Term
| What is an Electrocardiogram? |
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Definition
| A graphic record of the electrical activity generated by the heart |
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Term
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Definition
| An increase in the resting membrane potential |
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Term
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Definition
| A decrease in the resting membrane potential |
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Term
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Definition
| The return of the resting membrane potential to its resting level at the end of an action potential |
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Term
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Definition
| A positive and negative charge separated by a small distance, which can generate local current flow and a small electrical field |
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Term
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Definition
| Physical quantities that have both magnitude and direction |
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Term
| Vector arrows, in terms of an EKG |
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Definition
| The direction of cardiac depolarization is represented by a vector arrow |
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Term
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Definition
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Term
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Definition
| Combination of two electrodes |
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Term
| Active (exploring) electrode |
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Definition
| Senses the electrical field |
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Term
| Passive (indifferent) electrode |
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Definition
| A reference electrode, considered to be at 0 mV |
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Term
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Definition
| Combination of an active plus a passive electrode |
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Term
| Where should the voltage be measured on a unipolar lead? |
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Definition
| Only at the active electrode |
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Term
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Definition
| Combination of two active electrodes |
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Term
| Where should the voltage be measured on a bipolar lead? |
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Definition
| Between the two electrodes; Subtract the voltage at the negative electrode from the voltage at the positive electrode |
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Term
| What are the 4 things needed to record an EKG? |
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Definition
| Recording System with Amps and Electrode Junction Box; Surface Electrodes with low and similar Resistance; Recording Paper; Patient |
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Term
| Describe the paper used to record an EKG |
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Definition
| It is a grid, consisting of 5 X 5 mm dark squares, subdivided into 1 X 1 mm light squares |
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Term
| Describe the X- axis on the EKG paper |
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Definition
| It represents the paper speed, which equals 25 mm/sec; The dark lines are 0.2 seconds apart; The light lines are 0.04 seconds apart |
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Term
| Describe the Y- axis on the EKG paper |
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Definition
| It represents the voltage gain, which equals 1 mV/cm |
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Term
| Describe Voltage Polarity |
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Definition
| Up is positive; Down is negative; The baseline is the isoelectric line and it equals 0 mV |
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Term
| What is the standardization marker on an EKG? |
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Definition
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Term
| Where and how is Lead I arranged on the body? |
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Definition
| On the right arm is a negative electrode and on the left arm is a positive electrode |
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Term
| Where and how is Lead II arranged on the body? |
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Definition
| On the right arm is a negative electrode and on the left leg is a positive electrode |
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Term
| Where and how is Lead III arranged on the body? |
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Definition
| On the left arm is a negative electrode and on the left leg is a positive electrode |
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Term
| What part of the body is used as a ground electrode? |
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Definition
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Term
| What is the normal pacemaker of the heart? And what is its normal rate? |
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Definition
| Sinoatrial (SA) Node; 60-100 beats/min |
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Term
| What are the 3 escape pacemakers of the heart? |
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Definition
| AV Junction; Bundle of His; Purkinje Fibers |
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Term
| What is an internodal tract? |
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Definition
| Specialized pathways of cells which more rapidly conduct the impulse from the SA node to the AV node and both atria |
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Term
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Definition
| Major tract to left atrium, which coordinates from the right atrium to the left atrium |
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Term
| What are the 3 components of the EKG? |
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Definition
| Waveforms; Segments; Interval |
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Term
| How are waveforms created by the body? |
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Definition
| Electrical impulses starting in the SA node produce waves as they spread throughout the heart |
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Term
| What do waveforms represent on an EKG? |
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Definition
| Deviation from the baseline, either in the positive or negative direction |
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Term
| What is a segment on an EKG? |
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Definition
| A period of time between waveforms |
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Term
| True or False: The segment of an EKG is normally isoelectric |
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Definition
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Term
| What is an interval on an EKG? |
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Definition
| A period of time that includes waves |
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Term
| Describe the P WAVE, including how and where it affects the heart and how long it lasts |
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Definition
| The P wave is the first wave in the cardiac cycle; It depolarizes both atria and lasts 0.08-0.10 seconds |
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Term
| Describe the QRS COMPLEX, in terms of how and where it affects the heart and how long it lasts |
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Definition
| Depolarization of both ventricles occurs, lasting 0.05-0.10 seconds |
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Term
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Definition
| First negative deflection following the P WAVE |
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Term
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Definition
| First positive deflection following the P WAVE |
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Term
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Definition
| Negative wave following the R WAVE |
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Term
| True or False: Q, R, and S waves MUST be present in all QRS complexes |
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Definition
| FALSE; They may NOT be present in all QRS Complexes |
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Term
| Describe the T WAVE, in terms of how and where it affects the heart |
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Definition
| Repolarization of both ventricles |
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Term
| Despite the fact that repolarization occurs in the opposite direction of depolarization, why is the T WAVE in the same direction as the QRS COMPLEX? |
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Definition
| Even though the QRS COMPLEX depolarizes both ventricles, while the T WAVE repolarizes both ventricles, the waves are in the same direction to show an electrical current |
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Term
| Where is the wave corresponding to atrial repolarization? |
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Definition
| It is buried inside the QRS COMPLEX and therefore, rarely observed |
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Term
| Why isn't the depolarization of both the SA node and the AV node reflected on an EKG? |
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Definition
| Neither of these nodes has enough tissue mass to produce an electrical signal |
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Term
| Describe the P-R Interval, in terms of what it measures and/or represents and its normal value |
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Definition
| It is measured from the beginning of the P WAVE to the beginning of the QRS COMPLEX; It represents the time it takes for atrial depolarization and the delay through the AV node; Its normal value is 0.12-0.20 seconds |
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Term
