Short- and long-term prognostic value of the corrected QT interval in the non-ST-elevation acute coronary syndrome
Javier Jiménez-Candil1, Ignacio Cruz González, José M González Matas
1Department of Cardiology, University Hospital, Salamanca, Spain. jjimenezcandil@yahoo.es
Insights
Prolonged QTc interval at admission predicts adverse events in non-ST-elevation acute coronary syndromes (NST-ACS). A QTc of 450 milliseconds or higher indicates higher risk for death and major adverse cardiac events.
Area of Science:
- Cardiology
- Clinical Electrophysiology
- Acute Coronary Syndromes
Background:
- Myocardial ischemia is known to prolong the QTc interval.
- Limited data exists on the prognostic significance of QTc interval in non-ST-elevation acute coronary syndromes (NST-ACS).
Purpose of the Study:
- To evaluate the prognostic implications of the admission QTc interval (AQTc) in patients with NST-ACS.
- To assess both short-term and long-term outcomes associated with AQTc.
Main Methods:
- An observational, prospective study was conducted.
- The AQTc was measured at admission for patients with NST-ACS.
- Follow-up data was collected for a median of 17 months.
Main Results:
- AQTc demonstrated a significant correlation with adverse events (P < .001), with an optimal cutoff at 450 milliseconds.
- Patients with AQTc ≥450 ms had higher in-hospital death rates (8.8% vs 1.2%) and MACE (72% vs 25%).
- Independent predictors of cardiovascular death post-discharge included AQTc ≥450 ms, age >65, and LVEF <40%.
Conclusions:
- Admission QTc interval is a valuable prognostic marker in NST-ACS.
- AQTc ≥450 ms predicts unfavorable short- and long-term outcomes.
- Coronary revascularization improved outcomes in patients with AQTc ≥450 ms.
Background And Purpose:
Myocardial ischemia prolongs the QTc interval. Very little data exists about its prognostic implications in the non-ST-elevation acute coronary syndromes (NST-ACS).
Methods:
This is and observational and prospective study in which we evaluated the prognostic implications of the QTc obtained at admission (AQTc) in the short- and long-term of the NST-ACS. The median of the follow-up was 17 months.
Results:
AQTc correlated adequately with the incidence of adverse events in the short- and long-term (P < .001), with the best cut-off point in 450 milliseconds. Patients with AQTc > or =450 presented higher frequency of in-hospital death: 8.8% vs 1.2%; P = .001, and MACE (death, recurrent ischemia, or urgent coronary revascularization): 72% vs 25%; P < .001. In a Cox regression analysis, we found 3 independent predictors of cardiovascular death after discharge: AQTc > or =450 (14.7% vs 2.1%; P < .0001), age >65 years and left ventricular ejection fraction <40%. Coronary revascularization reduced the risk of posthospitalary cardiovascular death in AQTc > or =450 milliseconds (5% vs 24%; P < .0001) but had no significant effect in AQTc<450 milliseconds.
Conclusion:
These findings provide a new evidence supporting the prognostic value of the AQTc in predicting unfavorable events in the short- and long-term of the NST-ACS.
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