ECG Exam UPDATED Questions and CORRECT Answers

ECG Exam UPDATED Questions and
CORRECT Answers
ECG Electrode placement V1-V6 - CORRECT ANSWER- ✔✔V1: right 4th ICS
V2: Left 4th ICS
v3: half way between V2 and V4
V5: horizontal to V4, anterior axillary line
V6: Horizontal to V5, mid-axillary line


ECG - CORRECT ANSWER- ✔✔recording of heart cells' electrical activity



Indications for ECG - CORRECT ANSWER- ✔✔-Pre-op evaluation
-Chest Pain, Syncope, Palpitations, dizziness, SOB, Nausea
-Screening in individuals with risk factors


Direction of cardiac cell current - CORRECT ANSWER- ✔✔-Polarized at rest
-negative inside
- positive outside


Pacemaker cell - CORRECT ANSWER- ✔✔Where wave of depolarization starts, normal
source of electricity
-SPONTANEOUSLY depolarize at particular rate (dominant is sinus node)
-ALL CARDIAC CELLS CAN PACE


Conducting Heart Cells - CORRECT ANSWER- ✔✔Pathways the electricity take
- Intra-nodal pathway, bundle of HIS, bundle branches, Purkinje fibers


Myocardial Heart Cells - CORRECT ANSWER- ✔✔Contractile element via the purkinje
fibers
- Perform cell work

, -Release calcium and contract
-Cause waves of ECG


What is the main pacemaker cell of the heart? What happens if that is dysfunctional? -
CORRECT ANSWER- ✔✔Sinus Node, AV node will kick in next



What does the left bundle branch divide into? - CORRECT ANSWER- ✔✔-Septal
-Anterior
-Posterior


Where are purkinje fibers located? - CORRECT ANSWER- ✔✔All throughout walls of the
heart and extend away from the conduction pathway


The waves seen on the ECG are primarily caused by the activity of which cells? - CORRECT
ANSWER- ✔✔Myocardial cells



Horizontal Axis ECG Paper - CORRECT ANSWER- ✔✔Time
SMall= .04 sec
Large: .2 seconds


Vertical Axis ECG Paper - CORRECT ANSWER- ✔✔Voltage
small= .1 mv (1mm)
large= .5 mV (5 mm)


Standard ECG runs at - CORRECT ANSWER- ✔✔25 mm/s



P wave - CORRECT ANSWER- ✔✔Atrial depolarization and then contraction
<.12 seconds, <2.5 mm
Upright in I, II, AVF
Biphasic in III, V1
Down in AVR