Conduction problems
Andrew R Houghton, David Gray in Making Sense of the ECG, 2014
Block of the anterior fascicle of the left bundle branch is known as left anterior fascicular block (LAFB). On the ECG, the primary consequence of LAFB is left axis deviation. LAFB is discussed in more detail in Chapter 10 (p. 114).
Cardiovascular system
Brian J Pollard, Gareth Kitchen in Handbook of Clinical Anaesthesia, 2017
Bundle branch blocks result from damage to the His-Purkinje system. This causes broadening of the QRS complex (>120 ms). The most common causes are age-related fibrotic changes, ischaemic heart disease, hypertension, cardiomyopathies, infiltration from systemic disease, cardiac surgery or trauma, and, for RBBB, pulmonary embolism or cor pulmonale. Diagnosis relies on careful examination of the ECG to ensure a supraventricular origin of the impulse. Left bundle branch block (LBBB) – The left bundle is made up of two branches, the smaller anterior fascicle supplied by septal braches of the left anterior descending artery (LADA) and the posterior fascicle supplied from both the LADA and right coronary artery (RCA). A delayed depolarisation of the left ventricle gives rise to prominent notched R waves in all leads and an ‘M’ shape is often seen in V6. If involvement is limited to the anterior fascicle (anterior fascicle hemiblock), then the ECG will show left axis deviation (LAD), and minimal prolongation of the QRS. If limited to the posterior fascicle (posterior fascicle hemiblock), right axis deviation (RAD) greater than 120 degrees will be evident with minimal prolongation of the QRS. Most commonly LBBB is seen with ischaemic heart disease, and development of a new LBBB should be considered as an acute ischaemic event equivalent to ST-elevation, and treated as such. Right bundle branch block (RBBB) – Delayed depolarisation of the right ventricle produces an RSR pattern in V1 and a prominent S wave in leads I and V6. RBBB is relatively common in the adult population and has been reported in up to 2% of inpatients. However, if a new RBBB develops, it should be considered to be the result of acute ischaemia until proven otherwise and treated as equivalent to ST-elevation. Bifascicular block – RBBB and L anterior or posterior hemiblock.
Assessment of the general surgical patient
Sam Mehta, Andrew Hindmarsh, Leila Rees in Handbook of General Surgical Emergencies, 2018
Table 2.3 shows safe doses in adults. Local anaesthetic (LA) agents have a limited role in the acute general surgical patient.They are useful for:minor procedures in the accident and emergency department, e.g. cleaning, exploring, suturing small superficial wounds, draining perianal haematomalocal analgesic blocks, e.g. at the site of rib fracturesto aid cannulation in children, e.g. topical application of local anaesthetic cream.Caution should be taken in the presence of overt infection or pus because:injection of local anaesthetic may disseminate infection into deeper tissueslocal anaesthesia will not work as well.Symptoms of LA toxicity include: light-headedness, tinnitus, tongue numbness, visual disturbances, muscle twitching, convulsions and loss of consciousness.
Masquerading bundle branch block: a variety of right bundle branch block with left anterior fascicular block
Published in Expert Review of Cardiovascular Therapy, 2013
Marcelo V Elizari, Adrian Baranchuk, Pablo A Chiale
The so-called ‘masquerading’ type of right bundle branch block is caused by the simultaneous presence of a high-degree left anterior fascicular block often accompanied with severe left ventricular enlargement and/or fibrotic block in the anterolateral wall of the left ventricle. These conditions tend to reorient the terminal electrical forces of the QRS complex towards the left and upwards, in such a way that the characteristic slurred S wave in lead I becomes smaller or even disappears. In many cases of standard masquerading right bundle branch block, a small Q wave in lead I is present due to the initial forces of the left anterior fascicular block, which are oriented rightwards and inferiorly. However, in some cases, the Q wave in lead I also vanishes, and the mimicking of a left bundle branch block becomes perfect in standard leads. This is commonly associated with an inferior myocardial infarction or severe inferior fibrosis in cardiomyopathies. The typical QRS changes of right bundle branch block may eventually be concealed even in the right precordial leads; under such circumstances, the ECG diagnosis may be mistaken and the right bundle branch block totally missed. The masquerading right bundle branch block carries a poor prognosis, since it always implies the presence of a severe underlying heart disease.
Electrocardiographic and echocardiographic features in patients with major arterial vascular disease assigned to surgical revascularization
Published in Acta Cardiologica, 2019
Dimitri Tsialtas, Maria Giulia Bolognesi, Stephania Assimopoulos, Riccardo Volpi, Roberto Bolognesi
Background: We aimed to depict the electrocardiographic and echocardiographic aspects in patients before elective major vascular surgery. Methods: We evaluated through standard 12 lead electrocardiography and transthoracic echocardiography 469 patients with asymptomatic large abdominal aortic aneurysm (AAA), 334 with critical carotid stenosis (CAS), and 238 with advanced peripheral artery disease (PAD) before surgical revascularization. Results: Patients with AAA were predominantly males (p
Related Knowledge Centers
- Bundle Branch Block
- Electrocardiogram
- Left Bundle Branch Block
- Left Posterior Fascicular Block