Advanced EKG AV Blocks, Hypertrophies, BBB, and Hemiblocks
AV Block Types
- 1st degree - 2nd degree = Type I and Type II Type I = also called Morbitz I or Wenckebach. Type II = called Morbitz II - 3rd degree will need a pacemaker.
RT. Axis Deviation Hyperthrophy
>+90 degrees to 180 degrees Lead I: S wave is negative Lead V6: S wave is > than R wave
Left Axis Deviation Hyperthropy
>-30 degrees Increased R waves in leads V5 and V6 (Tall R waves) Negative deflection S wave in V1 and V2 exceeding 35 mm (deep long S waves). Secondary repolarization abnormalities 50% with asymmetric T wave inversion (abrupt).
Third degree AV block
Also referred as complete heart block (CHB). Any electrical impulse trying to pass through the AV junction is completely blocked. - Ventricles are working independently from the atria's. - No PR interval consistency . - No relationship you can't measure the distance between P waves and QRS. - P waves are showing up everywhere.
AV Blocks
Caused by a disturbance or blockage within the AV node or bundle of His that delays or prevents the impulse from getting to the bundle branches. - Also referred to as conduction disturbances.
Bundle Branch Block
Delay in depolarization in one of the bundle branches. - We focus on width and morphology of QRS. - RBBB = right bundle branch block - LBBB = left bundle branch block
First degree AV block
Is consider a Sinus rhythm, because you have a P wave for every QRS. - Prolonged PR interval that is consistent from beat to beat. - PR interval greater than 0.20 seconds. - Benign rhythm and generally does not required treatment. Progression to a higher level block is possible, therefore monitoring is recommended.
Hemiblocks
Is the re-routing of the left bundle branch (fascicular block). - Is a conduction block in left anterior or left posterior fascicle, due to lack of blood in coronary arteries (MI). - We look for left or right axis deviations.
Left Anterior Hemiblock
Normal QRS, ST and T wave. - Axis deviation (LAD) -30 to - 90 degrees. - Large S (neg) wave in inferior leads II, III, AVF - Rt to left route travels to the posterior fascicle.
Left Posterior Hemiblock
Normal QRS, ST, and T wave. - Axis deviation (RAD) going away from lead I and AVl. >+90 to +180 degrees. - Negative lateral leads in I, and AVL - Negative S wave in I and AVL - Left to right route, travels to left anterior fascicle.
Left Bundle Branch Block
QRS >.12 (greater) - Broad or notched V5,V6, I, AVL (lateral leads), ST segment depression and T wave maybe inverted. - Left axis deviation maybe present.
Right Bundle Branch Block
QRS complex are wider and have a different morphology (shape). - QRS is greater than 3 small boxes >.12 - RR' in V1 and V2 (rabbit ears), ST segment depression and T wave inversion. - Reciprocal deflection in the lateral leads negative or S waves.
Hyperthrophy
Something is wrong with the valves causing pressure on the heart, and changing the shape of the heart. - Volume overload the heart muscle gets thicker changing the axis deviation. - Rt and left axis deviation.
Second degree Type I AV block
Type I (Mobitz I or Wenckebach heart block), there is a gradual lengthening of P waves until you have a missing QRS. Therefore no sinus rhythm (1:1 ratio not present). - Type one is less serious, but more common. - Progressively lengthening of PR interval until a missing QRS (a non conducted P wave). - It has a pattern which repeats itself. - Considered a benign rhythm. No treatment is necessary, but observation is needed.
Second degree Type 2 AV Block
Type II also know as Mobitz II is less common but more serious between the second degree AV blocks. - No P wave for every QRS you will have more P waves than QRS, therefore you will have irregularity. (Irregular rate) - Block occurs below the AV node (distal to the bundle of his) - Morbitz II, conduction through AV junction/node is an all or none occurrence. (normal or prolonged or just get dropped). - Intermittent non conducted P waves without the progressive prolongation of the PR interval.
