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Can AV Conductance Disturbance Cause Bradycardia In A Heart Patient?
Question: Hello Dr. Sharka,
You've answered several cardiology questions for me in previous months, all relating to my Dad who is 78 and had a heart attack 3 and-a-half years ago. (Most recently on April 13th of this year.)
As things are right now, he very definitely has a bradycardia problem. We have a good picture of his heart rate because it's essentially monitored 24-hours a day. He wears an sleep and activity-tracking watch that records your heart rate, your motion (in steps), your skin temperature, AND and it does an incredible job of automatically recording your sleep --- even identifying when you go into and out of Light sleep, REM sleep, and Slow Wave sleep; and it tracks the number of times you turn over and get up. We really love everything this watch collects. I were one myself. So I can say with confidence that my Dad's overall, average 24-hour heart rate is currently 50 bpm. Looking at his sleeping hours, it's typically between 41 and 44 bpm the entire night. Although there have been a few nights every couple of weeks where it has gone down to 37 bpm for a couple of hours during the night. During the the day, it tends to be about 46 when at rest, and only getting into the 80's when he's active, in the garden, of walking intentionally. About 8 months ago, he had an Afib episode that wasn't resolved for about four months. To help resolve it, his doctor increased his metoprolol dosage twice, to a high of 25mg twice a day. Went he went back into normal sinus rhythm, his doctor wanted to leave him on 12.5mg twice a day of metoprolol. (Also at that time he was taking 10mg of lisinopril twice a day. We switch to losartan two weeks ago because of a long-standing cough.) But about four weeks ago, his doctor dropped his metoprolol down to 12.5mg once a day, and we expected his heart rate to finally get back up to well above 50. But it went up for two days, about two points, them settled back down to 49/50 bpm. Now the obvious question, is whether or not he is having any symptoms. And the answer to that is yes. His energy level is very low. He gets light headed if he stands up too quickly. The architecture of his sleep is fragmented. And he mind is foggy. So hopefully, that is sufficient background for you to answer the following three questions. If not you can ask me to elaborate on anything you need.
1) First, is there anyway for us to know, before we see the electrophysiologist on Thursday, if his bradycardia is in fact an electrical problem, and if it is a problem with the Sinus node, or with the AV node? (You may remember that I have a rudimentary, 3-lead EKG sensor.)
2) Next, I'm guessing that his doctor is unlikely to take him off the beta blocker and ACE inhibitor before putting in a pacemaker, just to see if his heart rate would come up without those meds. Would you agree?
3) That said, if he does have a pacemaker put in, is there any reason he would have to continue taking either amiodarone or motoprolol or losartan. (He doesn't have hypertension--just the opposite.) So what meds. WOULD he likely have to take if he got a pacemaker?
That's it for the moment. I will await your learned reply.
Thank you very much.
XXXX
You've answered several cardiology questions for me in previous months, all relating to my Dad who is 78 and had a heart attack 3 and-a-half years ago. (Most recently on April 13th of this year.)
As things are right now, he very definitely has a bradycardia problem. We have a good picture of his heart rate because it's essentially monitored 24-hours a day. He wears an sleep and activity-tracking watch that records your heart rate, your motion (in steps), your skin temperature, AND and it does an incredible job of automatically recording your sleep --- even identifying when you go into and out of Light sleep, REM sleep, and Slow Wave sleep; and it tracks the number of times you turn over and get up. We really love everything this watch collects. I were one myself. So I can say with confidence that my Dad's overall, average 24-hour heart rate is currently 50 bpm. Looking at his sleeping hours, it's typically between 41 and 44 bpm the entire night. Although there have been a few nights every couple of weeks where it has gone down to 37 bpm for a couple of hours during the night. During the the day, it tends to be about 46 when at rest, and only getting into the 80's when he's active, in the garden, of walking intentionally. About 8 months ago, he had an Afib episode that wasn't resolved for about four months. To help resolve it, his doctor increased his metoprolol dosage twice, to a high of 25mg twice a day. Went he went back into normal sinus rhythm, his doctor wanted to leave him on 12.5mg twice a day of metoprolol. (Also at that time he was taking 10mg of lisinopril twice a day. We switch to losartan two weeks ago because of a long-standing cough.) But about four weeks ago, his doctor dropped his metoprolol down to 12.5mg once a day, and we expected his heart rate to finally get back up to well above 50. But it went up for two days, about two points, them settled back down to 49/50 bpm. Now the obvious question, is whether or not he is having any symptoms. And the answer to that is yes. His energy level is very low. He gets light headed if he stands up too quickly. The architecture of his sleep is fragmented. And he mind is foggy. So hopefully, that is sufficient background for you to answer the following three questions. If not you can ask me to elaborate on anything you need.
1) First, is there anyway for us to know, before we see the electrophysiologist on Thursday, if his bradycardia is in fact an electrical problem, and if it is a problem with the Sinus node, or with the AV node? (You may remember that I have a rudimentary, 3-lead EKG sensor.)
2) Next, I'm guessing that his doctor is unlikely to take him off the beta blocker and ACE inhibitor before putting in a pacemaker, just to see if his heart rate would come up without those meds. Would you agree?
3) That said, if he does have a pacemaker put in, is there any reason he would have to continue taking either amiodarone or motoprolol or losartan. (He doesn't have hypertension--just the opposite.) So what meds. WOULD he likely have to take if he got a pacemaker?
That's it for the moment. I will await your learned reply.
Thank you very much.
XXXX
Brief Answer:
I would explain as follows:
Detailed Answer:
Hello XXXX!
It's a pleasure to have a discussion about these important cardiac issues and to be helpful for your Dad's medical treatment.
