JASON WHITING and MICHELLE SIMON
ZOLL, Pittsburgh, PA
KEYWORDS. sudden cardiac arrest, wearable cardioverter-defibrillator.
J. Whiting and M. Simon are employed by ZOLL.
Manuscript received February 6, 2012.
Address correspondence to: Jason T. Whiting, ZOLL, 121 Gamma Drive, Pittsburgh, PA 15238. E-mail: firstname.lastname@example.org
The wearable cardioverter-defibrillator (WCD) has been shown to significantly reduce total mortality at both 90 days and over a mean follow-up of over 3 years for patients at risk for sudden cardiac arrest (SCA),1 providing protection during their changing condition and while permanent SCA risk has not been established. Interestingly, the total mortality benefit is not fully explained by treatment shock events. In addition, following the end of WCD use, a continued survival benefit was observed. The WCD is commonly worn by patients for 40–90 days (e.g. post myocardial infarction, post percutaneous coronary intervention, or post coronary artery bypass graft). The purpose of this patient study was to understand and quantify the potential health and lifestyle benefits of the WCD (LifeVest®, ZOLL, Pittsburgh, PA), beyond primary therapy of defibrillation for ventricular tachyarrhythmias.
The study was conducted by an independent market research firm (In2ition, Forest Lake, MN). Current WCD patients were recruited and consented by letter to participate in the study. The criteria for inclusion in the study were: 1) patient must have worn the WCD for at least 1 week; and 2) patient must have been wearing the WCD at the time of the interview. Characteristics of health and lifestyle benefits were assessed using a scale from 1 = strongly disagree to 5 = strongly agree, using a Top Two Box method where a score of 4 or 5 was considered positive and a minimum of 80% using the Top Two Box method was required to support the association for the population.
Interviews were conducted by telephone between June 27 2011 and August 16 2011 and averaged 10–15 min (N = 300). The duration of patient WCD use at time of interview was greater than 4 weeks in 60% of patients, 2–4 weeks in 38%, and 1–2 weeks in 2%. The interview sample patient age distribution matched closely the patient age distribution from the total WCD population. The margin of error for this study at a 95% confidence level is ±6%.
The results from the survey demonstrated that many of the health and lifestyle benefits studied met or exceeded the 80% Top Two Box threshold, including more confidence in returning to normal daily activities, confidence in performing exercise or cardiac rehabilitation, and adherence with lifestyle modification recommendations (Table 1).
Use of the WCD was positively associated with many health and lifestyle benefits. These health and lifestyle benefits may explain the additional total mortality benefit of WCD use not explained by treatment shock events as well as the continued survival benefit beyond end of use.