Abstract 14046: Cardiac Tamponade: A Handy Case of Early Detection

Case Presentation: A 63-year-old man with severe bicuspid aortic valve stenosis underwent surgical aortic valve replacement and the post operative echocardiogram was normal.In the month after discharge, the patient developed progressive episodes of lightheadedness, fatigue, and exertional weakness. He had no associated dyspnea on exertion, chest pain or fever. He was alerted of new sinus tachycardia on his Apple Watch, and the ECG morphology began changing with an overall decrease in QRS amplitude as well as alternating QRS amplitudes consistent with electrical alternans (Figure 1). These ECG strips were sent to the patient’s cardiologist who suspected a pericardial effusion due to these characteristic ECG findings.The patient underwent outpatient echocardiography which showed a normal functioning bioprosthetic valve with new large circumferential pericardial effusion and signs of cardiac tamponade physiology. The patient was admitted and underwent urgent pericardial drain placement with removal of 250cc of serosanguineous fluid. He recovered and was discharged with 3 months of colchicine.

Discussion: Pericardial effusions are a known potential complication after cardiac surgery and often have an occult presentation making detection difficult. Smart watches with ECG capabilities provide valuable data because they can be used to detect the development of a new tachycardia and changes in QRS morphology. By observing the progressive changes in the QRS morphology from baseline, it is possible to monitor for the development of electrical alternans. This finding coupled with the patient’s clinical presentation prompted rapid evaluation and treatment.

Conclusions: The Apple Watch can perform single-lead ECGs which are capable of diagnosing arrhythmias including atrial fibrillation. This case now opens the door to the early detection of postoperative pericardial effusions by monitoring the Apple watch for electrical alternans.