Chapter 4 CV + hematology -- arrhythmias pg 76!

Question 1

arrhythmias categories

Answer 1

1) beating too slow (bradycardia)
2) beating too fast (sinus or vent tachy, atiral or ventricular premature depolarization, atrial flutter)
3) beating automatically w/o regard for impulses originating from SA node (multifocal atrial tachycardia, atiral fib, ventricular fib)
4) allow impulses to travel along an accessory pathway to areas of herat whihc sould be depolarized at particular moment (AV reentry, wolff-parkinson-white syndrome)

Question 2

sinus bradycardia

Answer 2

< 60
increased parasympathetic (Vagal) tone
slow, but regular rate

Question 3

sinus tachycardia

Answer 3

• inc sympathetic tone (100-160 beats per min)
• rapid, but regular rate

Question 4

multifocal atiral tachycardia

originate in atrium

Answer 4

• depolarization orginates from several atrial foci at irregular intervals
• multiple spots (in one atrium)
• 100-200
• irregular; p waves present but are morphologically different from each other

pg 76

Question 5

premature atrial depolarization (PAT)

originate in atrium

Answer 5

• heart beats b/c a focus of atiral cells fire spontaneously before SA node is ready to fire (single spot in one atrium)
• interrupted regular rhythm by an early P wave
• p wave may be followed by normal ORS if SA node and ventricle have enough time to repolarize

Question 6

atrial flutter

originate in atrium

Answer 6

• atrial impulse reenters and depolarizes atrium (one spot in one atrium)
• 250-350 impulses per minute
• ventricle responds to every 2nd or 3rd impulse
• both rhythms are regular
• series of 2-4 closely spaced P waves followed by a normal QRS complex

Question 7

atrial fibrillation

originate in atrium

Answer 7

• multiple ectopic foci of atrial cells generate 350-450 impulses per minute (both atria)
• ventircle responds to occasional impulse
• both rhythms are irregular
• p waves unable to discerend
• baseline is irregular w/ uneven QRS complexes

Question 8

AV reentry

AV Junction

Answer 8

• AV node is split into 2 pathways (one back to atrium and one toward ventricle)
• reentry of impulse into atrium causes atrium and venctirlce to contract simultaneously
• generally normal QRS following normal P waves
• the inverted p wave (retrograde atrial contraction) is bured in QRS
• rate is 150-250/minute

Question 9

Wolff-parkinson-white

AV junction

Answer 9

• strip of conducting tissue (other than AV node) connects atrium and ventricle
• Impulses reach ventricle via AV node then circle back to atrium via accessory pathway
• the circuit may be reversed
• p wave followed rapidly by QRS
• delta wave
• rate exceed 300 beats/min

Question 10

Venricular premature depolarization

ventricle

Answer 10

• spontaneous depolarization of ectopic focus in ventricle (bottom left ventricle)
• benign if > 6 mins
• wide tall QRS complexes not associated with a P wave
• prominent T wav often point in opposite direction as QRS complex

Question 11

Ventricular tachycardia

ventricle

Answer 11

• usually secondary to reentry circuit
• BOTH AV reentry and wolff-parksinon-white may progress to v tach
• Wide QRS compelxes with abnormal S-T segment and T wave deflections (opposite in direction to QRS)
• AV dissociation and right bundle branch block often associated

Question 12

ventricular fibrillation

Answer 12

• erractic discharge from many ectopic foci in ventricle
• rate 350-450
• irregular
• completely erratic
• cannot distinguish normal waves or complexes