Atrial fibrillation Flashcards
What is a significance of the P wave?
Atrial contraction
what is the significance of the QRS complex?
Ventricular contraction
what is the significance of the T wave?
Ventricular repolarizations
what is the significance of the PR interval?
it is the impulse through the atria and AV node
what is the significance of the QTc interval? What is the equation?
it is the time between the ventricle polarization and depolarization
prolonged QT interval precedes torsades de pointes
QTc= QT interval/sqrt(RR interval)
RR interval is the duration of one cardia cycle
which drugs can cause proarrhythmias
Class 1A /III antiarrhytmics Macrolides Quinolones Famotidine TCAs, ziprasidone, haloperidol etc
which factors may contirbute to arrhythmias
MI
HF
Medications
what are the class 1 A antiarrhytmics
disopyramide (double)
quinidine (quarter)
Procainamide (pounder)
what are the class 1B antiarrhythmics
lidocaine (lettuce)
tocainide (tomato)
mexiletine (mayo)
Phenytoin (pickles)
what are the 1C antiarrhytmics
moricizine (more)
flecainide (fries)
propafenone (please)
what are the class 2 antiarrhythmics
beta blockers (propronolol, esmolol)
what are the class 3 antiarrhytmics
amiodarone dronaderone sotalol ibutilide dofetilide
what are the class IV antiarrhytmics?
Verapamil and diltiazem
quinidine
class 1A Qunidex, quinaglute MOA=stabilize the membrae channel by interfering with sodium channel influx I=Supraventricular Tachy, Ventricular tachycardia EKG= prolong QT, prolong QRS because block potassium channels also in phase 3 PK= strong cyp3a4 inhibitor/substrate CI= patients taking quinolines that prolong QT Se= Diarrhea* hypotension, syncope, QT prolongation, cinchonism (HA, diz, tinitus) Other: different salt forms gluconate and sulfate not interchangeable, take with food or milk, keep constant Na intake cuz dec Na inc qunidine levels DDI=digoxin(inc d) warfarin (inc INR), grapefruit juice, verapamil, diltiazem, amiodarone, erythromycin
procainamide
class 1A Pronestyl (SR)
MOA=stabilize the membrae channel by interfering with sodium channel influx
I= Supraventricular Tachy, Ventricular tachycardia
EKG= prolong QT, prolong QRS because block potassium channels also in phase 3
has metabolite NAPA that is renally cleared
SE=hypotension, bradycardia, can cause blood dyscrasias , can become ANA+
Other: take on an empty stomach, monitor x 3months for blood dyscrasia
disopyramide
class 1A Norpace MOA=interfering with sodium channel influx, negative inotrope I= Supraventricular Tachy, Ventricular tachycardia EKG=prolong QT, prolong QRS because block potassium channels also in phase 3 PK=major cyp3a4 substrate SE= strong anticholinergic CI=do not use in BPH, urinary retention, glaucoma, myasthenia gravis Other: take on an empty stomach
lidocaine
class 1B - xylocaine MOA=block sodium ion channels I=ventricular tachy, especially faolowing an MI (ischemic tissue) EKG= decrease the QT PK=hepatically eliminated SE=hypotension, hallucinations, diorientation, Other:can give in endotrachial tube but need higher dose
mexiletine
class 1B- Mexitil MOA=block sodium ion channels I= ventricular tachy EKG= shorten QT PK= SE=GI Side effects*, hypotension, hallucinations, diorientation, Other:can give in endotrachial tube but need higher dose
flecainide
class 1 c - Tambocor MOA=block sodium channels, negative inotrope I=SVT, (VT) EKG=really increase QRS PK=kidney and liver clearance CI=do not use if Structural changes to the heart like LVH, HF, CAD SE=dizziness, visual disturbance Other: not commonly used cuz pro arrhythmia, amiodarone DDI dec dose F 50%
beta blockers
esmolol, propranolol, metoprolol, atenolol
MOA= esmolol is b1 selective, propranolol is not
I=SVT, VT
EKG=increase PR segment, can cause AV block
PK=decrease the heart rate
SE=do not use propranolol with patients who hae problem breathing copd asthma
metoprolol/timolon in long-term prophylaxis in pat with an MI, esmolol short acting IV used for acute surgical arrhythmias
amiodarone
class III -Cordarone
MOA=increase refractory period, block potassium channels, Na channels, beta blocker
I=SVT, VT, most arrhythmias
EKG=prolong QT
PK=VERY LONG half-life and Vd
CI=
SE=HYPOTHYROID*/hyperthyroid, hypotension, inc LFTs, photosensitivity/blue skin discoloration if extended sun, <3% Pulmonary fibrosis (5-15%)
BBW: lung damage, liver toxicity, exacerbate arrythmias, corneal micro deposits
Other: most popular, preg cat D, dec IV50% of PO,
dronaderone
MOA=increase refractory period, block potassium channels I=SVT, VT EKG=prolong QT PK=cyp3a4 substrate, CI=class 4 HF, recent decompensated HF, QTc > 500msec, bradycardia < 50, strong cyp inhibitor, severe heaptic impairment, 400mg po SE=GI side effects Other:pregnancy category X
sotalol
class III MOA=increase refractory period, block potassium channels, non selective beta blocke I=SVT, VT Dose 80-160mg BID, adjust by CrCL EKG=prolong QT CI= If baseline QTc > 450 , betapace AF in CrCl =160mg/day, Magnesium can be given to reverse torsades de pointes w/ these agents
ibutilide
Class 3-Corvert
MOA=increase refractory period, block potassium channels
I=SVT, VT
EKG=prolong QT
PK=
SE=
Other: class 1A or 3 should be avoided withing 4 hours after infusion
dofetilide
class 3 Tikosyn MOA=increase refractory period, block potassium channels I=SVT, VT EKG=prolong QT PK=metabolized by CYP3A4 CI=baseling QTc > 440 msec, CrCl <20, cimetidine, TMP, prochlorparezine, megestrol, ketoconazole, verapamil SE= Other:mandatory 3 day hospitalization for initiation, MD must be certified to prescribe, Pharmacy msut be enrolled in TIPS to dispense
verapamil
class IV MOA=calcium channel blocker I=supraventricular arrhytmias invovling AV nodal reentry EKG= PK= CI= SE=can worsen AV block and ventricular failure Other:
diltiazem
MOA= I= EKG= PK= CI= SE= Other:
propafenone
MOA= I= EKG= PK= CI= SE= Other:
digoxin
MOA=enhances vagal tone I= EKG=increase PR PK= CI= SE= Other:
