Heart Rhythm Help: Is Single-Ring Isolation Kinder for Elderly AF Patients?

Hey there! Let’s chat about something super important, especially as we get a little older or know someone who is: persistent atrial fibrillation (PeAF). It’s that stubborn, irregular heartbeat that can really throw things off balance. For folks dealing with PeAF, especially seniors, finding the best way to manage it is key. One common approach is called catheter ablation, where doctors use energy to create tiny scars in the heart to block those chaotic electrical signals.

Now, when it comes to persistent AF, just isolating the pulmonary veins (where a lot of the trouble starts) often isn’t quite enough. We often need to do more work on the heart’s posterior wall. Two main ways to do this are called Box Isolation (BOXI) and Single-Ring Isolation (SRI). BOXI creates a sort of “box” around the area, while SRI aims for a single, continuous loop. Both techniques aim to isolate the same general area, but they go about it differently.

Recently, using higher power during these procedures has become more common because it can create better, more lasting lesions. But, let’s be real, doing this kind of work near sensitive areas like the esophagus or nerves can cause issues, especially in older patients who might be more prone to things like acid reflux. So, the big question is: which of these high-power techniques is better, particularly for our elderly population? Is one safer or more comfortable? That’s exactly what a recent study dug into, and I’m here to tell you what they found.

Diving into the Study: What They Looked At

This study, conducted at Wujin People’s Hospital, took a look back at elderly patients (aged 65 and over) with persistent AF who had their first catheter ablation procedure between 2017 and 2023. They compared those who received the BOXI approach to those who received the SRI approach, specifically using high power (40-45W). To make the comparison fair, they used a statistical method called propensity score matching (PSM) to pair up patients in each group who were similar in age, health conditions, and other factors. They ended up with 45 matched pairs – 45 patients in the SRI group and 45 in the BOXI group.

What did they track? A whole bunch of things!

• Basic patient characteristics (age, sex, other health issues)
• Details about the procedure itself (total time, ablation time, number of lesions)
• Markers of heart muscle injury (cardiac troponin levels)
• Patient experience during the procedure (pain scores using a visual analogue scale – VAS)
• Procedure interruptions due to pain-induced movement (mismatched 3D maps)
• Complications (like fever, gastrointestinal symptoms)
• Whether the heart went back into a normal rhythm right after the procedure
• And most importantly, whether the irregular heartbeat came back within 12 months

They wanted to see if high-power SRI was not only feasible and safe but perhaps *superior* to high-power BOXI for these older patients, especially concerning their experience and safety profile.

Efficiency and Injury: SRI Pulls Ahead

When we look at the nuts and bolts of the procedure, the study found some interesting differences. While the *total* procedure time wasn’t significantly different between the two groups overall, the SRI group actually got faster with experience. For the later cases (cases 26-45) in the SRI group, the procedure time was significantly shorter than in the BOXI group. This suggests a learning curve, but once mastered, SRI might be quicker overall.

But here’s where SRI really shone:

• Total Ablation Time: The actual time spent delivering energy was significantly shorter in the SRI group (about 55 minutes) compared to the BOXI group (about 69 minutes). That’s a solid chunk of time saved!
• Number of Lesions: SRI required significantly fewer ablation lesions, especially on the posterior wall. Remember how BOXI creates a “box” with multiple lines? SRI aims for that single ring, which means less zapping needed in that sensitive area.
• Myocardial Injury: They measured a marker in the blood called cardiac troponin (cTnI), which goes up when heart muscle is injured. The levels were significantly lower in the SRI group 24 hours after the procedure. This suggests less damage to the heart muscle itself, and potentially less risk to nearby structures like the esophagus.

So, from a procedural standpoint, high-power SRI seemed more efficient and caused less immediate tissue injury compared to high-power BOXI.

Patient Comfort: A Clear Win for SRI

This is where the study’s findings are particularly compelling, especially for elderly patients. Ablation, especially on the posterior wall, can be painful even with sedation.

