Accelerated idioventricular rhythm is more closely related to the extent of infarction than to reperfusion Sustained VA that occurs in the setting of an ACS is more often polymorphic VT or VF than monomorphic VT. Risk factors for VT/VF include prior history of hy- pertension, prior MI, ST-segment changes at presenta- tion, and chronic obstructive pulmonary disease.S2.2.2-30 A nationwide Danish study found that 11.6% of pa- tients with ST-segment elevation MI who underwent PCI had VF prior to the PCI, and that VF was associ- ated with alcohol consumption, preinfarction angina, anterior infarct location, and complete coronary occlu- sion at the time of coronary angiography.S2.2.2-31 In a select group of patients undergoing primary PCI in a clinical trial, 5.7% developed sustained VT or VF, with two thirds of these events occurring prior to the end of the catheterization, and 90% within 48 hours from the procedure. VT or VF after primary PCI was associ- ated with lower blood pressure, higher heart rate, poor coronary flow at the end of the procedure, and incom- plete resolution of ST elevation.S2.2.2-32 Importantly, and in contrast to some earlier studies, VT or VF at any time was associated with a substantially higher risk of death within 90 days. Late VT or VF (after 48 hours of hos- pital presentation) was associated with a higher risk of death than early VT or VF (within 48 hours of hospital 2.1.3. Sustained VT and VF Not Associated With ACS Patients with structural heart disease are at an in- creased risk for sustained VT and VF. 