CV Anti-tachyarrhythmics

Question 1

Class IA

Answer 1

block Na channel - decreases conduction + automaticity increases QRS. block K channel - increases refractoriness + QT. effective against supra/ventricular arrhythmias caused by re-entry or ectopic, terminate A-fib. decrease ventricular contractility, clinical use decreasing causing arrhythmias

Question 2

Class IB

Answer 2

block Na channel when HR high or ischemia. doesn’t really change EKG, slight decrease QT in patients with long QT. effective against ventricular arrhythmia caused by re-entry or ectopic. useful against digoxin induced arrhythmia. given IV

Question 3

Class IC

Answer 3

strongest Na channel block - decrease conduction and prolongs QRS a lot. used for serious ventricular arrhythmia caused by re-entry, A-fib, AV nodal re-entry. prone to cause arrhythmias, decrease ventricular contractility

Question 4

Class II

Answer 4

β blockers. decrease AV conduction - increase PR. treat those involved with anesthesia, surgery, exercise, cocaine. control ventricular rate in A-fib. treat long QT. proven to decrease sudden cardiac death after MI

Question 5

Class III

Answer 5

block K channels - increase refractoriness + QT. effective against supra/ventricular arrhythmias caused by re-entry or ectopic, terminate A-fib. drug of choice for post-cardiac resuscitation and HF. less likely to cause arrhythmias

Question 6

Class IV

Answer 6

block L-type Ca channels. decrease AV conduction - increase PR. act similar to β blockers but better at treating AV nodal re-entry tachycardia, ventricular rate control and A-fib

Question 7

Digoxin

Answer 7

blocks Na/K ATPase. decrease sympathetic, increase parasympathetic. ventricular rate control in HF + A-fib patients. propensity to cause arrhythmias

Question 8

Adenosine

Answer 8

increase K channel opening, decrease intracellular cAMP - decrease AV conduction, increase PR. slows heart. treat AV nodal re-entry tachycardia. short duration, given IV