JAMA study suggests novel treatment strategy for VT storm: Transcutaneous magnetic stimulation.

Transcutaneous magnetic stimulation (TcMS) has previously been used for management of psychiatric disorders. Since autonomic neuromodulation provides therapeutic benefit in ventricular tachycardia (VT) storm, therefore hypothetically TcMS can noninvasively and nondestructively modulate a patient's nervous system activity and may reduce VT burden in patients with VT storm. In a proof of concept study, authors Markman et al have shown that treatment with TcMS is safe and may be an effective option to stabilize patients in VT storm. These results were recently published in JAMA Cardiology.

VT storm is associated with considerable morbidity and mortality. Autonomic neuromodulation via local blockade of the left stellate ganglion provides therapeutic benefit by reducing cardiac sympathetic input in patients with VT storm. Magnetic stimulation has previously been shown to modify arrhythmia risk by targeting cardiac sympathetic innervation in animal models.

The present double-blind, randomized pilot study was conducted to characterize the effects of a single session of TcMS for patients with VT storm. The study included 26 adult patients with 3 or more episodes of VT in 24 hours. Patients were randomly assigned to receive a single session of either TcMS that targeted the left stellate ganglion (n = 14) or sham stimulation (n = 12).

The primary outcome was freedom from VT in the 24-hour period following randomization. Key secondary outcomes included safety of TcMS on cardiac implantable electronic devices, as well as burden of VT in the 72-hour period following randomization.

The study gave following results:

1. In the 24-hour period after randomization, VT recurred in 29% patients in the TcMS group vs. 58% patients in the sham group (P = .20). This difference was not statistically significant.

2. But, in the 72-hour period after randomization, patients in the TcMS group had a mean of 4.5 episodes of VT vs 10.7 in the sham group (P < .001). this difference was significant.

3. Patients in the TcMS group were taking fewer antiarrhythmic drugs (AADs) 24 hours after randomization compared with baseline, whereas no such change occurred in the number of AADs taken for the sham group.

4. None of the 7 patients in the TcMS group with a cardiac implantable electronic device had clinically significant effects on device function.

Although 24-hour freedom from VT was not different between groups, there was a substantial reduction in the number of episodes of VT in the 72-hour period following randomization in patients who received TcMS that was driven by a reduction in the initial 24-hour period postrandomization.

The subset of patients with evidence of unilateral peripheral vasodilation consistent with sympathetic blockade remained free of sustained or nonsustained VT for greater than 24 hours after randomization.

Perks of this technique:

Transcutaneous magnetic stimulation is a well-developed technique that exploits the plasticity of a patient's nervous system and can promote excitation or inhibition depending on stimulation parameters. This treatment is valuable not only because of its ability to modify neural circuitry, but also because it is uniquely noninvasive and non-destructive.

These findings suggest that treatment with TcMS is safe and may be an effective option to stabilize patients in VT storm.

Source: JAMA Cardiology: doi:10.1001/jamacardio.2021.6000