Case Presentation: A 68-year-old man presented to the Emergency Department complaining of diaphoresis with concomitant alerts on his Apple Watch which reported his heart rate was irregular. He has a known history of CAD with previous stent placement but did not report any chest pain, shortness of breath, palpitations, or recent medication changes. He did note recent right lower extremity pain but no preceding trauma or immobiliztion. Electrocardiogram returned with a bigeminy rhythm. Labwork was significant for a troponin level of 4.32 ng/mL. Left heart catheterization was performed and stents were found to be patent. Transthoracic echocardiogram revealed right ventricular dilation without evidence of strain. Right lower extremity DVT was identified on ultrasound and subsequent chest CT angiogram revealed bilateral pulmonary emboli with moderate clot burden. Age appropriate cancer screenings were up to date, however, the patient was found to have a large prostate nodule concerning for malignancy. PSA returned at 10 ng/mL. Anticoagulation treatment was initiated and follow up was arranged with urology for prostate biopsy.

Discussion: Pulmonary embolism remains an under recognized diagnosis with potentially grave consequences. An estimated 100,000 deaths are reportedly caused by pulmonary emboli each year. One study reported a 30 day and one year mortality of 4% and 13%, respectively. Incidence is higher in men; 56 per 100,000 than in women; 48 per 100,000. It is a challenging diagnosis due to the variety of potential presenting symptoms and ability to masquerade as numerous other disease processes. Chest pain and dyspnea are common presenting complaints but both are nonspecific and can be mistaken for exacerbations of other conditions such as coronary artery disease, COPD, heart failure, or pneumonia. The most specific signs, hemoptysis and calf pain, unfortunately are not frequently reported. This patient presented with a nonspecific symptom of palpitations and tachycardia, which was identified by his Apple watch. The most common arrhythmia associated with a diagnosis pulmonary embolism is sinus tachycardia.
Smart watches are increasing in popularity. Many of them include a heart rate monitor, which in this case was arguably life-saving. Despite examples like the one we have presented, concern remains that these monitors are not accurate or useful for diagnostic purposes. Preliminary data from a study at the University of California San Francisco notes Apple watches are able to detect atrial fibrillation successfully 97% of the time. As this technology continues to advance, the Apple watch or similar devices may improve care through at-home monitoring.

Conclusions: This case demonstrates that how technology can be helpful in diagnosing arrhythmia and even unmasking pulmonary emboli and underlying malignancy. Hospitalists should be aware of these at-home monitors that will likely increase in frequency in the near future.