If you have a pacemaker or implantable cardioverter-defibrillator (ICD), you’ve probably been warned about magnets, microwaves, and metal detectors. Some of those warnings are outdated. Some are still critical. And the rise of MagSafe phones, electric vehicles, induction cooktops, and 5G towers has introduced an entirely new set of questions.
Here’s what the research actually says about electromagnetic interference (EMI) and cardiac implantable electronic devices (CIEDs) — what’s dangerous, what’s not, and what you should actually worry about in 2026.
How Pacemakers and ICDs Can Be Affected by EMF
Before diving into specific devices, it helps to understand how electromagnetic fields interact with cardiac implants. There are two main mechanisms:
1. Electromagnetic Sensing Interference
Your pacemaker or ICD continuously monitors your heart’s electrical signals through its leads. External electromagnetic fields can be “heard” by these leads as if they were antennas, potentially mimicking cardiac signals. This can cause:
- Inappropriate inhibition — the device thinks your heart is beating normally when it isn’t, so it stops pacing
- Inappropriate pacing — the device delivers pacing pulses your heart doesn’t need
- Inappropriate shock (ICDs) — the device misreads EMI as a dangerous arrhythmia and delivers a shock
- Mode switching — the device detects interference and reverts to a fixed-rate “asynchronous” backup mode
2. Magnetic Switch Activation
Most CIEDs have a built-in magnetic reed switch or Hall-effect sensor. When a sufficiently strong static magnet is placed directly over the device, it activates “magnet mode” — a safety feature designed for clinical use. In a pacemaker, this typically means asynchronous pacing. In an ICD, it disables shock therapy.
This is the mechanism behind the iPhone MagSafe concern. (For details on how wireless charging pads interact with CIEDs, see our wireless charging EMF guide.)
The Critical Variable: Unipolar vs. Bipolar
One finding runs through almost every study in this field: unipolar pacing configurations are far more vulnerable to EMI than bipolar ones.
In unipolar systems, the sensing circuit spans from the lead tip in the heart to the metal housing of the pulse generator in the chest — essentially a large antenna. Bipolar systems sense between two electrodes just millimeters apart on the lead tip itself, making them far less susceptible to external signals.
A landmark Finnish study (Tiikkaja et al., 2013, Europace, PMID 23125355) tested 11 pacemaker patients and 13 ICD patients against multiple EMF sources. Not a single bipolar pacemaker or ICD experienced interference — even at field strengths up to 300 µT, which exceeds what you’d encounter in almost any everyday environment. Only the three unipolar-configured pacemakers were affected, and only at the highest test intensities.
Good news: The vast majority of modern pacemakers and ICDs use bipolar configurations. If yours was implanted in the last 10-15 years, it’s almost certainly bipolar. Ask your cardiologist if you’re not sure.
Cell Phones: The MagSafe Problem
For decades, the advice was simple: keep your phone 6 inches from your pacemaker and you’re fine. Older studies showed that digital cell phones posed minimal risk at normal usage distances, and the concern largely faded.
Then Apple introduced MagSafe.
The iPhone 12 Wake-Up Call
In early 2021, a letter in Heart Rhythm by Greenberg et al. demonstrated that the iPhone 12’s ring of magnets — designed for wireless charging alignment — could trigger magnet mode in an ICD when placed directly over the device. This got major media attention.
A comprehensive follow-up by Italy’s National Institute of Health (Censi et al., 2022, Pacing Clin Electrophysiol, PMID 35076120) tested the iPhone 12 against 12 different pacemakers and ICDs from all major manufacturers. Key findings:
- Magnets triggered magnet mode in all 12 devices when placed directly over them (0 cm distance)
- The effect disappeared at just 1 cm distance
- Apple’s recommended 15 cm (6-inch) safety distance provides a huge safety margin
- No device was permanently affected — removing the phone immediately restored normal function
But Regular Phone Use Is Safe
A separate clinical study (EMI-PHONE Study, Apakuppakul et al., 2022, J Arrhythm, PMID 36237870) tested 80 patients with CIEDs against three different smartphones — a Nokia 3310, iPhone 7, and Samsung Galaxy S9 — placed directly on the chest during standby, calling in, and calling out.
