The Wearable Cardioverter Defibrillator: A Safe, Noninvasive Solution for Patients with High-Risk for Sudden Cardiac Death following Heart Surgery

Objectives: To study the benefits, effectiveness and compliance of a wearable cardioverter defibrillator (WCD) on patients with high risk for sudden cardiac death (SCD) following cardiac surgery and to aid in preventing the premature implantation of a permanent defibrillator.

Background: The WCD is a noninvasive device capable of detecting ventricular tachycardia or fibrillation and treating a relevant arrhythmia.

Methods: From April 2013 to June 2017, all patients following cardiac surgery who were prescribed a WCD were retrospectively analyzed through hospital discharge letters and a consented commercial database to ascertain demographics, left ventricular ejection fractions (LVEF), the cause of cardiac insufficiency, wear time of the WCD, significant arrhythmias and reasons for returning the WCD.

Results: 58 Patients (93% males, aged 66 ± 9.8 SD and with a 28% median preoperative LVEF, 28 post-CABG, 15 post-valvular reconstruction or replacement, 10 combined operations, 4 TAVIs and 1 LVAD) received a WCD before hospital discharge. 65% of the patients suffered from ischemic cardiomyopathy and 25% from dilated cardiomyopathy. 17 Patients (29%) developed ventricular tachycardia (VT) preoperatively and 5 patients (8%) postoperatively. The median daily wear time was 23.5 hours. The WCD was worn for a median of 63 days. One patient suffered a sustained VT and was successfully defibrillated. No asystole was documented and no inappropriate treatment was observed. Upon returning the WCD 31% of the patients had obtained a permanent defibrillator, while 48% reported an improvement of the LVEF values.

Conclusion: Through a high compliance, ease of use and a significant number of patients declaring an increase in LVEF values we demonstrate the benefits of choosing a WCD in patients at risk for SCD after cardiac surgery. This study also confirms that this non-invasive device can be used to prevent a premature implantation of a permanent transvenous defibrillator. The WCD was successfully able to recognize and treat significant ventricular tachycardias. Further studies are needed to standardize the indication criteria and the optimal wear time of the WCD after cardiac surgery.