LBBB

左脚ブロック left bundle branch block

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/24 05:51:10」(JST)

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Left bundle branch block
ECG characteristics of a typical LBBB showing wide QRS complexes with abnormal morphology in leads V1 and V6.
Classification and external resources
ICD-10	I44.4 - I44.7
DiseasesDB	7352
eMedicine	ped/2501

Left bundle branch block (LBBB) is a cardiac conduction abnormality seen on the electrocardiogram (ECG). In this condition, activation of the left ventricle is delayed, which causes the left ventricle to contract later than the right ventricle.

ECG diagnosis

Electrocardiogram showing left bundle branch block and irregular rhythm due to supraventricular extrasystoles.

A left bundle branch block

The criteria to diagnose a left bundle branch block on the electrocardiogram:

• The heart rhythm must be supraventricular in origin
• The QRS duration must be ≥ 120 ms
• There should be a QS or rS complex in lead V1
• There should be a notched ('M'-shaped) R wave in lead V6.

The T wave should be deflected opposite the terminal deflection of the QRS complex. This is known as appropriate T wave discordance with bundle branch block. A concordant T wave may suggest ischemia or myocardial infarction.

Causes

Among the causes of LBBB are:

• Aortic stenosis
• Dilated cardiomyopathy
• Acute myocardial infarction
• Extensive coronary artery disease
• Primary disease of the cardiac electrical conduction system
• Long standing hypertension leading to aortic root dilatation and subsequent aortic regurgitation
• Lyme disease

Treatment

• Patients with LBBB require complete cardiac evaluation, and those with LBBB and syncope or near-syncope may require a pacemaker.
• Some patients with LBBB, a markedly prolonged QRS (usually > 150 ms), and systolic heart failure may benefit from a biventricular pacemaker, which allows for better synchrony of heart contractions.

Classification

There are also partial blocks of the left bundle branch: "left anterior fascicular block" (LAFB) and a "left posterior fascicular block" (LPFB). This refers to the bifurcation of the left bundle branch.

See also

• Bundle branch block
• Right bundle branch block
• Sgarbossa's criteria

References

External links

• http://library.med.utah.edu/kw/ecg/mml/ecg_lbbb.html

UpToDate Contents

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• 1. 左脚ブロック left bundle branch block
• 2. 左脚ブロックまたはペースメーカーによる心室リズムの患者における負荷試験 stress testing in patients with left bundle branch block or a paced ventricular rhythm
• 3. 心室内伝導遅延への基本的アプローチ basic approach to delayed intraventricular conduction
• 4. 脚ブロックまたはペーシング調律存在下での心筋梗塞の心電図による診断 electrocardiographic diagnosis of myocardial infarction in the presence of bundle branch block or a paced rhythm
• 5. 心電図チュートリアル：心室内ブロック ecg tutorial intraventricular block

English Journal

• Application of higher order cumulant features for cardiac health diagnosis using ecg signals.

• Martis RJ, Acharya UR, Lim CM, Mandana KM, Ray AK, Chakraborty C.SourceDepartment of Electronics and Computer Engineering, Ngee Ann Polytechnic, Singapore 599489, Singapore.
• International journal of neural systems.Int J Neural Syst.2013 Aug;23(4):1350014. doi: 10.1142/S0129065713500147. Epub 2013 May 31.
• Electrocardiogram (ECG) is the electrical activity of the heart indicated by P, Q-R-S and T wave. The minute changes in the amplitude and duration of ECG depicts a particular type of cardiac abnormality. It is very difficult to decipher the hidden information present in this nonlinear and nonstation
• PMID 23746287

• Clinical significance of ventricular tachyarrhythmias in patients treated with CRT-D.

• Kutyifa V, Klein HU, Wang PJ, McNitt S, Polonsky B, Zima E, Merkely B, Moss AJ, Zareba W.SourceUniversity of Rochester Medical Center, Rochester, New York; Semmelweis University, Heart Center, Budapest, Hungary.
• Heart rhythm : the official journal of the Heart Rhythm Society.Heart Rhythm.2013 Jul;10(7):943-50. doi: 10.1016/j.hrthm.2013.04.006. Epub 2013 Apr 29.
• BACKGROUND: Data on the outcome of cardiac resynchronization therapy with defibrillator (CRT-D) in patients developing ventricular arrhythmias are limited.OBJECTIVE: To evaluate the prognostic value of ventricular tachycardia (VT) or ventricular fibrillation (VF) episodes by heart rate in patients e
• PMID 23639624

• Double left ventricular pacing following accidental malpositioning of the right ventricular electrode during implantation of a cardiac resynchronization therapy device.