Result: Zero interference detected in any test, with any phone, at any position.
The difference? The iPhone 7 and Samsung S9 don’t have the same strong magnet arrays as MagSafe devices.
The Bottom Line on Phones
The risk isn’t from the phone’s radio signal — it’s from magnets in MagSafe-compatible devices. Keep any MagSafe phone or accessory at least 6 inches (15 cm) from your CIED. Don’t put your phone in a breast pocket on the same side as your implant. For actual phone calls, holding the phone to your ear on either side is perfectly safe.
A 2024 systematic review from Loma Linda University (Kewcharoen et al., J Interv Card Electrophysiol, PMID 38443707) confirmed: the only smartphone EMI risk comes from MagSafe magnets in direct contact with the CIED pocket. No other phone model, position, or use case showed interference.
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Search Your AddressInduction Cooktops: Real but Manageable
Induction cooktops are one of the few household items that can genuinely interfere with pacemakers — under specific conditions.
Induction stoves work by generating a powerful alternating magnetic field (typically 20-100 kHz) to heat ferromagnetic cookware. That same field can potentially be detected by pacemaker leads.
The Key Studies
Irnich & Bernstein (2006, Europace, PMID 16635999) conducted the most thorough investigation, testing 11 European induction cooktops with a worst-case pacemaker-patient model:
- With pots centered on the burner: induced voltages stayed below the critical 100 mV threshold
- With pots placed off-center (eccentric): voltages reached up to 800 mV — well above the interference threshold
- At 35 cm distance: all voltages dropped to ≤60 mV, regardless of pot position
- The most sensitive pacemaker tested reacted at 90.5 mV
Rickli et al. (2003, Pacing Clin Electrophysiol, PMID 12914627) tested 40 pacemaker patients sitting at the closest possible distance to two cooking pots, with pacemakers programmed to unipolar sensing. No interference occurred in any test.
Tiikkaja et al. (2013, Europace, PMID 23125355) tested an induction cooktop in their Finnish EMI study. No interference — even with unipolar pacemaker settings.
The Real-World Risk
A comprehensive 2019 systematic review from RWTH Aachen University (Driessen et al., Europace, PMID 29992289) found that induction cooktops can provoke interference, but the conditions are specific:
- Left-sided unipolar implant (increasingly rare)
- Leaning directly over the cooktop (torso within ~20 cm)
- Off-center pot placement (stray fields are much stronger)
For patients with modern bipolar devices who stand at a normal cooking distance, the risk is essentially zero.
Practical rule: Stand at least 12 inches (30 cm) from your induction cooktop while it’s on. Keep pots centered on the burner. If your pacemaker is unipolar and left-sided (uncommon), discuss with your cardiologist. For more on induction cooktop EMF in general, see our induction cooktop EMF radiation guide.
Electric Vehicles: An Emerging Question
With EVs generating significant electromagnetic fields from motors, batteries, and charging systems, CIED patients have a legitimate new question.
Driving Is Safe
The 2024 Loma Linda systematic review (PMID 38443707) evaluated three EV studies and found no reports of EMI during normal driving in any electric or hybrid vehicle tested.
Charging Deserves Caution
One 2024 study from Wright State University (Salih et al., Pacing Clin Electrophysiol, PMID 38830796) found something noteworthy. Using a loop antenna that mimics the subcutaneous ICD (S-ICD) antenna, they tested a Tesla Model 3 during 220V Level 2 charging:
- Most locations inside and outside the car showed no concerning signals
- Near the cup holder area, voltages of 400-504 millivolts were detected — within the S-ICD’s R-wave detection spectrum (30-300 Hz)
- The authors called for further in vivo studies
This doesn’t mean EV charging is dangerous — this was a bench study with a simulated antenna, not actual patients. But it’s an area where more research is needed, particularly for subcutaneous ICDs and wireless (inductive) charging systems.
