Final answer:
Several factors can interfere with a VVI pacemaker, including strong electromagnetic fields from MRI machines that can induce a Hall voltage, other sources of EMI, proximity to devices like mobile phones, and certain medications. Patients with pacemakers are generally advised against MRI scans due to potential risks.
Step-by-step explanation:
Apart from electrocautery, there are several other factors that can interfere with a VVI pacemaker. Strong electromagnetic fields, such as those produced by MRI machines, can induce a Hall voltage that affects the pacemaker's function. MRI machines can induce electrical currents in the wires of a pacemaker, which can lead to inappropriate pacing or even damage the device. Additionally, a certain amount of metallic content in a pacemaker may become heated during an MRI. This is why patients with pacemakers are usually advised against having MRI scans.
Potential interference with pacemakers is not limited to MRI machines. Other sources of electromagnetic interference (EMI) include metal detectors, anti-theft systems, high-voltage power lines, and certain medical procedures. Mobile phones and MP3 players, if held close to the pacemaker, can also cause interference. Moreover, certain medications such as potassium channel blockers, like amiodarone and procainamide, may also interact with the pacemaker's function by affecting the heart's electrical activity, though indirectly.
It should also be noted that microshock-sensitive patients, such as those in surgery or intensive care, are at higher risk from electrical interference due to lower overall body resistance. A current as small as 20.0 μA applied to the heart may induce ventricular fibrillation, so safety precautions must be taken to minimize these dangers.