I reviewed again your Dad's medical history (prior myocardial infarction, heart failure, 3 months atrial fibrillation, his current therapy, etc).
I would like to explain as follows:
(1) Regarding his bradycardia, I exclude an AV conductance disturbance (there are no medical data to support this option).
A sinus node dysfunction sometimes could be an option in ischemic cardiac patients with persistent symptomatic bradycardia and history of atrial fibrillation, but this needs a more profound investigation.
It is hard to think clearly of a separated distinct elctrical system dysfunction of the heart, as long as your Dad is using a potent bradycardic combination (Amiodarone & Metoprolol). The electrophysiologist would need to ask your dad to wean off his bradycardic medications (at least Amiodarone) before planning a possible electrophysiological study. Nevertheless, it depends on the electrophysiologist's discretion to make a certain decision on a selected diagnostic strategy.
On my personal opinion, I think that there is a need for therapy modulation, facing this persistent and especially symptomatic bradycardia. I would stop Metoprolol and wait for a couple of days before judging any further decision about Amiodarone.
(2) Regarding a medical strategy for differentiating the origin of his symptoms (low energy, light headed, foggy mind, etc), it is important to investigate other possible reasons (to clarify the role of a low LV EF, and decreased cardiac output regarding his insufficient physical performance, investigate other potential metabolic disorders, like thyroid dysfunction, low hemoglobin, neurological status, renal dysfunction which may lead to drug accumulation and toxicity, etc). A new cardiac ultrasound review an the underlying blood tests are necessary to check again.
I agree with you that, it is important to check again the overall cardiac status after therapy modulation (stopping Metoprolol, adjusting at least temporarily Amiodarone dose, ex reducing to a half actual dose), before drawing to inappropriate conclusion of a pacemaker implantation.
We have to definitely exclude excessive medical implications before arriving to the idea of any separated intrinsic electrical heart system disturbances.
(3) If we arrive to the point a pacemaker is indicated (a possible sinus node dysfunction, etc), the reason why Amiodarone should be continued is the fact that pacemaker does protect against bradicardia and extreme bradyarrhythmia, but does not offer any solution regarding tachyarrhythmias (like atrial fibrillation, ventricular arrhythmia, etc). So an effective antiarrhythmics would be necessary.
A very important and helpful option would be to discuss about a possible CRT (cardiac resynchronization therapy), which would offer a possibility of a much better overall cardiac performance (increase LV EF, increase cardiac output, improve HF symptoms, decrease the risk serious arrhythmias, reduce the need for complex medical therapy, etc). But, a comprehensive evaluation by his electrophysiologist should be performed to ascertain whether underlying CRT criteria are met.
Hope that the above opinion would be useful for you!
Feel free to ask me whenever you have any uncertainty to resolve!
Greetings! Dr. Iliri
I would explain as follows:
Detailed Answer:
Hello XXXX!
It's a pleasure to have a discussion about these important cardiac issues and to be helpful for your Dad's medical treatment.
I reviewed again your Dad's medical history (prior myocardial infarction, heart failure, 3 months atrial fibrillation, his current therapy, etc).
I would like to explain as follows:
(1) Regarding his bradycardia, I exclude an AV conductance disturbance (there are no medical data to support this option).
A sinus node dysfunction sometimes could be an option in ischemic cardiac patients with persistent symptomatic bradycardia and history of atrial fibrillation, but this needs a more profound investigation.
It is hard to think clearly of a separated distinct elctrical system dysfunction of the heart, as long as your Dad is using a potent bradycardic combination (Amiodarone & Metoprolol). The electrophysiologist would need to ask your dad to wean off his bradycardic medications (at least Amiodarone) before planning a possible electrophysiological study. Nevertheless, it depends on the electrophysiologist's discretion to make a certain decision on a selected diagnostic strategy.
On my personal opinion, I think that there is a need for therapy modulation, facing this persistent and especially symptomatic bradycardia. I would stop Metoprolol and wait for a couple of days before judging any further decision about Amiodarone.
(2) Regarding a medical strategy for differentiating the origin of his symptoms (low energy, light headed, foggy mind, etc), it is important to investigate other possible reasons (to clarify the role of a low LV EF, and decreased cardiac output regarding his insufficient physical performance, investigate other potential metabolic disorders, like thyroid dysfunction, low hemoglobin, neurological status, renal dysfunction which may lead to drug accumulation and toxicity, etc). A new cardiac ultrasound review an the underlying blood tests are necessary to check again.
I agree with you that, it is important to check again the overall cardiac status after therapy modulation (stopping Metoprolol, adjusting at least temporarily Amiodarone dose, ex reducing to a half actual dose), before drawing to inappropriate conclusion of a pacemaker implantation.
We have to definitely exclude excessive medical implications before arriving to the idea of any separated intrinsic electrical heart system disturbances.
(3) If we arrive to the point a pacemaker is indicated (a possible sinus node dysfunction, etc), the reason why Amiodarone should be continued is the fact that pacemaker does protect against bradicardia and extreme bradyarrhythmia, but does not offer any solution regarding tachyarrhythmias (like atrial fibrillation, ventricular arrhythmia, etc). So an effective antiarrhythmics would be necessary.
A very important and helpful option would be to discuss about a possible CRT (cardiac resynchronization therapy), which would offer a possibility of a much better overall cardiac performance (increase LV EF, increase cardiac output, improve HF symptoms, decrease the risk serious arrhythmias, reduce the need for complex medical therapy, etc). But, a comprehensive evaluation by his electrophysiologist should be performed to ascertain whether underlying CRT criteria are met.
Hope that the above opinion would be useful for you!
Feel free to ask me whenever you have any uncertainty to resolve!
Greetings! Dr. Iliri
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Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Answered by
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