Practical advice: Normal EV driving appears safe. During charging, don’t lean over the charging port or sit in the car near the cup holder area for extended periods. More data is coming. For broader context, see our electric car EMF guide.
5G Cell Towers and Base Stations
This is the fear most CIED patients bring up — and it’s largely unfounded.
A 2023 analysis by Italy’s Istituto Superiore di Sanità (Mattei et al., Health Phys, PMID 37195187) specifically examined 5G technology and pacemakers/ICDs:
- Current pacemaker/ICD immunity standards already cover pre-5G cellular frequencies
- For 5G frequencies above 3 GHz (including mmWave), the short wavelength means the fields can’t effectively couple to implant leads — the waves are essentially too small to be “heard” by the sensing circuit
- The power levels from base stations at any distance a person would encounter are far below interference thresholds
Cell phone signals (as opposed to magnets) have been extensively studied since the 1990s. The foundational Mayo Clinic study (Hayes et al., 1996, Pacing Clin Electrophysiol, PMID 8904532) established the basic safety framework. Modern digital cell networks use much lower power and different modulation than the early analog systems that occasionally caused interference.
No study has ever shown that living or working near a cell tower causes pacemaker or ICD interference. The field strengths from towers at any habitable distance are orders of magnitude below what would be needed. Use our cell tower map to check proximity, but this isn’t a concern for your implant.
Anti-Theft and Security Systems
Store anti-theft systems (Electronic Article Surveillance, or EAS) and airport metal detectors are common concerns:
The Finnish study (Tiikkaja et al., 2013) tested an EAS gate directly. Bipolar CIEDs showed no interference. One of three unipolar pacemakers was affected.
The general guidance: Walk through security gates and anti-theft systems at a normal pace. Don’t linger in the detection zone. Don’t lean against or stand next to the system panels. The brief transit exposure is well below interference thresholds for modern bipolar devices.
For airport body scanners (millimeter-wave), these use extremely high-frequency, low-power signals that cannot interact with CIED circuitry. They’re safe.
High-Speed Rail: Just Resolved
A brand-new study published this week (Tian et al., March 2026, J Radiol Prot, PMID 41875488) addressed the pantograph-catenary arc on high-speed electric trains — the electromagnetic pulse generated when the train’s power collector sparks against the overhead wire.
Their simulation of dual-chamber pacemaker patients (both standing and seated positions) found:
- Maximum induced voltage on monopolar electrodes: 0.068 mV (threshold: 2 mV)
- Maximum induced voltage on bipolar electrodes: 0.00147 mV (threshold: 0.3 mV)
- Maximum tissue SAR: 0.7065 nW/kg (vanishingly small)
All values were far below the ISO 14117:2019 safety thresholds. High-speed rail is safe for pacemaker patients.
Smartwatches and Wearables
Apple Watch, Fitbit, and similar wearables use Bluetooth and sometimes cellular signals. The 2024 Loma Linda systematic review (PMID 38443707) found no reports of EMI from smartwatches, even when worn on the wrist near a chest implant.
The main concern would be magnets in charging docks — similar to MagSafe, keep charging cradles at least 6 inches from your CIED.
For more on wearable EMF in general, see our Apple Watch EMF guide.
Medical Environments: Where the Real Risks Are
Ironically, the biggest EMI risks for CIED patients aren’t in your kitchen or at the cell tower — they’re in medical settings:
- MRI machines — extremely powerful magnetic fields. Historically contraindicated, though MR-conditional devices are now common. Always inform your imaging team about your implant.
- Electrocautery/electrosurgery — the #1 medical EMI risk during surgery. Requires careful CIED management by the surgical team.
- Radiation therapy — can damage CIED circuitry directly. Requires dose planning to shield the device.
