Alok Kumar (Grp 09) Sem 09 Types Of Heart Block.pptx
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This document discusses types of heart block, including: 1) Atrioventricular block which can be first, second, or third degree, with second degree having Mobitz type I and II. 2) Bundle branch block which can be right or left. It provides details on characteristics of each type of block such as causes, symptoms, and treatments when relevant.
Alok Kumar (Grp 09) Sem 09 Types Of Heart Block.pptx
- 1. NAME – ALOK KUMAR GROUP – 09 SEMESTER – 09 TOPIC – TYPES OF HEART BLOCK
- 2. TYPES OF HEART BLOCK 1. ATRIOVENTRICULAR BLOCK i. First - Degree AV Block ii. Second – Degree AV Block ● Mobitz Type I ● Mobitz Type II iii. Third – Degree AV Block 2. BUNDLE BRANCH BLOCK i. Right Bundle Branch Block ii. Left Bundle Branch Block
- 3. AV BLOCK • This usually occurs as the result of disease affecting the AV node. • AV block can be intermittent, however, and may become evident only when the conducting tissue is stressed by a rapid atrial rate. • Reflecting this fact, atrial tachyarrhythmias are often associated with AV block
- 4. FIRST-DEGREE ATRIOVENTRICULAR BLOCK • In this condition, AV conduction is delayed and so the PR interval is prolonged (> 0.20 sec. • It rarely causes symptoms and does not usually require treatment.
- 5. SECOND-DEGREE ATRIOVENTRICULAR BLOCK • Here dropped beats occur because some impulses from the atria fail to conduct to the ventricles. • In Mobitz type I second-degree AV block , there isprogressive lengthening of successive PR intervals, culminating in a dropped beat. The cycle then repeats itself. This is known as the Wenckebach phenomenon and is usually due to impaired conduction in the AV node itself. The phenomenon may be physiological and is sometimes observed at rest or during sleep in athletic young adults with high vagal tone.
- 7. • In Mobitz type II second-degree AV block , the PR interval of the conducted impulses remains constant but some P waves are not conducted. This is usually caused by disease of the His–Purkinje system and carries a risk of asystole. • In 2 : 1 AV block . alternate P waves are conducted, so it is impossible to distinguish between Mobitz type I and type II block.
- 10. THIRD-DEGREE ATRIOVENTRICULAR BLOCK • In third-degree AV block, conduction fails completely and the atria and ventricles beat independently. This is known as AV dissociation, . Ventricular activity is maintained by an escape rhythm arising in the AV node or bundle of His (narrow QRS complexes) or the distal Purkinje tissues (broad QRS complexes). Distal escape rhythms tend to be slower and less reliable. Complete AV block produces a slow (25–50/min), regular pulse that does not vary with exercise, except in the case of congenital complete AV block. There is usually a compensatory increase in stroke volume, producing a large- volume pulse. Cannon waves may be visible in the neck and the intensity of the first heart sound varies due to the loss of AV synchrony.
- 12. BUNDLE BRANCH BLOCK • Right Bundle Branch Block • Left Bundle Branch Block
- 18. THANK YOU !