All concepts, explanations, trials, and studies have been
re-written in plain English and may contain errors. I am
not a doctor
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Class 1 (INa block) - sodium channel blockers
These drugs slow conduction:

Class 1A drugs, for ventricular arrhythmias,
narrow QRS tachycardia, a-fib:

procainamide (Procan, Pronestyl)
quinidine (Quinidex, Cardioquin)
disopyramide (Norpace)

Class 1B drugs, for ventricular arrhythmias:
These drugs shorten repolarization:

lidocaine (Xylocaine)
mexiletine (Mexitil)
moricizine (Ethmozine)
phenytoin (Dilantin)
tocainide (Tonocard)

Class 1C drugs are powerful for converting a-fib and for
maintaining sinus rhythm but can only be used in patients
with structurally normal hearts.
	Ventricular premature beats are an independent risk
factor for Sudden Cardiac Death. Class 1C antiarrhythmic
drugs suppress these premature contractions, significantly
slowing conduction:

cibenzoline
encainide - 12% of patients have arrhythmogenic drug effect
flecainide (Tambocor) - high proarrhythmic risk
propafenone (Rhythmol)
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Class 2 (anti-adrenergic) - beta-blockers 
For ventricular arrhythmias, a-fib.
These drugs have zero arrhythmogenic drug effect.

acebutolol (Sectral)
atenolol (Tenormin)
betaxolol (Kerlone)
bisoprolol (Zebeta)
bucindolol
carvedilol (Coreg)
esmolol - ultra-short-acting beta blocker, often useful
          in controlling ventricular response within
          15 minutes.
metoprolol (Toprol, Lopressor)
nadolol (Corgard)
propranolol (Inderol)
timolol (Blocadren)

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Class 3 (IK block) - potassium channel blockers
For ventricular arryhthmias, narrow QRS tachycardia, a-fib.
These drugs lengthen repolarisation without affecting
conduction.

amiodarone (Cordarone)
azimilide - has both IKr and IKs blocking properties
bepridil
bretylium tosylate
clofilium
dofetilide (Tikosyn) - Dofetilide is the prototype "pure"
                       or "simple" class 3 anti-arrhythmic
                       drug. It was approved in late 1999
                       by the FDA for managing A-fib. It
                       is a highly selective drug that
                       delays repolarization in the atria,
                       ventricles, and Purkinje fibers by
                       IKr blockade.
ibutilide (Corvert)
d-Sotalol or l-Sotalol (not the same as sotalol)
sotalol (Betapace) - proarrhythmia occurs in about 4%
                     of patients and torsades de pointes
                     occurs in about 2.5%. Most episodes
                     of torsades de pointes occur within
                     3 days of starting sotalol therapy.
                     Risk of torsades de pointes
                     increases sharply at doses over 320mg
                     daily.
tedisamil
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Class 4 (ICa-L block) - Calcium channel blockers
These drugs lower blood pressure through vasodilation
and may decrease the strength of the heart's pumping.
Not to be taken by CHFers in general.
For narrow QRS tachycardias:

amlodipine (Norvasc, Lotrel)
bepridil (Vascor)
diltiazem (Cardizem)
gallopamil
verapamil (Covera, Isoptin, Calan)
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arrhythmogenic drug effect = the occurrence of a new form of
ventricular tachyarrhythmia associated with start of drug
therapy or dose increase
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Proarrhythmia = causing new cardiac arrhythmias or
aggravation of preexisting arrhythmias by antiarrhythmic
drugs.
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IKr = the rapid rectifier current in the inflow of potassium
ions.
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IKs = the slow rectifier current in the inflow of potassium
ions.
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