| Describe the Q-T Interval, in terms of what it measures and/or represents |
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Definition
| It is measured from the onset of the QRS COMPLEX to the end of the T WAVE; It represents the time for ventricular depolarization and repolarization |
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Term
| What can the Q-T Interval approximate? |
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Definition
| The time it takes for a ventricular action potential |
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Term
| True or False: The Q-T Interval is VERY dependent on heart rate |
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Definition
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Term
| True or False: The Q-T Interval makes up 25% of the EKG duration |
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Definition
| FALSE: The Q-T Interval makes up 50% of the EKG duration |
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Term
| True or False: As the heart rate decreases, the Q-T Interval shortens |
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Definition
| FALSE; If the heart rate increases, the Q-T Interval will lengthen |
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Term
| Describe the P-P Interval, in terms of what it measures and/or represents |
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Definition
| It is the time between consecutive atrial depolarizations and it is measured from the beginning of one P WAVE to the beginning of the next P WAVE |
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Term
| What can the P-P Interval be used to determine? |
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Definition
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Term
| Describe the R-R Interval, in terms of what it measures and/or represents |
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Definition
| It is the time between consecutive ventricular depolarizations and it measured from the beginning of one QRS COMPLEX to the beginning of the next QRS COMPLEX |
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Term
| What can the R-R Interval be used to determine? |
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Definition
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Term
| True or False: In a NORMAL heart, the P-P Interval and R-R Interval will look the same |
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Definition
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Term
| Describe the P-R Segment, in terms of what is measures and/or represents |
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Definition
| It is the isoelectric period between the end of the P WAVE and the beginning of the QRS COMPLEX and it represents the period between atrial and ventricular depolarization |
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Term
| Describe the S-T Segment, in terms of what is measures and/or represents |
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Definition
| It is the period of time between the end of the QRS COMPLEX and the beginning of the T WAVE; It represents the period between completion of ventricular depolarization and the beginning of ventricular repolarization |
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Term
| True or False: The S-T segment is normally isoelectric |
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Definition
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Term
| True or False: The ventricles are at rest during the S-T segment |
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Definition
| FALSE; Even though this segment represents an isoelectric point, the ventricles are not at rest |
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Term
Electrical Event- Impulse initiated in SA node
EKG Representation- _____________ |
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Definition
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Term
Electrical Event- Depolarization of atria
EKG Representation- _______________ |
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Definition
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Term
Electrical Event- Depolarization of AV node
EKG Representation- _______________ |
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Definition
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Term
Electrical Event- Repolarization of atria
EKG Representation- ____________ |
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Definition
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Term
Electrical Event- Depolarization of ventricles
EKG Representation- _______________ |
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Definition
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Term
Electrical Event- Plateau of ventricular AP's
EKG Representation- _______________ |
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Definition
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Term
Electrical Event- Repolarization of ventricles
EKG Representation- _________________ |
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Definition
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Term
| What does it mean for the heart to be a synctium? |
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Definition
| It means that depolarization (or repolarization) of one cell will depolarize (or repolarize) adjacent cells |
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Term
| True or False: Because the heart is a synctium, many dipoles will be formed and their summation will generate an electrical field |
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Definition
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Term
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Definition
| Voltage= (+ electrode) - (- electrode) |
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Term
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Definition
| The sum of the positive and negative deflections of the waveform |
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Term
| A wave of depolarization moving towards the positive electrode of a lead will cause a ____________ deflection |
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Definition
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Term
| A wave of depolarization moving away from the positive electrode of a lead will cause a ___________ deflection |
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Definition
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Term
| A wave of repolarization moving towards the positive electrode of a lead will cause a __________ deflection |
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Definition
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Term
| A wave of repolarization moving away from the positive electrode of a lead will cause a ___________ deflection |
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Definition
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Term
| A wave of depolarization or repolarization moving perpendicular to a lead will cause ______________ |
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Definition
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Term
| Math Practice: Given a QRS Complex, there is a positive wave at +10 mm and a negative wave at -2 mm; What is the net vector for this wave? |
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Definition
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Term
| Math Practice: Given a QRS complex, there is a positive wave of +18 mm and two negative waves at -2 mm and -6 mm; What is the next vector for this wave? |
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Definition
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Term
| What is the normal QRS axis? |
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Definition
| Between 0 degrees and +90 degrees |
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Term
| What is left axis deviation? |
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Definition
| When the mean QRS axis is more negative than 0 degrees |
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Term
| What is right axis deviation? |
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Definition
| When the mean QRS axis is more positive than +90 degrees |
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Term
| Name 3 common causes of left axis deviation |
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Definition
| Left Ventricular Hypertrophy; Pregnancy; Obesity |
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Term
| Name 3 common causes of right axis deviation |
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Definition
| Right Ventricular Hypertrophy; Infarct in Left Ventricle; Tall and Thin Body Type |
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Term
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Definition
| Rate (bpm) = beats per 6 seconds X 10 |
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Term
| What does Heart Rhythm describe? |
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Definition
| How regularly waves occur |
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Term
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Definition
| Irregular rhythms and regular rhythms of abnormal frequency |
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Term
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Definition
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Term
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Definition
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Term
| Damage to what 2 regions of the heart will adversely affect conduction? |
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Definition
| AV node and Bundle of His |
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Term
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Definition
| Prolonged P-R Interval (slowed conduction through the AV node or Bundle of His); There is only one P WAVE for every QRS COMPLEX |
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Term
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Definition
| Partial dissociation of atria and ventricles; Not every P WAVE is followed by a QRS COMPLEX |
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Term
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Definition
| No conduction through the AV node and complete dissociation of atria and ventricles; The P WAVE and QRS COMPLEX act totally independent of one another |
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