Get answers to your VT ablation questions by e-mailing Dr. Stephen Shorofsky.
Cardiologists at the University of Maryland Heart Center’s heart rhythm service have joined with the University of Maryland Medical Center’s nuclear medicine and radiology departments to bring real-time imaging into the electrophysiology laboratory. They have combined highly detailed PET/CT and IR images with traditional catheter-based mapping to determine where to apply radiofrequency ablation. (Radiofrequency ablation destroys scar tissue on the underside of the heart that may cause electrical abnormalities in ventricular tachycardia.) The addition of imaging speeds up the process, enhances accuracy, and improves success rates. In fact, the imaging component has helped boost the success rate of the procedure from 50 percent nationally to 80 percent.
Below, Dr. Stephen Shorofsky, director of the Maryland Heart Center’s Electrophysiology Laboratory and an associate professor of medicine at the University of Maryland School of Medicine, answers questions about ventricular tachycardia ablation and explains more about the new imaging techniques.
What is ventricular tachycardia?
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Ventricular tachycardia (VT) is a dangerous rapid heart rhythm from the bottom chambers of the heart usually from the left side (the left ventricle).
How common is it?
Sudden cardiac death, which is what VTs lead to, is the leading cause of death in the country. Many of the patients have had heart attacks but about half the patients haven’t had heart attacks and sudden cardiac death is usually a dangerous heart rhythm, at least 80 percent of the time.
What is radiofrequency ablation?
Ablation is a technique of eliminating or destroying some small part of the heart tissue to correct a rhythm disturbance problem. This procedure uses energy high-frequency radio waves, or severe cold, to eliminate the tissue in the heart that is causing the arrhythmia.
How is ventricular tachycardia usually treated? When is it necessary to use ablation in addition to the defibrillators?
All patients get implantable defibrillators. But as many as 30 to 40 percent of patients with defibrillators will have multiple bad heart rhythms and the defibrillator doesn’t stop the bad heart rhythm from coming, it just keeps you alive if you have them. Many of them have been treated unsuccessfully with drugs to try and control some of the bad heart rhythms.
So the patients we’re talking about treating with ablation are patients who usually have a defibrillator, and the goal of the procedure is to eliminate their most prominent ventricular arrhythmias so that their defibrillator is activated less often.
How is the Maryland Heart Center unique in the treatment of ventricular tachycardia?
Some of the uniqueness of what we are doing here is that we do the procedures both from the endocardium (inside the heart) and from the epicardium (outside of the heart) through a catheter manipulation. Not many places do the procedure outside the heart.
The imaging aspect of what we do is also very unique. We are developing imaging modalities that we can incorporate into the procedure to try to better identify the tissues that need to be destroyed or modified to get a higher procedural success rate.
And that’s not normally done?
No, and as a matter of fact, some of what we’ve done has never been done anywhere.
We’re able to work with the radiologists to incorporate both structural imaging (CT scan) and MRI scans into our 3-D mapping system as well as functional imaging from either an MRI scan or a PET scan into our 3-D mapping system to better identify the tissues that need to be identified.
Who would be a good candidate for this treatment?
A good candidate for this treatment is a person who has received an ICD (defibrillator) but still is having VTs, and this could be considered with or without drug therapy.
Why come to the University of Maryland?
The reason to come here is several fold: we have a focus on looking at these arrhythmias and treating them. Plus we have a focus on integrating certain modalities which will help the procedure become more successful. We have a lot of experience with this plus we have a research interest and a focus as a program to work towards this area.