The patient is a man with a history of diabetes. He presented to the emergency department complaining of cough, chest pain and dyspnea. He was diagnosed with right lower lobe pneumonia and sepsis. The following day an echocardiogram showed a markedly decreased left ventricular ejection fraction (LVEF) of 10%. A cardiac catheterization showed a chronic total occlusion of the left anterior descending coronary artery; the distal vessel filled via collaterals. There was a 95% proximal right coronary artery occlusion. Myocardial perfusion imaging showed diffusely viable myocardium. The patient then underwent coronary artery bypass graft surgery. Postoperatively, a LifeVest wearable cardioverter defibrillator (WCD) was prescribed. The health plan denied the LifeVest as not medically necessary. The health plan's determination is overturned.

Depressed left ventricular systolic function is a risk factor for, and powerful predictor of, sudden arrhythmic death. Consequently, implantation of an implantable cardioverter defibrillator (ICD) for the primary prevention of sudden cardiac death is a widespread practice, proven to be beneficial to heart failure patients with a variety of cardiac diagnoses. Current guidelines support ICD implantation in patients, such as this man, with ischemic cardiomyopathy, and left ventricular ejection fractions of 35% or less.

However, due to the possibility that left ventricular function may improve with revascularization, it is recommended that device implantation be delayed for at least 90 days following coronary artery bypass graft surgery or percutaneous coronary intervention. If, 90 days post-revascularization, the LVEF remains less than or equal to 35%, ICD implantation is then recommended. However, the degree to which revascularization mitigates the risk for serious ventricular arrhythmias during this 90 day period is unclear. Accordingly, many physicians prescribe the LifeVest wearable cardioverter defibrillator (WCD) as a "bridge" to potential ICD implantation in these patients. The efficacy of the WCD in terminating serious ventricular arrhythmias compares favorably to that of the implanted device. In one large retrospective study of patients with left ventricular ejection fractions of 35% or less after coronary artery bypass graft surgery (CABG) or percutaneous coronary intervention (PCI), the WCD was associated with a lower 90-day mortality in patients after CABG (no WCD: 7% vs WCD: 3%) and after PCI (no WCD: 10% vs WCD: 2%). Per the 2016 Science Advisory from the American Heart Association, use of the WCD in cases such as this one is a reasonable approach.