Dr. John Sapp

Dr. John Sapp

Dr. John Sapp


Fixing short circuits: Dr. John Sapp fine-tunes treatments for dangerous heart rhythms

While most of us take the steady beating of our hearts for granted, people with a dangerous heart rhythm known as ventricular tachycardia live in fear. Caused by an electrical short circuit in the heart, this arrhythmia can trigger sudden death. While a defibrillator can help regulate the erratic heartbeat, it can also give shocks strong enough to knock a person down.

Cardiac electrophysiologist, Dr. John Sapp is leading long-term international studies to see if a procedure known as catheter ablation works better than aggressive drug therapy for treating ventricular tachycardia.

"Catheter ablation is an invasive procedure that carries certain risks," notes Dr. Sapp, a professor in Dalhousie Medical School's Division of Cardiology. "However, the best drugs for regulating heart rhythm don't always work and may damage the lungs, liver, skin and thyroid." The research will reveal which is the safest and most effective way to reduce shocks and prevent sudden death, in which circumstances.

At the same time, Dr. Sapp is pioneering new techniques and instruments to make catheter ablation safer and more effective. The procedure involves inserting a thin wire into the heart through a blood vessel in the leg, to deliver a surge of energy that repairs the electrical short circuit.

"The challenge with ablation is to pinpoint the exact location of the short circuit and deliver the right amount of energy," says Dr. Sapp. "Too little won't fix the problem; too much can damage surrounding tissues."

Dr. Sapp and his colleagues are pioneering a non-invasive technique called body-surface mapping, which uses electrodes on the skin to find the precise location of the short circuit, and has co-developed a catheter that repairs short circuits so deep inside the heart muscle that standard technology cannot reach them.

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