal Couplets | Normal, Normal, PVC, PVC, Normal, Normal, PVC, PVC... |
| NS-VT | Normal, Normal, PVC, PVC, PVC, PVC, Normal, Normal, PVC... |
Diagnosis
ECG
Shown below is an EKG depicting atrial bigeminy. The EKG shows a regularly irregular rhythm at a rate of about 75/minute. There are two P wave morphologies best seen in lead V1.
Copyleft image obtained courtesy of ECGpedia,http://en.ecgpedia.org/wiki/Main_Page
Shown below is an EKG depicting bigeminy. The pacemaker is an atrial pacer set at 30/min. Note the marker channel documenting atrial pacing and then sensing of the QRS in the refractory period of the pacemaker. The paced atrial beats seem to stimulate a normal sinus beat and hence create the bigeminal rhythm.
Copyleft image obtained courtesy of ECGpedia,http://en.ecgpedia.org/wiki/Main_Page
Treatment
- Asymptomatic atrial bigeminy is treated with digitalis or quinidine.
- Ventricular bigeminy is treated with suppressive drugs.
- Escape capture bigeminy that results from a bigeminal rhythm in the setting of SA node block or AV block requires an artificial pacemaker.[2]
References
- ↑ Henry SA, Makaryus AN, Loewinger L, Boal B (2006). "The great escape: junctional escape-capture bigeminy". Am J Geriatr Cardiol. 15 (6): 377–8. PMID 17086032.
- ↑ 2.0 2.1 2.2 Wing JP, Phibbs B (1977). "The differential diagnosis of bigeminal rhythms". Heart Lung. 6 (6): 995–1004. PMID 244329.