Future of AF ablation depends on advances +++

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Future of AF ablation depends on advances +++

Post by freckles1880 » June 30th, 2011, 5:07 pm

http://www.theheart.org/article/1246039 ... _Heartwire

Future of AF ablation depends on advances to make PV isolation more permanent
JUNE 29, 2011 | Reed Miller

Madrid, Spain - The next stage in the evolution of atrial fibrillation ablation will be to understand how to prevent the gradual reconnection of the electrical pathways following pulmonary-vein (PV) isolation ablation, according to Dr Hans Kottkamp (Clinic Hirslanden Zurich, Switzerland).
Here at the EUROPACE 2011 conference, Kottkamp, one of the authors of the 2007 international consensus statement on atrial fibrillation ablation, told heartwire, "The concept of PV isolation is so great, we just have to make it permanent. So now we need more detailed work on . . . the durability of the isolation."
The PV-isolation technique is "definitely not just hype and certainly more than a hope . . . and the end points are clear: it is bidirectional PV isolation," Kottkamp said during his presentation at the conference. "But right now we can't cure more than 50% with a single procedure. The problem will be in the beginning to make permanent PV isolations [on the first try]."
He cited the recent study by Dr Feifan Ouyang (Allgemeines Krankenhaus, Hamburg, Germany) et al, in which continuous circular lesions isolating the ipsilateral pulmonary veins restored sinus rhythm in 75 of 161 patients on the first try, but 66 patients needed a second procedure, 12 needed a third procedure, and stable sinus rhythm was achieved in only 128 of 161 patients (79.5%) over a median follow-up of about five years [1]. Also, a recent study in France, reported by heartwire, found that arrhythmia-free survival rates after a single catheter-ablation procedure were only 29% at five years and 63% after the last ablation procedure.
"The problem these days is the reconnection of the pulmonary-vein [electrical pathways] after acute isolation, and this can happen just hours or days later," he said. But even though these reconnections begin almost as soon as the ablation is complete, it usually takes months or years for them to begin to show symptoms, so the electrophysiologist cannot always tell how long the ablation scar will last. "PV isolation is certainly the cornerstone, but one size does not fit all. It's difficult to identify patients who need more than a PV isolation and, if they need more, what precisely they do need."
Electrophysiologists are also holding out hope that new technology will lead to more permanent ablation scars that do not have to be revised. For example, real-time ultrasound and MRI as well as catheter tips that can read electrical impedances may allow the electrophysiologist to more easily track the electrical pathways that need to be blocked during the ablation procedure instead of waiting to see which pathways reconnect over the subsequent weeks. Kottkamp told heartwire that it is hard to know which of the many new technologies or techniques will prove most effective, but that he believes electromagnetic 3-D mapping is especially powerful in experienced hands.
Kottkamp also cited some recent research on new methods for identifying which patients are the best candidates for the PV-isolation procedure. For example, Dr Christian Mahnkopf (University of Utah, Salt Lake City) et al have shown that the degree of left-atrial structural remodeling caused by atrial fibrosis is an independent predictor of the success of a catheter ablation procedure for AF and that this fibrosis can be detected by delayed-enhanced MRI [2]. This approach may allow physicians to select appropriate candidates for AF ablation and avoid unnecessary intervention, Kottkamp suggested. He also said that advances in genetic testing may help to identify which patients are more likely to benefit from AF ablation.

Bigger studies on the horizon
Large long-term studies will be needed to demonstrate that new technologies and techniques can create more durable ablation scars, Kottkamp said. He highlighted the importance of the National Institutes of Health-sponsored Catheter Ablation Versus Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial (CABANA), which began enrolling patients in 2009 and will be completed in 2015. CABANA is comparing percutaneous left atrial catheter ablation with either rate- or rhythm-control drugs for reducing total mortality in about 3000 patients with untreated or incompletely treated AF.
But because the technology continues to improve, CABANA will reveal only how effective AF ablation was a few years earlier, when the trial began enrolling, he told heartwire. "Perhaps CABANA might be a little bit too early, because some of the new problems like early reconnections have not been solved yet," he said. By the time the CABANA results are available, "the benefit of catheter ablation will be bigger than we'll see from the CABANA study, but still, studies like CABANA are extraordinarily important."

Medtronic-Visia AF implanted 7-8-2016 stayed with the with 6947 Sprint Quattro Secure lead. Original ICD implant 2-4-2009. ICD turned off 10-6-17 as stage 4 lung cancer taking over.
Major heart attack, carcinogenic shock and quad bypass 10-13-08 post myocardial infarction, old inferior MI complicated by shock and CHF, combined, Atherosclerosis, abdominal aortic Aneurysm, Seroma 7 cm, left leg. Stent in the left main vein 10-7-2014

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