Ivo Strebel1, Raphael Twerenbold2, Desiree Wussler1, Jasper Boeddinghaus1, Thomas Nestelberger1, Jeanne du Fay de Lavallaz1, Roger Abächerli3, Patrick Maechler4, Diego Mannhart1, Nikola Kozhuharov1, Maria Rubini Giménez5, Karin Wildi1, Lorraine Sazgary1, Zaid Sabti1, Christian Puelacher1, Patrick Badertscher1, Dagmar I Keller6, Òscar Miró7, Carolina Fuenzalida7, Sofia Calderón7, F Javier Martin-Sanchez8, Sergio Lopez Iglesias8, Stefan Osswald1, Christian Mueller1, Tobias Reichlin9. 1. Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland. 2. Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; Department of General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany. 3. Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; Institute of Medical Engineering, Lucerne University of Applied Sciences and Arts, Horw, Switzerland. 4. Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; Emergency Department, University Hospital Zurich, Switzerland. 5. Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; Emergency Department, Hospital Clinic, Barcelona, Catalonia, Spain. 6. Emergency Department, University Hospital Zurich, Switzerland. 7. Emergency Department, Hospital Clinic, Barcelona, Catalonia, Spain. 8. Servicio de Urgencias, Hospital Clínico San Carlos, Madrid, Spain. 9. Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland; Department of Cardiology, Swiss Cardiovascular Center Bern, Bern University Hospital, Bern, Switzerland. Electronic address: tobias.reichlin@insel.ch.
Abstract
BACKGROUND: The value of the 12-lead ECG in the diagnosis of non-ST-elevation myocardial infarction (NSTEMI) is limited due to insufficient sensitivity and specificity of standard ECG criteria. The QRS-T angle reflects depolarization-repolarization heterogeneity and might assist in detecting patients with a NSTEMI (diagnosis) as well as predicting patients with an increased mortality risk (prognosis). METHODS: We prospectively enrolled 2705 consecutive patients with symptoms suggestive of NSTEMI. The QRS-T angle was automatically derived from the standard 10 s 12-lead ECG recorded at presentation to the ED. Patients were followed up for all-cause mortality for 2 years. RESULTS: NSTEMI was the final diagnosis in 15% (n = 412) of patients. QRS-T angles were significantly greater in patients with NSTEMI compared to those without (p < 0.001). The use of the QRS-T angle in addition to standard ECG criteria indicative of ischemia improved the diagnostic accuracy for NSTEMI as quantified by the area under the ROC curve from 0.68 to 0.72 (p < 0.001). An algorithm for the combined use of standard ECG criteria and the QRS-T angle improved the sensitivity of the ECG for NSTEMI from 45% to 78% and the specificity from 86% to 91% (p < 0.001 for both comparisons). The 2-year survival rates were 98%, 97% and 87% according to QRS-T angle tertiles (p < 0.001). CONCLUSION: In patients with suspected NSTEMI, the QRS-T angle derived from the standard 12-lead ECG provides incremental diagnostic accuracy on top of standard ECG criteria indicative of ischemia, and independently predicts all-cause mortality during 2 years of follow-up.
BACKGROUND: The value of the 12-lead ECG in the diagnosis of non-ST-elevation myocardial infarction (NSTEMI) is limited due to insufficient sensitivity and specificity of standard ECG criteria. The QRS-T angle reflects depolarization-repolarization heterogeneity and might assist in detecting patients with a NSTEMI (diagnosis) as well as predicting patients with an increased mortality risk (prognosis). METHODS: We prospectively enrolled 2705 consecutive patients with symptoms suggestive of NSTEMI. The QRS-T angle was automatically derived from the standard 10 s 12-lead ECG recorded at presentation to the ED. Patients were followed up for all-cause mortality for 2 years. RESULTS: NSTEMI was the final diagnosis in 15% (n = 412) of patients. QRS-T angles were significantly greater in patients with NSTEMI compared to those without (p < 0.001). The use of the QRS-T angle in addition to standard ECG criteria indicative of ischemia improved the diagnostic accuracy for NSTEMI as quantified by the area under the ROC curve from 0.68 to 0.72 (p < 0.001). An algorithm for the combined use of standard ECG criteria and the QRS-T angle improved the sensitivity of the ECG for NSTEMI from 45% to 78% and the specificity from 86% to 91% (p < 0.001 for both comparisons). The 2-year survival rates were 98%, 97% and 87% according to QRS-T angle tertiles (p < 0.001). CONCLUSION: In patients with suspected NSTEMI, the QRS-T angle derived from the standard 12-lead ECG provides incremental diagnostic accuracy on top of standard ECG criteria indicative of ischemia, and independently predicts all-cause mortality during 2 years of follow-up.