Prolonged QT interval in ST-elevation myocardial infarction: predictors and prognostic value in medium-term follow-up
Alessandro Galluzzo1, Cristina Gallo, Alberto Battaglia
1Division of Cardiology, Department of Medical Sciences, Città della Salute e della Scienza Hospital, University of Turin, Italy.
Insights
A prolonged corrected QT interval (≥480 ms) in ST-elevation myocardial infarction predicts cardiovascular death. Combining this with low ejection fraction improves risk prediction accuracy for better patient outcomes.
Area of Science:
- Cardiology
- Clinical Electrophysiology
- Cardiovascular Medicine
Background:
- The prognostic significance of the corrected QT interval (QTc) in ST-elevation myocardial infarction (STEMI) remains under investigation.
- Early identification of high-risk patients post-STEMI is crucial for timely intervention and improved survival.
Purpose of the Study:
- To evaluate the prognostic value of a prolonged corrected QT interval (≥480 ms) in patients with acute coronary syndrome, specifically STEMI.
- To determine if QTc prolongation independently predicts adverse cardiovascular outcomes.
Main Methods:
- Prospective enrollment of 185 consecutive STEMI patients.
- Continuous electrocardiographic monitoring of the corrected QT interval throughout hospitalization.
- Univariate and multivariate analyses to assess the association between QTc interval and cardiovascular events.
Main Results:
- A prolonged QTc interval (≥480 ms) was significantly associated with cardiovascular death, aborted sudden cardiac death, cerebral ischemic stroke, and recurrent myocardial infarction.
- Multivariate analysis identified QTc prolongation as an independent predictor of cardiovascular death (OR 6.38, P=0.004), alongside reduced ejection fraction (≤35%, OR 4.20, P=0.021).
- The combined assessment of QTc interval and ejection fraction significantly enhanced the accuracy (AUC 0.83) for predicting cardiovascular death.
Conclusions:
- A QTc interval peak of ≥480 ms during the acute phase of STEMI is an independent predictor of cardiovascular mortality.
- The combination of prolonged QTc interval and reduced ejection fraction (≤35%) improves risk stratification accuracy in STEMI patients.
- These findings highlight the importance of QTc interval monitoring for risk assessment in STEMI management.
Aims:
The prognostic role of corrected QT interval in ST-elevation myocardial infarction is still unknown. This study aims to identify the prognostic value of corrected QT interval prolongation (≥480 ms) in acute coronary syndrome.
Methods:
One hundred and eighty-five consecutive patients with ST-elevation myocardial infarction were prospectively enrolled and electrocardiographic monitoring of corrected QT interval was performed during the hospitalization.
Results:
Over a mean period of 17.6 ± 11 months, 16 (8.6%) patients died because of cardiovascular diseases, 6 (3.2%) patients experienced aborted sudden cardiac death, 3 (1.6%) cerebral ischemic strokes, 11 (6%) recurrent myocardial ischemia and 6 (3.2%) acute heart failure. At univariate analysis a corrected QT interval peak of at least 480 ms relates to cardiovascular death (P < 0.001), aborted sudden cardiac death (P = 0.037), cerebral ischemic stroke (P = 0.016) and recurrences of myocardial infarction (P = 0.032). Multivariate analysis confirms its role an independent predictor of cardiovascular death [odds ratio 6.38, 95% confidence interval (CI) 1.77-22.92, P = 0.004], together with an ejection fraction of 35% or less (odds ratio 4.20, 95% CI 1.24-14.16, P = 0.021). The presence of either corrected QT of at least 480 ms or ejection fraction of 35% or less increases the sensitivity and the accuracy to correctly predict cardiovascular death without a significant reduction in specificity (sensitivity 88%, specificity 69%, accuracy 88%, area under curve 0.83, 95% CI 0.72-0.94, P < 0.01).
Conclusion:
A corrected QT interval peak of at least 480 ms in the acute phase of ST-elevation myocardial infarction is an independent predictor of cardiovascular death. Its association with reduced ejection fraction (≤35%) increases risk stratification accuracy.
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