Ekg Rhythm-Part Ii

Front 1

Blocks develop in these areas...

Back 1

SA, AV, HIS bundle, bundle branches, or in either of the 2 subdivisions of the left bundle branch.

Hint 1

Block defn: is a block that stops/retards depolarization.

Front 2

Sinus Block

Back 2

occurs when: an unhealthy SA node misses a pace-results in a complete missed cycle. The next cycle is identical to the others and begins exactly 1 cycle from where the missed cycle should have started.
looks like: flatline following complete cycle, than identical cycle following.

Hint 2

NOTE: atrial foci may be excited by the lack of pacing and therefore may emit an "escape" beat.

Front 3

Sick Sinus Syndrome (SSS)

Back 3

occurs when: there is SA node block/arrest and both Atrial and Junctional foci fail to emit escape beats/rhythms. Usually Bradycardic.
Looks like: Irregular bradycardic rhythm with long periods of no activity.

Front 4

Bradycardia-Tachycardia syndrome

Back 4

occurs when: patients with SSS develop intermittent episodes of SVT.
looks like: alternate SSS bradycardia mixed with atrial flutter/afib.

Hint 4

SSS/B-T common in elderly with heart disease.

Front 5

1st degree AV block

Back 5

lengthens delay between atrial and ventricular depolarization.
-PR is longer than .2 sec (or one square) and is consistent in EVERY cycle.
-Every cycle component is important!

Hint 5

Note: PR is the start of the P wave to the beginning of the QRS complex.

Front 6

Types of 2ndary AV block

Back 6

-2ndary AV block allows some atrial conductions to reach the ventricle, but not all.
Type I-Wenckebach: progressive blocking of the AV NODE until QRS complex is eliminated-occurs in ratios of P to QRS where there is 1 less QRS to every P (3:2, 4:3 etc.)
Type II-Moblitz-blockage of purkinje fibers (bundle of HIS or the bundle branches).
looks like: Progressive cycle starting with normal P-QRS-T cycle followed by series of paced p waves that fail to produce QRS complex.

Front 7

Wenckebach 2ndary AV block

Back 7

occurs in the AV Node.
occurs when: PR Interval gets longer and longer until the last cycle of the series, there is a long P wave with no QRS complex. Happens in series of: 4:3, 5:4, 3:2, etc.

Hint 7

Can be caused by parasympathetic excess!
-Remember: Lengthy PR Interval followed by NO wide QRS pattern.

Front 8

Moritz 2ndary AV block

Back 8

occurs in the Bundle of HIS/Lower bundle branch.
occurs when: multiple P waves needed for one QRS to arise. Ratios of P to QRS of 3:1, 2:1, 4:1 etc...
Looks like: normal P waves (no P' waves) with QRS waves only occurring in intervals.

Hint 8

remember: p wave is punctual and consistent!
-normal PR interval with a widened QRS complex.

Front 9

2:1 block in both Wenckebach and Moritz..how to distingiush?

Back 9

Vagal maneuvers: if you inhibit the AV node further, it will cause:
Wen- more cycles/series so 2:1 becomes 3:2/4:3.
Moritz-no change or a 1:1 normal conduction

Front 10

Complete 3 AV block

Back 10

occurs when: there is a total block of conduction to the ventricles and a foci below the block escapes to pace.

Front 11

Complete AV block above the AV junction

Back 11

occurs when: AV block is above the AV junction so junctional foci take over ventricular pacing.
Looks like: Sinus based P waves with independent QRS complexes in the 40-60 range. They QRS look normal: conduction is occurring down the normal pathway.

Hint 11

Because junctional/ventricular tissue can be diseased int his case, conduction can take longer and therefore QRS is widened.

Front 12

Complete AV block below the AV junction

Back 12

occurs when: AV block is below the AV junction and ventricular foci (20-40 rate) pace the ventricle. Comes with AV dissociation.
looks like: PVC like complexes (wide and large QRS's) with AV dissociation. Ventricular rate between 20 and 40 and

Hint 12

patients with AV block are in danger and will require a pace-maker.

Front 13

downward displacement of the pacemaker

Back 13

there is no supraventricular activity.

Hint 13

Prognosis worsens with wider complexes, decreased amp, and slower V rate.

Front 14

Bundle Branch Block (BBB)

Back 14

occurs when: one of the Bundles (either left of right) is blocked, therefore depolarization proceeds normally to the unaffected side abnormally on the affected side (one ventricle depolarized before the other).
looks like: Two joined QRS complexes!

Hint 14

Represented via R and R' (R' signifying the delayed ventricular depolarization).

Front 15

BBB characteristics

Back 15

-QRS is widened to greater than .12 ( or 3 small blocks).

Hint 15

can imitate ventricular tachycardia-careful to distinguish :)

Front 16

Right bundle branch block (RBBB)

Back 16

occurs when: right bundle branch is blocked-therefore right ventricle depolarizes after the left (right ventricle is R').
looks like: widened QRS complex (larger than .12/ 3 small squares) with R and R' waves.

Hint 16

If there is an R and R' in the V1 and V2 chest leads, assume block is coming from the right side.

Front 17

Left bundle branch block (LBBB)

Back 17

occurs when: left bundle branch is blocked-therefore left ventricle depolarizes after the right (left ventricle is R').
looks like: widened QRS complex (larger than .12/ 3 small squares) with R and R' waves.

Hint 17

If there is an R and R' in the V5 and V6 leads, assume block is coming from the left side. Can sometimes appear as a flattened peak with 2 tiny points instead of DEFINED/separated peaks.

Front 18

Intermittent Mobitz

Back 18

occurs when: permanent bundle branch block on one side and intermittent block on the other side.
looks like: R and R' for the entire rhythm with intermittent episodes of AV block (no QRS in response to P wave).

Front 19

Differences in appears of LBBB and RBBB

Back 19

LBBB-Flattened peak with 2 small peaks OR 2 small spikes with minimal distance between R and R'.
RBBB-2 peaks with distance between R and R'.