Predictors and implications of Q-waves in ST-elevation acute coronary syndromes
Troy LaBounty1, Hitinder S Gurm, Shaun G Goodman
1Weill Cornell Medical College, New York, NY, USA.
Insights
Q-waves in ST-elevation acute coronary syndromes are decreasing. Presenting Q-waves predict higher in-hospital mortality, but not 6-month mortality. Targeted interventions are advised for these high-risk patients.
Area of Science:
- Cardiology
- Clinical Electrophysiology
- Acute Coronary Syndromes
Background:
- Q-waves on electrocardiograms (ECG) in ST-elevation acute coronary syndromes (STE-ACS) are linked to adverse outcomes.
- The impact of Q-waves in the current era of primary percutaneous coronary interventions (PCI) requires evaluation.
Purpose of the Study:
- To determine the incidence, predictors, and implications of Q-waves in patients with STE-ACS.
- To assess changes in Q-wave frequency over time with modern treatment strategies.
Main Methods:
- A multicenter observational study included 14,916 patients with STE-ACS from 1999 to 2006.
- Clinical variables were compared between patients with and without presenting Q-waves.
- Subsequent Q-wave development was analyzed in patients without initial Q-waves.
Main Results:
- The incidence of Q-waves (presenting or developing later) decreased significantly from 61% to 39% between 1999 and 2006.
- Presenting Q-waves were associated with increased age, male sex, diabetes, smoking, and prior heart conditions.
- Presenting Q-waves independently predicted increased in-hospital mortality (OR 1.46) but not 6-month mortality.
Conclusions:
- The incidence of Q-waves in STE-ACS is declining, likely due to advancements in treatment.
- Q-waves remain a significant predictor of in-hospital mortality.
- Interventions should focus on identifying and managing high-risk patients with Q-waves.
Background:
Q-waves in ST-elevation acute coronary syndromes carry adverse implications. We sought to determine the frequency, predictors, and implications of Q-waves in the current era that includes primary percutaneous coronary interventions.
Methods:
There were 14,916 patients evaluated in a multicenter observational study. They presented with ST-elevation acute coronary syndromes between 1999 and 2006. Clinical variables were compared between patients with versus without presenting Q-waves, with an additional comparison in the latter group between those with versus without subsequent development of Q-waves.
Results:
ST-elevation myocardial infarction occurred in 88.6% of patients. Q-waves were present on the initial electrocardiogram in 3929 patients and developed later in an additional 3085 patients. The incidence of Q-waves at presentation or during hospitalization decreased from 61% to 39% between 1999 and 2006 (linear trend P<.001). Both presenting and subsequent Q-waves were associated with greater likelihood of coronary occlusions and higher cardiac marker elevations (P <.001). Multivariate analysis showed that presenting Q-waves were associated with male sex (odds ratio [OR] 1.28), increased age (OR 1.06 per 5 years), diabetes (OR 1.26), smoking (OR 1.11), chronic aspirin (OR 0.79), acute aspirin (OR 0.87), other chronic cardiac medications (OR 0.80), prior heart failure (OR 0.67), and prior coronary artery disease (OR 0.61). Presenting Q-waves were independently associated with increased in-hospital mortality (OR 1.46), but Q-waves at presentation or during hospitalization did not impact 6-month mortality.
Conclusions:
Q-waves in ST-elevation acute coronary syndromes are decreasing in incidence. Q-waves are a major determinant of in-hospital mortality, and targeted interventions should be directed to these high-risk patients.
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