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49 Cards in this Set
- Front
- Back
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What are the three types of cardiac pacemakers?
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SA node (60-80)
AV junction (40-60) Ventricular (25-40) |
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Which area of the heart conducts the fastest? Which conducts the slowest?
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Intraventricular system- fastest
AV node- slower Muscle- slowest |
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In what pattern are the ventricles activated?
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Interventricular septum (Q)
Lateral walls of the ventricles (R) Basal areas (S) |
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What does the P wave represent? Where is it best seen?
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SA node firing to the atria
Leads II and V1 |
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What does the QRS complex represent? Where is the R wave the largest? Where is the S wave? Where is the Q wave?
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Q wave from septal depolarization, R wave from left ventricle apex depolarization, S wave from basal ventricles depolarizing.
R wave increases in amplitude up to V5, V6. S wave best seen in V1. Q wave best seen in I, aVL, V5 and V6 |
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What does the T wave represent? Where is it best seen?
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Repolarization of the heart.
Inverted in aVR; seen similarly in all leads. |
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What is the ST segment? Where is it best seen?
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Ventricular systole.
Seen in V1-V3 |
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What is the method for interpreting ECGs?
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Rate
Rhythm Axis Intervals |
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What are the types of rhythm found on ECG?
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Sinus rhythm
Ectopic atrial Junctional Ventricular |
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What determines sinus tachycardia on ECG?
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P wave for every QRS wave.
Upright P waves. Rate usually 100-160. |
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What is normal sinus rate? What is normal junctional rate? Ventricular escape rate?
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Sinus: 60-100
Junctional: 40, normal QRS Ventricular: less than 40, wide QRS |
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What abnormality is associated with an inverted P wave?
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Ectopic atrial focus, dextrocardia
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What abnormality is associated with a tall upright P wave? Wide P wave?
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Right atrial enlargement; Left atrial enlargement.
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What abnormalities are associated with PR interval?
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Too long- first degree AV block
Too short- WPW syndrome |
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What abnormalities are associated with QT shortening? QT prolonging?
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shortening- hypercalcemia, -kalemia, -thermia, -thyroidism, acidosis
lengthening- hypokalemia; -mangesemia, -calcemia, -thermia, drugs, ion channelopathies |
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What abnormalities are associated with inverted T waves? Tall peaked T waves?
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Inverted- ischemia, MI, LVH, RVH, WPW
Tall peaked- hyperkalemia, acute MI, LVH, RVH |
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What is a U wave? What causes abnormality?
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Afterpotential or repolarization of purkinje fibers.
Hypokalemia, hypothermia, CAD, meds |
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Which SA block is detected on ECG? What are the types?
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Second degree SA block.
Type I- shortening P-P, PP pause less than twice normal P-P interval. Type II- constant P-P, dropped P with pause near multiple, normal P-P |
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What are the types of AV block?
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1st degree
2nd degree (type I and II) 3rd degree |
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what distinguishes a 1st degree AV block on ECG? Where is the block? What are the causes?
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PR interval >.2 sec
block within the AV node Caused by aging, AV blocking agents, vagal tone. |
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What distinguishes a 2nd degree AV block, type I on ECG? Where is the block?
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Sequentially prolonged AV interval with 3:1 block.
Block at AV node. |
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What distinguishes a 2nd degree AV block, type II on ECG? Where is the block?
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Occassional AV block with QRS, but PR interval is constant. QRS is abnormal.
Block is infranodal. |
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What distinguishes a 3rd degree AV block? Where is the lesion?
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Atria and ventricles depolarize independently, so no relationship between P waves and QRS.
Lesion above or below AV node. |
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What are ECG features of right bundle branch block? What are causes?
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QRS> 120ms
R' in V1 and V2 Wide S in I, V5, V6 Causes: hypertension, cardiomyopathy, increase in RV pressure, RV failure/ cor pulmonale, trauma. |
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What are ECG features of left bundle branch block? What are causes?
