Baseline Q waves and time from symptom onset to ST-segment elevation myocardial infarction: insights from PLATO on the influence of sex.

BACKGROUND

The prognostic value of time from symptom onset to reperfusion may be enhanced by the identification of Q waves on the presenting electrocardiogram (ECG) in patients with ST-segment elevation myocardial infarction (STEMI). We evaluated whether the relative prognostic utility of these 2 metrics was altered by sex.

METHODS

Q waves in the distribution of the ST-segment elevation on the baseline ECG were evaluated by a blinded core laboratory in 2838 STEMI patients (2163 men and 675 women) from the PLATelet inhibition and patient Outcomes (PLATO) trial who underwent percutaneous coronary intervention (PCI) within 12 hours of symptom onset.

RESULTS

Women were older (median 63 vs 57 years), more likely to be diabetic (24.1% vs 15.5%), hypertensive (69.2% vs 50.9%), and a higher Killip class > I (8.6% vs 5.9%), as compared with men. Whereas the Q waves frequency rose progressively over time to ECG in men, this relationship was attenuated in women (P = .057). Q waves on the baseline ECG were associated with a higher excess hazard of 1-year vascular death in men (hazard ratio [HR] 2.03; 95% confidence interval [CI], 1.13-3.72), and a similar trend existed in women (HR 1.97; 95% CI, 0.86-4.51). Women with baseline Q waves tended to have higher risk of 1-year vascular death than men as continuous time from symptom onset to PCI increased (P[interaction] = .182).

CONCLUSIONS

These differences in the evolution of baseline Q waves and relationship between time from symptom onset and vascular death in women and men deserve recognition in future studies of STEMI.