Emergency Med_Cardiac

Question 1

Pulselessness – causes?

Answer 1

• Asystole
• Ventricular Fibrillation
• Ventricular Tachycardia
• Pulseless Electrical Activity (PEA)

**best initial management of all forms of pulselessness is CPR

Question 2

Asystole – management

Answer 2

1. CPR
2. Epinephrine or Vasopressin
   - - both constrict blood vessels in tissues such as skin, shunting it to critical areas like heart & brain

Question 3

Ventricular Fibrillation – therapy?

Answer 3

1. Immediate Unsynchronized Cardioversion (defibrillation) followed by CPR if ineffective.
2. Defibrillation a 2nd time
3. Epinephrine or vasopressin
4. Defibrillation a 3rd time
5. Amiodarone or Lidocaine given next to try to get subsequent shocks to be more successful

(shock, drug, shock, drug, shock, drug, & CPR at all times in between shocks)

Question 4

When should cardioversion be UNsynchronized?

Answer 4

VF & pulseless VT are only indications for unsynchronized cardioversion.
There is no organized electrical activity to synchronize with.

Question 5

Hemodynamically stable VT – management?

Answer 5

Amiodarone, then Lidocaine, then Procainamide.

If medications fail, then cardiovert the patient.

Question 6

Hemodynamically Unstable VT – management?

Answer 6

Electrical cardioversion several times, followed by medications such as amiodarone, lidocaine, or procainamide

Question 7

How is Hemodynamic Instability defined?

Answer 7

• • Chest pain
• • Dyspnea/CHF
• • Hypotension
• • Confusion

Question 8

Varying P waves – what does this indicate?

Answer 8

That the impulse may be coming from different sites, such as with a wandering pacemaker rhythm, irritable atrial tissue, or damage near the SA node.

Question 9

Absent P waves – what does this indicate?

Answer 9

May signify conduction by a route other than the SA node, as with a junctional or atrial fibrillation rhythm

Question 10

PR interval

• • how to measure?
• • duration?

Answer 10

– from beginning of P wave to beginning of QRS complex

– 0.12 - 0.20 seconds

Question 11

Short PR intervals – what does this indicate?

Answer 11

That the impulse originated somewhere other than the SA node, such as with junctional arrhythmias or pre-excitation syndromes

Question 12

Prolonged PR intervals – what does this indicate?

Answer 12

Conduction delay through the atria or AV junction
– due to digoxin toxicity or heart block

Heart block = slowing related to ischemia or conduction tissue disease

Question 13

QRS complex

– duration?

Answer 13

0.6 - 0.10 seconds.

Considered abnormal if > 0.12 seconds

Question 14

Normal ECG Axis

Answer 14

-30 to +90 degrees

so from ~2 O’clock to 6 o’clock

Question 15

What to consider when you think you see a Premature Ventricular Contraction?
(aka when you see random QRS complexes that’re different from those of the normal rhythm)

Answer 15

Ventricular Escape beats – these will appear as a late QRS complex, rather than premature

Normal beats with aberrant ventricular conduction – these will have a P wave, whereas a PVC does not.
(they’re caused by a supra ventricular impulse taking an abnormal pathway through the ventricular conduction system)

Question 16

How to recognize Premature Atrial Complexes?

Answer 16

– Narrow smooth complexes

– QRS in early beat looks the same as other QRS complexes

– PR is constant for sinus beats; P wave morphology is different for the premature beat, since it originates from an ectopic focus in the atrium

Question 17

What is Ventricular Bigeminy & Trigeminy?

Answer 17

V. Bigeminy = PVCs that occur every other beat

V. Trigeminy = PVCs that occur every third beat

Question 18

How to recognize Multifocal Atrial Tachycardia?

Answer 18

• • Heart rate > 100 bpm (usually 100-150 bpm; may be as high as 250 bpm).
• • Irregularly irregular rhythm with varying PP, PR and RR intervals.
• • At least 3 distinct P-wave morphologies in the same lead.
• • Isoelectric baseline between P-waves (i.e. no flutter waves).
• • Absence of a single dominant atrial pacemaker (i.e. not just sinus rhythm with frequent PACs).
• • Some P waves may be nonconducted; others may be aberrantly conducted to the ventricles.
• • Most commonly seen in patients with severe COPD or congestive heart failure.

Question 19

How to recognize Wandering Atrial Pacemaker?

Answer 19

Rhythm = May be irregular
Rate = Normal (60-100 bpm)
P Wave = Changing shape and size from beat to beat (at least three diffferent forms)
PR Interval = Variable
QRS = Normal (0.06-0.10 sec)

** T wave is normal. If heart rate exceeds 100 bpm, then rhythm may be Multifocal Atrial Tachycardia (MAP)

Question 20

What does the differential diagnosis of an irregularly irregular rhythm include?

Answer 20

• • Atrial fibrillation
• • Atrial flutter with variable conduction
• • Multifocal atrial tachycardia
• • Wandering atrial pacemaker.

Question 21

What arrhythmia is most specific for Digitalis toxicity?

Answer 21

Atrial Tachycardia with AV block

(increases ectopy in atria/ventricles – A. tachycardia. Also increases vagal tone – AV block)

** Atrial Tachycardia is different from Atrial Flutter based on heart rate. AT is slower at 150-250 BPM, wheres A. Flutter is 250-350 BPM.