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QRS > 120ms
Broad, deep S in V1, V2, V3 Broad R in I, V5, V6 Causes: LVH, MI, congenital heart disease, degenerative conduction system |
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What are ECG features of left anterior fascicular block? What are causes?
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Left axis deviation.
rS in III, qR or R in I and aVL. Normal QRS. Causes: organic heart disease, congenital heart disease, |
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What are ECG features of left posterior fascicular block? What are causes?
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Right axis deviation.
Normal QRS. Causes: CAD |
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What are the criteria for left ventricular hypertrophy on ECG?
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Sokolow-Lyon criteria: S wave in V1 + R wave in V5/V6 > 35mm
Sokolow-Lyon "stand alone": R wave in aVL > 11mm Cornell criteria: R wave in aVL + S wave in V3 >28 in males or > 20 in females. |
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What are criteria for right ventricular hypertrophy on ECG?
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R/S in V1 > 1
R/S in V5 or 6 < 1 |
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When is ST elevation normal?
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Diffuse early repolarization
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What is the appearance of pericarditis on ECG?
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Diffuse ST elevation.
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What is the ECG pattern in STEMI? What leads are associated with which?
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>1mm ST elevation in two continguous leads.
V1-V4 (anterior) II, III, aVF (inferior) I, aVL, V5, V6 (lateral) |
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What do Q wave indicate?
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Old transmural indicate.
Must be 1/3 total height of QRS and be in consecutive leads. |
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How do inverted P waves occur in junctional rhythm?
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Due to retrograde activation of the atria by the ventricles.
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What are causes of 2nd degree AV block type I?
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Normal athletes
Myocarditis, inferior MI, cardiac surgery Congenital heart disease. |
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What are causes of 2nd degree AV block type II?
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Fibrous degeneration of conduction system.
AV blocking agents. |
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What are causes of 3rd degree AV block?
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Fibrosis/ sclerosis
AV blockers/ digitalis toxicity Hyperkalemia Endocarditis Cardiac surgery Lyme disease |
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What are causes of premature atrial complexes? What do they look like on ECG?
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Stimulants- caffeine, stress, etc.
Extra large P wave due to overlap of P and T waves. |
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What are premature junctional complexes?
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Signal with focus in the AV junction. Can cause anterograde QRS or retrograde P wave.
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What are causes of multifocal atrial tachycardia? What are the ECG findings?
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Pulmonary disease, electrolyte imbalance, infection, acidosis.
3 different P wave morphologies. Rate 100-180 |
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What are causes of atrial tachycardia? What are ECG findings?
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Age, atrial fibrillation and cardiomyopathy.
Rate 100-220 bpm; sinus rhythm with P wave inversions |
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What are ECG findings of atrial flutter? What is the potential complication?
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Rapid and regular form of tachycardia. Rate 220-300 bpm. AV node controls ventricle rhythm.
Can progress to atrial fibrillation. |
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What are ECG features of atrial fibrillation? What are the two mechanisms that can cause it?
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Atrial rate of >300.
Caused by rapid firing of pulmonary veins or multiple reentrant wavelets. |
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What is AV nodal reentry tachycardia? What are ECG features?
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Simultaneous activation of the atria and ventricles.
Cannon A wave and pseudo R' wave in V1. |
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What is Wolff-Parkinson-White syndrome? What are ECG features?
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Accessory pathway from the SA node to the ventricles.
Delta wave, predisposition to ventricular fibrillation. |
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What causes premature ventricular complexes?
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Ischemia, cardiomyopathy, myocarditis, drugs, hypoxia, hypercapnia, electrolyte imbalance.
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What are ECG signs of ventricular tachycardia? When is it suspected?
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Abrupt onset and termination.
R waves interspersed among wide QRS. Suspect with known CAD, MI, cardiomyopathy |
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What are ECG findings of torsades de pointes? What are causes?
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Long QT, wide QRS, changing QRS morphology.
Causes: hypokalemia, prolongation of action potential, early afterdepolarization |
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What are ECG features of ventricular fibrillation? What is the treatment?
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Irregular rhythm, multiple wavelets, no QRs,
Defibrillation. |
