Lab quiz #4 Flashcards
EKG or ECC
electrocardiogram
Graphical recording of the electrical current generated in the electrical conductive system of the heart
- quantity and quality of heartbeats
- mechanical activity follows electrical activity
- shows waves of depolarization/repolarization
EKG function
resting membrane is predominantly + on the outside and - on the inside
depolarization
wave of _ is an influx of positive ions making the inner membrane less negative (shift in ions)
depolarization
P wave is the _ in an EKG
depolarization of the atria
QRS complex is the _ in an EKG
depolarization of the ventricles
T wave is the _ in an EKG
repolarization of ventricles
Where is atrial repolarization in an EKG?
Hidden during QRS complex
Step 1 in the electrical system of the heart
Sinoatrial Node (SA node)
Step 2 in the electrical system of the heart
- What happened here?
Atrioventricular Node (AV node)
- pause to allow ventricles to fill
Step 3 in the electrical system of the heart
Left bundle branch
Step 4 in the electrical system of the heart
- What are they called?
- What happens here?
Conduction pathways
- Perkinje
- stimulates heart contractions
How many electrodes and leads (pictures)?
10 electrodes and 12 leads
Electrical signals = _
deflections
- Direction
- speed
- Mass of the tissue
electrical signals
Direction:
Signal is _ electrode
- voltage above isoelectric line ( _ )
towards (+)
Direction:
signal is _ electrode
- voltage is below isoelectric line ( _ )
away from (-)
Speed:
Fast moving signal
sharp spike
Speed:
Slow moving signal
rounded wave
Mass of tissue:
Moving through smaller mass
small wave
Mass of tissue:
Moving through larger mass
large wave
Where do the Limb Leads go? (standard)
Right arm (RA)
Left arm (LA)
Left leg (LL)
Right leg (RL) - grounded
- Bipolar
- sense electric potential between two limbs/points
standard limb lead (leads I, II, & III)
Limb Lead _
- Electrode = LA +
- Electrode = RA -
- Angle of heart = lateral
Lead I
Limb Lead _
- Electrode = LL +
- Electrode = RA -
- Angle of heart = inferior
Lead II
Limb Lead _
- Electrode = LL +
- Electrode = LA -
- Angle of heart = inferior
Lead III
- unipolar
- compare a central point of the standard limb leads to the RA, LA & LL electrodes
Augmented limb leads (aVR, aVL, aVF)
Lead _
- Electrode = RA +
- Angle of heart = no specific view
Lead aVR
Lead _
- Electrode = LA +
- Angle of heart = lateral
Lead aVL
Lead _
- Electrode = LL +
- Angle of heart = inferior
Lead aVF
Limb lead I: RA - – LA +
Limb lead II: RA - – LL +
Limb lead III: LA - – LL +
Einthoven’s triangle (standard)
aVR: RA +
aVL: LA +
aVF: LL +
Einthoven’s triangle (augmented)
Limb leads view
frontal plane view
chest (precordial) leads view
cross-sectional (transverse) plane view
Chest lead _
- + electrode position: 4th intercostals space; R sternal border
- Heart viewed: septum
V1
Chest lead _
- + electrode position: 4th intercostals space; L sternal border
- Heart viewed: septum
V2
Chest lead _
- + electrode position: midway between V2 and V4
- Heart viewed: anterior
V3
Chest lead _
- + electrode position: 5th intercostals space; midclavicular line
- Heart viewed: anterior
V4
Chest lead _
- + electrode position: level with V4; anterior axillary line
- Heart viewed: lateral
V5
Chest lead _
- + electrode position: level with V5; midaxillary line
- Heart viewed: lateral
V6
EKG paper speed
25 mm*s^-1
- 0.1 mV
- 0.04 s
- 1 mm
small square on EKG paper
- o.5 mV
- 0.20 s
- 5 mm
large square on EKG paper
beats originate from sinus node
sinus rhythm
Normal bpm =
60-100
< 60 bpm =
brachycardia
> 100 bpm =
tachycardia
any irregular rhythm of heartbeats
arrythmia/dysrhthmia
beat originating outside of sinus node
- PAV
- PVC
ectopic beat
when the number of ectopic beats exceed number of sinus beats, person is in _, not sinus rhythm
Atrial or ventricular rhythm