• Dissmann R, Wolthoff U, Zabel M.AbstractAccidental malpositioning of a right ventricular (RV) electrode has not been previously reported in the context of cardiac resynchronization therapy (CRT).The case of a 75-year old male patient with dilative cardiomyopathy, left ventricular (LV) ejection fraction 23%, New York Heart Association functional heart failure status stage III, left bundle branch block (LBBB) with QRS width of 136 ms, and misplacement of the RV lead to the LV apex during implantation of a CRT defibrillator is described.Following unremarkable implantation, routine interrogation of the CRT device on the first day after the implantation revealed uneventful technical findings. The 12-lead surface electrocardiogram (ECG) showed biventricular stimulation featuring a narrow QRS complex with incomplete right bundle branch block (RBBB) and R>S in V1. The biplane postoperative chest X-ray was graded normal. On routine follow-up one month later, a transthoracic echocardiogram revealed an increased ejection fraction of 51% but the RV lead was placed in the LV apex. An additional transesophageal echocardiogram exhibited an Eustachian valve guiding the lead via the patent foramen ovale through the mitral valve into the LV apex. Operative revision was scheduled and the active fixation lead was uneventful removed from the LV. A new electrode was inserted and placed in the RV apex.Accidental malplacement of the RV electrode to the LV may be difficult to diagnose in the context of CRT patients as a stimulated biventricular ECG with incomplete RBBB appearance is expected in this situation. Careful analysis of lateral radiographic views during the operation is important to ensure correct lead positioning. As timely revision is the preferred procedure, early routine transthoracic echocardiography may be considered for detection of malplacement.
• Journal of cardiothoracic surgery.J Cardiothorac Surg.2013 Jun 27;8(1):162. [Epub ahead of print]
• Accidental malpositioning of a right ventricular (RV) electrode has not been previously reported in the context of cardiac resynchronization therapy (CRT).The case of a 75-year old male patient with dilative cardiomyopathy, left ventricular (LV) ejection fraction 23%, New York Heart Association func
• PMID 23806123

Japanese Journal

• Anatomical predictors of conduction damage after transcatheter implantation of the aortic valve

• Tretter Justin T.,Mori Shumpei,Anderson Robert H.,Taylor Michael D.,Ollberding Nicholas,Truong Vien,Choo Joseph,Kereiakes Dean,Mazur Wojciech
• Open Heart 6(1), e000972, 2019-01
• … The variables were compared with the occurrence of both permanent pacemaker insertion (PPI) and left bundle branch block (LBBB) following TAVI. … New LBBB occurred in 23.5%, 21.3 % of whom required PPI. … CI 0.38 to 0.99) were all associated with PPI, with similar associations with LBBB. … Conclusions Gross anatomical variation of the aortic root and its underlying support, including the membranous septum, were not associated with the occurrence of either PPI or new LBBB. …
• NAID 120006653232

• Circ Rep

• Matsumura Koichiro,Shiojima Ichiro,Kin Hiromi,Fujii Kenichi,Shibutani Hiroki,Matsumoto Hiroshi,Otagaki Munemitsu,Yokoi Mitsuru,Yamamoto Yoshihiro,Sugiura Tetsuro
• Circulation Reports 1(8), 320-325, 2019
• … Seventy-one patients had ST elevation or left bundle branch block (LBBB; … group 1) and 109 patients did not have ST elevation or LBBB (group 2) on post-resuscitation electrocardiogram (ECG). …
• NAID 130007689182

• 症例報告(第20回若手奨励賞受賞論文) 大動脈弁人工弁(機械弁)置換術後遠隔期に生じたOMI-VT stormに対し経心房中隔的に施行したカテーテルアブレーションが著効した1例

• 高橋 未奈,飛梅 威,松本 和久,松浦 朋美,添木 武,藤本 裕太,原田 貴文,Zheng Robert,數藤 久美子,西條 良仁,上野 理絵,川端 豊,坂東 美佳,山田 なお,伊藤 浩敬,轟 貴史,伊勢 孝之,楠瀬 賢也,山口 浩司,八木 秀介,福田 大受,山田 博胤,若槻 哲三,佐田 政隆
• 四国医学雑誌 = Shikoku acta medica 74(5・6), 201-208, 2018-12-25
• … At ６７ years old, She admitted to the prior hospital due to ventricular tachycardia with LBBB and superior axis at heart rate of ２１０ per minutes. …
• NAID 120006552371

Related Links

• Left bundle branch block - Wikipedia, the free encyclopedia

Left bundle branch block (LBBB) is a cardiac conduction abnormality seen on the electrocardiogram (ECG). In this condition, activation of the left ventricle is delayed, which causes the left ventricle to contract later than the right ventricle.

