Outcome of Patients With In-Hospital Ventricular Tachycardia and Ventricular Fibrillation Arrest While Using a Wearable Cardioverter Defibrillator.

In-hospital sudden cardiac arrests occurring during nighttime and weekend hours or within unmonitored hospital areas have been reported to have a poorer outcomes than monitored cardiac arrest. This study sought to assess the outcome of in-hospital ventricular tachycardia (VT) and ventricular fibrillation (VF) arrest by time of day, day of week, and within-hospital location when using a wearable cardioverter defibrillator (WCD). We retrospectively identified and reviewed consecutive in-hospital VT/VF arrests from January 2011 to May 2015 experienced by patients wearing a WCD using the manufacturer's postmarket registry. An index shockable sudden cardiac arrest event was defined as the first arrest caused by VT/VF. Event location and clinical outcome were extracted from patient call logs. Survival analysis was performed using the Kaplan-Meier method. A total of 234 in-hospital VT/VF arrests were included (mean age = 65 ± 12 years, male = 74%); 50% had a history of congestive heart failure. The median follow-up time was 6 days (interquartile range 1-4). In the 128 (55%) daytime events (7:00 a.m. to 7:00 p.m.), 24-hour survival was 91%. The 106 (45%) nighttime events (7:01 p.m. to 6:59 a.m.) had 89% 24-hour survival (p = 0.54). Survival outcome by monitored or unmonitored hospital locations were similar. Kaplan-Meir analyses showed no difference in 30-day survival either between weekend and weekday events (72% vs 65%, p = 0.79), or between daytime and nighttime events (64% vs 69%, p = 0.37). In conclusion, WCD use during in-hospital VT/VF arrest correlated with high survival rates regardless of event time or location inside a hospital. Use of a WCD appears to mitigate some of the risks associated with in-hospital VT/VF arrest.

Study of the wearable cardioverter defibrillator in advanced heart-failure patients (SWIFT).

INTRODUCTION: The wearable cardioverter defibrillator (WCD) may allow stabilization until reassessment for an implantable cardioverter defibrillator (ICD) among high-risk heart failure (HF) patients. However, there are limited data on the WCD benefit in the acute decompensated HF setting. METHODS AND RESULTS: The Study of the Wearable Cardioverter Defibrillator in Advanced Heart Failure Patients (SWIFT) was a prospective clinical trial carried out at two medical centers. Patients hospitalized with advanced HF symptoms and reduced left ventricular ejection function (LVEF) were enrolled and prescribed a WCD prior to discharge for a total of 3 months. Outcome measures included arrhythmic events, WCD discharge, and death. Study patients (n = 75, mean age 51 ± 14 years, 31% women) had a mean LVEF of 21.5 ± 10.4%. Non-ischemic cardiomyopathy was present in 66% of patients. The median WCD wearing time was 59 (interquartile range 17-97) days, and 80% of patients wore the device >50% of daily hours. WCD interrogations showed a total of 8 arrhythmic events in 5 patients, including 3 nonsustained or self-terminating ventricular tachycardia (VT) events, and one polymorphic VT successfully terminated by the WCD. None of the patients died while wearing the device and no inappropriate device therapies occurred. Upon termination of treatment with the WCD, 21 patients (28%) received an ICD. At 3 years, the cumulative death rate was 20% in the ischemic and 21% in non-ischemic cardiomyopathy patients. CONCLUSION: A management strategy incorporating the WCD can be safely used to bridge the decision regarding the need for ICD implantation in high-risk patients with advanced HF.

The impact of body mass index on the wearable cardioverter defibrillator shock efficacy and patient wear time.

BACKGROUND: The impact of body mass index (BMI) on the shock efficacy and patient adherence among patients using a wearable cardioverter defibrillator (WCD) is unknown. METHODS: Patients prescribed the WCD between January 1, 2008 and June 1, 2013, who experienced at least one episode of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and who received appropriate WCD therapy, were identified within a registry maintained by the manufacturer for regulatory, reimbursement, and administrative purposes. The registry contained patients' Body Mass Index (BMI) which was categorized as normal (18.0

Benefit of the Wearable Cardioverter-Defibrillator in Protecting Patients After Implantable-Cardioverter Defibrillator Explant: Results From the National Registry.

OBJECTIVES: This study reports on the time course of reimplantation and benefits of the wearable cardioverter-defibrillator (WCD) in patients post implantable cardioverter-defibrillator (ICD) explantation. BACKGROUND: The WCD is used to treat patients at high risk for ventricular tachycardia (VT) and ventricular fibrillation (VF), including patients with ICD-related infections who undergo device removal and cannot be immediately reimplanted. METHODS: This retrospective study included consecutive patients from 2002 to 2014 who underwent ICD removal because of device-related infection and were prescribed a WCD. WCD-stored electrocardiograms were reviewed. Event outcome was assessed through either the manufacturer WCD registry or the Social Security death index search. RESULTS: A total of 8,058 patients (mean age 62 ± 14 years, 75% male) were included in the analysis. Median time to reimplantation of an ICD was 50 days (interquartile range: 24 to 83 days). While wearing the WCD, 334 patients (4%) experienced 406 VT/VF events, of which 348 events were treated. Shocks were averted in 54 events by conscious patients. The overall 24-h survival, both treated and nontreated, was 93% (312 of 334). VT/VF occurrence was the highest in the initial weeks after ICD removal (0.9%, 0.7%, and 0.7% per week for weeks 1, 2, and 3, respectively). The 12-month cumulative event rate was 10%. For all patients, the 30-day post-event survival was 81%. An ICD was reimplanted in 80% of patients. CONCLUSIONS: The risk of VT/VF reaches 4% during the first 2 months and 10% at 1 year after ICD removal. WCD demonstrated a high efficacy for protecting patients from VT/VF. Clinicians may use the WCD as an ICD alternative when reimplantation is medically delayed.

