Cardiology #7 (Rhythms #2)

Question 1

What does the ECG show if the patient has paroxysmal supra ventricular tachycardia?

Answer 1

Orthodromic (MC type): regular, narrow-complex tachycardia (no discernible P waves due to rapid rate).

-If you can’t tell if the bump is a P or a T, it must be SVT

Question 2

Treatment for PSVT

Answer 2

• Stable (narrow complex): Vagal maneuvers. Adenosine. Second line is CCB, BB, Digoxin.
• Stable (wide complex): Amiodarone.
• Unstable: direct current cardioversion
• Definitive: radio frequency catheter ablation.

Question 3

What is unique about the ECG of a patient with multifocal atrial tachycardia?

Answer 3

heart rate > 100 bpm and 3 or more P wave morphologies

Question 4

Multifocal atrial tachycardia is most commonly associated with what condition?

Answer 4

severe COPD

Question 5

Treatment for multifocal atrial tachycardia?

Answer 5

CCB (Verapamil)

Question 6

What is the pathophysiology of Wolff-Parkinson-White (WPW)

Answer 6

Accessory pathway (bundle of Kent) outside the AV node pre-excites the ventricles, leading to a Delta wave

Question 7

What are the 3 ECG components of a patient with WPW

Answer 7

W: Delta wave (slurred QRS upstroke)
P: PR interval that is short
W: Wide QRS complex

Question 8

Treatment for WPW

Answer 8

Stable: Procainamide (preferred) or Amiodarone
Unstable: Cardioversion
Definitive: radio frequency catheter ablation

Question 9

What should be avoided in patients with WPW?

Answer 9

AV nodal blocking agents (Adenosine, BB, CCB, Digoxin)

Avoid ABCD in WPW

Question 10

In AV junctional dysrhythmias, what happens?

Answer 10

The AV node becomes the dominant pacemaker in the heart

Question 11

What is seen on the ECG in a patient with AV junctional dysrhythmias?

Answer 11

P waves inverted (negative) if present in leads they are normally positive (I, II, avF) or are not seen. Narrow QRS complex.

Question 12

What are the three types of AV junctional dysrhythmias? (has to do with heart rate)

Answer 12

Junctional: 40-60 bpm
Accelerated: 60-100 bpm
Tachycardia: > 100 bpm

Question 13

What is a PVC?

Answer 13

Premature beat originating from ventricle –> wide, bizarre QRS occurring earlier than expected. The T wave is opposite direction of QRS.

Question 14

Treatment for a PVC

Answer 14

No treatment usually needed, as it is a common finding on an ECG

Question 15

What is ventricular tachycardia defined as?

Answer 15

3 or more consecutive PVC’s at a rate of 100 bpm or more

Question 16

MC etiology of ventricular tachycardia

Answer 16

• Ischemic heart disease (post-MI)

- Others: Prolonged QT interval, Hypomagnesemia, hypokalemia, Digoxin toxicity

Question 17

Treatment for ventricular tachycardia

Answer 17

• Stable sustained VT: Amiodarone, Lidocaine, Procainamide
• Unstable VT with a pulse: Cardioversion
• VT with no pulse: Defibrillation + CPR

Question 18

What is the pathophysiology of Torsades de Pointes?

Answer 18

Prolonged repolarization and early after depolarization + triggered activity

Question 19

Causes of Torsades

Answer 19

• Prolonged QT interval
• Hypomagnesemia, Hypokalemia, Hypocalcemia
• Female
• Macrolides, Antipsychotics, Antiemetics

Question 20

What does the ECG in Torsades de Pointes show?

Answer 20

Polymorphic ventricular tachycardia (alterations of the QRS amplifies on ECG around the isoelectric line)

Question 21

First-line treatment for Torsades de Pointes?

Answer 21

IV Mag Sulfate

-Discontinue all QT prolonging drugs

Question 22

MC cause of V-fib

Answer 22

ischemic heat disease (post MI)

Question 23

Symptoms of V-fib

Answer 23

Unresponsive, pulseless patient, syncope

Question 24

ECG of V-fib shows

Answer 24

-Erratic pattern of electrical impulses, no p waves

Question 25

Treatment for V-fib

Answer 25

Unsynchronized cardioversion (Defibrillation) + CPR

Question 26

Which leads correspond to a RBBB?

Answer 26

Leads V1-V3 (M shaped QRS complex)

-Wide QRS complex

Question 27

What are the criteria for a LBBB on an ECG?

Answer 27

• Wide QRS complex
• Absence of Q wave in I, V5, V6
• Monomorphic R wave in I, V5, V6
• ST and T wave displacement opposite to major deflection of QRS complex

Question 28

What are the two indications for Adenosine?

Answer 28

• PSVT: slows AV node conduction time and blocks AV nodal reentry pathways
• Pharm Cardiac Stress Testing: produces vasodilation of normal coronary arteries

Question 29

Adverse effects of Adenosine

Answer 29

• Chest discomfort, dyspnea, flushing, headache, lightheadedness
• Serious: bronchospasm, MI

Question 30

When should you NOT use Adenosine?

Answer 30

• 2nd and 3rd degree heart blocks
• WPW
• Asthma, COPD

Question 31

Amiodarone is a _________ which prolongs the action potential

Answer 31

-Class III antiarrythmic (K+ channel blocker)

Question 32

Amiodarone is MC used for

Answer 32

stable, wide-complex tachycardias

Question 33

Adverse effects of Amiodarone

Answer 33

• Hypotension MC
• Corneal deposition with > 6 month use (MC side effect)
• Thyroid disorders
• Pulmonary fibrosis
• Increased LFTs
• Blue-green discoloration of the skin

Question 34

When should you NOT use Amiodarone?

Answer 34

• 2nd or 3rd degree heart blocks

- WPW with concurrent A-fib

Question 35

What is a useful pneumonic to remember the order of the four classes of Anti-Arrhythmic Agents, and which classes are used primarily for rhythm control and which are used for rate control?

Answer 35

Nets play in BK for Championship (NA+ channel blockers, BB, K+Channel blockers, Ca2+ channel blockers)

• Rhythm: Class I and III
• Rate: II and IV

Question 36

Name 4 Na+ Channel Blockers

Answer 36

• Procainamide
• Quinidine
• Lidocaine
• Flecainide

Question 37

Beta Blockers such as _______, ______, and ______ are cardio-selective. They are used in conditions such as _____ and ______.

However, they have side effects such as ______, ____, and they may mask the symptoms of _____.

Answer 37

• Atenolol, Metorpolol, Esmolol
• Atrial flutter, Atrial fibrillation

-Bradycardia, AV blocks, hypoglycemia