Heart rate drop

When exercising (biking, elliptical machine or walking hills), my pulse can suddenly drop from 120/145 to 85/105. (I wear a chest strap pulse meter.)  It takes some time to recover. The explanation given is that a PVC will cause this. Needless to say a drop from 135 to 85 is quite a challenge while working fairly hard. Lately these drops have become more frequent and make it tough to keep exercising. Any thoughts?


Heart rate drop

by Leofred - 2018-05-15 21:27:35

Thank you; I do have a pacemaker and have had one for 4 years. I think electrolyte imbalance may be the key as it has come on more frequently as I have been about 1 month into a strict diet and drinking perghaps too much water. Before the pacemaker insertion, I had a complete AV blockage at rest althiough the heart performed quite well during exercise. I also had atrial flutter that was resolved by an ablation. I very recently had a stress  test that showed no ischemia. 

go back

by Tracey_E - 2018-05-16 14:19:26

First advice is when it drops like that, stop exercising when it happens. It's really hard on the body when you are suddenly getting half the oxygen it needs. 

I'm no doctor, but pvc's as the cause don't make sense. Pvc's are extra half beats, shouldn't have anything to do with heart rate or pacing. If I had to bet, I'd say your settings need tweaked. Was the stress test chemical or treadmill?  I had similar things happen twice. Once was the pacer. I was going fast enough that it thought I was in afib and cut my rate in half. Great feature if you're in afib, like hitting a wall if you're just working out. The other time my heart was suddenly plummeting. They turned in a feature (rate drop?) so that my rate couldn't suddenly drop, the pacer would kick in and keep it up. 

If you talked to a nurse or tech, go back and talk to the doctor, preferably an ep. If the stress test didn't duplicate the drops, ask to do it again, or get a Holter. Push for answers,  they should be able to program it so you don't suddenly have drops. 


Heart rate drop

by Leofred - 2018-05-16 21:33:19

Thank you. I think I may have solved why the problem has gotten so much worse very recently. The last few days I have drunk less water , eaten more food and ate more potassium rich foods. Today the drop only occurred twice briefly and not until my pulse had been in the 140s for some time. My maximum setting is 170 so your thought of pseudo afib shouldn't be the cause. I will check again about other settings. The stress test was chemical as the cardiologist said a normal stress test doesn't work right for a person with a pacemaker. The personnel doing the test agreed with the cardiologist.

stress test

by Tracey_E - 2018-05-16 22:36:37

The reason for doing it on the treadmill isn't the same as the reason for doing it chemical. With a chemical stress test, they want to see how the heart functions under exertion. On the treadmill, they can see exactly what happens when you exert, when your rate drops. It can be a helpful tool for programming the pacer. It won't show funtion as well, but that's not the point of doing it in this case. 

If you were nowhere near your upper limit, then it was not the afib safety thing. 

Diet doesn't usually have a direct impact on the electrical system of the heart. Dizziness and fatigue, yes. Blood pressure, yes. Heart rate, not so much. Whatever the cause, when you have a pacer there's no reason to put up with sudden drops. 

I think the feature they turned on for me was called rate drop response. It watches for sudden drops and kicks in with atrial pacing to keep the rate steady. If it's a slow drop, like the heart rate coming down normally after exertion, it doesn't do anything. I only need this when working out, it doesn't kick in any other times. I primarily have the pacer for av block. 

Rate drop

by Wired28 - 2018-05-23 19:28:28

really interesting comments TraceyE. I’ve been having the same issue when I do strenuous exercise. It seems to come and go, sometimes I don’t have an issue for months then it reappears again. I’m 54 pretty fit and I ride horses and when working really hard 160ish (upper limit 170) I can suddenly crash to 80 then go down to 55 and stay there for 15min then it jumps back up to say100. Very hard to do anything during  that time. I have a medtronic dual chamber that was put in for heart block and bradycardia so do you think this rate drop response program is an option for me?

Heart rate drop

by Leofred - 2018-09-18 15:47:15

Since I originally posted my comment on significant heart rate drop during exercise (140s to 80s), I believe I have mostly resolved the problem for me. My cardiologist and Medtronic both said that the drop was caused by PVCs causing the heart to basically need a re-set. As I researched PVCs online, one of the potential causes was caffeine. I stopped all caffeine prior to execise about 2 months ago. (caution "decaf" coffee has enough caffeine to trigger them for me) and the only time I had a big drop occur was the morning after taking a 12 hour Sudafed which also can act as a heart stimulant. It's so nice to do hard exercise without the sudden drop and the fatigue that then accompanies the workout. So I don't have any caffeine the day of exercise until after the workout and then fairly small amounts, if any. For me, that works but it's only one potential cause of PVCs so it won't work for everyone.

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