What is the risk level of cardiac stimulation in first-level controlled operation mode for a patient with no implanted devices?

In a first-level controlled operation mode, the risk of cardiac stimulation for a patient without implanted devices is categorized as low. This classification is based on the understanding that patients who do not have any implanted devices are generally less susceptible to electromagnetic interference from the magnetic resonance imaging (MRI) system.

In this mode, the MRI environment is regulated to minimize the risk of any potential adverse effects from the magnetic field or radiofrequency energy on the patient's cardiac function. Since there are no devices that could respond to or be affected by the MRI's magnetic field, the likelihood of inducing unwanted cardiac stimulation is significantly reduced.

Moreover, patients without implanted medical devices typically have a normal physiological response to the magnetic fields produced during an MRI scan. Thus, the safety protocols in place and the absence of any implanted electronics lead to a low risk classification in such scenarios.