心室性二段脈

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of or relating to a ventricle (of the heart or brain)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/05/20 19:18:26」(JST)

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Bigeminy as seen on a 12 lead ECG

A rhythm strip demonstrating bigeminy

simple ECG of a Supraventricular Bigeminy

Bigeminy (Latin: bi-two, gemini-twins) is a descriptor for a heart arrhythmia in which there is a continuous alternation of long and short heart beats. Most often this is due to ectopic heart beats occurring so frequently that there is one after each sinus beat, typically premature ventricular contractions (PVCs). For example, a sinus beat is shortly followed by a PVC, then followed by a pause. The normal beat then returns, only to be followed by another PVC.^[1]

Etiology

After any PVC there is a pause that can lead to the development of bigeminy. A PVC wavefront often encounters a refractory AV node that does not conduct the wavefront retrograde. Thus the atrium is not depolarized and the sinus node is not reset. Since the sinus p wave to PVC interval is less than the normal P-P interval, the interval between the PVC and the next p wave is prolonged to equal the normal time elapsed during two P-P intervals. This is called a "compensatory" pause. The pause after the PVC leads to a longer recovery time which is associated with a higher likelihood of myocardium being in different stages of re-polarization. This then allows for re-entrant circuits and sets up the ventricle for another PVC after the next sinus beat.^[2] The constant interval between the sinus beat and PVC suggests a reentrant etiology rather than spontaneous automaticity of the ventricle.^[3]

Atrial premature complexes (APCs) do not have a compensatory pause since they reset the sinus node but atrial or supraventricular bigeminy can occur. If the APCs are very premature, the wave front can encounter a refractory AV node and not be conducted. This can be mistaken for sinus bradycardia if the APC is buried in the t wave since the APC will reset the SA node and lead to a long P-P interval.^[2]

Rule of bigeminy

When the atrial rhythm is irregular (as in atrial fibrillation or sinus arrythmia) the presence of bigeminy depends on the length of the P-P interval and happens more frequently with a longer interval. As with post PVC pauses, a longer P-P interval leads to a higher chance of re-entrant circuits and thus PVCs. The term "rule of bigeminy" is used to refer to the dependence of bigeminy on the ventricular cycle length in irregular rhythms.^[3]

Classification

There can be similar patterns depending on the frequency of abnormal beats. If every other beat is abnormal, it is described as bigeminal. If every third beat is aberrant, it is trigeminal; every fourth would be quadrigeminal. Typically, if every fifth or more beat is abnormal, the aberrant beat would be termed occasional.^[1]

Bigeminy is contrasted with couplets, which are paired abnormal beats. Groups of three abnormal beats are called triplets and are considered as a brief run of non-sustained ventricular tachycardia (NSVT) and if the grouping last for more than 30 seconds, it is ventricular tachycardia (VT).^[2]

Treatment

In people without underlying heart disease and who do not have any symptoms, bigeminy in itself does not require any treatment. If it does become symptomatic, beta-blockers can be used to try and suppress ventricular ectopy. Class I and III agents are generally avoided as they can provoke more serious arrhythmias.^[4]

References

^ ^a ^b Shvilkin, Ary L. Goldberger, Zachary D. Goldberger, Alexei (2013). Goldberger's Clinical Electrocardiography: A Simplified Approach (8th ed. ed.). Philadelphia, PA: Elsevier/Saunders. ISBN 9780323087865.
^ ^a ^b ^c Wagner, Galen S. (2001). Marriott's Practical Electrocardiography (10th ed. ed.). Philadelphia, PA: Williams & Wilkins. ISBN 0683307460.
^ ^a ^b Langendorf, R.; Pick, A.; Winternitz, M. (1 March 1955). "Mechanisms of Intermittent Ventricular Bigeminy: I. Appearance of Ectopic Beats Dependent Upon Length of the Ventricular Cycle, the "Rule of Bigeminy"". Circulation 11 (3): 422–430. doi:10.1161/01.CIR.11.3.422.
^ Papadakis, Maxine A.; Stephen J. McPhee; Michael W. Rabow, ed. (2013). Current Medical Diagnosis and Treatment 2014 (53 ed.). New York: McGraw-Hill Medical. ISBN 9780071806336.

UpToDate Contents

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English Journal

Human G109E-inhibitor-1 impairs cardiac function and promotes arrhythmias.

