ECG biomarker identifies AFib patients most likely to benefit from electrical stimulation

Reuters Health - 17/06/2021 - P-wave alternans (PWA) may act as a biomarker for identifying patients with atrial fibrillation (AF) who are most likely to benefit from chronic low-level transcutaneous electrical stimulation of the tragus (LLTS), new research suggests.

PWA is a variation in atrial electrocardiographic waveform morphology thought to be produced by the substrate also responsible for AF. In the new study, researchers found LLTS significantly reduced PWA as well as AF burden in patients presenting with paroxysmal AF.

"Although PWA has been associated with AF in the past, it has never been used as a biomarker for guiding low-level tragus stimulation (LLTS), a form of vagal nerve stimulation," lead study author Dr. Stavros Stavrakis of the University of Oklahoma Health Sciences, in Oklahoma City, told Reuters Health by email.

He added that while previous research has demonstrated LLTS can modulate AF burden, clinical trials have so far shown mixed results, primarily due to poor identification of patients who would benefit from this treatment, as well as sub-optimal LLTS parameter selection.

To investigate the role of PWA in guiding LLTS decision-making, Dr. Stavrakis and colleagues analyzed data on 28 patients with AF who were randomly assigned to either active LLTS (n=16) or a sham earlobe simulation (n=12). The researchers delivered LLTS through a transcutaneous electrical nerve stimulation device. Treatment was administered for an hour each day over six months.

Using noninvasive continuous electrocardiogram monitoring, the research team assessed AF burden over two-week periods at baseline as well as after three and six months.

Acute LLTS was associated with a significant increase in PWA burden at baseline. Patients who received chronic LLTS, however, had a significant reduction in PWA as well as AF burden at six-month follow-up (P<0.05). Additionally, those who experienced an increase in PWA burden at baseline with acute LLTS subsequently demonstrated a significant drop in AF burden following six months of treatment with chronic LLTS (P<0.05).

An acute PWA increase at baseline was predictive of a significant reduction in AF burden by six months (odds ratio, 0.4; 95% confidence interval, 0.17 to 0.94).

"Chronic LLTS may be used as an alternative treatment option in selected patients with AF, and PWA may serve as a potential biomarker for identifying patients who are most likely to benefit from LLTS, guiding treatment of paroxysmal AF," the researchers write in Journal of the American Heart Association.

They caution, however, that the study had a small sample size and limited follow-up. Dr. Stavrakis noted that he and his research colleagues plan to launch a prospective clinical trial to further investigate the clinical implications of the findings.

"Specifically," he said, "we aim to determine which patients are likely to benefit from LLTS while setting optimal LLTS parameters for these selected patients."

The study did not have commercial funding, and the researchers report no conflicts of interest.

SOURCE: https://bit.ly/3xeitg9 Journal of the American Heart Association, online June 2, 2021.

By Brandon May



Posted on 17 June 202128 June 2021