The extent of ST elevation and ST deviation as predictors of mortality in ST-segment elevation myocardial patients planned to undergo primary percutaneous coronary intervention.

Background: Only few data are available on the predictive value of ST deviation (both ST elevation and depression). Therefore, we have examined the predictive value of ST elevation and ST deviation in STEMI patients on 30-day and long term mortality.

Methods: All STEMI patients with an interpretable diagnostic electrocardiogram, who were referred to the Isala hospital and were planned to undergo a primary coronary intervention (pPCI) in the period 2001 until 2009, were prospectively registered in a cohort study. These patients were divided in tertiles based on the cumulative (cum) ST deviation (D1, D2 and D3) and cum ST elevation (E1, E2 and E3), as assessed by an independent core-lab.

Results: In total, 4513 patients were registered. 30-day mortality increased with cum ST deviation (0-9 mm: 1.9%, > 9-16 mm: 2.4%, > 16 mm: 3.9%, P = 0.001), but not significant with cum ST elevation. Long term mortality increased with cum ST-deviation (0-9 mm: 18.6%, > 9-16 mm: 22.1%, > 16 mm: 25.7%, P < 0.001) and with cum ST-elevation (0-6mm: 19.7%, > 6-11 mm: 22.7%, > 11 mm: 24.2%, P = 0.070). After multivariable adjustment using Cox proportional Hazard models, cum ST deviation (D1: reference, D2: HR: 1.09 95% CI (0.67-1.77), D3: HR: 1.76 95% CI (1.14-2.73)) was independently associated with 30-day mortality. Both cum ST deviation (D1: reference, D2: HR: 1.14 95% CI (0.98-1.34), D3: HR: 1.32 95% CI (1.13-1.53)) and ST elevation (E1: reference, E2: HR: 1.17 95% CI (1.00-1.38), E3: HR: 1.21 95% CI (1.04-1.42)) were independently associated with long term mortality.

Conclusions: Besides ST elevation, taking the extent of ST depression into account improves the predictive value of the diagnostic 12 lead electrocardiogram especially for 30-day mortality in STEMI patients who are planned to undergo pPCI.