To date, personal ECG devices have only really detected one kind of heart arrhythmia: atrial fibrillation. While that's helpful, it doesn't cover other conditions that could be just as dangerous. You might not be left wondering for much longer. AliveCor's KardiaMobile has received the first FDA clearance allowing a personal device to detect two other relatively common conditions, bradycardia (where your heart rate dips to 40-50BPM) and tachycardia (a jump to 100-140BPM). While these conditions are sometimes innocuous and might not show symptoms, they can also be representative of issues like heart disease.