The mortality benefit of thrombolytic therapy is time-dependent, with the greatest benefit observed in those receiving therapy the earliest.¹² The mortality advantage of primary percutaneous coronary intervention (PCI) is also critically dependent on the time required to achieve reperfusion. Although the data examining the relationship of time to primary PCI in STEMI patients have yielded somewhat inconsistent findings, most of the information available provides strong evidence that a shorter time to reperfusion with PCI is more efficacious.^1,8,13 Moreover, there appears to be an almost linear relationship between door-to-balloon time and mortality, at least with times longer than 90 minutes;¹⁴ the door-toballoon time and mortality relationship is less well characterised for times less than 90 minutes. By extrapolation from the thrombolytic era, where a mortality benefit was observed in reducing time to lytics from 60 to 30 minutes,¹² it could be postulated that a similar mortality benefit should be observed by shortening oor-to-balloon times as much as possible.

The Role of Culprit Percutaneous Coronary Intervention
In spite of the recent emphasis on reducing door-to balloon times, there has been little change in the management of patients once in the catheterisation laboratory to further reduce door-to-balloon times.^6,15,16 As a result, relatively few data exist to guide strategies to decrease the arteryto- balloon’ time, i.e. the time elapsed between the establishment of arterial access in the catheterisation laboratory and coronary angioplasty. PCI for STEMI usually follows the traditional method observed in elective cases: initial diagnostic coronary angiography of all coronary territories to define the extent and severity of coronary artery disease (CAD), coronary dominance and the potential presence of collateral circulation. Frequently, left ventriculography is also performed prior to PCI to evaluate left ventricular function, measure end-diastolic pressure and check for the presence of mechanical complications, including ventricular septal defect or mitral regurgitation. Coronary angiography and left ventriculography can usually be rapidly performed. However, they may require significant time and substantially delay the PCI portion of the procedure. This delay may be of particular importance in older patients, in patients with prior bypass grafting and in patients with concomitant aortic valvular disease and/or significant disease of the aorta. Whether door-to-balloon time could be reduced by first performing culprit-vessel PCI and then completing coronary angiography and left ventriculography after reperfusion had been achieved, without undermining subsequent care, has not been studied.