Fig. 2: Featured cases of arrhythmias captured on Apple Watch.

Exemplary ECG tracings taken by patients using the Apple Watch. a A patient s/p OHT in infancy for Ebstein’s anomaly with LVNC. The patient presented with palpitations and Apple Watch captured an episode of atrial flutter. b An otherwise healthy patient presenting with a 2-month history of racing heartbeat. The patient was unable to tolerate a Patch monitor for more than 1 day. Apple Watch captured an episode of SVT. c A patient with 6 years of palpitations and chest tightness, originally thought to be due to reactive airway disease. A patch monitor worn for 2 weeks was negative for any arrhythmias, even during symptomatic episodes. An exercise study was also normal. Apple watch recorded wide complex tachycardia during one of his episodes about 1 year later. d A patient with a history of neonatal valve-sparing repair of TOF with recurrent palpitations with exercise. During a symptomatic event an episode of monomorphic VT was recorded on the patient’s apple watch, and further episodes were confirmed on a patch rhythm monitor. Further workup following this recording revealed RVOT VT. e A patient who was being evaluated for palpitations and ventricular bigeminy and trigeminy identified on ECG. The patient had patch rhythm monitor confirming bigeminy and trigeminy, but no tachycardia. Apple watch captured this episode of polymorphic ventricular tachycardia during a severe episode of palpitations. OHT orthotopic heart transplant, LVNC left ventricular noncompaction, SVT supraventricular tachycardia, TOF Tetralogy of Fallot, VT ventricular tachycardia, RVOT right ventricular outflow tract, ECG electrocardiogram.