Inappropriate Sinus Tachycardia and Echocardiogram

I am a 51 year old male, 6 feet two inches and 185 pounds. During the last few years I have been experiencing fairly consistent high resting heart rates (about 100), and what seem to be inappropriately high rates with even limited activity (120 to 130 while just shaving, 150 while walking in yard).  I have had various holter monitors, and the conclusion has been that I have inappropriate sinus tachycardia. My heart rate is fast but in a normal sinus rhythm.  I was told to not be concerned about it. About six months ago I started to notice premature beats that were quite significant - I would get a feeling of pressure up into my throat.  After monitoring I was told I have PACs, and that they are nothing to be concerned about. Coincident with the PACs, I started to feel shortness of breath and fatigue with limited exertion.  This continues.  I just had a resting echocardiogram and a myoview stress test, and was told that they were fine, except an abnormal relaxation pattern of diastolic filling on the echo - again, told nothing to worry about.  However, the values were as follows:  E/A: 0.6, DT: 68 msec, Em velocity: 0.06 m/sec and E/Em ratio: 7.  I have done some research and seem to have found that these numbers are all abnormal. I am concerned about this abnormal finding. (The DT looks particularly unusual.) Could my high heart rate have damaged my heart and have caused the abnormal relaxation pattern, and could the abnormal relaxation pattern be causing me to feel short of breath and fatigued? What should one do next?  My cardiologist is saying to do nothing.

[Michael J. McWilliams, M.D.]

Could my high heart rate have damaged my heart and have caused the abnormal relaxation pattern, and could the abnormal relaxation pattern be causing me to feel short of breath and fatigued?

The truth of the matter is that we do not know for sure what causes inappropriate sinus tachycardia.  We also do not know if slowing the the heart rate with medications like beta blockers or calcium channel blockers helps in any way.  

It is possible that the faster heart rates are causing an abnormal relaxation pattern.  I personally do not use the numbers and ratios you used above.  I use a different method to assess diastolic function (filling patterns).  Decreased filling time (faster heart rates) does affect diastolic function.  I am not sure if this reflects "damage" to your heart or simply a value that is affected by fast heart rates.


What should one do next?

If you are short of breath, I personally would start a beta blocker or a calcium channel blocker to slow the heart rate.  If these medications did not help, I would not do anything further.  Some people/institutions will do sinus node modifications to decrease the sinus rate. there is not great data to support this and this does not mean that your doctor is doing something wrong.  In the EP world this is a relatively common problem that is not well studied.

I think my answers only point out that the reason you feel like you are not getting good answers is because we don't know the answers yet.

I hope this helps.  thanks for posting.