Very low resting heart rate - what could be wrong!

My heart rate averaged in the 40’s and would dip to 39 rarely and I also had AFIB. My cardiologist put in a pacemaker to keep my heart rate at 60. However, this was not done until I kept records from my apple watch, offering the cardiologist facts and printed charts of my heart rate. I suggest you compile data from your smartwatch and schedule another cardiology visit in a few months.

Isadora, congratulation on beating cancer.
Push for answers; ask for a Holter Monitor.
Low resting heart rate is common for elite athletes. And with abdominal cancer treatment low heart rate increases survival rates. But abdominal cancer and treatments can cause damage to the heart's electrical system that might not be evidenced on the few seconds captured on an office ECG.
Rainyday's advice is well taken.
You shouldn't have any trouble getting the holter.

I'd second Gently's suggestion to contact your physician ( ?cardiologist) about your low heart rate, especially if it's continuing and you're feeling bad as a result of this heart rate. A heart rate monitor ( either a Holter or one of the longer monitoring monitors) should give you, and your doctor a good picture of what is happening with your heart.
Your heart rate may well be a lower rate ( normal for you) as a result of your athletic activity, but how low is normal for you? If you're symptomatic with those lower heart rates it seems to me that could be a problem that needs to be checked out.

And congratulations on your achieving the NED status with your cancer. Best wishes that it will stay that way for a long, long time!

My own history, certainly I have not been through your challenges,
When my heart had been dropping to the 40’s, my doctor insisted on a pacemaker. Ask your doctor about a pacemaker. I’m on my 4th pacemaker. The first one in 1998!
Blessings and congratulations on your NED status as well!

@verdine Thank you so much for sharing your own experience. Very helpful to know I’m not necessarily making a fuss about nothing. Because of my background, it makes it easy to shrug and put it down to treatment. Even if it is treatment related it’s good to know there are still potential options.

Thank you. I will go and see my GP again.

@rainyday541 Thank you for sharing that.

Absolutely. It’s been my smartwatch which has made me aware of how much things have changed. I’ll definitely take my smartwatch data back to my GP for further referral. Thank you.

@marybird Thank you for that suggestion of asking my GP for a proper medical heart rate monitor to wear for a while. Now that you mention it I recall a friend some time ago needing to wear one after taking her smartwatch data into her GP.

Thank you too for the support! I’ve been so lucky. Cancer changes so much, but I’ve been lucky to not just be alive but get off relatively unscathed physically. I’m aware that delayed side effects can pop up at any time. Trying hard not to be over reactive to changes but also not let something go that I shouldn’t. Thank you.

@isadora2021 Isadora,
You may have to ask for a cardiologist referral from your internest.
Sometimes we have to be our
Own advocate.
God Bless!

isadora 2021, while it doesn't seem that you have need for immediate help, you should be able to send a note to the doctor telling them that you would like to have Holter monitoring. If you experience the low rate every day 24 hours might capture it. Monitoring can be extended to 48 hours or more.
You shouldn't need another appointment with the PCP to have this ordered. Some PCP offices have the equipment. If your doctor's office doesn't, your primary should honor your request for a referral, maybe to a Cardiac electrophysiologist.

@verdine Thank you!