My grandfather is over 80-years-old and has suffered from severe heart conditions for quite a long time. He underwent a bypass surgery 12 years back and has a heart valve replacement which is not functioning normally; he is considered unfit to undergo surgery to correct it due to his medical conditions. He also has thyroid, for which he is under medications. Recently, he experienced breathing difficulty and got admitted, following which he is regularly using an oxygen therapy machine atleast thrice a day. He also has a history of angina. I recently bought him a smartwatch which monitors oxygen levels and heartbeat. Would he benefit from any preventive warnings that this watch may provide? And is it safe for him? Because the manual states that it is not for patients diagnosed with an arrhythmia other than atrial fibrillation.