Using the LifeVest as a Bridge to ICD Implantation: One Urban Community Hospital’s Experience

At the American Heart Association’s Scientific Sessions in 2004, the results of the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) were first announced publicly and subsequently published.1 This led to expanded Medicare coverage of primary prevention implantable cardioverter-defibrillators (ICD) on January 27, 2005. All patients with an ejection fraction (EF) of 35% or less with NYHA class II or III congestive heart failure (CHF) became eligible to receive primary prevention ICDs. The cause of the reduced EF (ischemic or non-ischemic) did not matter. There were, however, a number of caveats thrown into the coverage decision: • If a patient had experienced a recent MI, there was to be a 40-day waiting period; • If the patient was revascularized, either by coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA), then there was to be a 90-day waiting period. • If a patient had cardiomyopathy from a non-ischemic cause, the diagnosis had to have been established for a minimum of three months. These limitations put clinicians in a precarious situation. On the one hand, we did not want to place patients at any undue risk of sudden cardiac death by withholding ICD therapy. In fact, in June 2005, data from the Valiant trial showed that the period of highest risk of sudden death in post-MI patients occurred in the first 30 days post infarction.² On the other hand, we could not expect our patients to be able to cover the costs of an ICD implant. One solution to our problem was the option of a wearable automatic defibrillator called the LifeVest® (Zoll Lifecor Corporation, Pittsburgh, Pennsylvania). This would allow us to offer our patients protection from sudden cardiac death without an invasive procedure. In July 2005, Medicare expanded its coverage of the wearable defibrillator to include patients who had an EF of 35% or less but who could not receive an ICD for some reason. We quickly adopted this strategy to deal with our CHF patients who did not qualify for an immediate ICD implant. In-hospital Experience Early on in our LifeVest experience, we had a number of treated ventricular fibrillation (VF) and ventricular tachycardia (VT) events. The most memorable case was a 62-year-old man with an ischemic cardiomyopathy who was admitted with a non-ST elevation myocardial infarction. Coronary angiography revealed severe three-vessel disease, which was not amenable to revascularization, and an EF of 20%. He was noted to have non-sustained ventricular tachycardia on the hospital telemetry and was referred for an electrophysiology study. The EP study revealed a normal conduction system with no inducible VT. As the patient was in the 40-day cooling off period post MI and had no inducible VT, he was discharged home with a wearable automatic defibrillator. Approximately two weeks after discharge, the patient presented to the office after waking up with gel on his skin. Interrogation of the LifeVest revealed that the patient had not only one but two appropriate lifesaving shocks for VT/VF. After seeing this early success, we decided to collect data on our LifeVest patients. Our data was presented at the American Heart Association meeting in October 2007. ³ We had made the following observations. The indications for a wearable defibrillator were: recent MI (n=7), ischemic cardiomyopathy (ICM) with recent revascularization (n=10), untreated non-ischemic dilated cardiomyopathy (n=9), and tachycardia-induced cardiomyopathy (n=1). Twenty-five of 27 patients agreed to a wearable defibrillator and 23 complied. Two patients had three clinical events: one (not wearing the wearable defibrillator) was resuscitated from sudden cardiac arrest; one (treated by the wearable defibrillator) survived sustained syncopal VT/VF but later died suddenly while not wearing the WD. One patient was shocked for atrial fibrillation. After the cooling off period (n=24), six out of 24 (25%) patients had an EF of >35% (3 ICM and 3 NICM), and no ICD was implanted. Eighteen of 24 (75%) patients had an EF ≤35% and received an ICD. Three of 24 (12.5%) patients that received an ICD ultimately had an EF ≥35% over continued follow-up. We concluded from this data that in patients with newly diagnosed LV systolic dysfunction or after revascularization, the wearable defibrillator was a viable option for patients who had an increased risk of sudden cardiac death but may not yet meet current indications for an implantable defibrillator. This made for a safe bridge to an ICD implant in patients who would eventually meet criteria for an implantable device. In addition, a fair number of patients went on to see improvement in their left ventricular systolic function, so an unnecessary ICD implant was avoided. Conclusion We still advocate for this approach in our current clinical practice. Compliance for most patients exceeds 90%. Some patients find the wearable defibrillator a little cumbersome at first, but they soon adjust to the situation. Therefore, we believe the wearable defibrillator is a safe, non-invasive and effective treatment option for patients at high risk of sudden cardiac arrest but who are not yet candidates for ICD implantation.