left anterior hemiblock

左脚前枝ブロック LAH

WordNet

1. toward or on the left; also used figuratively; "he looked right and left"; "the political party has moved left"
2. a turn toward the side of the body that is on the north when the person is facing east; "take a left at the corner"
3. the hand that is on the left side of the body; "jab with your left" (同)left_hand
4. those who support varying degrees of social or political or economic change designed to promote the public welfare (同)left wing
5. location near or direction toward the left side; i.e. the side to the north when a person or object faces east; "she stood on the left"
6. intended for the left hand; "I rarely lose a left-hand glove" (同)left-hand
7. being or located on or directed toward the side of the body to the west when facing north; "my left hand"; "left center field"; "the left bank of a river is bank on your left side when you are facing downstream"
8. of or belonging to the political or intellectual left
9. of or near the head end or toward the front plane of a body
10. earlier in time (同)prior

PrepTutorEJDIC

1. leaveの過去・過去分詞
2. 《名詞の前にのみ用いて》『左の』,左方の / 《しばしばl-》(政治上の)左翼の,左派の,革新派の / 左に,左方に / 《通例 the ~》『左』,左方,左側 / 《しばしばthe L-》左翼の政党(団体),左派 / 〈U〉(野球で)左翼,レフト(left field);〈C〉左翼手(left fielder) / 〈C〉(ボクシングで)左手打ち
3. (場所などが)前の,前部の;(…より)前に位置する《+『to』+『名』》 / (時・事件などが)以前の,先の;(…より)前の《+『to』+『名』》

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/10/02 19:15:20」(JST)

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Left anterior fascicular block
Classification and external resources
Specialty	cardiology
ICD-10	I44.4

Left anterior fascicular block (LAFB) is an abnormal condition of the left ventricle of the heart, related to, but distinguished from, left bundle branch block (LBBB).

It is caused by only the anterior half of the left bundle branch being defective. It is manifested on the ECG by left axis deviation.

It is much more common than left posterior fascicular block.

Characteristics

Normal activation of the left ventricle (LV) proceeds down the left bundle branch, which consist of three fascicles, the left anterior fascicle, the left posterior fascicle, and the septal fascicle. The posterior fascicle supplies the posterior and inferoposterior walls of the LV, the anterior fascicle supplies the upper and anterior parts of the LV and the septal fascicle supplies the septal wall with innervation. LAFB — which is also known as left anterior hemiblock (LAHB) — occurs when a cardiac impulse spreads first through the left posterior fascicle, causing a delay in activation of the anterior and upper parts of the LV. Although there is a delay or block in activation of the left anterior fascicle there is still preservation of initial left to right septal activation as well as preservation of the inferior activation of the LV (preservation, on the EKG, of septal Q waves in I and aVL and predominantly negative QRS complex in leads II, III, and aVF). The delayed and unopposed activation of the remainder of the LV now results in a shift in the QRS axis leftward and superiorly, causing marked left axis deviation. This delayed activation also results in a widening of the QRS complex, although not to the extent of a complete LBBB.

Criteria

• Abnormal left axis deviation (usually between –45° and –60°)
• qR pattern (small q, tall R) in the lateral limb leads I and aVL
• rS pattern (small r, deep S) in the inferior leads II, III, and aVF
• Delayed intrinsicoid deflection in lead aVL (> 0.045 s)

LAFB cannot be diagnosed when a prior inferior wall myocardial infarction (IMI) is evident on the ECG. IMI can also cause extreme left-axis deviation, but will manifest with Q-waves in the inferior leads II, III, and aVF. By contrast, QRS complexes in the inferior leads should begin with r-waves in LAFB.

Effects of LAFB on Diagnosing Infarctions and Left Ventricular Hypertrophy

LAHB may be a cause of poor R wave progression across the precordium causing a pseudoinfarction pattern mimicking an anteroseptal infarction. It also makes the electrocardiographic diagnosis of LVH more complicated, because both may cause a large R wave in lead aVL. Therefore, to call LVH on an EKG in the setting of an LAHB you should see the presence of a “strain pattern” when you are relying on limb lead criteria to diagnose LVH. _____

Clinical Significance

• It can be seen in approximately 4% of cases of acute myocardial infarction
  • It is the most common type of intraventricular conduction defect seen in acute anterior myocardial infarction, and the left anterior descending artery is usually the culprit vessel.
  • It can be seen with acute inferior wall myocardial infarction.
• It is also associated with hypertensive heart disease, aortic valvular disease, cardiomyopathies, and degenerative fibrotic disease of the cardiac skeleton.

See also

• Bundle branch block

References

External links

• ECG course notes at the university of Utah

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 左脚前枝ブロック left anterior fascicular block
• 2. 心電図チュートリアル：心室内ブロック ecg tutorial intraventricular block
• 3. 慢性二枝ブロックの経過および治療 course and treatment of chronic bifascicular block
• 4. 非同期性興奮と早期興奮の一般原則 general principles of asynchronous activation and preexcitation
• 5. 心室内伝導遅延への基本的アプローチ basic approach to delayed intraventricular conduction

English Journal

• Right bundle branch block: a predictor of mortality in early systemic sclerosis.

• Draeger HT, Assassi S, Sharif R, Gonzalez EB, Harper BE, Arnett FC, Manzoor A, Lange RA, Mayes MD.SourceDivision of Rheumatology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America.
• PloS one.PLoS One.2013 Oct 31;8(10):e78808. doi: 10.1371/journal.pone.0078808.
• OBJECTIVE: To evaluate the prognostic significance of baseline electrocardiogram (ECG) abnormalities in a multiethnic cohort of patients with early systemic sclerosis (SSc) and to determine the serological, clinical, and echocardiogram correlates of ECG findings.METHODS: SSc patients with disease du
• PMID 24205321

• Prevalence of ventricular conduction blocks in the resting electrocardiogram in a general population: the Health 2000 Survey.

