Dr.S.Venkatesan MD

Which is the best drug  for  “ventricular rate  control” in atrial fibrillation  ?

1. Digoxin alone
2. Diltiazem alone
3. Atenolol alone
4. Digoxin +Atenolol
5. Digoxin + Diltiazem

The answer is 4.

This is based on a study  done by Bramh N  Singh  and his team  from California published in 1999 . (http://content.onlinejacc.org/cgi/reprint/33/2/304.pdf  )It  was  a wonderful study   involving  just  12 patients ,  still good enough to prove a  point . It was a sequential cross over study a rare theme in medical trials !  where same patients act as control .Hence bias and host variations are  nil. Few excerpts from the study .

It is very clear, for optimal rate control we need a combination regimen , Digoxin must be one of them .Atenolol combined well with Digoxin , even as though Diltiazem resulted in maximum dip in nocturnal heart rate.

Digoxin + Atenolol is clear winner in rate control during exertion as well ! Note Digoxin has absoutely no control over the heart rate at times of exercise !

Few thoughts about this study

This study has clearly documented superiority of combined drug regimen for rate control in AF .

Still it leaves a  lingering question !  Why verapamil was not used as an agent in this study  ?

If only ,  verapamil was used (As we do in our hospital )   Digoxin -Atenolol  combination would have  faced a  really  tough competiton.

Another  curiosity is  ,  what would  have  been the power of a unique combination   of Atenolol  and Diltiazem  in controlling  ventricular  rate in AF ?

Any way , it was a wonderful cross over study  . Such studies are a rare breed ,  always welcome in this world  of  funny  pharma trials  wherein  a new drug is  compared with a dud drug called placebo !

Now  . . . Try this  one

Amiodarone

1. Corrects  rhythm
2. Controls  ventricular rate
3. Does both ?

How can it correct the rhythm alone ? If rhythm is corrected ,  rate will automatically be controlled unless Amiodarone converts AF into Sinus tachyardia !

Of course  Amidarone  fais to  convert to sinus rhthm in many , still it may control the rate  by its beta blocking action.

Reference

http://content.onlinejacc.org/cgi/reprint/33/2/304.pdf