Oregon Health & Science University
  • Charles Henrikson, M.D.Charles Henrikson, M.D.
    Dr. Henrikson is the director of the Electrophysiology Program at the OHSU Knight Cardiovascular Institute. He performs the full range of EP procedures, including laser lead extraction, epicardial access and ablation, and ablation for atrial fibrillation. He also has an active research program.

Mapping the heart 10 times faster

Electroanatomic systems for mapping cardiac arrhythmias have been available for more than a decade. A new mapping system available to you and your patients at the OHSU Knight Cardiovascular Institute allows faster, more accurate diagnosis and treatment during cardiac ablation. OHSU was the first center in the Pacific Northwest with this new system.

About electroanatomic mapping

Electroanatomic mapping uses a computer and a series of magnets placed around the patient to track the movements of the catheter in a cardiac ablation. This tracking system shows the electrophysiology team where the catheter has been. As the catheter is advanced, it creates a picture of the cardiac anatomy, showing the cardiac chamber and recording exactly where ablation is done. The resulting three-dimensional reconstructions of the heart chamber help guide the procedure.

The evolution of arrhythmia mapping

Originally, fluoroscopy was used to locate arrhythmia sources during cardiac ablation. However, fluoroscopy alone offers relatively low resolution, can interfere with the ablation process and exposes patients and staff to radiation.

Developing electroanatomic mapping was thus an important advance in arrhythmia care. Currently, most electrophysiology laboratories use a mapping catheter with a single electrode on the end. The catheter records one point of activation at a time. The single-point catheter’s main drawback is that mapping requires significant time from the cardiac catheterization team, as well as time on the table for the patient.

Mapping the heart 10 times faster

The OHSU Knight Cardiovascular Institute’s EP team uses the Rhythmia system from Boston Scientific for arrhythmia mapping. This system uses a basket catheter with 64 electrodes spaced 2.5 millimeters apart, so it maps 64 discrete points at every pass of the catheter. The system software collects and processes this information, automatically deletes points that are not relevant, and creates a high-resolution map of the heart. Deleted points are those internal to the heart chamber (as opposed to points on the wall) and not of the target rhythm.

With a single-point catheter, a typical 200-point map takes about 30 minute to create. With the Rhythmia system, OHSU electrophysiologists can create a 2,000-point map in five minutes. Because this new mapping generates so much more information, ablation is more precise and effective. Fluoroscopy time is greatly reduced, increasing the safety of cardiac ablation for patients and operators.

Who is a candidate for cardiac mapping?

Any patient who can benefit from cardiac ablation benefits from electroanatomic mapping. This precise, efficient technique is particularly helpful for patients in whom ablation is the main or best treatment. These may include:

  • Patients receiving ablation as first-line therapy — for example, relatively young, otherwise healthy patients with supraventricular tachycardia.
  • Patients whose atrial fibrillation remains significantly symptomatic despite medication trials.
  • Patients with arrhythmias who prefer ablation to medication.

Specific benefits of mapping

Using electroanatomic mapping renders cardiac ablation more effective, requires less “table time” for the patient and is safer for the patient and EP team. Ablation is more effective because unlike fluoroscopy, in which the operator cannot refer to previous ablation sites, 3-D mapping shows precisely where ablation has been done. This also takes less time and is safer for the patient. In cases of slight unintended movement, the electrophysiologist can return to the precise site of treatment and continue or re-ablate as needed. Using mapping eliminates any need to estimate or triangulate the next treatment location.

Experienced electrophysiology team

Electroanatomic mapping has been in use at OHSU for a number of years. The team led by Charles Henrikson, M.D., has daily experience with these systems, including the Rhythmia mapping system. The OHSU electrophysiology service receives referrals from around Oregon and the Northwest, including patients who have had previous ablation at other centers.

Contact us

The electrophysiology specialists at OHSU’s Knight Cardiovascular Institute are always available to consult with you. If you have questions, or to refer a patient, please call the OHSU Consult & Referral Line at 800 245-6478 or fax to 503 346-6854.

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