**4. Clinical trials and other evidence**

There are many observational studies about the use of the WCD, but to date only one large randomized clinical trial has been published, the Vest Prevention of Early

guidance made the WCD a Class I indication for Status 18 patients awaiting trans-

recommended that the WCD be considered as an alternative treatment for patients who needed early ICD revision following device explant in the setting of suspected continuing infection [9]. In 2013, the ACC/AHA guideline stated that the utility of the WCD in high-risk patients in the first 4 to 6 weeks after myocardial infarction was being investigated [10]. The European Heart Rhythm Association, Heart Rhythm Society, and Asia Pacific Heart Rhythm Society (EHRA/HRS/APHRS) Expert Consensus on Ventricular Arrhythmias stated that patients with heart failure

plant at home [8]. In 2009, the Heart Rhythm Society expert consensus

*Report from the WCD about a tachycardia that was detected but did not require therapy delivery.*

**Figure 3.**

*Sudden Cardiac Death*

**66**


**Study description**

**69**

Heart Opreanu et al. 121 patients awaiting

Seven patients (6%)

Two patients (1.7%)

Median wear time 39 days

Eleven patients (9%) died in the

study

*The Wearable Cardioverter-Defibrillator DOI: http://dx.doi.org/10.5772/intechopen.90663*

> Median daily use 20 h/day

heart National registry based on

convenience

55% NICM, 17% ICM, 27% mixed

32% were NYHA Class III and 34%

Class IV Hemodialysis

Wan et al. 75 with a history of SCA

hemodialysis

 patients

75 patients (100%) experienced least 1 SCA event while wearing the

WCD

84 total events 136 total shocks delivered

> Infected device

Ellenbogen

had an ICD removed for infection

and used WCD as bridge to

reimplant

 et al. 8058 patients who

334 patients (4%) experienced

VT/VF events, of which 348/406

(86%) were treated by WCD, all

successfully

54 patients aborted shocks for

arrhythmias

spontaneously

12-month cumulative

10%

Observational

Bhaskaran et al.

None

None

Median duration 77 days

1/8 patients in the study were

noncompliant

 with WCD

Mean daily wear 23.4 0.6 h/day

Eight WCD patients

 studies from a single center

 event rate

 that resolved

 406

159 patients (2%), no associated

Median wear duration 53 days

Risk of VT/VF was highest in initial

weeks after ICD removal at 0.9%,

0.7%, and 0.7% for first, second, and

third weeks, respectively 30-day post-event survival rate was

81% overall

80% of patients in this study got an

ICD

(25–94)

Daily wear time not reported

deaths

 at

Not reported

Mean duration of wear

Among patients with shockable

rhythms, 30-day survival rate was

63.0%

62.9 73.1 day (2–308 days)

Mean daily wear 18.9 4.6 h/day

 sample

transplantation

transplantation

**Appropriate**

 **therapy**

**Inappropriate**

 **therapy**

**Wear time**

**Comments**

33% of patients improved within

3 months to ejection fraction >35%


### *The Wearable Cardioverter-Defibrillator DOI: http://dx.doi.org/10.5772/intechopen.90663*

**Study description**

**68**

Acute myocardial Barraud et al. 24 consecutive

Two VT occurred (8.3%); one

terminated

spontaneously,

 and one

None

Mean 3.0 Daily wear time 21.5 hours/day

 1.3 months duration

The WCD offered life-saving

intervention

 for one patient

*Sudden Cardiac Death*

patients with LVEF <30% and

recent myocardial Kondo et al. 24 patients with

myocardial

Controlled studies Olgin et al. VEST 2302 patients

20 patients (1.3% of WCD group)

 Nine patients (0.6% of WCD

Mean follow-up was

Arrhythmic

and 2.4% of WCD and controls,

respectively

All-cause mortality rates were 3.1%

and 4.9% for WCD and controls,

respectively

Of the 48 WCD patients who died,

only 12 were wearing the WCD at

time of death

 (p = 0.04)

