ECG waveforms and cliques

Question 1

P wave

Answer 1

Atrial depolarization

Question 2

PR interval

Answer 2

Time for atrial depolarization and conduction of SA to AV node

(.12-.20 seconds)

Question 3

QRS Complex

Answer 3

Ventricular depolarization

Atrial repolarization

(.06-.10 seconds)

Question 4

ST segment

Answer 4

Ventricles depolarized

Question 5

T wave

Answer 5

Ventricular repolarization

Question 6

What is normal sinus rhythm?

Answer 6

Normal electrical conduction

between 60-100 bpm

Question 7

What is sinus bradycardia?

Answer 7

Sinus rhythm

< 60 bpm

Question 8

What is sinus tachycardia?

Answer 8

Sinus rhythm

> 100 bpm

Question 9

What is sinus arrest?

Answer 9

Sinus rhythm

Occasional complete absence of P or QRS interval

Question 10

What is a Premature Atrial Contraction (PAC)?

Answer 10

Ectopic focus in atrium initiates impulse before SA node

**Usually harmless. > 9 = get a physician!**

Question 11

What is Atrial Flutter

Answer 11

Ectopic Focus (1) - takes over normal pacemaker of the heart

Very rapid atrial tach

F wave (“saw tooth pattern”)

Question 12

What is Atrial Fib?

Answer 12

Ectopic Foci (1+)

Atria depolarized 350-600x/min

“bouncy baseline”

Question 13

What is a Premature Ventricular Contraction (PVC)?

Answer 13

Ectopic focus (1) - premature ventricular depolarization

Bigeminy: every 2

Trigeminy: every 3

Couplet: 2 in a row

Unifocal PVC: look the same - coming from same spot

Multifocal PVC: look different - coming from different spots

Question 14

What is Ventricular Tach?

Answer 14

Ectopic Focus (1)

3 or more PVCs at rate of > 150 bpm

**EMERGENCY: longer than 30 seconds = life threatening**

Common cause: MI, Cardiomyopathy, and Valvular Disease

Question 15

What is Ventricular Fibrillation (v-fib)?

Answer 15

Ectopic Foci (1+)

Chaotic activity in ventricles

**EMERGENCY: pt in cardiac arrest!**

Question 16

What is a 1st Degree Heart Block?

Answer 16

Consistent long PR interval

Consistent beat to beat

**No symptoms**

Question 17

What is a 2nd Degree Heart Block - Mobitz Type I or Wenkebach?

Answer 17

progressively longer PR interval until one impulse DROPS

Question 18

What is a 2nd Degree Heart Block - Mobitz Type II?

Answer 18

Consecutive normal PR intervals and then DROPPED segment

**No PT. Treat with meds or pacemaker**

Question 19

What is a 3rd Degree (Complete) Heart Block?

Answer 19

Complete block of impulse for SA node

Atria and ventricles depolarizing independently

**EMERGENCY**

Question 20

What causes ST Segment Depression?

Answer 20

• Subendocardial ischemia
• Dig toxicity
• Hypo or hyperkalemia

Question 21

What causes ST segment eleveation?

Answer 21

Acute transmural infarction

Question 22

What causes a T wave inversion?

Answer 22

• Occurs hours or days after MI
• May occur with R or L bundle branch blocks

Question 23

If a patient has a PVC during treatment, what is the first thing you should do?

Answer 23

• Make sure patient can rest on stable surface
• Determine frequency of PVC’s