Cardiogram, a startup seeking to make the sensor data from the Apple Watch more useful for the average watch user, and, eventually, useful in a clinical context, has raised $2 million in a round led by Andressen Horowitz's new bio fund, led by Vijay Pande.

A number of angel investors also contributed: Homebrew (Satya Patel, VP Product of Twitter and Hunter Walk, Director of Product for YouTube), Elad Gil and Othman Laraki (cofounders of Color Genomics), Jeff Hammerbacher (Assistant Professor, Mount Sinai School of Medicine), Justin Palmer (former VP Data of LendingHome), Joshua Reeves (CEO of Gusto), Kevin Scott (SVP Engineering of LinkedIn), and Halle Tecco (founder of Rock Health).

"If you own an Apple Watch, its native software already measures your heart rate once every 5 minutes, or continuously if you're working out," CEO Brandon Ballinger said in a statement. "That data does get stored in your Health app, but it's just raw data, and not easily understandable. What Cardiogram does is organize this info in graphs both real-time short-term graphs, like your heart rate over the course of a stressful meeting, and long-term trend graphs, like resting heart rate over time. Plus, we give you full access to the underlying metrics."

As well as creating a product for consumers, Cardiogram has been working with UCSF since March to collect user data in a study called mRhythm and use it to develop an app for detecting atrial fibrillation based on on Apple Watch data. 

"In the last six months, we’ve gathered more than 10 billion sensor measurements from more than 100,000 contributors," Ballinger wrote in a blog post about the funding. "Of course, raw sensor data is not a biomarker, a biomarker is not a diagnosis, and a diagnosis is not a therapeutic. Our first clinical application is detection of atrial fibrillation, the most common abnormal heart rhythm, and early tests with UCSF Cardiology's Health eHeart Study suggest an accuracy above 90 percent will be attainable, even with consumer grade heart rate sensors."

Cardiogram announced a new feature with the funding called Habits. Habits is an app-store like feature that lets users of the app select healthy behaviors and pair them with a biomarker, than track how that marker improves as they engage in the activity. 

"Habits fall into three categories: Fitness, Sleep, and Stress," Ballinger wrote. "Each category offers a handful of Habits you can try for 14 days. Each day, you can 'check off' your daily progress, monitor whether this Habit is improving key biomarkers, and to make it more fun, you can invite friends to join you."