This view is supported by the fact that the enzyme myeloperoxidase (MPO), which is released primarily by activated neutrophils and is regarded as part of innate immune defence, is also associated with the level of collagen deposition and susceptibility to both atrial and ventricular fibrillation, which can have detrimental effects in the post-acute phase of infarct healing [7]. The gene discussed is MPO; the disease is ventricular fibrillation.