Wearable defibrillator helps avoid sudden cardiac death after surgery

Wearable cardioverter defibrillators (WCD) can effectively protect cardiac surgery patients from sudden cardiac death (SCD), according to a recent study, noting that SCD risk was substantial within the first 3 months after the procedure.

Majority of the patients did not require implantable cardioverter defibrillator (ICD) following WCD use because of significant left ventricular ejection fraction (LVEF) improvement. Compliance was also high despite sternotomy.

“This multicentre experience confirms existing data regarding effectiveness, safety, and compliance,” the researchers said. “Therefore, WCD should be considered in cardiac surgery patients with severely reduced LVEF.”

The current retrospective analysis included 1,168 patients (median age 66 years, 87 percent men) who had WCD. Participants were eligible if they had undergone cardiac surgery and had LVEF ≤35 percent or ICD explantation.

During the observation period, a total of 250 ventricular tachycardia (VT)/ventricular fibrillation (VT) episodes occurred in 106 patients (9.1 percent). Notably, 93.2 percent of these episodes occurred during the first 3 months after the procedure. [Eur J Cardiothorac Surg 2022;doi:10.1093/ejcts/ezac086]

Eighteen patients (1.5 percent), corresponding to 26 VT/VF episodes, received appropriate defibrillation shocks by WCD, all of which were successful. In comparison, eight patients (0.7 percent) received a total of nine inadequate shocks, resulting in supraventricular tachycardias with rapid transition in four patients. Artefacts accounted for four inadequate shocks.

Of the participants, 678 underwent coronary artery bypass graft (CABG) surgery. In this patient subset, a total of 81 VT/VF episodes occurred in 36 patients (7.1 percent). WCD delivered 11 adequate shocks to seven patients (1.4 percent). In three cases (0.6 percent), the response button to withhold shocks during consciousness was pressed.

After surgery, participants had a median LVEF of 28 percent, which improved to 35 percent during the follow-up examination. Of note, changes in LVEF were highly varied across different patient subgroups. ICD implantation was performed in nearly half (48.6 percent) of patients after WCD use. Meanwhile, use of the wearable device averted implantation in 471 patients (42.2 percent) due to improved LVEF.

In terms of adherence, participants wore the WCD for a median of 65 days, with the longest wearing period detected after valve surgery and after isolated CABG (median, 74 days for both). Patients wore the WCD daily for a median of 23.4 hours. Overall wear time was shortest for those who had ICD explantation (median, 48 days).

“Patients who recover after CABG or valve surgery show a significant improvement in LVEF within 3–6 months and at the same time confirm their willingness to wear a WCD with a high therapy compliance,” the researchers said. “Therefore, wearing the device during this temporary high-risk phase can provide safe and effective protection from SCD and simultaneously avoid permanent ICD implantation in a relevant proportion of patients.”

Of note, prematurely implanted ICDs could lose their justification at the end of the recovery period. If no indication was present, this could lead to complications such as infections or lead failure, according to the researchers.

“Thus, the use of a WCD can overall improve the patient’s quality of life and reduce the financial burden on healthcare systems,” they said.