**6.1 Pediatric patients**

condition is potentially reversible, but while patients experience the cardiomyopathy, they are at risk for potentially life-threatening ventricular tachyarrhythmias, and some develop concomitant QT interval prolongation, further increasing their risk for arrhythmia [5]. In a study based on all data from the USA involving WCD wear from 2007 through 2012, a total of 102 takotsubo patients were identified by the ICD-9 code 429.83. This population was overwhelmingly female (89%) with an initial ejection fraction of 27 6% who wore the WCD for a mean duration of 44 31 days with a mean follow-up of 440 374 days. During the WCD wear time, 2% of patients (n = 2) received an appropriate shock, 1% (n = 1) received two inappropriate shocks, and 2% (n = 2) suffered bradyarrhythmias that required pacing. Two patients in the study died (one asystole and one from an arrhythmia

Peripartum cardiomyopathy results in left ventricular dysfunction that can predispose the patient to SCD. About half of these patients will recover significantly or entirely over the course of about 6 months even without intervention; however, some will not, and all are at high risk for arrhythmias during the course of the condition [5]. In a study of 12 consecutive women with peripartum cardiomyopathy observed at a single center (of whom seven wore the WCD), four episodes of VF occurred in three of the patients wearing the WCD, all of which were successfully terminated. One patient experienced numerous alarms for inappropriate shocks but

was able to abort them so that no inappropriate shocks occurred. No deaths

Long QT syndrome (LQTS) is a heritable and potentially fatal cardiac channelopathy that exposes patients to the risk of SCD. LQTS patients are typically treated with beta blockade, left cardiac sympathetic denervation, and, in some cases, a permanent ICD. It is unclear what, if any, role the WCD might play for treating LQTS. A retrospective review of 1027 LQTS patients who were prescribed a WCD as a bridge to possible ICD implantation or other treatments found no inappropriate shocks that were administered by the WCD and only 1 patient received an appropriate shock to terminate VF [61]. Since LQTS is a lifelong condition, the WCD is not an optimal permanent solution in this population, but it may be helpful as newly diagnosed patients consider their therapeutic options or for LQTS patients on medical therapy who are entering high-risk periods of life, such as having to take a medication that might prolong their QT interval further or

The WCD is available in different sizes and has an elasticized waistband and adjustable straps, making it suitable for use in a variety of patients, including children. The role of the WCD in certain special populations is being addressed, but

those with a higher ejection fraction at baseline [60].

occurred. During therapy for heart failure, over the course of the 12-month followup, ejection fractions improved significantly from 24.0 11.8% at baseline to 46.6 7.6%. Patients with a lower ejection fraction at baseline improved more than

while not wearing the WCD) [59].

*Sudden Cardiac Death*

*5.8.2 Peripartum cardiomyopathy*

*5.8.3 Long QT syndrome*

in postpartum women [61].

**6. Special populations**

**78**

there is limited evidence about these groups.

Guidance is available to schools and teachers for children prescribed the WCD. In particular, it is important that educators realize that unlike the automatic external defibrillator systems available in many schools, the WCD will detect arrhythmias and treat them without any bystander intervention [62, 63]. Children seem to adjust well to the WCD. In a study of 231 pediatric WCD patients between the ages of 8 and 17 years monitored a median of 39 days with daily wear time around 21 h/day, a step-counter accelerometer device reported that activity levels for these children increased significantly over baseline in the first 3 weeks after getting the WCD (p < 0.001) [64]. This suggests that the WCD does not inhibit or curtail the children's activities and may help them achieve recommended levels of daily exercise.
