Devices › Wearable automated external defibrillator
Device brand name · Wearable cardioverter defibrillator
LifeVest WCD 4000 System: medical device reports filed with FDA
140,785 reports name it, 2009–2026. Manufacturer given most often on reports: Zoll Manufacturing. Product code MVK.
- 140,785
- device reports naming the brand
- 0.5% of all MAUDE reports · about 8,492 a year
- 10,693
- reports, 12 months to August 2026
- 11,704 in the 12 months before
- 71.9%
- classified as malfunction
- 73.1% across the product code
- 2.5%
- classified as death, as reported
- 3,566 reports · not verified by FDA
FDA's MAUDE database holds 140,785 reports that name the brand "LifeVest WCD 4000 System" (wearable cardioverter defibrillator), received between December 2009 and August 2026; the manufacturer given most often on reports is Zoll Manufacturing. Spellings of one product vary from report to report.
10,693 reports arrived in the 12 months to August 2026, close to the 11,704 of the 12 months before. FDA releases MAUDE data monthly; reports can arrive months after an event, so the newest months grow in later releases. The event types recorded are malfunction (71.9%), injury (25.5%) and death (2.5%); across all wearable automated external defibrillator reports (product code MVK) death is recorded in 2.5% and malfunction in 73.1%. Event type is the reporter's classification of the report, not a verified outcome.
The device problems coded most often are battery problem (10.5%), failure to power up (10.2%) and inappropriate/inadequate shock/stimulation (9.2%). The patient problems coded most often are skin inflammation/ irritation, shock from patient lead(s) and arrhythmia. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data."
Reports by month, five years
Reports by the month FDA received them. FDA releases MAUDE data monthly; reports can arrive months after an event, so the newest months grow in later releases.
By year received
Event type and report source
Event type, as classified on the report
Who filed the report
Grey bar: all 149,799 reports carrying product code MVK. Event type is the filer's classification and is not verified by FDA.
Device problems coded
| Device problem (FDA code) | Reports | Share | Share across product code |
|---|---|---|---|
| Battery problema problem with the battery | 14,759 | 10.5% | 10.5% |
| Failure to power up | 14,336 | 10.2% | 10.1% |
| Inappropriate/inadequate shock/stimulation | 12,982 | 9.2% | 9.1% |
| Device displays incorrect message | 12,358 | 8.8% | 9.1% |
| Circuit failure | 7,705 | 5.5% | 5.2% |
| Patient device interaction problem | 6,320 | 4.5% | 4.3% |
| Breakthe device broke | 6,117 | 4.3% | 4.5% |
| Signal artifact/noise | 5,908 | 4.2% | 4% |
| Device operates differently than expectedthe device behaved unexpectedly | 5,756 | 4.1% | 4.2% |
| Charging problem | 4,764 | 3.4% | 3.3% |
| Incorrect interpretation of signal | 3,921 | 2.8% | 2.7% |
| Key or button unresponsive/not working | 3,789 | 2.7% | 2.6% |
| Failure to charge | 3,506 | 2.5% | 2.8% |
| Device inoperablethe device could not be used | 3,466 | 2.5% | 2.5% |
| Over-sensing | 3,438 | 2.4% | 2.3% |
| Patient-device incompatibilitythe device did not suit the patient | 3,373 | 2.4% | 2.3% |
| Structural problem | 3,056 | 2.2% | 2% |
| Protective measures problem | 3,012 | 2.1% | 2% |
| Contamination /decontamination problem | 2,984 | 2.1% | 2% |
| Failure of device to self-test | 2,512 | 1.8% | 1.7% |
FDA's device problem codes as entered on the report; one report can carry several. Generic codes such as "no apparent adverse event" are left out.
Patient problems coded
| Patient problem (FDA code) | Reports | Share |
|---|---|---|
| Skin inflammation/ irritation | 9,718 | 6.9% |
| Shock from patient lead(s) | 8,306 | 5.9% |
| Arrhythmia | 7,355 | 5.2% |
| Skin irritationirritated skin | 5,795 | 4.1% |
| Deaththe patient died; cause not stated by this term | 2,180 | 1.5% |
| Rashskin rash | 1,953 | 1.4% |
| Atrial fibrillationan irregular heart rhythm | 1,679 | 1.2% |
| Electric shockan electric shock | 1,204 | 0.9% |
| Shockshock, a collapse of the circulation | 756 | 0.5% |
| Tachycardiafast heart rate | 556 | 0.4% |
| Asystole | 536 | 0.4% |
| Irritationirritation | 453 | 0.3% |
| Loss of consciousnesspassing out | 437 | 0.3% |
| Itching sensation | 431 | 0.3% |
| Ventricular fibrillationa chaotic rhythm from the lower heart chambers | 378 | 0.3% |
Patient problem codes are present mainly in reports filed since 2019 and are often blank.
In context
| Measure | LifeVest WCD 4000 System | Product code MVK | All MAUDE reports |
|---|---|---|---|
| Reports | 140,785 | 149,799 | 26,136,888 |
| Share of that pool | — | 94% | 0.5% |
| Classified as death, per 1,000 reports | 25 | 25 | 9 |
| Classified as injury | 25.5% | 24.4% | 36.2% |
| Classified as malfunction | 71.9% | 73.1% | 62.3% |
| Filed by the manufacturer | 100% | 100% | 94.9% |
Shares are of reports, not of devices in use. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data."
Other brands with product code MVK
| Brand | Reports | Latest 12 months | Classified as death |
|---|---|---|---|
| Lifevest Wcd 3000 System | 4,109 | 0 | 1.8% |
| Lifevest Wcd 3100 System | 1,500 | 0 | 2.3% |
| LifeVest WCD 5100 System | 1,189 | 1,076 | 1% |
| Assure Wearable Cardioverter Defibrillator | 1,118 | 730 | 3.5% |
| Lifevest Wcd 4000 Sys | 371 | 0 | 3% |
| Assure Cardiac Recovery System | 208 | 0 | 4.8% |
Ordered by report count for navigation only. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data." FDA also states that "common products may have a higher number of adverse events due to the higher total number of people using the product."
Questions about LifeVest WCD 4000 System reports
How many FDA reports name LifeVest WCD 4000 System?
140,785 medical device reports in the openFDA MAUDE release of 28 Sep 2026, covering reports received through August 2026; 10,693 in the latest 12 months.
What kinds of events are reported?
malfunction (71.9%), injury (25.5%) and death (2.5%). "Event type" is how the report was classified when filed: death, injury, malfunction or other.
What device problems are coded?
battery problem (10.5%), failure to power up (10.2%), inappropriate/inadequate shock/stimulation (9.2%), device displays incorrect message (8.8%) and circuit failure (5.5%). These are FDA's device problem codes as entered on the report.
Who files these reports?
manufacturer reports (100%) and voluntary reports (0%). Manufacturers and user facilities are required to report; voluntary reports come from health professionals and the public.
Do these reports show that LifeVest WCD 4000 System was at fault?
No. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data." FDA adds that "a causal relationship cannot be established between product and reactions listed in a report."
How do I report a problem with a medical device?
Through FDA MedWatch (Form FDA 3500 for health professionals and consumers), or to the manufacturer. See the guide on how to report.
Where this comes from. Counts are built from the openFDA Device Adverse Event (MAUDE) bulk export released 28 Sep 2026, which holds reports FDA received through 31 Aug 2026. Brand, generic and manufacturer names are as written on the reports; product code names come from FDA's device classification. A report counts here when any device it lists carries this brand name after punctuation and capitalisation are normalised. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.
Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.