Sometimes, doctors don't know what sets off the racing, thumping heartbeat caused by supraventricular tachycardia (SVT).
What they do know for certain: It starts in the upper chambers of your heart with electrical signals that tell it when to pump. These impulses go in a loop instead of heading off to the right place. This causes your heartbeat to speed up -- sometimes to three times its normal pace.
With a little detective work, you and your doctor might be able to figure out what your triggers are. That could help you control this condition.
Here are some common things that trigger the condition:
Too Much Caffeine or Alcohol
Do you drink a lot of coffee to jump-start the day? You would probably have to have a lot of cups o’ joe to set your heart racing, although the amount varies from person to person. Caffeine is found in tea, chocolate, and energy drinks, too. Figure out how much you’re really taking in.
Alcohol can also be a trigger, and possibly in smaller amounts than caffeine.
Medications and Stimulants
Certain medications have been known to trigger the pounding heart rhythm of SVT. These include:
Digoxin (Digitek, Digox, Lanoxin), for treating heart failure.
Theophylline (Elixophyllin, Norphyl, Phyllcontin), for treating asthma and other lung problems.
If you’re taking either of those prescription drugs and you start feeling your heart beating rapidly, let your doctor know at once. Other things to watch out for:
Herbal supplements and diet pills.
Always check with your doctor before taking any drugs, either prescription or over-the-counter.
Feeling Tired or Stressed
If you are worn out or anxious, you may be more likely to have a bout of SVT. One small study was able to record electrical changes in the hearts of people with the condition who were mentally stressed.
Another study concluded that panic attacks can trigger this. The symptoms are similar: a racing heart, light-headedness and a hard time breathing.
Cigarettes may be a trigger, although scientists aren't absolutely sure. Even if smoking isn’t directly linked, it causes a host of other problems.
If you've had heart surgery, you may be left with scars that increase the chances you may get SVT. Up to 25% of people who've had a heart transplant will have this happen. This doesn't mean your body is rejecting the new organ.
Working out too hard can sometimes be a trigger. Most of the time, though, exercise is one of the best things you can do for your heart. Talk with your doctor about the right amount of activity for you.
Fortunately, most cases of SVT are harmless. But if you have lots of spells that last a long time, that can weaken the heart muscle and lead to problems. Talk to your doctor if you have any concerns.