Non-fluoroscopic Catheter Tracking for Fluoroscopy Reduction in Interventional Electrophysiology

The overall goal of the following experiment is to reduce fluoroscopy exposure during complex electrophysiological procedures using non fluoroscopic catheter visualization. This is achieved by first recording two short fluoroscopic loops at the appropriate projection angles. Catheters with a miniaturized sensor at the tip are then introduced into the patient via femoral access and then visualized non fluoroscopically as projected through the two prerecorded loops.

The ablation procedure is then performed to treat the underlying arrhythmia of the patient. Ultimately, the results demonstrate that this method provides an effective treatment for arrhythmia with a significantly reduced radiation exposure compared to conventional procedures. The main advantage of this technique over existing methods like three dimensional mapping systems, is that the operator can work in a virtual fluoroscopy environment without using any radiation.

One important implication of this technique is the fact that the staff of the AP lab no longer needs to wear heavy lead aprons in order to protect themselves against the potential risks associated with radiation exposure During these lung procedures. On the day of hospital admission, perform a routine physical exam of the patient. The international normalized ratio should be between two and three.

Then to start the procedure, place the 3D mapping system, patches on the neck, belly, and left and right sides of the front and back of the patient's thorax. Then equip the patient with a finger clip to monitor the oxygen saturation and the non-invasive blood pressure and disinfect the groin region slightly sedate the patient. Then start the procedure with an injection of 40 milliliters of 1%mepivacaine to the left and right groin areas.

Next place, one seven French puncture for the venous access, one centimeter medial to the femoral artery and one centimeter below. The connection between the synthesis and Krista Ileka anterior superior Place a second seven F venous puncture, one centimeter superior to the venous access sites after the vessels have been successfully punctured. Advance a G wire, remove the puncture needle and place a sheath over the wire as per the Seldinger technique.

Then place a four F puncture in the right femoral artery for invasive blood pressure measurements and an 11 F puncture in the right femoral vein. Using fluoroscopy to control the intra vasal position of the wire for placing the transseptal sheath when the sheath is in place. Administer heparin for anticoagulation, checking the activated clotting time or a CT every 20 minutes.

Next, using an x-ray fluoroscopy system in a right anterior oblique projection of 15 degrees and a left anterior oblique projection of 50 degrees, acquire two live synap loops each approximately three seconds long. Now advance the coronary sinus diagnostic catheter tip to the superior vena CVA or SVC, and slowly pull it back, deflecting the catheter to its maximum allowable curve and rotating it clockwise to bring the tip to the coronary sinus osteum. Then advance the catheter as deeply as possible into the coronary sinus.

To bring it in a stable position, use the other diagnostic catheter to place landmarks for the superior and inferior vena cava and fossa vallis. Next to perform a transseptal puncture, insert a long guide wire into the SVC. Place one of the diagnostic catheters inserted via the long steerable sheath in the fossa vals, and bring the catheter to the left atrium through the persistent foramen valet.

Then advance the steerable sheath over the catheter and bring it in a position at the center of the left atrium under fluoroscopic control. Advance the sheath over the wire and bring it into the inferior vena cva. Then disconnect the dilator from the sheath.

Aspirate 10 milliliters of blood from the sheath and carefully flush the channel with heparinized saline at a constant flow rate of two milliliters per hour. Use the decapo diagnostic catheter to start mapping the left atrium using the 3D mapping system. Then advance the sheath to the superior pulmonary veins and inject 15 milliliters of contrast die.

This is followed by fusion of the electro anatomical map with a 3D reconstructed CT anatomy. Map the anatomical landmarks in the left atrium, carefully marking at least 10 to 15 points for the fusion process, and then double check and optimize the co-registration process with the roving catheter. Upon completion, the segmented CT model will be positioned at the anatomically correct position in 3D space.

Now, trans orally place a temperature probe with three thermocouples to measure the intraluminal intra esophageal temperature at the level of the left atrium. Then insert the ablation catheter via the transseptal sheath and ablate the area around the ipsilateral pulmonary veins at 35 watts anterior and 25 watts posterior power at an irrigation rate of 17 milliliters per minute. If the intraluminal temp reaches above 39 degrees Celsius, stop the ablation and adjust the power settings.

Then use a deck apolar circular catheter from all the bis of the spiral catheter to pace maneuvers at the maximum output. To check the completeness of the pulmonary vein isolation, check the signals on the coronary sinus catheter to make sure that the stimulus does not capture the left atrium at this time as well. If necessary, move the ablation catheter around the circumferential lesions and stimulate the tissue with the maximum output from the tip of the ablation catheter to detect and close any gaps observed in the lesion set.

If the atrium is captured, ablate until the local capture disappears for the area around all of the pulmonary veins as necessary. Once the isolation line is complete, create a voltage map of the left atrium to determine where the atrium is healthy and where it is fibrotic, using the cutoff values of 0.5 millivolts for normal tissue and 0.2 millivolts for scar tissue. Next to check for inducibility, initiate ten second burst pacings from the coronary sinus with cycle lengths of 300, 250 and 200 milliseconds of atrial refractory time to test the inducibility of the left atrium.

Then remove the transseptal sheath and catheters and antagonize the heparin with protamine sulfate. Manually compress the femoral artery for 10 minutes. Then remove the sheaths from the groin and compress the puncture sites on both sides for at least 10 minutes.

If there is no active bleeding place, pressure bandages on the punctures for six hours by using non fluoroscopic catheter tracking technology. This procedure was performed with 18 seconds of fluoroscopy and a radiation dose of 92.4. Micro gray by square meter equaling an effective dose of less than 0.2 milli seaward.

If the left atrium has fibrotic tissue with low voltage areas as observed here, the chance of repeat arrhythmia increases compared to patients with healthy left atrial tissue. Using the pace and ablate approach, however, ablation of a paroxysmal atrial fibrillation can be successfully performed by electrically isolating all four pulmonary veins as represented here. By stimulating with the maximum output from the ablation catheter, local gaps can be detected and immediately closed with simultaneous ablation.

Indeed, as illustrated in the graph, even complex ablation procedures can be performed with minimal fluoroscopy exposure. The same results are observed with right atrial procedures like the ablation of typical atrial flutter, atrial ventricular nodal, reentrant tachycardias, and the implantation of cardiac resynchronization therapy devices. This is not only relevant for the patients, but also for the staff in the electrophysiology lab who are exposed to radiation daily.

Once master, this technique can be completed within two hours if performed properly.