• Haataja P, Nikus K, Kähönen M, Huhtala H, Nieminen T, Jula A, Reunanen A, Salomaa V, Sclarovsky S, Nieminen MS, Eskola M.SourceHeart Centre, Department of Cardiology, Tampere University Hospital, Finland. petrihaataja@gmail.com
• International journal of cardiology.Int J Cardiol.2013 Sep 1;167(5):1953-60. doi: 10.1016/j.ijcard.2012.05.024. Epub 2012 May 27.
• AIMS: The prevalence of eight different ventricular conduction blocks and their association with risk factors and major cardiovascular diseases were studied in a major Finnish population study.METHODS: Data, including 12-lead electrocardiograms, were collected from 6315 subjects. The prevalence of l
• PMID 22640691

• Transcatheter closure of postoperative residual ventricular septal defects using Amplatzer-type perimembranous VSD occluders.

• Zhang B, Liang J, Zheng X, Jiang G, Yang Z, Zhang L, Zhang Y, Sun H.SourceDepartment of Cardiovascular Surgery, The General Hospital of Jinan Military District, Jinan, China.
• The Journal of invasive cardiology.J Invasive Cardiol.2013 Aug;25(8):402-5.
• OBJECTIVES: The reoperations of postoperative residual ventricular septal defects (VSDs) are associated with higher risks. Our aim is to assess the efficacy and safety of transcatheter closure of postoperative residual VSDs using perimembranous VSD occluders.METHODS: Twenty-one patients with residua
• PMID 23913605

Japanese Journal

• Long-term Prognostic Value of Major and Minor ECG Abnormalities in Latent Keshan Disease With Suspect Chronic Keshan Disease

• Journal of Epidemiology 24(5), 385-391, 2014
• NAID 130004449416

• 術中完全房室ブロックに移行した慢性３枝ブロック症例の麻酔管理

• 日本臨床麻酔学会誌 26(7), 683-690, 2006
• NAID 130004449602

• Carvedilol Therapy Improved Left Ventricular Function in a Patient With Arrhythmogenic Right Ventricular Cardiomyopathy

• Japanese Heart Journal 45(1), 169-177, 2004
• NAID 130000067287

Related Links

• Left Anterior Hemiblock - definition of Left Anterior Hemiblock ...

hemiblock [hem´e-blok″] failure in conduction of electrical impulse in either of the two main divisions of the left branch of the bundle of his; the interruption may occur in either the anterior (superior) or posterior (inferior) division.

• udatsu.vs1.jp

1．左脚分枝ブロックの概念 Rosenbaumら（1969）は、左室伝導系は左脚前枝および左脚後枝の2枝からなるとし、その一方の障害をヘミブロック(hemibloock)と呼び、それぞれ左脚前枝ヘミブロック(left anterior hemiblock)および左脚後 ...

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★リンクテーブル★

リンク元	「左脚前枝ブロック」「LAH」「LAHB」
関連記事	「left」「anterior」

「左脚前枝ブロック」

　　[★]

英

left anterior fascicular block LAFB, left anterior hemiblock LAH LAHB

同

左脚前枝ヘミブロック

関

心室内伝導障害、左脚ブロック、左脚後枝ブロック、束枝ブロック。右脚ブロック

概念

• 心室内刺激伝導路の左脚は前枝と後枝に分かれている。
• 左脚前枝は左室前壁を左方に向かい、左脚後枝は後側壁を下方に向かう。
• 左脚前枝はもっぱら左冠動脈前下行枝から血流を得ている。

心電図所見

心電図の読み方パーフェクトマニュアル.99

• 電気軸：左軸偏位(-30ﾟ～-80ﾟ)
• I,aVLがqR型(通常RaVL>RI)
• II,III,aVFがrS型(SIII>SaVF>SII)

左脚前枝の走行

心電図の読み方パーフェクトマニュアル.99

• 左室前壁を左方に向かう

興奮の伝達

心電図の読み方パーフェクトマニュアル.99

• 後枝を下り、前枝を逆行性に左上方に伝達
• QRS時間は延長せず、QRS軸は初期に下方、後期には左上方となる　→　-30～-80(左軸変位)

左脚前枝ブロックと左脚後枝ブロック 心電図パーフェクトマニュアルp.99

		左脚前枝ブロック	左脚後枝ブロック
走行		左室前壁を左方に向かう	後側壁を下降する
		大動脈弁の近くを走行
形状		より細長い
栄養		左冠動脈前下行枝のみ	左冠動脈回旋枝、右冠動脈
疾患との関連		解剖学的特性より効果病変に巻き込まれやすく、障害されやすい。また、血流のバックアップに乏しく虚血に弱い
心電図	QRS	ほとんど延長しない	ほとんど延長しない
	電気軸	左軸偏位(-30°～-80°)	右軸偏位(+110°以上)
	側壁誘導	qR	rS
	下壁誘導	rS	qR

「LAH」

　　[★] 左脚前枝ブロック left anterior hemiblock

「LAHB」

　　[★] 左脚前枝ブロック left anterior hemiblock

「left」

　　[★]

• adj.

• 左の、左方の

• n.

• 左、

• v.

• (leaveの過去-過去分詞として)去る

関

leave

　 　 　 　 　 　 　 　 　 　

「anterior」

　　[★]

• adj.

• 前側の、前の

関

anterioris、anteriorly、before、fore、former、pre、prior