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What Causes Recurring Tachycardia With History Of SVT And RF Ablation?

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Posted on Tue, 12 Apr 2016
Question: 56 y.o. male with h/o of SVT and RF ablation of AV node slow pathway in July 2015. Extensive workups (chest x-ray, thallium stress test, ultrasound, etc.) prior to the ablation revealed no structural abnormalities and a CHADS2 score of 0. Apart from increased PACs, I hadn't noticed any tachycardia until recently. However, for the past several weeks, I've been experiencing exercise induced tachycardia, almost exclusively while lifting weights. While engaging in cardio type activities, I notice only occasional PACs but no tachycardia that I couldn't otherwise attribute to exercising. The tachycardia typically lasts from 30-45 seconds and is NOT associated with any other symptoms such as shortness of breath, dizziness or chest pain. Of course, it makes me anxious when this occurs so I'm not sure how much I'm contributing to the tachycardia, although I am not aware of being anxious when the tachycardia begins. Is this most likely a recurrence of the SVT or possibly NSVT? Is it possible/likely that the structure of my heart has changed since July 2015? Why would weightlifting, but not cardio, produce the tachycardia? Thanks so much for your consideration.
doctor
Answered by Dr. Ilir Sharka (2 hours later)
Brief Answer:
I would explain as follows:

Detailed Answer:
Hello,

I passed carefully through your medical history and would explain that strenuous physical exertion by increasing the level of circulating catecholamines may trigger tachycardia.

Tachycardia is more likely to be normal sinus tachycardia or supraventricular tachycardia (SVT).

Facing your normal cardiac structure and function (excluding also cardiac ischemic disorder by actually performed tallium stress test) non-sustained ventricular tachycardia (NSVT) is almost excluded.

And there is not any rational reason why this structurally normal heart would change.

This latter conclusion (almost nonexistent possibility of VT) is supported also by the absence of the underlying clinical symptomatology (dyspnea, dizziness, chest pain, etc.) commonly obvious in the case of ventricular arrhythmia (VT).

But, only by your subjective feeling of palpitations is impossible to differentiate between a normal sinus tachycardia and any supraventricular tachycardia (SVT).

In such case a useful tool in the correct diagnosis would be an ambulatory 24 to 48 hours ECG monitoring (Holter).

The reason why you experience tachycardia more frequently during weights lifting than cardio training, is the fact that weight lifting is part of strength training and as such by releasing greater amounts of circulating catecholamines (compared to cardio training) imposes a sudden pressive burden on body circulation, produces a fast and pronounced anaerobic response and promotes a prompt compensatory sinus tachycardia mimicking a supraventricular tachycardia.

That's why you are feeling this difference.

My advice is to not worry too much, as it doesn't seem to be any dangerous arrhythmia issue in the horizon.

Just try to discuss with your attending cardiologist (or internist) for the possibility of Holter monitoring during those strenuous exertions (eight lifting). This would definitely clarify this issue.

I personally recommend performing a more gradual training and under close supervision of a certified expert, as a very strenuous and excessive exertion may be dangerous in every normal individual.

Hope to have been helpful to you!

In case of any further uncertainties, feel free to ask me again.

Kind regards,

DR. Iliri




Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Ilir Sharka (11 minutes later)
Dr. Sharka...thanks for your rapid and thorough response. It was quite helpful. I've actually been weight training since I was 16 years old and the weights I've been using recently are quite light since I recently suffered a rib strain. So whether a sinus tachycardia or an SVT, is it safe to continue weight lifting, either before or after my heart rate has gone down? Very happy to hear that a ventricular tachycardia is all but ruled out!
doctor
Answered by Dr. Ilir Sharka (13 minutes later)
Brief Answer:
My opinion:

Detailed Answer:
Hello again,

I am glad to hear you are a well trained person. But, you shouldn't forget that our physical performance declines with aging.

Also our compensatory cardiovascular mechanisms (maximal theoretical heart rate, anaerobic threshold, overall endurance, etc) follow the same trend.

That's why lighter weights produce the same effects.

At the end, weights lifting, whichever be the workload remains a pressive stress over blood circulation by increasing cardiac afterload.

I would recommend cardio training a more suitable for you age. It is a dynamic training, imposing greater beneficial effects over blood circulation and the entire psychological and physical health.

