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EKG
Interpretation of EKG's
53
Medical
Graduate
01/26/2010

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Cards

Term
Myocardium
Definition
Cardium=Heart
Myo=Muscle

Heart Muscle
Term
[image]
Definition
[image]
Term
Heart Cells are called:
Definition
Myocytes
Term
Myocytes are (+ or -) at rest but when (polarized or depolarized) the interiors become (+ or -) and contract
Definition
Negative, depolarized, Positive
Term
What causes the depolarization of the myocardium?
Definition
Sodium Ions (Na+)
Term
Atrial depolarization is represented by a
Definition
P Wave
Term
Ventricular depolarization is represented by a
Definition
QRS Wave
Term
Why does the QRS complex look like a triangle?
Definition
As the + wave depolarization flows toward a positive electrode on the skin an positive (upward) deflection is recorded on the EKG
Term
The Heart's dominant pacemaker
Definition
The SA (Sinus) Node
Term
The generation of pacemaking stimuli is
Definition
Automaticity
Term
What initiates depolarization?
Definition
The SA node initiates a wave of depolarization (positive charge) that spreads outward, stimulating the artia to contract as the circular wave advances
Term
Which area of the heart contracts first?
Definition
Both artia
Term
Simultaneous contraction of the atria forces the blood they contain to pass through the...
Definition
Atrio-Ventricular (AV) valves between the atria and the ventricles
Term
What are the responsibilities of the AV valves?
Definition
  • Prevent blood backflow to the atria
  • Electrically insulate the ventricles from the atria
Term
What is the only conducting path between the atria and the ventricles?
Definition
The AV node
Term
The tricuspid valve is located where?
Definition
Seperating the right atrium from the right ventricle
Term
The mitral valve is located where?
Definition
Seperating the left atrium from the left ventricle
Term
Describe the pathway of blood through the right side of the heart
Definition
Oxygen-depleted venous blood enters the right atrium. Atrial contraction forces blood through the tricuspid valve into the right ventricle, which pumps it into the lungs
Term
Where does the blood go which is pumped from the right ventricle?
Definition
From the right ventricle the under-oxygenated blood goes through the pulmonary valve into the pulmonary artery and thence to the lungs
Term
Describe the pathway of blood through the left side of the heart
Definition
Oxygenated blood from the lungs enters the left atrium, which contracts to force blood through the mitral valve into the left ventricle. The left ventricle pumps blood through the aorta to the body
Term
Where does blood go which is pumped through the left ventricle?
Definition
From the muscular left ventricle oxygenated blood goes through the aortic valve into the aorta and then into the body
Term
What causes the pause after the P wave?
Definition
When the wave of atrial depolarization enters the AV node, depolarization slows, allowing time for the blood in the atria to enter the ventricles
Term
Slow conduction through the AV node is carried by...
Definition
Calcium (Ca++) Ions
Term
Depolarization conducts slowly through the...since it is carried by slow-moving...
Definition
AV Node, Ca (Calcium) ions
Term
Depolarization shoots rapidly through the ventricular conduction system beginning in the...and the...
Definition
His Bundle, Left and Right bundle branches
Term
The His Bundle and both Bundle Branches are made up of...
Definition
Purkinje Fibers
Term
[image]
Definition
[image]
Term
The rapid conduction of the His bundle and the right and left bundle branches use...
Definition
Na+ Ions
Term
The first downward deflection of the ventricular contraction, this wave is often absent on and EKG
Definition
The Q wave
Term
Any downward wave PRECEDED by an upward wave is an...
Definition
S Wave
Term
Following the QRS complex there is a segment of horizontal baseline known as...
Definition
The ST Segment
Term
Give the 3 most important characteristics of the ST semgemt
Definition
  1. It is horizontal
  2. It is flat
  3. It is level with other areas of the baseline (elevated or depressed ST segments usually indicate serious pathology)
Term
Rapid ventricular repolarization is represented by...
Definition
the T wave
Term
Repolarization is accomplished by...
Definition
Potassium (K+) ions
Term
The...represents ventricular activity (depolarization and repolarization)
Definition
the QT interval. [Depolarization begins with the Q wave (through the R and S waves) and repolarization begins during the ST segment and ends with the T wave]
Term
Long QT intervals are vulnerable to..
Definition
Rapid ventricular rhythms
Term
Describe a normal cardiac cycle
Definition
  • P Wave - contraction of the atrium inititated from the SA node and accomplished through Na+ ions
  • Slight pause as the blood flows through the atrial valves and into the AV node. Slow conduction through the AV node is carried by Ca++ ions
  • Depolarization rapidly shoots through the His bundle and the R/L bundle branches through Na+ ions
  • QRS - contraction (depolarization) of the ventricles
  • ST Segment - horizontal, level segment following the QRS complex; beg of ventricular repolarization
  • T Wave - final ventricular repolarization accomplished through K+ ions
Term
The release of Na+ ions into the interiors of the myocytes produces myocardial
Definition
Depolarization / Contraction
Term
Following depolarization, repolarization is due to outflow of...
Definition
K+ (Potassium)
Term
AV node conduction is due to...
Definition
Slow moving Ca++ (Calcium) ions
Term
What are the dimensions of each square on EKG graph paper?
Definition
1mm x 1mm
Term
EKG graph paper is broken into...squares
Definition
5mm x 5mm
Term
The deflection of am EKG wave is the...
Definition
Direction in which it records; upward deflection (+) or downward deflection (-)
Term
The horizontal axis on EKG paper represents...
Definition
Time
Term
The amount of time represented by the distance between two heavy black lines is...
Definition
.2 of a second
Term
Each small square on EKG paper represents...(time)
Definition
.04 of a second
Term
Limb leads are placed where?
Definition
On the right arm, left arm, and left leg
Term
What comprises Lead I?
Definition
Lead I is horizontal from the L arm + electrode to the R arm - electrode
Term
What comprises Lead III?
Definition
L arm - electrode connects to the L leg + electrode
Term
What comprises Lead II?
Definition
Right arm - electrode connects to the left foot + electrode
Term

Label the correct leads and their charges

 

[image]

Definition
[image]
Term
Describe the AVF lead
Definition
AVF uses the L foot (+) electrode and both the R and L arm (-) electordes
Term
What does AVF stand for?
Definition
Augmented Voltage Left Foot
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