Your Good Health: Lightheadedness leads to unusual diagnosis

Inappropriate sinus tachycardia most often seen in women in their 30s

Dear Dr. Roach: I had symptoms of lightheadedness, so my doctor ordered an EKG and sent me to a cardiologist. They did a heart monitor for a week and said I have inappropriate sinus tachycardia but that I don’t need any treatment. I’m still having symptoms. What can I do?


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Inappropriate sinus tachycardia is an uncommon diagnosis, most often seen in women in their 30s. The heart rate is fast (“tachycardia”), but on an EKG it appears normal, meaning it comes from the sino-atrial node, the natural pacemaker of the heart, hence “sinus.” The average heart rate must be over 90 for 24 hours.

It’s important to be sure there isn’t another cause for the tachycardia, such as elevated thyroid levels, fever, volume depletion (dehydration) or anemia. The symptoms may continue for months or even years. Common symptoms include the lightheadedness you felt, but may also include palpitations, shortness of breath, dizziness and decreased ability to exercise.

The diagnosis can sometimes be confused with POTS (postural orthostatic tachycardia syndrome), where the heart rate dramatically increases with changing to an upright position. A tilt-table test is the diagnostic test for POTS.

If there is no other reason for sinus tachycardia, then medication may be used to reduce symptoms. A beta blocker is the usual first choice, but there are others available.

I found some more information at that may be useful for you.

Dear Dr. Roach: Which of these is safest to clean kitchen countertops where we eat: vinegar, alkyl dimethyl benzyl ammonium chloride or sodium hypochlorite?


Vinegar and baking soda is a time-honoured, effective treatment using products you can eat, so it is very safe.

Alkyl dimethyl benzyl ammonium chloride, also called benzalkonium chloride, is found in many household cleaners, such as Lysol. They can be quite dangerous if ingested in a large quantity. When used properly, at low concentration (such as the residual amount left after wiping down a counter), they should be fine. They are used as preservatives in some medications, such as eyedrops. As with all chemicals, the dose makes the poison.

Sodium hypochlorite is bleach. It is also found in many cleaning products, such as Clorox. Although it is very effective, the odour even at low concentration is offensive to many people (including me). It, too, is safe if used properly.

Personally, I advise mostly using soap and water, and if cooking something with high risk of bacteria, such as raw meat, using a cutting board you can toss in the dishwasher. That is nearly as effective as a sterilizer.

Dear Dr. Roach: I have a question about undigested food. Are you getting any nutrients, other than fibre, from foods that come out looking the same as they went in? I’m thinking of foods such as corn and sunflower, flax or chia seeds. How well do they need to be chewed to get any nutrition from them?


Many seeds and corn need to be chewed very well in order to be absorbed by the body. They have a large amount of undigestible fibre, which will never be absorbed. Chia seeds, unlike flax or sunflower seeds, are pretty easily digested by most people, but you can grind them and soak them ahead of time to make it easier for your body to digest.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers can email questions to

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