ECG Quiz 1 questions with complete solutions

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