Unresponsive heart rate

[rogergordon]

I am 69 years old and had a mitral valve repair last September, immediately following which I was in atrial fibrillation and given Amiodarone and Warfarin. This has now settled and I now have first degree heart block and am doing a cardiac rehab programme. My resting heart rate is 80 and my target exercise range is 101 - 113 but it only goes up to 98 during exercise (15 on Borg scale). Can you suggest what is causing this and what the implications / remedies may be.
Many thanks, R

[rogergordon]

Many thanks for the advice which makes a lot of sense.  Will be seeing the cardio at the end of the month.  Having a better understanding of my condition will help me to get the most from this.
R

[itdood]

It's probably the first degree heart block.  That slows conduction.  The heart cycle takes a bit longer.  

In general 1st degree heart block is not treated if there aren't any symptoms.  If it isn't broken, don't fix it!

I think doing the cardiac rehab is your best bet.  If it improves, great.  If it stays the same, you won't be breaking any marathon records but life is good.  If the heart block becomes symptomatic, cross that bridge when you get there, you will still have options.