The study used a pain score (VAS) where patients rated their discomfort. The results were striking:

• Pain Scores: Patients in the SRI group reported significantly lower pain scores (average 3.4) compared to the BOXI group (average 5.5). That’s a big difference in comfort!
• Movement and Mapping Issues: Sometimes, pain causes patients to move, which can mess up the 3D mapping doctors use to guide the procedure. Significantly fewer patients in the SRI group had these pain-induced mapping mismatches, and the average number of mismatches per patient was also lower. This means a smoother procedure with less interruption.
• Gastrointestinal Symptoms: This is a key safety concern when working near the esophagus. Significantly fewer patients in the SRI group experienced GI symptoms like chest pain, nausea, or vomiting after the procedure (15.56%) compared to the BOXI group (37.78%). This strongly suggests that the reduced ablation on the posterior wall with SRI translates to a lower risk of irritating or injuring the esophagus or nearby nerves.

Think about it – less pain, less movement disrupting the procedure, and fewer tummy troubles afterward. For an elderly patient, these factors can make a huge difference in their overall experience and recovery.

Immediate Results and Safety

The study also looked at what happened right after the ablation. A higher percentage of patients in the SRI group achieved immediate normal sinus rhythm after the procedure compared to the BOXI group. They also needed fewer electrical shocks (DC cardioversion) to get back into a normal rhythm if ablation alone didn’t do the trick. This hints that SRI might be more immediately effective in restoring a normal heartbeat.

And the big safety news? Thankfully, there were no major complications like death, heart perforation, or the dreaded atrioesophageal fistula (a serious connection between the heart and esophagus) in *either* group. This is reassuring and suggests that both techniques, when performed carefully, can be safe in experienced hands, even with high power. However, the lower rate of minor but still uncomfortable issues like GI symptoms in the SRI group is a definite plus.

The Long-Term Picture: Still More to Learn

Okay, so SRI seems better for the procedure itself and the immediate patient experience. But what about keeping the AF away in the long run?

The study followed patients for about 13 months on average. They checked for the return of AF or other atrial arrhythmias. The finding here was that there was no significant difference in arrhythmia-free survival at 12 months between the two groups. About 75.6% of the SRI group and 73.3% of the BOXI group were free from arrhythmias at the 1-year mark.

Why might this be? The researchers suggest it could be because both techniques aimed to isolate the *same extent* of the posterior wall and pulmonary veins. Even though SRI used fewer lesions and was potentially gentler, the overall electrical isolation achieved was similar. It’s like taking two different routes to the same destination – the journey might feel different, but you still end up in the same place. Also, 12 months is a relatively short follow-up period for AF ablation studies; sometimes differences show up later.

Bringing It All Together for Elderly Patients

So, what’s the takeaway from all this? For elderly patients with persistent AF undergoing high-power catheter ablation, this study suggests that the Single-Ring Isolation (SRI) technique offers some significant advantages over Box Isolation (BOXI).

It seems to be:

• More Efficient: Shorter ablation time, fewer lesions.
• Potentially Safer: Less heart muscle injury (based on troponin), significantly fewer gastrointestinal symptoms.
• Much More Comfortable: Significantly lower pain scores, less procedure interruption due to movement.

While the 12-month success rate for keeping AF away was similar in this study, the benefits in terms of procedural efficiency, reduced injury markers, and especially improved patient experience (less pain, fewer GI issues) make high-power SRI look like a really promising option for this specific population. Elderly patients can be more fragile and sensitive to discomfort and complications, so a technique that is gentler on the body and the patient’s experience is a big deal.

What’s Next?

Like any good study, this one has limitations. It was retrospective (looking back at data), involved a relatively small number of patients after matching, and the follow-up was only 12 months. The pain assessment wasn’t *just* for the posterior wall ablation part, though that’s often the most painful bit. Future studies with more patients, a prospective design (following patients forward), longer follow-up periods, and more detailed pain/injury assessments (like esophageal temperature monitoring) would be fantastic to confirm these findings. Using things like 7-day Holter monitors or wearable devices might also catch more instances of AF recurrence.

But for now, this research gives us a strong indication that high-power SRI is a safe, feasible, and potentially superior approach for improving the *experience* of elderly patients undergoing ablation for persistent AF. It’s exciting to see techniques evolving to be not just effective, but also kinder to the people receiving them.

Source: Springer