https://apnews.com/6cf7790448ee48b3a4844213c78e783b > CHICAGO (AP) — Two centuries after its invention, the stethoscope — the very symbol of the medical profession — is facing an uncertain prognosis. > It is threatened by hand-held devices that are also pressed against the chest but rely on ultrasound technology, artificial intelligence and smartphone apps instead of doctors' ears to help detect leaks, murmurs, abnormal rhythms and other problems in the heart, lungs and elsewhere. Some of these instruments can yield images of the beating heart or create electrocardiogram graphs.