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★リンクテーブル★

リンク元	「II音」「奇異性分裂」「左脚ブロック」「left bundle branch block」
拡張検索	「ILBBB」「CLBBB」

「II音」

　　[★]

英

second heart sounds, S2

関

心音

まとめ

II音亢進	IIA	高血圧	AR	動脈硬化
	IIP	肺高血圧	PR	MS
II音減弱	IIA	低血圧	AS
	IIP		PS

II音増大

MSとASとでは、同じstenosisでも心音の大きさに関与の仕方が違うんですね。

• (体循環)高血圧症、肺動脈高血圧症。(PHD.35)

拡張期における大動脈圧、肺動脈圧が高い　→　弁に衝突する血液の流速が早い　→　弁の閉鎖音が大きい

• 動脈硬化の強いとき

• 大動脈弁が閉じるとき、拡張期早期 back pressureが高い？

• 大動脈弁閉鎖不全症 AR

• 拡張期に大動脈弁を挟んだback pressureが高いから？

• 肺動脈弁閉鎖不全症 PR

• 心室中隔欠損症

• 右室へのvolume load。PHで顕著

II音減弱

• 大動脈弁狭窄症(AS)、肺動脈弁狭窄症(PS)。(PHD.35)

• 駆出できる血液量がへるから？

分裂音

呼吸性分裂

PHD.33-35

• 生理的状態では、

		横隔膜の相対的位置	II音
呼気	expiration	￣	｜	single sound
吸気	inspiration	＿	｜　｜	splitting sound

• (1)吸気時には、肺の血管抵抗性が低下　→　拡張期におけるP弁へのback pressureは呼気時と比べ比較的低下する　→P弁の開放時間が延長
• (2)吸気時には、肺静脈が拡張　→　左房・左室への血液還流量が減少　→　左室を充満する血液量減少　→　一回拍出量減少　→　駆出時間の短縮　→　A弁の開放時間が短縮

• 心音#まとめ

widened splitting

• right bundle branch block(RBBB), pulmonic stenosis(PS)

IIAが早まる：MR, VSD

IIPが遅れる：RBBB, PS, pulmonary hypertension

固定性分裂 fixed splitting

• atrial septal defect (ASD)

奇異性分裂 paradoxical splitting

• left bundle branch block(LBBB), advanced aortic stenosis(AS), 高血圧？

単一II音 single S2

• Eisenmenger症候群、Fallot四徴症、肺動脈狭窄・肺動脈弁閉鎖

「奇異性分裂」

　　[★]

英

paradoxical splitting

関

II音、生理的分裂 physiologic splitting

概要

• 通常の心音はS1→A2→P2　だけど、奇異性分裂ではS1→P2→A2となる。

原因

• A弁閉鎖の遅延：(1)left bundle branch block(LBBB), (2)advanced aortic stenosis(AS), 高血圧？, (4)閉塞性肥大型心筋症 HOCM(YN.C-135).

• (1) left bundle branch block(LBBB)：心筋収縮の時間的な遅れによる。収縮が右室→左室の順に起これば、P弁→A弁の順に閉鎖する。
• (2)大動脈弁狭窄症：A弁の狭窄により大動脈側の押し戻す圧力(back pressure)が上がるのに時間がかかり、A2音のdelayとなる。
• (4)閉塞性肥大型心筋症：(2)のASと同じ理屈

呼吸性変動との関連

生理的分裂では、吸気時には、肺血管抵抗が下がる事によるP2の遅れ + 肺静脈拡張にともなうLVの拍出量減少によるA2の早期閉鎖により大きくA2→P2と広がっている。

• 呼気時：S2(P2→A2が打ち消されるため)
• 吸気時：P2→A2(A2のdelay)

「左脚ブロック」

　　[★]

英

left bundle branch block, LBBB

関

右脚ブロック、束枝ブロック、脚ブロック

分類

• 完全左脚ブロック：QRS幅が0.12sより長い(>3mm)
• 不完全左脚ブロック：QRS幅が0.10-0.12s

脚ブロックと心音、電気軸との関係

		心機能の予後	心音	電気軸	原因
右脚ブロック		良好	病的分裂(IIP遅延)	不変(YN.C-50)/右軸偏位
左脚ブロック		良好ではない	奇異性分裂(IIA遅延)		虚血性心疾患、高血圧、心筋症、心不全、左室肥大
	左脚前枝ブロック			左軸偏位
	左脚後枝ブロック			右軸偏位

「left bundle branch block」

　　[★] 左脚ブロック LBBB

「ILBBB」

　　[★] 不完全左脚ブロック incomplete left bundle branch block

「CLBBB」

　　[★] 完全左脚ブロック complete left bundle branch block