A Heart’s Tale: Sinus Bradycardia and Right Bundle Branch Block

During my month-long sabbatical from running (due to an injury) last December 2008, I also decided to have a complete blood work-up. I had a hunch that I had high levels of uric acid. I consulted the company doctor and after reviewing my medical history, she recommended that I also take an ElectroCardioGram (ECG). (Fortunately, I can have all those tests for free courtesy of the health insurance benefit in the office).


True enough, I had high levels of uric acid, which can be treated by a prescription drug. What got me really worried was the result of my ECG. I was intimidated by the diagnosis: Severe Sinus Bradycardia and Incomplete Right Bundle Branch Block. I sat for a while and pondered what those things mean. I guess, anyone would get nervous when the “heart” is associated to the words “severe,” “incomplete” and “block.”


I immediately called my brother, a doctor at Medical Center Manila. His explanation was that I had a low resting heart rate but the beat or rhythm was regular (which is good). The reading in my ECG was 45 beats/minute (bpm), below the normal of about 70 bpm. He did mention that it is also common to those who exercise (or run) regularly and may indicate a healthy heart.


I then informed my wife of the result and mentioned to her the explanation of my brother. After several minutes, she sent me an email that also gave a comforting explanation. An excerpt of it read (from a Q&A article from The American Running Association website):


“In general terms, the presence of a mild sinus arrhythmia is really a finding of increased vagal tone. This can be a feature of athletes’ hearts.”


“Incomplete right bundle branch block is a common normal variant found on electrocardiogram and is also another finding that is often associated with an athletic heart and is of no consequence.”


“Overall, the findings of an incomplete right bundle branch block and mild sinus arrhythmia are signs of an athletic heart, and they are not likely to develop into an unhealthy condition. I believe you should forget about it and continue with your excellent running.”


Just the same, and upon advice from my wife and brother, I took a half-day off from work the following day and went to my cardiologist. This visit proved to be very comforting and reassuring. He said:

  • That I have nothing to worry about because, like my brother said, it is a sign of a healthy heart.
  • That my condition also allows me exercise and do long-distance and endurance runs because it takes longer for me to reach my maximum heart rate (MHR).
  • He advised me to continue going to the gym and with running.
  • However, he also said that once I feel any dizziness and/or chest pains, I should immediately see him. That while there are advantages, there are also some symptoms to watch out for that may cause me to faint.

Looking back, I am glad that I made the decision to have that check-up. It seems pretty intimidating but, at least, I now know my limits and I know how to go about it. From now on, I will make it a point to have this kind of checkup at least twice a year. I guess, it’s always better to be on the safe side.


PS: Sharing some articles I’ve read about the topic:









Happy Running!


One Response

  1. Hi Jan, nice to meet you during our LSD in the Fort 2 weeks ago. I guess we both have similar low resting heart rates. However I also have a slow Maximum Heart Rate of only 179bpm. This is actually bad news for me. Have you measured your MHR already?

    Hi Natz. Very good to meet you too at the LSD. Unfortunately, I have not measured my MHR yet (in a scientific way at least). Thanks, you gave me a good idea. I have not really discussed that with my doctor. Since I’m scheduled for a checkup next month, I will ask my doctor for that. Is this done through the treadmill test?

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