Initial Experience with High-Density Mapping: Interview with Firas Zahwe, MD

In this feature interview, Dr. Zahwe discusses his use of the Advisor^™ HD Grid Mapping Catheter, Sensor Enabled^™ (Abbott) and EnSite Precision^™ Cardiac Mapping System (Abbott) at Aurora St. Luke’s Medical Center in Milwaukee, Wisconsin. 

What mix of cases do you primarily treat?

I take care of all complex ablations, from atrial fibrillation, atrial flutter, ventricular tachycardia, PVCs, SVTs, and all kinds of devices as well.

What attracted you to start using the EnSite Precision with Advisor HD Grid?

I was interested in high-density mapping to understand the arrhythmia mechanism and form a plan for ablation. We always try to have a goal of ablating less, so the Advisor HD Grid with EnSite Precision allows us to create high-density maps in a shorter period of time with reliable data. With the AutoMap module, you do not have to annotate any points manually — it has very high accuracy for annotation. Additionally, the waveform software with the Advisor HD Grid also allows us to better understand the mechanism and have more targeted mapping for ablation. 

How many and what kinds of cases have you performed so far with the Advisor HD Grid?

I believe I’ve done more than 15 cases so far. This includes ventricular tachycardia, PVCs, atrial flutter, atrial tachycardia, and atrial fibrillation. 

Has the Advisor HD Grid helped you to achieve successful results thus far? 

Absolutely, especially with ventricular tachycardia and atrial flutter cases — it created an accurate high-density map, which allowed us to understand the arrhythmic mechanism and minimize the ablation as well.  

Has it provided additional insight in patients with complex substrate such as persistent AFib?

Yes, the Advisor HD Grid has allowed us to get an accurate anatomy and voltage map to plan for the substrate modification in patients with persistent atrial fibrillation. Also, patients will often have atrial flutter, so this has helped us to create a quick and accurate flutter map in order to treat the atrial flutter as well.  

As with any new technology, new catheter manipulation techniques evolve in the first 10-15 cases. What techniques have you adopted to access hard-to-reach anatomical areas?

We are still in the learning phase with the Advisor HD Grid. In some cases, I use the steerable sheath to help with manipulation in the left atrium, while in other cases, I use the regular transseptal sheath. I’ve also done a couple of cases in the right atrium where I didn’t have to use a sheath. The manipulation of the Advisor HD Grid is different than other multipolar mapping catheters in that it’s very easy to manipulate. The bidirectional handle allows us to use two different curves to get to the difficult areas. I think we are getting better and better at using the catheter with each case, and like any other new technology, there is always a learning curve to master the skills.  

Like many electrophysiologists, you may traditionally have used circular mapping catheters to assess PV isolation. How have you utilized the Advisor HD Grid to assess isolation and previous-ablation effectiveness?

The Advisor HD Grid has allowed us to create high-density voltage maps in the pulmonary veins and PV antrum. I believe this is probably a better way to assess for isolation rather than with a circular mapping catheter, because it has allowed us to map all the tissue inside the ablation area to make sure there is no connection, even in the antrum of the vein. 

Could you give an example with a recent case?

Yes, we had a recent case of a patient who had previous hybrid atrial fibrillation ablation, with an epicardial posterior wall ablation and endocardial PV isolation in 2015. The patient did well for a while, but recently started experiencing symptomatic atrial flutter. I initially mapped the flutter with the Advisor HD Grid using HD Wave. It was a figure-8 dual-loop flutter, using an isthmus on the posterior wall of the left atrium; the flutter terminated with minimum ablation (2 lesions only); it was not inducible after that. This same patient had reconnection in 3 veins out of 4. Also, the voltage and activation maps allowed us to assess the area of reconnection in the veins, and target it to achieve isolation of the pulmonary veins.    

How do you feel AutoMap and Advisor HD Grid work together to provide you with the information needed to help your patients?

The AutoMap is a nice feature because when you collect that number of points, it’s difficult to annotate point by point. Therefore, you need to trust the software, which provides excellent accuracy in terms of annotation. The HD Wave software also allows us to look at the directionality of the wavefront in the flutter. 

What advice would you have for your peers who are considering using this catheter?

I think the Advisor HD Grid is a must. I suggest trying it first on a simple case such as a right-sided flutter or focal atrial tachycardia, and then advance to ventricular tachycardias and left atrial flutters. It provided us with an excellent map for ventricular tachycardia, with less ectopy than what we usually see with mapping using an ablation catheter or other mapping catheter in the left ventricle. I think you will love the Advisor HD Grid after you try it.

Disclosure: The author has no conflicts of interest to report regarding the content herein.

This article was published with support from Abbott.