Atrial Fibrillation

[Fran60]

I have Hypertrophic Obstructive Cardiomyopathy and sinus bradycardia/tachycardia which have been well controlled with a pacemaker, a betablocker and a calcium channel blocker. Atrial Fibrillation is now a further complication and is treated with Warfarin and controlled with Amiodarone (which has led to hypothyrodism) and shortness of breath is a recurring issue. Apart from Dronedarone, are there any other suitable drugs to treat the combination of HOCM and Atrial Fibrillation?

[Professor William McKenna]

Usually once AF is established, the heart rate can be controlled with a beta blocker + /- a calcium antagonist, and amiodarone is rarely required for rate control. It is useful to review why the amiodarone was started in the first place. It probably was for AF prevention, and if so, it would no longer be needed. If it was started for prevention of ventricular arrhythmia, then more detailed assessment will be needed to determine safety/appropriateness of discontinuing. If it is needed, concomitant treatment with thyroid replacement is usually feasible. If amiodarone is not required for ventricular arrhythmias, then it would be best to discontinue as it is a complex drug and there are probably easier ways to control the heart rate.

[Fran60]

Professor McKenna,
Thank you for your outline for the use of amiodarone. You seem to suggest that without the presence of ventricular arrythmias, amiodarone is preferably avoided. When in AF, my exercise capacity is reduced and there is discomfort in my chest. I am always concerned that my expectations for my quality of life are too high and that perhaps it's time to moderate my expectations. Having said that, are some betablockers or calcium channel blockers more suited to treating AF? Until AF occurred, I was very well and happy with atenolol and amlodipine.

[Professor William McKenna]

Thank you. You should review with your cardiologist the ongoing indication for amiodarone. If it is for rate control in AF, it is probably not necessary. If it is for ventricular arrhythmia, it may well be indicated and an important treatment.

Your reduced exercise capacity, which you associate with the AF, is a concern to you. This may be because the heart rate response during exercise is inadequate, or because the heart rate response is excessive. A 24 hour ECG and/or exercise test will enable your cardiologist to advise.