ECG Rhythms And Disturbances

Question 1

What is a normal axis?

Answer 1

Positive lead I and AVF

Question 2

What is a left axis deviation?

Answer 2

Positive lead I and negative AVF

Question 3

What is a right axis deviation?

Answer 3

Negative lead I and positive aVF

Question 4

What are the sx of arrhythmia?

Answer 4

Palpitations (skips, pounds, irregular)
Lightheadedness
Syncope (near syncope)
CP, dyspnea, sudden death

Question 5

What are the etiologies for arrhythmias?

Answer 5

Stress, ischemia, MI, HF, hypoxia, PE, COPD, metabolic acidosis, infection (endocarditis, RF), inflammation (myocarditis, pericarditis), cardiomyopathy, alcohol, chemo, electrolyte imbalance, drugs, HTN

Question 6

What can cause sinus tachycardia?

Answer 6

Emotion, anxiety, fear, drugs, hyperthyroidism, fever, pregnancy, anemia, CHF, hypovolemia

Question 7

What medical conditions are associated with bradycardia?

Answer 7

Can be seen in normal individuals or healthy athletes
Physiologic component to sleep, fright, carotid sinus massage, carotid hypersensitivity, avoid tight collars, shave neck lightly, massage or ocular pressure (glaucoma), mental control
Obstructive jaundice
Sliding hiatal hernia
Valsalva maneuver (lifting heavy objects, straining bowels)
Drugs & electrolytes (digitalis, quinidine, hyperkalemia)
Beta blockers

Question 8

What are some other medical conditions associated with bradycardia?

Answer 8

Acute inferior MI (increased vagal tone, N/V)
Ischemia 
Decreased PO2 and pH 
Increased pCO2 and BP
Sick sinus syndrome

Question 9

What is the treatment for sinus bradycardia?

Answer 9

Depends on clinical setting/Dx the cause (may not need to be treated)
Depends on hemodynamics/impaired
Atropine (AE include urinary renting, abd distention, transient)
Use cation in glaucoma (can increase IOP)

Question 10

What is automaticity?

Answer 10

Property of a cardiac cell to depolarize spontaneously during phase 4 of AP/leads to generation of an impulse

Question 11

Premature atrial contractions (PAC/APC) are usually associated with what?

Answer 11

Can be seen in an absence of heart disease

Associated with stress, alcohol, tobacco, coffee, COPD and CAD

Question 12

What is the treatment for symptomatic PACs?

Answer 12

Reverse causes, beta adrenergic antagonist (BB), metoprolol 25-50mg BID/TID

Question 13

What is paroxysmal atrial tachycardia?

Answer 13

Sudden HR greater than 100
Rate 150-250/min
ID irritable focus
Rapid rate, spiked P waves, 2:1 ratio of P:QRS

Question 14

What is multifocal tachycardia (MAT)?

Answer 14

3 or more different P waves 
PR interval varies 
Irregular ventricular rhythm 
Atrial rate >100 
Associated with lung disease (COPD, pneumonia, ventilators theophylline), beta agonists, electrolyte abnormalities, digitalis toxicity, sepsis

Question 15

How is MAT treated?

Answer 15

Focus on the underlying cause 
Ca channel blockers to control vent rate and dec ectopic atrial impulse 
Diltiazem 20mg IV then 5-15mg/hr drip
Verapamil 
MgSO4 then amiodarone/adenosine

Question 16

What is atrial fibrillation?

Answer 16

Atrial rate >350-600/min 
Undulating baseline 
No discernible P waves 
Irregular PR interval 
Irregularly irregular ventricular rhythm

Question 17

How is atrial flutter described on an EKG?

Answer 17

Saw tooth appearance

Leads II, III, AVF and V often best leads to view this

Question 18

What are junctional (nodal) rhythms?

Answer 18

Paroxysmal junctional tachycardia
150-250/min
P wave may be lost (buried), inverted before or after each QRS

Question 19

What is the etiology for premature ventricular contractions (PVCs)?

Answer 19

Normal heart
CAD, MI, HF, ischemia, hypoxia
Valvular heart disease, congenital heart disease
Cardiomyopathy, electrolyte abnormalities
Acid base imbalance
Hyperthyroid
Drugs

Question 20

What are the EKG characteristics for PVCs?

Answer 20

Premature, bizarre wide QRS
No preceding P wave; may produce a retrograde P wave in ST segment
ST-T wave moves in opposite direction of QRS
Usually full compensatory pause

Question 21

What is the treatment for PVCs?

Answer 21

If stable, no Rx
If symptomatic or in setting of ACS use metoprolol 2.5-10mg
If unstable use amiadarone, lidocaine, procainamide

Question 22

What is ventricular tachycardia?

Answer 22

3 or more consecutive bizarre QRS complexes
Ventricular rate 120-200
Usually regular, wide QRS (> 0.12 seconds)
P wave often lost; if seen, no relationship to QRS (AV dissociation)
Last longer than 30 seconds (sustained)

Question 23

What is torsades de pointes?

Answer 23

Twisting of the points 
QRS swings from positive to negative direction 
May be inherited (prolonged QT) or acquired (class I, II anti-arrhythmias, alcohol, TCA, electrolyte imbalance—K, Ca, Mg)

Question 24

What is the treatment for torsades de pointes?

Answer 24

MgSO4 1-2g IV boys
Overdrive pacing
Isoproterenol

Question 25

What is ventricular fibrillation?

Answer 25

Disorganized depolarization
Not effective pump
Clinical setting — AMI, HF, IHD, K disturbance (low or high)