Is EMI Still a Threat in the 5G Era?

Electromagnetic interference (EMI) may sound like an abstract engineering nuisance, something more relevant to lab bench oscilloscopes than real lives. But for millions of people living with pacemakers, EMI can be more than a silent killer of circuits. It has the potential, however rare, to disrupt life-sustaining cardiac rhythms. And now, with the widespread adoption of 5G and increasingly powerful mobile devices, the question is resurfacing: Are we truly out of the woods?

A groundbreaking study recently published in the Journal of Interventional Cardiology—titled The Effect of Electromagnetic Interference Produced by Smartphones Using 5G Network on Patients With Permanent Pacemakers—provides the most comprehensive real-world answer to date.

What the EMS5G-PPM Study Found

Conducted at Songklanagarind Hospital in Thailand, the study enrolled 489 patients with modern pacemakers and subjected them to 4,824 controlled tests using a Samsung S21+ smartphone operating on a live 5G network. The device was placed at the pacemaker pocket and contralateral ear during standby, data, and call modes. Real-time ECGs monitored any disruptions.

The results were reassuring: not a single instance of clinically significant EMI was detected during active phone use, even when the phone was placed directly over the pacemaker.

Yet there's a caveat. While pacemaker function itself remained stable, telemetry interference -disruptions to the communication link between pacemakers and their programming devices - was observed in 11.5% of cases, primarily during incoming calls. This was especially common in older pacemakers (implanted over 8 years ago), non-MRI-conditional systems, and devices with unipolar leads, particularly those manufactured by Abbott.

These glitches didn’t cause harm to patients directly, but they can confuse physicians, creating false alerts of malfunction or arrhythmia during routine device checks. In the context of a misread electrogram, a harmless blip can easily snowball into an unnecessary intervention—or worse, a missed real issue masked by phantom interference.

The Problem Beneath the Surface

EMI has plagued electronics since the birth of the digital age. In earlier generations of phones (2G/GSM), up to 28% of pacemaker users experienced EMI symptoms, ranging from pacing inhibition to asynchronous firing. Thanks to hardware improvements like feed-through filters and algorithmic noise suppression, today’s pacemakers, especially MRI-conditional models, are significantly more robust.

The mobile networks have evolved too. As the authors note, 5G signals use higher frequency, lower power RF transmissions than their 2G or 3G predecessors. In theory, this makes them less likely to penetrate device shielding or induce stray currents in leads.

But even as the risks decline, the vulnerabilities persist, especially at the intersection of hardware and software. Today’s implantable devices are not standalone systems; they communicate wirelessly, store data, and rely on real-time telemetry for critical diagnostics. And here, EMI remains an Achilles’ heel.

A Wake-Up Call for Hardware Design

This is where companies like Slip Signal Technologies come into the picture. Slip Signal isn’t building shields or filters to defend against EMI—they’re attacking it at the root cause. Their patented Spectrally Efficient Digital Logic (SEDL) design eliminates EMI emissions at the circuit level by replacing square-wave logic with smooth, sine-wave transitions. It’s a foundational redesign of how digital devices operate.

In high-stakes industries like aerospace and automotive, EMI isn't just a technical inconvenience—it can ground systems or compromise safety in an instant. But the risks are just as critical in healthcare. Medical devices such as pacemakers, defibrillators, and insulin pumps don’t have the luxury of uncertainty. They require uncompromising reliability. Relying on after-the-fact fixes or layered defenses isn’t enough - we need to eliminate interference at the source.

What Should Patients Do?

The EMS5G-PPM study offers a clear takeaway: if you have a modern, MRI-compatible pacemaker implanted within the last decade, 5G smartphones are unlikely to pose a direct threat to your heart. Still, patients should:

• Avoid placing an active phone directly over the device, especially during calls.

• Keep your phone out of your chest pocket or bra.

• Avoid using phones near interrogation wands during clinical checkups.

For physicians and device manufacturers, the message is subtler but more urgent: as devices become smarter, they also become more vulnerable. We need next-generation circuit design that prevents EMI, not just survives it.

Final Thoughts

In an age when every car, drone, and wearable is a node in a digital web, EMI isn’t just an engineering challenge: it’s a public health issue. The pacemaker in your chest, the insulin pump on your hip, or the telemetry monitor on your wrist all rely on unbroken signals to sustain life.

Studies like EMS5G-PPM show we’ve come a long way. But the next leap - true EMI immunity - won’t come from better filters or longer cables. It’ll come from a rethink of how we design logic itself.