3 lead ECG

Question 1

first degree HB

Answer 1

Regular rate.
Increased P-R interval- more than 0.2 seconds
Patho-
Delayed conduction at AV node.
Most common cause is ischaemia at AV junction can also be caused by infection, rheumatic fever.

Question 2

Second degree- Type 1

Answer 2

P wave gets progressively longer until a QRS is missed. Repeating pattern. Irregular rhythm. (also known as Wenkebach or mobitz 1)

Patho-
Ischaemia at AV node causing a block. The AV node takes longer and longer to conduct atrial beat until one atrial beat is not conducted, then the rythm starts again.

Question 3

Second degree- Type 2

Answer 3

Av node selectively blocks or conducts impulses from atria. P-R interval stays the same but more p waves than QRS. Can be 2:1 ratio and this can be dangerous.

Question 4

Third degree HB

Answer 4

AV node fully blocks impulses from atria. REgular P waves with random QRS and sporadic PRI. Atrial rate 60-100, ventricular rate 20-40.

Atria conduct impulses which travel throughout atria however complete block at AV node so the ventricles independently generate there pacing. No association.

Question 5

Junctional rhythm

Answer 5

When SA node becomes tired the AV node starts working as main pacemaker, however as it is in the middle of the heart when it fires atria or ventricles may depolarizeJunctional first or at the same time. So sometimes p waves seen and sometimes not.

Question 6

Junctional Escape

Answer 6

regular rate but p wave hidden in QRS or if present inverted. Rate usually between 40-60.

Question 7

Accelerated junctional rhythm

Answer 7

Usually caused by sympathetic activation or Ischemia. Rate 60-100. Pwaves inverted or not present. Narrow QRS.

Question 8

junctional tachy

Answer 8

juctional rythm over 100 bpm

Question 9

wandering pacemeker

Answer 9

rate 60-100 p wave changes from inverted to upright to none.

Question 10

NSR with PAC

Answer 10

a different P wave appears in a sinus rhythm, due to the atria randomly firing. not actually a rhythm.

Question 11

NSR with PVC

Answer 11

Random beats which come from the ventricles. Wide strange looking QRS ( this is a conduction is through muscle not the conduction system) and the T wave is negative.

Question 12

Idioventricular

Answer 12

usually just before arrest, SA and AV have failed jst ventrictcle working, ventricular rate 20-40.

Ventricles become pacemaker, slow wide QRS as impulse is travelling myocardium. No P waves.

Question 13

finding rate in irregular rhythm

Answer 13

count number of beats in 6 second strip and x10.

Question 14

finding rate in regular rhythm

Answer 14

count number of small squares between 2 r waves and then go 1500 divided by number u get.

Question 15

Vfib

Answer 15

Multiple foci within the ventricles each generating impulses causing the ventricles to quiver. No contractile force or cardiac output generated

Question 16

Atrial flutter

Answer 16

Sawtooth p wave pattern
There is a re-entrant circuit. For every impulse from the atria only every 2nd (2:1) or every 3rd is being conducted throught to the ventricles. Atrial rate a lot higher then ventricular rate.

Question 17

Svt

Answer 17

The origin is probably avnrt- the AV node has 2 pathways a slow and fast pathway and an ectopic neat has caused a re- entrant which has caused the fast beat.
Svt anything over 150

Question 18

Atrial tachcardia

Answer 18

A tachycardia with an abnorma p wave, p wave more prominent than SVT.

Patho-
There is a single atrial focus that has taken over the pacemaker function from the sa node because it is faster. Otherwise conduction is normal after atria.