- Diathermy — therapeutic heat via RF or microwave energy. Generally contraindicated near CIEDs.
- Lithotripsy — shock waves can potentially affect sensing. Modern devices handle it better, but monitoring is required.
These are managed by your medical team. The key is always: tell every healthcare provider you have a CIED before any procedure.
The Complete Guide: What’s Safe and What Needs Caution
Based on the current evidence, here’s your practical reference:
✅ Safe (No Special Precautions Needed)
- Cell phone calls — hold to either ear normally
- Non-MagSafe smartphones — no magnet concern
- WiFi routers — even nearby, no interference risk
- 5G cell towers — at any habitable distance
- Microwave ovens — modern ovens are well-shielded (older advice to avoid was based on 1960s-era leaky units)
- High-speed trains — confirmed safe (PMID 41875488)
- Electric vehicles — normal driving
- Bluetooth headphones and earbuds — no risk (but keep charging cases 6 inches from CIED)
- Airport millimeter-wave body scanners
- TV, radio, computers, tablets
- Smartwatches — worn on wrist, no concern
⚠️ Use Caution (Follow Safety Distance Rules)
- MagSafe phones and accessories — keep 6+ inches (15 cm) from CIED
- Induction cooktops — stand 12+ inches back; keep pots centered
- Anti-theft/EAS gates — walk through at normal pace, don’t linger
- Airport/courthouse metal detectors — walk through, don’t stand in the arch
- Power tools with strong motors — keep distance from chest when running
- Wireless charging pads — keep 6+ inches from CIED
- EV charging — don’t lean over charging port or linger near it
- MagSafe-compatible phone cases and wallets — same 6-inch rule as the phone
🚫 Discuss With Your Doctor First
- MRI scans — only with MR-conditional devices and proper protocol
- Any surgery involving electrocautery
- Radiation therapy
- Diathermy or therapeutic ultrasound near chest
- Welding (especially arc welding — strong EMF at close range)
- Working on high-voltage electrical systems
FAQs
Can my cell phone interfere with my pacemaker?
Standard phone calls and cellular signals don’t interfere with modern pacemakers. The concern is specifically with strong magnets in MagSafe-compatible phones and accessories. Keep MagSafe devices at least 6 inches (15 cm) from your implant. The FDA, Apple, and cardiac device manufacturers all recommend this distance.
Are induction cooktops safe with a pacemaker?
For the vast majority of patients with modern bipolar pacemakers, yes — at normal cooking distance. The risk is primarily for patients with older unipolar, left-sided implants who lean directly over the cooktop with off-center cookware. Standing at least 12 inches back and centering your pots eliminates the risk.
Can 5G towers affect pacemakers and defibrillators?
No. 5G signals — both sub-6 GHz and millimeter-wave — operate at power levels and frequencies that cannot meaningfully interact with CIED sensing circuits. A 2023 analysis by Italy’s National Institute of Health confirmed that 5G frequencies above 3 GHz can’t effectively couple to implant leads. Living near a 5G tower poses no risk to your cardiac device.
Should I avoid electric vehicles if I have an ICD?
Normal driving in an EV is safe based on current evidence. The only area flagged for further study is charging — specifically, the electromagnetic fields near EV charging ports and some interior locations during Level 2 charging. Don’t lean over the charging port, and you should be fine.
Do I need to worry about my Apple Watch or Fitbit?
No. Studies show no EMI from smartwatches during normal wear. Keep the watch’s magnetic charging dock at least 6 inches from your CIED, just like any other magnetic accessory.
What’s the most dangerous everyday EMF source for pacemaker patients?
Based on the evidence, the highest everyday risk comes from strong permanent magnets — including those in MagSafe phones/cases, magnetic closures on purses and tablet covers, and magnetic name badge holders. These can activate magnet mode if pressed directly against your CIED. The good news: the effect is immediate and reversible — remove the magnet and normal function resumes.