Stellate ganglion (SG) phototherapy using low-intensity laser is a promising lifesaving therapy for patients with refractory ventricular arrhythmias, clinicians from Japan report.
In a small study, SG phototherapy decreased sympathetic activity in healthy volunteers and effectively suppressed drug-refractory ventricular arrhythmias in some patients with electrical storms (SE).
“SG phototherapy using low-intensity laser is safe, non-invasive and easy to perform,” said principal investigator Kyoko Soejima, MD, professor and chair of cardiovascular medicine, Kyorin University Hospital, Tokyo. theheart.org | Medscape Cardiology.
ILI phototherapy does not require local anesthesia, can be applied to patients with ES who are in poor general condition and too unstable to undergo ablation, and can “save time before patients can undergo more therapy. invasive but effective, ”said Soejima.
The study was published online June 30 in the Journal of the American College of Cardiology: Clinical Electrophysiology.
A bridge to More effective therapy?
Patients with ES experience clustered episodes of ventricular arrhythmias (VA) that affect quality of life and prognosis. Management of ES usually includes treatment with amiodarone and beta-blockers, deep sedation, and catheter ablation. Modulation of the autonomic nervous system has been shown to be an effective adjunct therapy for SE.
In a two-part study, Soejima’s group first determined the effects of SG phototherapy on the autonomic nervous system in 20 healthy volunteers (10 males; mean age, 41 years), mainly colleagues, nurses and nurses. doctors working at Kyorin University.
They underwent a 10-minute SG phototherapy session using a low-intensity laser on both sides of the neck near the OS, repeated twice a week for 4 weeks (eight sessions).
No adverse event was observed after SG phototherapy in any volunteers.
SG phototherapy significantly reduced sympathetic activity in volunteers, as evidenced by the significant reduction in low frequency power / high frequency power and norepinephrine, the researchers report.
No significant changes in heart rate, blood pressure, PR interval, QRS duration, or QTc interval were observed, and changes in heart rate variability (HRV) appeared temporary because HRV levels had returned to baseline at 3-month follow-up.
In the pilot clinical study, SG phototherapy was applied to 11 patients with ES and frequent episodes of ventricular tachycardia (VT) / ventricular fibrillation (VF) despite pharmacological treatment and / or catheter ablation.
The duration and type of ILI phototherapy varied depending on the patient, from 4 to 22 days, and xenon, near infrared light, or both were given at the discretion of the attending physicians.
SG phototherapy was considered successful if a patient did not require an automatic implantable defibrillator (ICD) shock or tachycardia pacing therapy within 72 hours of the first session.
In seven of 11 patients, ES was immediately suppressed with SG phototherapy and ICD therapy was not required within 72 hours of the initial SG phototherapy session.
“However, based on the recurrence of ES in patients without maintenance therapy, it was determined that there might be a time limit to the effectiveness of SG phototherapy,” report the researchers.
Of the seven responders, two presented with recurrent VA, but with less burden and controlled with additional drugs. In the remaining four patients, a “limited effect” of SG phototherapy was observed; two patients had a reduced arrhythmia frequency without complete SE suppression and two remained in SE.
On average, ILI phototherapy reduced VA load from 8.0 episodes per day to 2.0 per day (P = .066).
The researchers note that in one patient, SG phototherapy was performed daily for 10 minutes for 22 days, followed by monthly maintenance phototherapy.
This patient had only two episodes of VF in the 24 months following treatment, during which time he underwent catheter ablation. After successful VT ablation, the patient continued monthly SG phototherapy and was VT / VF free for 52 months.
As in healthy volunteers, no adverse effects were observed in the clinical sample.
This pilot study shows that SG phototherapy “may be a safe and effective adjunct therapy for some patients with ES, but its long-term effectiveness remains unknown,” write Soejima and colleagues.
“I think anyone who is preferably managed non-invasively with autonomic modulation (no stellate gangliectomy or SG block) can be a candidate for SG phototherapy,” Soejima said. theheart.org | Cardiology Medscape.
She said that SG phototherapy can serve as a bridge to catheter ablation or SG sympathectomy and that its chronic use could reduce ES recurrence, but more studies are needed to confirm this.
Investigators are currently recruiting patients with ES into a larger study.
Contacted for comment, Davendra Mehta, MD, PhD, cardiac electrophysiologist, Mount Sinai Morningside, New York, noted that the study’s principal investigator is a “highly respected electrophysiologist.”
“Stellate ganglion resection has been shown to be helpful in patients with resistant ventricular arrhythmias or electrical storms and it emerges from this report that (SG phototherapy) may also be helpful in lightning storms,” said Mehta .
However, “one study still means nothing, and the study is in a very small number of patients, so we clearly need more information and this needs to be confirmed,” he said.
Following this pilot study in Japan, “someone is obviously going to replicate the study here and see if it works or not,” Mehta added.
Also weighing in on the study, Stephen Winters, MD, cardiac electrophysiologist and director, Cardiac Rhythm Management Program, Atlantic Health-Morristown Medical Center, New Jersey, said that these “unique findings raise the possibility of a new, non-invasive way of potentially treat life-threatening ventricular arrhythmias. “
“The alterations in heart rate variability and reductions in adrenaline levels documented in healthy controls suggest a reduction in sympathetic tone following phototherapy. While the researchers report a reduction in events in seven of 11 patients with sustained VT, the real ability to claim that statistical significance is lacking and that the effects of chance cannot be excluded, ”noted Winters.
Nonetheless, the results are “intriguing and certainly hypothesis-generating” and deserve larger, well-controlled studies, Winters said. theheart.org | Cardiology Medscape.
“Further studies to document whether the technique may be of benefit in the treatment of non-life-threatening tachycardias, such as inappropriate sinus tachycardia, may also be worth considering,” he added.
The study did not have specific funding. Soejima received honoraria for lectures from Abbott Japan and Medtronic Japan . A complete list of author disclosures is available with the original article. Mehta has no relevant conflict of interest.
J Am Coll Cardiol EP. Published online June 30, 2021. Full text
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