Haghighi K1, Pritchard TJ1, Liu GS1, Singh VP1, Bidwell P1, Lam CK1, Vafiadaki E2, Das P1, Ma J1, Kunduri S1, Sanoudou D3, Florea S1, Vanderbilt E1, Wang HS1, Rubinstein J4, Hajjar RJ5, Kranias EG6.
Journal of molecular and cellular cardiology.J Mol Cell Cardiol.2015 Oct 6. pii: S0022-2828(15)30075-4. doi: 10.1016/j.yjmcc.2015.10.004. [Epub ahead of print]
A hallmark of human and experimental heart failure is deficient sarcoplasmic reticulum (SR) Ca-uptake reflecting impaired contractile function. This is at least partially attributed to dephosphorylation of phospholamban by increased protein phosphatase 1 (PP1) activity. Indeed inhibition of PP1 by t
PMID 26455482

Nadolol decreases the incidence and severity of ventricular arrhythmias during exercise testing compared with β1-selective β-blockers in patients with catecholaminergic polymorphic ventricular tachycardia.

Leren IS1, Saberniak J2, Majid E3, Haland TF2, Edvardsen T2, Haugaa KH4.
Heart rhythm : the official journal of the Heart Rhythm Society.Heart Rhythm.2015 Sep 30. pii: S1547-5271(15)01237-0. doi: 10.1016/j.hrthm.2015.09.029. [Epub ahead of print]
BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inheritable cardiac disease predisposing to malignant ventricular arrhythmias.OBJECTIVE: We aimed to explore the incidence and severity of ventricular arrhythmias in patients with CPVT who were not treated, treated with �
PMID 26432584

Diffuse fibrosis leads to a decrease in unipolar voltage: Validation in a swine model of premature ventricular contraction-induced cardiomyopathy.

Tanaka Y1, Rahmutula D1, Duggirala S1, Nazer B1, Fang Q1, Olgin J1, Sievers R1, Gerstenfeld EP2.
Heart rhythm : the official journal of the Heart Rhythm Society.Heart Rhythm.2015 Sep 28. pii: S1547-5271(15)01195-9. doi: 10.1016/j.hrthm.2015.09.025. [Epub ahead of print]
BACKGROUND: Frequent premature ventricular contractions (PVCs) may lead to dilated cardiomyopathy. A leftward shift in the unipolar voltage distribution in patients with cardiomyopathy has also been described and attributed to increased fibrosis.OBJECTIVES: We established a swine model of PVC-induce
PMID 26416621

Japanese Journal

Bradycardia Due To Sick Sinus Syndrome Induced Torsades de Pointes in a Patient with Takotsubo Cardiomyopathy and QT Prolongation

, , , , , , , , , , ,
Journal of Arrhythmia 27(Supplement), PJ2_027, 2011
… ECG showed first-degree atrioventricular block with a ventricular rate of 52 bpm and mild QT interval prolongation (QTc 517 msec). … Two days later, her ECG showed ventricular bigeminy and torsade de pointes. … The ECG after the administration of the magnesium sulfate showed junctional rhythm with a ventricular rate of 43 bpm and excessive QT interval prolongation (QTc 761 msec). …
NAID 130002130024

Exercise-Stress Test for Predicting Genetic Mutations and Future Cardiac Events in Asymptomatic Young CPVT Relatives

, , , , ,
Journal of Arrhythmia 27(Supplement), SY14_4-SY14_4, 2011
… Catecholaminergic polymorphic ventricular tachycardia (CPVT) is inherited arrhythmic disorder with highly malignant clinical course. … Exercise-stress test, which was considered positive if ventricular tachycardia or premature ventricular contractions consisting of bigeminy or couplets were recorded, was positive in 12 relatives (34%), and the following genetic analysis disclosed mutations in 20 (57%). …
NAID 130002129790

Return of the Living Dead: Unique Case of Spontaneous Asystole after Torsades Pointes Ventricular Tachycardia Caught on Holter in a Congenital Long QT Syndrome Patient

,
Journal of Arrhythmia 27(Supplement), PE4_123-PE4_123, 2011
… Congenital long QT syndrome is characterized by prolonged QT interval, associated with polymorphic ventricular tachycardia (Torsades pointes), related to repetitive episodes of syncope, and even sudden cardiac arrest. …
NAID 130002129771