ECG Quiz 1 QUESTIONS AND ANSWERS ALL CORRECT

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 PR Segment Correct Answer: SLows conduction to allow the atria to finish getting blood into the ventricles PR Interval Correct Answer: Measures the start of atrial depolarization to the start of ventricular depolarization .12-.2 seconds QRS Correct Answer: Ventricular contraction and atrial repolarization -Atrial depolarization is buried in the QRS - .12 seconds R-wave from V1 to V5 Leads 1 and V6 similar morphology Q-wave Correct Answer: first deflection downward (may to be present) - .1 mV R-wave Correct Answer: 1st deflection upward (above isoelectric line) R-prime Correct Answer: second upward deflection S-Wave Correct Answer: first downward deflection following an upward deflection ST segment Correct Answer: after depolarization when the cells are refractory until repolarization -Horizontal or gently upsweeping T wave Correct Answer: Ventricular Repolarization Upright when QRS is upright (2/3 of R wave) QT interval Correct Answer: .2-.3 seconds (Depends on heart rate) QTc Correct Answer: 440 milliseconds This is calculated by a machine Prolongation makes some prone to cardiac arrhythmias Positive deflection Correct Answer: depolarization toward an electrode Negative deflection Correct Answer: Depolarization away from an electrode Frontal Plane Correct Answer: I,II,II, AVL, AVR, AVF Horizontal Plane Correct Answer: V1-V6