UCLA EKG Test UPDATED Exam
Questions and CORRECT Answers
electrically polarized at rest - Correct Answer- - inside of heart cell has a high potassium
concentration, whereas the outside has a higher concentration of NA
-higher positive charge outside the cell cause more negative charge inside cell
electrical potential - Correct Answer- difference between the charges outside and inside of the
cell wall
Depolarization - Correct Answer- NA moves into the cell rapidly in response to an electrical
impulse
- inside cell loses negative potential
Replolarization - Correct Answer- ions return to their original resting state
- heart cells restore their resting polarity
4 Phases of Electrophysiology of the heart cell - Correct Answer- Phase 0: Na flow in and
rapid depolarization occurs when stimulated
Phase 1: Rapid return to isoelectric level
Phase 2: CA ions flow in and myocytes contract
Phase 3: K flow out and rapid depolarization occurs
Phase 4: Polarized resting phase
Pacemaker cells - Correct Answer- - Sinoatrial node ( SA) node
-Atrioventricular node )AV node
- Purkinjie fibers
SA node - Correct Answer- -primary pacemaker
- Rate: 60-100
,- SA node depolarizes the atria via intro nodal tracts and Bachmann;s bundle = resulting in
atrial contraction
AV node - Correct Answer- - responsible for slowing down conduction from the atria to
ventricles just long enough for atrial contraction to occur
- rate: 40-60
Bundle of His - Correct Answer- - divides left and right branches
-impulses are conducted down LBB faster than RBB, allowing both ventricles to contract at
same time
Purkunje fibers - Correct Answer- - send impulses into mycardial tissues of the ventricles and
causes them to contract
- rate: 20-40
Myocardial cells - Correct Answer- -contractile machinery of the heart
- myocardial cell is deplolarized, CA is released within cell causing cell to contract
Normal ranges for electrolytes - Correct Answer- NA: 135- 146 meq/L
K: 3.6-5.3 meq/L
Ca: 8.5- 10.3 mg/dl
Ionized Ca: 1.09 -1.29
Mg: 1.4- 1.9 mEq/L
Placement of precordial leads - Correct Answer- v1: right sternal boarder and 4th intercostal
space
v2: left sternal boarder and 4th intercostal space
v3: between v2 and v4
v4: midclavicular line and 5th intercostal space
v5: between v4 and v6
v6: between midaxillary line and 5th intercostal space
, EKG paper - Correct Answer- - small box: 0.04 secs
- 5 small box: 0.2 secs
- 5 Large box= 1 second
- 300 large boxes = 60 secs
PR interval - Correct Answer- 0.12- 0.20 secs
- beginning of the P wave to beginning of the QRS
QRS complex interval/ duration - Correct Answer- - 0.04- 0.12 secs
- ventricular deplolarization
U wave - Correct Answer- - small low amplitude that follows T wave
- indicative of hypokalemia
QT interval - Correct Answer- 0.36- 0.44 secs
- measures beginning of ventricular replarization to end of reploarization
medications that prolong QT interval - Correct Answer- - amiodarone
-sotalol
-levofloxacin
-zofran
-celexa
-haloperidol
-benedryl
-erthyromycin
Age specific heart rates - Correct Answer- NEONATES:
awake 100-180 RR 30-60
INFANTS:
Questions and CORRECT Answers
electrically polarized at rest - Correct Answer- - inside of heart cell has a high potassium
concentration, whereas the outside has a higher concentration of NA
-higher positive charge outside the cell cause more negative charge inside cell
electrical potential - Correct Answer- difference between the charges outside and inside of the
cell wall
Depolarization - Correct Answer- NA moves into the cell rapidly in response to an electrical
impulse
- inside cell loses negative potential
Replolarization - Correct Answer- ions return to their original resting state
- heart cells restore their resting polarity
4 Phases of Electrophysiology of the heart cell - Correct Answer- Phase 0: Na flow in and
rapid depolarization occurs when stimulated
Phase 1: Rapid return to isoelectric level
Phase 2: CA ions flow in and myocytes contract
Phase 3: K flow out and rapid depolarization occurs
Phase 4: Polarized resting phase
Pacemaker cells - Correct Answer- - Sinoatrial node ( SA) node
-Atrioventricular node )AV node
- Purkinjie fibers
SA node - Correct Answer- -primary pacemaker
- Rate: 60-100
,- SA node depolarizes the atria via intro nodal tracts and Bachmann;s bundle = resulting in
atrial contraction
AV node - Correct Answer- - responsible for slowing down conduction from the atria to
ventricles just long enough for atrial contraction to occur
- rate: 40-60
Bundle of His - Correct Answer- - divides left and right branches
-impulses are conducted down LBB faster than RBB, allowing both ventricles to contract at
same time
Purkunje fibers - Correct Answer- - send impulses into mycardial tissues of the ventricles and
causes them to contract
- rate: 20-40
Myocardial cells - Correct Answer- -contractile machinery of the heart
- myocardial cell is deplolarized, CA is released within cell causing cell to contract
Normal ranges for electrolytes - Correct Answer- NA: 135- 146 meq/L
K: 3.6-5.3 meq/L
Ca: 8.5- 10.3 mg/dl
Ionized Ca: 1.09 -1.29
Mg: 1.4- 1.9 mEq/L
Placement of precordial leads - Correct Answer- v1: right sternal boarder and 4th intercostal
space
v2: left sternal boarder and 4th intercostal space
v3: between v2 and v4
v4: midclavicular line and 5th intercostal space
v5: between v4 and v6
v6: between midaxillary line and 5th intercostal space
, EKG paper - Correct Answer- - small box: 0.04 secs
- 5 small box: 0.2 secs
- 5 Large box= 1 second
- 300 large boxes = 60 secs
PR interval - Correct Answer- 0.12- 0.20 secs
- beginning of the P wave to beginning of the QRS
QRS complex interval/ duration - Correct Answer- - 0.04- 0.12 secs
- ventricular deplolarization
U wave - Correct Answer- - small low amplitude that follows T wave
- indicative of hypokalemia
QT interval - Correct Answer- 0.36- 0.44 secs
- measures beginning of ventricular replarization to end of reploarization
medications that prolong QT interval - Correct Answer- - amiodarone
-sotalol
-levofloxacin
-zofran
-celexa
-haloperidol
-benedryl
-erthyromycin
Age specific heart rates - Correct Answer- NEONATES:
awake 100-180 RR 30-60
INFANTS:
