Arrhythmias

Question 1

Diagnosis of tachyarrhythmia: Tachycardia, regular rhythm, abnormal QRS morphology

Answer 1

***Ventricular tachycardia
Atrial tachycardia (FAT)
Atrial flutter
Focal junctional tachycardia
Accessory pathway mediated tachycardia

Question 2

Diagnosis of tachyarrhythmia: tachycardia, regular rhythm, normal QRS morphology

Answer 2

Atrial tachycardia (FAT), atrial flutter, focal junctional tachycardia, accessory pathway mediated tachycardia

Question 3

Diagnosis of tachyarrhythmia: tachycardia, irregular rhythm, QRS morphology doesn’t matter.

Answer 3

Atrial fibrillation

Question 4

The primary movement of electrolytes in each phase:

Answer 4

Phase 4: K+ ICF -> ECF
Phase 0: Na+ ECF -> ICF
Phase 1: K+ ICF ->->-> ECF
Phase 2: Ca2+ ICF -> ECF
and K+ ICF -> Ca2+
Phase 3: K+ ICF -> ECF

Question 5

Myocyte Phase 0 action potential: Describe what is happening and the primary ion channel conductance

Answer 5

Rapid depolarization
Fast Na+ channels open - Influx

Question 6

Myocyte Phase 1 action potential: Describe what is happening and the primary ion channel conductance

Answer 6

Initial reploarization
Na+ closed, K+ channels open - efflux

Question 7

Myocyte Phase 2 action potential: Describe what is happening and the primary ion channel conductance

Answer 7

Plateau
TMP 0mV
Ca++ (L-type) channels open - influx
K+ delayed rectifier channels open - efflux

Question 8

Myocyte Phase 3 action potential: Describe what is happening and the primary ion channel conductance

Answer 8

Repolarization
Ca2+ channels close but K+ delayed rectifier channels remain open and return TMP to ~90mV

Question 9

Myocyte Phase 4 action potential: Describe what is happening and the primary ion channel conductance

Answer 9

Na+ and Ca2+ channels closed, open K+ rectifier channels keep TMP stable at ~90mV

Question 10

Where in the myocyte membrane potential do class I antiarrhythmics work?

Answer 10

Class I sodium channel blockers
Na+ channels, Phase 0

Question 11

Where in the myocyte membrane potential do class II antiarrhythmics work?

Answer 11

Class II B-blockers
K+ rectifier, Phase 4

Question 12

Where in the myocyte membrane potential do class III antiarrhythmics work?

Answer 12

Class III Potassium channel blocker
Phase 3

Question 13

Where in the myocyte membrane potential do class IV antiarrhythmics work?

Answer 13

Class IV Calcium-channel blocker
Phase 2

Question 14

Write the Oxygen Delivery Equation

Answer 14

DO2 = CaO2 + CO
DO2 = (0.003 x PaO2) + (Hgb x SaO2 x 1.34) + HR x SV

Question 15

List at least 3 things that happen with hypocalcemia in regards to the cardiovascular system

Answer 15

1. Coagulopathy (2, 7, 9, 10, Prot C, S, fibrin product, platelet binding)
2. Contractility
3. Dysregulation of endothelium -> leakiness
4. Decreased vascular tone