A heart doctor explains four things she'd need to see before trusting the Apple Watch to monitor heart conditions

Apple announced a slew of new health features for its Apple Watch on Wednesday, including an FDA-cleared electrocardiogram sensor that is designed to alert users to potential problems with their heart so they get to a doctor in time. But cardiologists aren't yet convinced that it will be a net positive for their patients. The device could save lives — and already is — but it also comes with a set of risks.