A noninvasive radiation
therapy that has been used for cancer treatment has a new indication of
treating a condition of irregular heart rhythms called ventricular tachycardia
- Ventricular tachycardia, a
life-threatening irregular heart rhythm is now treated with noninvasive
radiation therapy, a technique used typically to treat cancerous tumors.
- Since the radiation is targeted
directly at the problem causing region, it significantly reduces the
number of ventricular arrhythmia events
- Study is currently enrolling
patients in a clinical trial to further evaluate radiation therapy as a
therapeutic approach for tachycardia.
, reports a study from the
Washington University School of Medicine in St. Louis. Ventricular tachycardia is
a condition where the heart beats very fast interfering with blood flow and
increasing the risk of sudden cardiac death
. Study suggests that when the radiation is
aimed directly at the problematic regions of the heart, there is a significant
reduction in the number of arrhythmia events in patients with ventricular
tachycardia. The study findings are published in The New England Journal of
tachycardiaTachycardia is a condition when the heart
rate exceeds the resting heart rate and beats over 100 beats per minute
. It often develops after
a heart attack. Tachycardia
is estimated to cause 300,000 deaths
per year in the U.S. alone and is the leading cause of sudden cardiac death. Standard treatment
includes medications and an invasive procedure where a catheter is inserted
through a vein into the heart where it selectively burns the tissue that causes
the electrical circuits of the heart to misfire leading to arrhythmia.
In patients with significantly high number of
arrhythmia events, defibrillators are implanted to save their lives in the case
of an arrhythmia. Phillip S. Cuculich, MD, an associate professor of medicine,
cardiologist and first author said, "The device recognizes a dangerous arrhythmia
and can deliver a life-saving electrical shock. While it's wonderful that we
can stop people from dying in that situation, the shock can be a traumatic
event. Patients understand that they have just avoided death. And when this
happens repetitively, often without warning, it can be devastating for
While there have been previous studies that
reported treating ventricular tachycardia with radiation therapy, this is the
first to do the same in a noninvasive manner.
‘A combination of two noninvasive techniques, one called electrocardiographic imaging that maps the starting locations of arrhythmias and the other that delivers the radiation directly at the problematic regions of the heart can be used to treat ventricular tachycardia.’
The study involved 5 individuals with ventricular tachycardia
, four in their 60s and
one over 80 years of age. All of them had either undergone catheter ablation
procedures and their ventricular tachycardia had returned, or they were unable
to go forward with the procedure due to other medical complications.
Collectively all patients
had experienced over 6,500 episodes of ventricular arrhythmia
a period of three months
before being treated with radiation therapy.
Following radiation treatment, the number of
arrhythmic episodes reduced drastically. During the first six weeks after
therapy, the patients collectively experienced a total of 680 episodes. At the
end of one year the collective number of episodes had decreased to four. Two
patients didn't experience any episodes at all.
How is the procedure done?
catheter ablation procedure can take six hours or
more and requires general anesthesia
, Cuculich said. "This new process
is entirely noninvasive. We take pictures of the heart with various imaging
methods -- MRI, CT, PET scans. But the unique piece is the noninvasive electrical
mapping called electrocardiographic imaging
. This allows us to pinpoint where the
arrhythmias are coming from. When we overlay the scar mapping with the
electrical mapping, we get a beautiful model of heart function that lets us see
not only where the arrhythmia comes from, but where it might progress.
"Based on these maps, Dr. Robinson is
then able to deliver the energy entirely noninvasively," Cuculich added.
"It's simply amazing to see a ventricular tachycardia patient get an
ablation therapy for a few minutes and then get up off the table and walk out
However, it is too early to say if the therapy
is completely safe. The team is still monitoring for long-term side effects of
radiation therapy, such as lung scarring and additional damage to the heart
itself. Currently the therapy is only being used for end stage patients who
have no other options. Vigorous research and clinical trials are required to
determine the safety of this procedure on younger and healthier patients. References :
- Phillip S. Cuculich, Matthew R. Schill, Rojano Kashani, Sasa Mutic, Adam Lang, Daniel Cooper, Mitchell Faddis, Marye Gleva, Amit Noheria, Timothy W. Smith, Dennis Hallahan,Yoram Rudy, Clifford G. Robinson. Noninvasive Cardiac Radiation for Ablation of Ventricular Tachycardia. The News England Journal of Medicine, (2017) DOI: 10.1056/NEJMoa1613773