Is tachycardia benign?

[Julia]

My 13-year-old daughter has recently had several episodes of tachycardia, the most recent lasting all day.  Her heart rate was 145.  At one point her nailbeds were purple.  In the evening it went down to 115.  She complained of feeling hot and being very aware of her heartbeat, but otherwise felt and looked fine.

I called her pediatrician's office and was told not to worry about it.  

She has no history of heart problems, except bradycardia as a premature infant.  She does have cerebral palsy and scoliosis.  She has been taking Baclofen and Elavil for four years.  She had a normal EKG four years ago before starting Elavil (as a precaution).  

Her identical twin (who also has cp) has also had tachycardia, which we were told in her case is part of "dysautonomia", along with drops in blood pressure, nausea, pallor, low-grade fever, purple hands during meals, and other symptoms.  

So, is it normal for a child to sometimes have tachycardia?  Or is it abnormal, yet benign?  Or does tachycardia typically deserve further study?  Might the Elavil be a factor?

Thank you.

[Cleveland Clinic, MD]

Thank you for your question.  Tachycardia at rest is not generally considered normal.  There are many causes of tachycardia with some benign and others not.

There are many causes of tachycardia  (fast heart beat) and they can be divided roughly into sinus (originating from the sinus node or heart's natural pacemaker) and non-sinus tachycardias.  Nonsinus tachycardias are either  supraventricular (coming from the upper chambers of the heart) or ventricular (coming from the lower chambers of the heart).  Supraventricular tachycardias include:  paroxysmal supraventricular tachycardia, atrial flutter, atrial fibrillation and AV nodal tachycardia. Ventricular tachycardias are more serious in nature and are due to a rapid depolarization of  the ventricles.  

Sinus tachycardia is defined as a heart rate of greater than 100 beats per minute originating from the sinus node.  Sinus tachycardia is classified as either appropriate or inappropriate.  There are many causes of appropriate sinus tachycardia such as exercise, anxiety, panic attacks, dehydration, deconditioning, volume loss due to bleeding or other loss of body fluids, hyperthyroidism, electrolyte abnormalities and many other conditions.

Inappropriate sinus tachycardia can only be diagnosed when all causes of appropriate sinus tachycardia have been ruled out.  It is not clear what causes inappropriate sinus tachycardia but possible etiologies are an increase in the rate at which the sinus node depolarizes and an increased sensitivity to adrenaline.  Once the diagnosis has been made by ruling out all of the potential causes of appropriate sinus tachycardia  there are several treatment options.  If the symptoms are not overly concerning no treatment needs to be done.  There is no increase in morbidity or mortality in persons with this condition and they can expect to have a normal life-span.  For persons in whom the symptoms are unbearable medications such as beta blockers or calcium channel blockers can be used, usually with good results.  In the rare person unable to tolerate medical treatment catheter ablation (burning) of the sinus node with insertion of a pacemaker or surgical removal of the sinus node have been used in the past.  Newer techniques are being developed using catheter ablation to modify and not destroy the sinus node thus avoiding the need for a pacemaker.  

I hope you find this information useful.  Information provided in the heart forum is for general purposes only.  Only your physician can provide specific diagnoses and therapies.  Please feel free to write back with additional questions.

If you would like to make an appointment at the Cleveland Clinic Heart Center, please call 1-800-CCF-CARE or inquire online by using the Heart Center website at www.ccf.org/heartcenter.  The Heart Center website contains a directory of the cardiology staff that can be used to select the physician best suited to address your cardiac problem.