Obvious physical changes do not occur in the heart until 6 hours after the infarction, when the infarcted region appears blue and swollen. These changes explain the need for intervention within the first 4 to 6 hours of symptom onset! After 48 hours, the infarcted area turns gray with yellow streaks as neutrophils invade the tissue and begin to remove the necrotic cells. By 8 to 10 days after infarction, granulation tissue forms at the edges of the necrotic tissue. Over a 2- to 3- month period, the necrotic area eventually develops into a shrunken, thin, firm scar. Tissue permanently changes the size and Shape of the entire left ventricle, called ventricular remodeling. Remodeling may decrease left ventricular function, cause heart failure, and increase morbidity and mortality. The scarred tissue does not contract nor does it conduct electrically. Thus this area is often the cause of chronic ventricular dysrhythmias surrounding the infarcted zone.