2014 Boston AF Symposium
A-Fib Producing Spots Outside the Pulmonary Veins
Report by Dr. Steve S. Ryan, PhD
Dr. Vivek Reddy of Mount Sinai Hospital in New York gave a presentation entitled “What is the true rate of Non-PV triggers?”
Why do ablations fail?
Dr. Reddy posed the question, ‘Why do ablations fail?’ The most common reason is a gap in an ablation lesion. Dr. Reddy showed slides of a typical wide area antrum isolation ablation with remarkably precise point-by-point burns. But there was a slight gap which let A-Fib signals escape from the pulmonary veins into the rest of the heart. But Non-PV triggers can also cause ablation failure.
Dr. Reddy asked the BAFS attendees:
“What is the rate of non-PV triggers after an extra-ostial PV isolation procedure?”
The choices ranged from 5% to over 25%.
The actual rate of non-PV triggers is approximately 23%.
Carina important origin of A-Fib triggers
Dr. Reddy showed how the ‘carina’ (the area in the heart between the left and right pulmonary vein openings) is often a source of A-Fib triggers and of recurrence after an ablation. According to the study cited, “the carina region (has an) apparently unique electrical behavior.” To effectively isolate PVs, it is frequently necessary to target within the circumferentially ablated veins in the carina region, even though there is a risk of stenosis.
Where are the non-PV triggers usually from?
In an older study of 248 Paroxysmal A-Fib patients, 28% had non-PV triggers. (These earlier studies often used segmental or ostial isolation and weren’t as durable as later procedures.) The most common locations were:
▪ LA Posterior Free Wall: 38% ▪ Superior Vena Cava: 37% ▪ Crista Terminalis: 13.7% ▪ Ligament of Marshall: 8.2%
(In this study, the Carina area and newer areas of interest such as the Left Atrial Appendage were not mentioned)
Left Atrial Appendage (LAA)
In a study of nearly 4,000 A-Fib patients that looked at redo procedures for paroxysmal, persistent and long-term persistent A-Fib, 27% had LAA firing (the LAA is the source of arrhythmia), much more in the long-term persistent (58%) compared to paroxysmal (18%). Most wound up having a LAA isolation procedure. (Many centers, as part of their protocol, now routinely first look at the LAA after isolating the PVs. See Bordeaux Five-Step Ablation Protocol for Chronic A-Fib.)
Paroxysmal patients over 80 years old had many more non-PV triggers than other patients.
Recurrence Associated with Predominately Non-PV Triggers
In a study of 197 paroxysmal A-Fib patients from 2009 to 2012 using irrigated tip RF catheters and extraostial PV isolation, there were non-PV triggers in 23.7% of patients. In patients who had recurrence, 70.8% had non-PV triggers.
In patients who had recurrence, 70.8% had non-PV triggers.
Dr. Reddy’s research is important for EPs who will now look more closely at areas like the Carina and the Left Atrial Appendage to find and ablate/isolate non-PV triggers.
What does Dr. Reddy’s research mean for patients? Since 23% of A-Fib ablation triggers are found in other areas of the heart than the pulmonary veins, a simple Pulmonary Vein Isolation (PVI) or Maze surgery may not be enough to cure your A-Fib.
One of the most important findings of Dr. Reddy’s research is that recurrence (a failed ablation) is most often associated with non-PV triggers (70.8%). When searching for the right Electrophysiologist (EP) to do your ablation, they have to have experience in tracking down these non-PV triggers. When interviewing EPs, maybe one of the questions needs to be “How often do you find non-PV triggers? How do you track them down and ablate them?”
You should probably avoid any EP who only isolates the PVs. [I’ve read Operating Room reports from EPs who only do a PVI, never look for non-PV triggers, and don’t terminate the A-Fib by ablation. Instead they shock the patients back into sinus rhythm, then load them up with powerful but toxic antiarrhythmic meds like amiodarone. This usually doesn’t work.)
If you are considering (Wolf) Mini-Maze surgery, be aware that most Mini-Maze surgeries only isolate the PVs. Your chances of having non-PV triggers which a Mini-Maze surgery will not ablate/isolate are approximately 23%. That translates to at least a 23% chance of failure.
If you have non-PV triggers or A-Fib/Flutter coming from the right atrium, most Maze surgeries won’t make you A-Fib free. Surgeons currently do not access the right atrium during most Maze surgeries. To take care of these other A-Fib spots, you will have to schedule a catheter ablation.
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Last updated: Friday, August 28, 2015