Wearable cardioverter defibrillator
A summary of the device, its technology and indications was published in 2017 and reviewed by the EHRA Scientific Documents Committee.
[17] Usual wearing time of a WCD is about 3 months but depends on the patient's needs and the prescription of the treating physician.
[21] An external, wearable cardioverter-defibrillator with defibrillation features similar to an ICD could be a solution to be used as “bridge” to protect these patients from SCD.
In 1986, M. Stephen Heilman and Larry Bowling founded LIFECOR and started the development of the first wearable cardioverter defibrillator (WCD).
This WCD was extensively tested for three years in multi-centre and multinational clinical trials (WEARIT and BIROAD) in the United States and Europe.
The clinical data collected from those trials[26] allowed Lifecor to obtain FDA approval for use of the WCD in the United States.
In July 2021, the FDA approved a second WCD product for the market developed by Kestra Medical Technologies, Inc.
[31] The WCD is covered by most health plans in the United States, including commercial, state, and federal plans as Durable Medical Equipment (DME) for those patients at high risk of cardiac arrest, including:[citation needed] The WCD uses dry, non-adhesive ECG electrodes to continuously monitor the patient's heart rhythm.
Three defibrillation electrodes are placed in the fabric garment, one on the chest (approximately at the level of the apex of the heart) and two on the back (between the shoulder blades).
Prior to delivering a therapeutic shock, the dry defibrillator electrodes automatically deploy conductive gel to protect the skin from possible injury from the treatment.
Action from bystanders is not required, but they are warned by voice information not to touch the patient during defibrillation and to call emergency services.
Three defibrillation electrodes are placed in the vest, one on the chest (approximately at the level of the apex of the heart) and two on the back (between the shoulder blades).
Prior to delivering a therapeutic shock, the dry defibrillator electrodes automatically deploy conductive gel to protect the skin from possible injury from the treatment.
By pressing two response buttons on the monitor simultaneously, an unjustified shock delivery can be prevented by the patient as long as she/he is conscious.
Action from bystanders is not required, but they are warned by voice information not to touch the patient during defibrillation and to call the emergency doctor.
[34] Long term follow-up studies showed that approximately 90% of all patients treated with the WCD are still alive one year after the heart failure incident.
They are intended for people of the general population with an unknown risk for heart failure and are usually available in public places and first responder ambulances.
[39] The WCD allows patients at high risk for SCD who are discharged from the hospital to return to most of the normal daily activities without constantly worrying about their heart issues and possible fatal outcomes.
The manufacturer also advises to avoid activities in loud and/or high vibration environments due to the possibility of missing an alert from WCD.
The WCD is generally recommended as temporary therapy for all patients who are at risk of SCD and can be prescribed in the UK as a monthly rental device.
A systematic cross-indication review and meta-analysis of studies reporting treatment rates of WCD was conducted by Masri et al. in 2019.
According to the authors, the rate of patients, who were appropriately treated with the WCD over 3 months of follow-up, was substantial and much higher in observational studies compared to the RCT included in the analysis.
An additional as-treated analysis (ATT) provided as supplemented appendix to the original publication, revealed statistical significance in all mortality endpoints, thus positive results for the use of the WCD.
Essential factors in successful WCD therapy in everyday clinical practice are high wearing compliance and the use of the monitoring system provided by the manufacturer (ZPM Network).
[56] They focused on cost-efficacy comparing the WCD to “standard of care” in patients at risk for SCD after MI or ICD explantation.
The authors found that the WCD is a cost-effective treatment option in patients after MI using the data from the VEST study.
The authors concluded that for the Italian NHS the WCD use contributes to a more effective utilization of resources and to the improvement of patient care in clinical practice.
