Accuracy of a Standalone Atrial Fibrillation Detection Algorithm Added to a Popular Wristband and Smartwatch: Prospective Diagnostic Accuracy Study.

BACKGROUND: Silent paroxysmal atrial fibrillation (AF) may be difficult to diagnose, and AF burden is hard to establish. In contrast to conventional diagnostic devices, photoplethysmography (PPG)-driven smartwatches or wristbands allow for long-term continuous heart rhythm assessment. However, most smartwatches lack an integrated PPG-AF algorithm. Adding a standalone PPG-AF algorithm to these wrist devices might open new possibilities for AF screening and burden assessment. OBJECTIVE: The aim of this study was to assess the accuracy of a well-known standalone PPG-AF detection algorithm added to a popular wristband and smartwatch, with regard to discriminating AF and sinus rhythm, in a group of patients with AF before and after cardioversion (CV). METHODS: Consecutive consenting patients with AF admitted for CV in a large academic hospital in Amsterdam, the Netherlands, were asked to wear a Biostrap wristband or Fitbit Ionic smartwatch with Fibricheck algorithm add-on surrounding the procedure. A set of 1-min PPG measurements and 12-lead reference electrocardiograms was obtained before and after CV. Rhythm assessment by the PPG device-software combination was compared with the 12-lead electrocardiogram. RESULTS: A total of 78 patients were included in the Biostrap-Fibricheck cohort (156 measurement sets) and 73 patients in the Fitbit-Fibricheck cohort (143 measurement sets). Of the measurement sets, 19/156 (12%) and 7/143 (5%), respectively, were not classifiable by the PPG algorithm due to bad quality. The diagnostic performance in terms of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy was 98%, 96%, 96%, 99%, 97%, and 97%, 100%, 100%, 97%, and 99%, respectively, at an AF prevalence of ~50%. CONCLUSIONS: This study demonstrates that the addition of a well-known standalone PPG-AF detection algorithm to a popular PPG smartwatch and wristband without integrated algorithm yields a high accuracy for the detection of AF, with an acceptable unclassifiable rate, in a semicontrolled environment.

Acute Compartment Syndrome of the Lower Leg after Coronary Artery Bypass Grafting: A Silent but Dangerous Complication.

BACKGROUND: Acute compartment syndrome (ACoS) is a serious, limb-threatening condition, but ACoS after coronary artery bypass grafting (CABG) is rare. ACoS is diagnosed with the help of typical symptoms, but due to the use of analgesics in a postoperative setting, these symptoms may vary. Identifying risk factors for ACoS after CABG could reduce the risk of developing this complication. METHODS: We describe the clinical presentation, diagnosis, and management of five cases of ACoS arising from CABG procedures at our institution during the last 5 years. We also review all cases found in literature about this complication. DISCUSSION: Both systemic and local factors may contribute to ACoS of the lower leg. These factors include increased microvascular permeability caused by cardiopulmonary bypass (CPB), the use of cardiac-assist devices causing arterial occlusion and reperfusion injury, diminished arterial blood flow in patients with peripheral vascular disease due to lithotomy position and the use of elastic bandages and local trauma and hematoma formation due to the harvesting of the greater saphenous vein (GSV). CONCLUSION: To prevent this serious complication, we advise to pay extra attention to the patients with a greater risk. Hemostasis after venectomy in CABG surgery is mandatory, especially in the endoscopic harvesting of the GSV. Elastic bandages should be applied after weaning from CPB. Elevated creatine phosphokinase values may indicate ACoS. When suspicion arises, intracompartmental pressure measurement is the preferred tool for early recognition and diagnosis. To prevent irreversible, extensive tissue damage and permanent disability fasciotomy must be performed immediately after the diagnosis is made.