 (not significant)

 death occurred in 1.6%

84.3

Wear time for WCD patients was

median 18.0 h/d (3.8–22.7) with

decreasing wear time over course of

study

 15.6 days

group)

with myocardial ejection fraction ≤35%

1524 in WCD arm 778 controls

Heart failure Barsheshet et al. 75 heart failure

Eight arrhythmic 6.6% of patients (n = 5), all

successful

 events occurred in

None

Median wearing duration was

At the end of study, 28% received an

ICD

59 days, 80% of patients wore the

WCD more than 50% of the day

patients prescribed a WCD in an

observational

SWIFT

Duncker et al. PROLONG

156 patients with ejection fraction

≤35% prescribed WCD for

3 months and then

re-evaluated

 study

Eleven patients received a total of 12

None

Cumulative

wear time; mean time per patient

was 101 Wear time 21.7

 4.0 h/day

 89 days

 42.7

patient-years

 of

48/156 3 months

improvement

ICD implanted, etc.)

 of ejection fraction,

discontinued

 therapy before

(noncompliance,

 early

appropriate

 shocks

 study at 2 centers,

 infarction with

 infarction

revascularization

was successfully Two patients (8.3%) received

None

Median duration of WCD therapy

In total, 58% went on to get ICD.

Ejection fraction improved over

baseline (p < 0.01) with 50%

having an ejection fraction >35%

Two patients (8.3%) died of fatal

but

3 months

non-arrhythmic

 events within

was 33 days (range 20–67 days) Median daily wear time 23.1 h/day

One patient excluded because of

irregular use of WCD

appropriate

were successful

 shock; both first shocks

 treated

 infarction

**Appropriate**

 **therapy**

**Inappropriate**

 **therapy**

**Wear time**

**Comments**


**Study description**

**71**

3569 WCD patients Compared against Social Security

Death Index Daimee et al. 1732 grouped as older

Older patients had higher event

rates per 100

sustained VT and VF (32.0 vs. 9.8,

(p = 0.027)

Older patients, especially those with

ICM were more likely to have VT/

VF treated with shock (6.9 vs. 2.4,

p = 0.034)

41 patients had 120 episodes of

0.5% of patients got an

Median duration of wear was

At the end of WCD use, 42% got an

ICD; most frequent reason not to get

an ICD was improved ejection

fraction

Two patients died (one refractory

VT and one bradycardia

transitioning

of patients stopped using the WCD

before the study ended, either

because they got an ICD, their

condition improved, they had

another

or other reasons

intervention

(transplant),

 to asystole), and 59%

90 days Median wear time 22.5 h/day

inappropriate

 shock

sustained VT, of whom 54%

received an appropriate

 shock

Kutyifa et al. 3195 (805 with ICM,

927 with NICM, 268 with

congenital heart disease)

WEARIT-II

Lamichhane

patients in

postmarket

who wore the WCD > 1 year 33.2% of the patients were African-

Americans

Retrospective

Bossory et al. 201 patients from 1

Five patients (2.5%), nine shocks

 One patient (0.5%), SVT

 Mean duration was 63 53.7 days

79% of WCDs were prescribed by

clinicians who were not EPs

Mean wear time 23.0 0.62 h/day

center prescribed a WCD with

1 year follow-up

 analyses

 registry of individuals

 et al. 220 WCD

4.1%

3.6%

Mean duration was 451 290 days Median wear time 20.4 h/day (15.5–

22.9)

A total of 13 sustained VT episodes

with 92.3% success rate (12/13

shocks)

manufacturer's

 Registry

patient-years

 for

(≥65, n = 722) and younger

(<65 years, n = 1010)

**Appropriate**

99% (79/80) for all VA

89.5% survival of VA events

 **therapy**

**Inappropriate**

Multiple reasons for

shock. Some of these shocks could have been aborted by patients, but

patients did respond Not reported except as being

"

"

rare

inappropriate

Median daily wear time was 21.7 h/

day

52% of patients wore WCD >90%

of day Older patients had significantly

Younger patients with NICM had

higher event rates per 100 patient-

years for atrial arrhythmias

vs. 74.9, p = 0.055)

Older patients were more likely to

get an ICD after WCD (41.8% vs.

36.5%, p = 0.034)

 (150.0

*The Wearable Cardioverter-Defibrillator DOI: http://dx.doi.org/10.5772/intechopen.90663*

> longer wear times (median 22.8 h/

day vs. 22.3 h/day p < 0.001)

 **therapy**

**Wear time**

**Comments**

no significant difference compared

to first ICD implant patients

