gail walraven, basic arrhythmias, seventh edition ©2011 by pearson education, inc., upper saddle...
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Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Gail Walraven
Basic ArrhythmiasSeventh Edition
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Appendix C12-Lead Electrocardiography
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Rule of Electrical Flow
• Current flowing toward a positive electrode creates an upright deflection.
• Current flowing toward a negative electrode creates a downward deflection.
• When the lead is at right angles to the current, the line is isoelectric (neither upright nor downward).
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Lead
• A combination of electrodes that reflects flow of electricity between two points on opposing sides of the heart.
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Leads
• Bipolar leads have one positive and one negative electrode.
• Unipolar leads have a positive electrode, but the opposing electrode is created by combining other electrodes into a central terminal, an electrically neutral point situated to reference the center of the heart.
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Electrode Placement for MCL1
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Frontal and Horizontal Planes
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Electrode Placement – Frontal Plane
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Standard Lead Lines
• Lead I: right arm to left arm
• Lead II: right arm to left leg
• Lead III: left arm to left leg
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Standard Limb Leads
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Augmented Leads
• aVR:central terminal to right arm
• aVL: central terminal to left arm
• aVF: central terminal to left leg
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Augmented Limb Leads
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Frontal Plane Leads
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Frontal Plane Leads
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Horizontal Plane Leads
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Electrode PlacementPrecordial Leads
• V1: right sterna border, fourth intercostals space
• V2: left sterna border, fourth intercostals space
• V3: midway between V2 and V4
• V4: midclavicular line, fifth intercostal space
• V5: anterior axillary line, fifth intercostal space
• V6: midaxillary line, fifth intercostal space
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Vector
• The arrow used to indicate direction and magnitude of electrical flow.
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Lead Axis
• An imaginary line from the positive electrode to the negative electrode for each lead, depicted by an arrow (vector).
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Mean QRS Axis
• The axis of the heart as a whole; the aggregate of all the electrical vectors in the heart.
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Lead Axis vs.Mean QRS Axis
• When the two are parallel, the deflections are either positive or negative.
• When the two are perpendicular, the complexes are biphasic.
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
EKG Deflections
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Wave Definitions
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Frontal Plane Vectors
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Horizontal Plane Vectors
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Mean QRS Axis
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Estimating QRS Axis
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Standard Layout of 12-Lead EKG
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Features of a Normal 12-Lead EKG
• All waves upright (except aVR)
• Small Q waves in lateral leads (I, aVL, V6)
• T waves in V1-V6 should be smooth, gradual
• T wave: positive, negative, or biphasic in V1; positive in V2–V6
• QRS transition from V1 (small R, large S) to V6 (small Q, large R), roughly equiphasic in V3(V4)
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Normal 12-Lead Wave Forms (Example 1)
Gail Walraven, Basic Arrhythmias, Seventh Edition©2011 by Pearson Education, Inc., Upper Saddle River, NJ
Normal 12-Lead Wave Forms (Example 2)