Electrocardiogram (ECG) heart monitoring technology has made great strides over the past decade, shrinking from machines found at doctors’ offices down to smartphone accessories and smartwatch features — but each size reduction has compromised the monitor’s clinical-grade accuracy. Today, AliveCor is bucking that trend with the announcement of KardiaMobile 6L, the first six-lead personal ECG device to receive FDA clearance.

Until now, a smartwatch or smartphone user effectively traded the simultaneous dozen-signal (12-lead) monitoring of a medical-grade ECG for the convenience of a one-signal (single-lead) device that could be carried anywhere. While 12-lead ECG machines are wheeled around on carts, requiring octopus-like wires and conductive gels to measure a heart’s electrical signals from various points across your body, a single-lead device places two electrodes on two body points — a wrist and finger, or two fingers — to make a simpler, less thorough measurement.

KardiaMobile 6L uses a form factor similar to the prior two-electrode KardiaMobile accessory, but instead is a three-electrode device, with twin steel pads on its top and a third on its bottom. Once again, the palm-sized device is roughly the same size as a thin, small TV remote control, and fits easily into a pocket or purse so you can carry it anywhere. Scans are conducted via an accompanying smartphone app.

But there’s a vast difference in the amount of information KardiaMobile 6L gathers. Across multiple scans — fingers plus ankle, and fingers plus left knee — the user forms Einthoven triangles that allow KardiaMobile 6L to gather as much information as a six-lead machine: three bipolar limb leads (I, II, and III) and three unipolar limb leads (aVR, aVL, and aVF). That leaves only six unipolar chest leads for separate monitoring in a hospital or clinic.

While Apple Watches and other devices can provide a basic ECG capable of detecting some irregular heart signals, the KardiaMobile 6L’s scans collectively provide a physician with data capable of revealing more¬†arrhythmias and heart issues. Moreover, because the AliveCor device is capable of shifting locations from knee to ankle, it’s capturing data from places that a wrist-bound ECG cannot — until and unless people start wearing additional wireless sensors.

“I am impressed with the quality and simplicity of 6-lead smartphone ECG tracings,” said Scripps Research Translational Institute director and cardiologist Eric Topol, MD, “which will unquestionably sharpen our ability to diagnose heart rhythm and conduction abnormalities. It’s a welcome and needed step forward for mobile heart diagnostics.”

As is typical for devices requiring FDA clearance, KardiaMobile 6L has been in development for some time, and was previously tested under the name Project Triangle. Now that clearance has been granted,¬†AliveCor plans to have the device in consumers’ hands by mid-June for $150, a 50% premium over the prior version. Preorders are available starting today at KardiaMobile6L.com.