DEAR DR. DONOHUE: What is SVT? What causes it? What is heart ablation?

My grandmother, my mother and I all have had SVT episodes. I required heart ablation. – J.P.

“SVT” is short for “supraventricular tachycardia.” Tachycardia is a fast heartbeat. “Supraventricular” indicates that the fast beat arises in the upper heart chambers, the ones above (supra) the ventricles, which are the heart’s pumping chambers. Those upper champers are the atria.

SVT covers many different conditions. Since you spoke of “episodes,” I assume you had PSVT, paroxysmal supraventricular tachycardia – fast heart-beating that comes on suddenly, doesn’t last too long and stops abruptly.

Causes for PSVT can involve the little electric generator that delivers a small jolt of electricity that initiates the heartbeat. Or it can come from an extra pathway that the electric impulse takes on its way to the lower heart chambers. Both conditions can be there from birth, and both can be a family affair, one controlled by genes. It sounds like yours is the genetic kind.

Medicines often can keep supraventricular tachycardia controlled. Your treatment, ablation, is a permanent cure. Literally, “ablation” means “a taking away.” In the case of supraventricular tachycardia, tissue that initiates the fast heartbeat is destroyed. That’s done with a catheter – a soft, thin tube advanced into the heart from a surface blood vessel. The catheter emits radio waves. When it reaches the place that gives rise to the fast beats, the radio waves are turned on, and that bit of tissue is erased, ablated.

Ablation is successful in preventing resumption of fast-heartbeat attacks in a high percentage of cases. I trust your procedure was successful.

DEAR DR. DONOHUE: Please explain ferritin. On lab testing, my iron is perfect, but my ferritin comes back high. Doctors haven’t given me an explanation for this. I am 77 and in good health, but I am always tired. – E.S.

Ferritin is a combination of iron with a protein. Think of it as an iron savings account. When the body needs more iron, it draws it from its ferritin account.

Ferritin becomes high from some infections, from chronic hepatitis, in chronic liver disease and with excessive alcohol use. It’s high in an inherited condition called hemochromatosis. Ask your doctor if some of these conditions are worth further investigation.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from

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