• Arrhythmias

  • Wolff-Parkinson-White Syndrome (WPW)

    Wolff-Parkinson-White Syndrome (WPW) is one of the causes of supraventricular tachycardia (fast heart rate originating above the ventricles).

    When you have WPW, along with your normal conduction pathway, you have an extra pathway(s) called an accessory pathway. It looks like normal heart muscle, but it:

    • conducts impulses faster than normal
    • conducts impulses in both directions

    The impulses can travel around the heart very quickly, in a circular pattern, causing the heart to beat unusually fast. This is called re-entry tachycardia.

    Re-entry arrhythmias occur in about 70 percent of people with WPW; some may also have atrial fibrillation (a common irregular heart rhythm distinguished by disorganized, rapid, and irregular heart rhythm).

    The greatest concern for people with WPW is the possibility of having atrial fibrillation with a fast ventricular response that, at times, may worsen to ventricular fibrillation, a life-threatening arrhythmia.

    In people with WPW, whose heart rate cannot be controlled with medications, ablation can improve symptoms and cure the abnormal arrhythmias. During ablation, high-frequency electrical energy is delivered through a catheter to "disconnect" the abnormal pathways.

    Supraventricular Tachycardia (SVT)

    Normally, the heart's electrical system precisely controls the rhythm and rate at which the heart beats. In supraventricular tachycardia, abnormal electrical connections (or abnormal firing of the connections) cause the heart to beat too fast. Typically, during supraventricular tachycardia episodes, the heart speeds up to rates of 150 to 200 beats per minute and occasionally as high as 300. Most often the heart may return to a normal rate (60 to 100 beats per minute) on its own. Sometimes medical treatment may be needed and occasionally urgent medical treatment is required.

    Supraventricular tachycardia (SVT) is an abnormal fast heart rhythm that starts in the upper chambers, or the atria, of the heart. ("Supraventricular" means above the ventricles, "tachy" means fast, and "cardia" means heart.)

    Treatment for SVT includes catheter ablation, which is usually done during an electrophysiology (EP) study. The most common type of catheter ablation uses radio waves (radiofrequency energy). These waves are directed through the catheter tip to the specific heart tissue that is generating abnormal electrical impulses. The radio waves cause the target area of the heart muscle to be heated and selectively destroyed, eliminating the SVT.