Wearable cardioverter-defibrillator as a bridge to cardiac transplantation: A national database analysis.

BACKGROUND: Life-threatening ventricular arrhythmias (VAs) and sudden cardiac death (SCD) are common in patients awaiting heart transplantation (HT), and the implantable cardioverter-defibrillator (ICD) is often used for primary prevention in this setting. Use of ICDs in these patients is not without risks and is sometimes contraindicated. The wearable cardioverter-defibrillator (WCD) may be a reasonable alternative to bridge the period of risk leading up to HT. METHODS: We obtained a convenience sample of patients prescribed an WCD as a bridge therapy to HT. The available data consisted of demographics, cardiac transplantation status, associated comorbidities, device use, device-stored electrocardiogram (ECG) and reason for discontinuing the WCD. Statistical analyses were performed using SPSS version 17 and GraphPad PRISM 5. RESULTS: The registry included 121 patients consisting of 83 (69%) men and 38 (31%) women. The mean age was 44 ± 18 years. Mean ejection fraction was 25 ± 15%. Non-ischemic cardiomyopathy (CMP) was the underlying diagnosis in 67 (55%) patients, whereas 21 (17%) patients had ischemic CMP and 33 (27%) had a mixed or uncharacterized CMP. New York Heart Association Class III heart failure was present in 32% and 34% were in Class IV. Eighty-eight patients (73%) were being evaluated for HT or were on an HT waiting list, and 33 patients (27%) had had a prior HT, experienced rejection, and were awaiting re-transplantation. The patients wore the WCD for an average of 127 ± 392 days (median 39 days) with average daily use of 17 ± 7 hours (median 20 hours). Seven patients (6%) received appropriate WCD shocks. Fifty-one patients (42%) ended use after ICD implantation and 13 patients (11%) after HT. There were 11 deaths (9%). CONCLUSIONS: A significant proportion of patients on the HT waiting list will have VA. WCD use in our study showed high compliance and efficacy and a low complication rate, suggesting that the WCD is a reasonable bridge therapy for preventing SCD in patients awaiting HT.

Sudden cardiac arrest in hemodialysis patients with wearable cardioverter defibrillator.

BACKGROUND: The survival outcome following a sudden cardiac arrest (SCA) in hemodialysis (HD) patients is poor regardless of whether an event takes place in or out of a dialysis center. The characteristics of SCA and post-SCA survival with HD patients using a wearable cardioverter defibrillator (WCD) are unknown. METHODS: All HD patients who were prescribed a WCD between 2004 and 2011 and experienced at least one SCA event were included in this study. Demographics, clinical background, characteristics of SCA events were identified from the manufacturer's database. An SCA event was defined as all sustained ventricular tachycardia/fibrillation (VT/VF) or asystole occurring within 24 hours of the index arrhythmia episode. The social security death index was used to determine mortality after WCD use. RESULTS: A total of 75 HD patients (mean age = 62.9 ± 11.7 years, female = 37.3%) experienced 84 SCA events (119 arrhythmia episodes) while wearing the WCD. Sixty six (78.6%) SCA events were due to VT/VF and 18 (21.4%) were due to asystole. Most SCA episodes occurred between 09:00 and 10:00 (RR = 2.82, 95% CI [1.05, 7.62], P < 0.0001), followed by the 13:00-14:00 time interval (RR = 2.22, 95% CI [0.79, 6.21], P = 0.006). Acute 24-hour survival was 70.7% for all SCA events; 30-day and 1-year survival were 50.7% and 31.4%, respectively. Women had a better post-SCA survival than men (HR = 2.41, 95% CI [1.09, 5.36], P = 0.03). CONCLUSIONS: The use of WCD in HD patients was associated with improved post-SCA survival when compared to historical data.

Successful use of wearable cardioverter defibrillator in a patient with dextrocardia and persistent left superior vena cava.

Congenital disorders, such as dextrocardia and persistent left superior vena cava, are rare. However, their presence is often associated with other cardiac anomalies, and may lead to lethal ventricular tachyarrhythmias, which result in sudden cardiac death. Treating patients with these disorders can present a challenge to clinicians, as it may cause technical difficulties during interventional procedures, and more often, altered defibrillation techniques in a setting of prehospital sudden cardiac arrest. This report describes the first case of successful defibrillation therapy delivered by the wearable cardioverter defibrillator to a patient with dextrocardia and persistent left superior vena cava during a ventricular tachycardia arrest.