Cardio: Anti-Arrythmics Flashcards
What parts of the heart has fast APs?
Cardiomyocytes and Purkinje fibers
What parts of the heart has slow APs?
SA and AV nodes
What are the class 1a anti-arrhythmics?
Quinidine
Procainamide
Disopyramide
MOA of class 1a anti-arrhythmics?
Block sodium channels, and have some K+ channel affect as well.
-will prolong QT and QRS due to this
what effect do the class 1a anti-arrhythmics have on the heart AP?
Reduce slope of phase 0=Prolong QRS complex
Prolong AP duration=prolong QT interval
Indication for procainamide?
Effective in sustained V-tach and arrythmias after MI
Adverse effects of procainamide?
QT prolongation=Torsades!
Drug induced lupus
- arthralgias, pleuritis, hepatitis, fever
- anti-histone Ab
is quinidine used much clinically?
Nope.
Not sure why we even learn it then??
Adverse effects of quinidine?
QT Prolongation=torsades due to K+
Cinchonism
-hearing loss, tinnitus, confusion, delirium
thrombocytopenia
GI Upset
Indication for Disopyramide?
Recurrent ventricular arrhythmias
Adverse effects of Disopyramide
QT Prolongation=Torsades
Negative inotrope=heart failure
Atropine like symptoms
-blind as a bat, mad as a hatter, dry as a bone
What are the class 1B anti-arrhythmics?
Mexitile (oral) and Lidocaine (IV)
What effect do class 1B anti-arrhythmics have on AP?
Shorten AP
DO NOT PROLONG QT like 1A
Clinical use of lidocaine?
Termination of V-tach after MI
Adverse effects of lidocaine?
Least toxic of all class 1
hypotension
Neurological side effects
-paresthesias, tremor, slurred speech
Clinical use of Mexiletine
Ventricular arrythmias after MI
Adverse effects of Mexiletine
Neurological side effects
-paresthesias, tremor, slurred speech
Do class 1C drugs prolong the QT interval?
Nope, just the QRS complex as they are pure Na+ blockers
-no K+ activity
what are the Class 1c anti-arrhythmic drugs?
Flecainide and propanefone
Would you use class 1c anti-arrhythmic drugs post MI?
Nope, they are only for healthy hearts
Clinical use of flecainide and Propafenone?
Both: SVTs
Only flecainide: refractory ventricular arrythmias that are life threatening
Class II anti-arrhythmic drug MOA?
B-blockers
- reduce cAMP to reduce contractility
- block the funny current to prevent calcium from entering
- -reduces HR
Class II anti-arrhythmic effects on AP?
Slow HR via SA node, so they prolong the RR interval
Reduce AV Conductance, so prolong PR interval
Clinical use for Propranolol
Arrhythmias associated w stress and thyroid storm
A fib and A Flutter, PSVTs, and post-MI arrhythmias
Which of the B-blockers is short acting?
Esmolol
-great for IV ifusion for rapid onset and termination
Clinical use for esmolol?
SVTs, thyrotoxicosis, post-MI arrhythmias
Used as adjunct w general anesthesias to control arrhythmias peri-operatively
Adverse effects of B-blockers?
Block B2, so:
- reduced CO, reduced glucose metabolism
- increased LDL, low HDL
- sedation
- withdrawl sydrome
Contraindications of B-blockers?
Asthma, PVD, Raynauds, T1DM, bradycardia
MOA of class 3 anti-arrhythmic drugs?
Block K+ channel
What are the class 3 anti-arrhythmic drugs?
amiodarone, sotalol, ibutilide/Dofetilide
Effects of class 3 anti-arrhythmic drugs on AP?
Prolong AP, QT interval, and ERP
Clinical use of Amiodarone?
Recurrent V-tach and a-fib
Adverse effects of Amiodarone?
AV block and bradycardia
Fatal pulmonary fibrosis**
Photodermatitis and deposits in corneas
Blocks thyroid=hyper/hypothyroidism
-iodine
Which of the class 3 drugs has B Blockers activity as well?
Sotalol
Clinical use of Sotalol
Life threatening Ventricular arrhythmias
Maintenance of sinus rhythm in patients w a fib
Side effects of sotalol
Depressed cardiac function
QT torsades
Clinical use of ibutilide/dofetilide?
Restore sinus rhythm in a fib and maintain sinus rhythm after cardioversion in those w a fib
Adverse effects of ibutilide/dofetilide?
QT prolongation and increase risk for ventricular arrhythmias
What are the class 4 anti-arrhythmics?
Verapamil, Dilitiazem
MOA of class 4 anti-arrhythmics?
block L-type calcium channels
-slow SA node depolarization
What effect do class 4 anti-arrhythmics have on AP?
Prolong ERP and PR interval
Clinical use of Verapamil, Dilitiazem?
Termination of PVST and ventricular rate control in a fib and flutter
Adverse effects of Verapamil, Dilitiazem?
Negative inotropy, AV block, SA arrest, bradycardia
Constipation and gingival hyperplasia (verapamil only)
MOA of adenosine?
Activates A1 receptor on Gi-coupled GPCR
-enhances K+ efflux and inhibits Ca2+ influx
Causes marked hyperpolarization, slowing AP
Effect of adenosine on AP?
Prolongs QT interval and ERP
Indication of adenosine?
PVST conversion to sinus rhythm
Adverse effects of Adenosine?
SOB, bronchospasm, chest burning, flushing, AV block
What is a proarrhythmia? What can cause it?
A proarrythmia is a drug induced new arrhythmia or worsening of an existing arrhythmia
-Flexainide can cause this
What are the non-pharm options to treating arrhythmias?
Catheter ablation
Implantable defibrillator
Artificial pacemaker
Direct current cardioversion
Which drug classes cause torsades?
Class 1A and Class 3
-slide 44
Which drug classes can cause excessive slowing of the heart and lead to persistent V-tach
Class 1A and 1C
-slide 44
Drugs to control rhythm in A-fib?
Class 1C drugs: reduce retrograde conductance Flecainide and propanefone
Class 3 drugs: terminate reentry by prolonging refractory period
-amiodarone, sotalol, ibutilide/Dofetilide
If a patient has a-fib with HF, what drug classes can you use?
Class 3 only
-1C contra in unhealthy hearts!
If a person has A-fib w/o HF, what drug classes can you use?
Class 1C or 3
Pharmological Rate control in A-fib if person has HF?
B-blocker
Pharmological Rate control in A-fib if person w/o HF?
CBB or B-blocker
Will you need to do anti-thrombotic therapy in someone with A-fib?
Yes, most of the time it is needed!
PSVT non-pharm treatment?
Vagal maneuvers
What is the preferred treatment in PSVT?
Vagal maneuvers->Adenosine is first
To prevent PVST episodes, what is first line?
Verapamil and Diltiazem
What drugs can cause torsades?
1a and 3, as well as hydroxychloroquine and azithromycin
-stop them, and torsades will stop
If pt is hemodynamically unstable with torsades, how would you treat?
Direct current cardioversion
If pt is hemodynamically stable with torsades, how would you treat?
correct electrolyte imbalance, MgSO4, may need pacemaker