Regards,

Dr. Iliri



Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
default
Follow up: Dr. Ilir Sharka (19 hours later)
Thank you again for your response. Just to be sure that I am understanding, since I have no associated symptoms with the tachycardia (such as shortness of breath, dizziness, pain) and since it is unlikely that my heart has changed structurally since last March, I should not be particularly worried about the tachycardia that occurs during exercise. Am I understanding correctly?

I started a 2 week event monitor yesterday afternoon, so hopefully that will clarify the problem. In the meantime, though you recommend cardio over weights for someone my age, is there a cardiac-related reason to not continue to lift weights while undergoing the event monitor (I assume it would be helpful to try to elicit the tachycardia so it can be recorded). Similarly, should I limit the intensity of my cardio workouts? Finally, while the exercise induced tachycardia has always resolved quite quickly, at what point should I seek medical attention if the tachycardia does not resolve?

Thanks again for your prompt and thorough responses.
doctor
Answered by Dr. Ilir Sharka (4 hours later)
Brief Answer:
I would explain:

Detailed Answer:
Hello,

You are quite right that under cardiac rhythm monitoring, it is advisable to follow the same daily life-style and physical activity.

So, you should continue performing weights lifting as usual at least these two weeks.

As I explained you above, facing your clinical symptomatology and the performed tests, I don’t believe your palpitations are an expression of a ventricular arrhythmia.

So, on my opinion, I would not discourage you from keeping the same physical training schedule.

The only point to consider is the conclusion that from a medical viewpoint, there is not any advantage of weights lifting over cardio training regarding health benefits.

Coming to this point it is better to practice a safer and more comfortable sport.
Nevertheless, you are free to exert the training you prefer, as long as no disturbing symptomatology occurs.

In the latter case you should discontinue that kind of training and consult with your doctor.

In case of chest pain, important dyspnea, or incessant arrhythmia you should seek immediate medical assistance.

If your training program is monitored by a licensed expert, potential adverse effects would be minimized.

Wishing you a good health!

Regards,

Dr. Iliri

Note: For further queries related to coronary artery disease and prevention, click here.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
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Answered by
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Dr. Ilir Sharka

Cardiologist

Practicing since :2001

Answered : 9536 Questions

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What Causes Recurring Tachycardia With History Of SVT And RF Ablation?

Brief Answer: I would explain as follows: Detailed Answer: Hello, I passed carefully through your medical history and would explain that strenuous physical exertion by increasing the level of circulating catecholamines may trigger tachycardia. Tachycardia is more likely to be normal sinus tachycardia or supraventricular tachycardia (SVT). Facing your normal cardiac structure and function (excluding also cardiac ischemic disorder by actually performed tallium stress test) non-sustained ventricular tachycardia (NSVT) is almost excluded. And there is not any rational reason why this structurally normal heart would change. This latter conclusion (almost nonexistent possibility of VT) is supported also by the absence of the underlying clinical symptomatology (dyspnea, dizziness, chest pain, etc.) commonly obvious in the case of ventricular arrhythmia (VT). But, only by your subjective feeling of palpitations is impossible to differentiate between a normal sinus tachycardia and any supraventricular tachycardia (SVT). In such case a useful tool in the correct diagnosis would be an ambulatory 24 to 48 hours ECG monitoring (Holter). The reason why you experience tachycardia more frequently during weights lifting than cardio training, is the fact that weight lifting is part of strength training and as such by releasing greater amounts of circulating catecholamines (compared to cardio training) imposes a sudden pressive burden on body circulation, produces a fast and pronounced anaerobic response and promotes a prompt compensatory sinus tachycardia mimicking a supraventricular tachycardia. That's why you are feeling this difference. My advice is to not worry too much, as it doesn't seem to be any dangerous arrhythmia issue in the horizon. Just try to discuss with your attending cardiologist (or internist) for the possibility of Holter monitoring during those strenuous exertions (eight lifting). This would definitely clarify this issue. I personally recommend performing a more gradual training and under close supervision of a certified expert, as a very strenuous and excessive exertion may be dangerous in every normal individual. Hope to have been helpful to you! In case of any further uncertainties, feel free to ask me again. Kind regards, DR. Iliri