Introduction: All chest pain protocols include the electrocardiogram (EKG) in the emergency room for suspected acute coronary syndrome (ACS) as an agile and indispensable resource for diagnostic definition. Serial EKG can identify dynamic EKG changes (dynEKG) and increase diagnostic accuracy.
Purpose: To evaluate the association between dynEKG changes and the occurrence of ACS in ptes admitted to the chest pain unit.
Methods: Prospective study of 2048 ptes admitted to emergency room with clinical suspicion of ACS. Ptes underwent serial assessment of EKG and troponin I on admission and after 6 hours. The dynEKG were diagnosed in ptes in which the admission EKG was normal or non-diagnostic and the second EKG evolved with typical ischemic findings in at least 2 contiguous leads (T wave inversion, ST depression or ST elevation>1mm). The diagnosis of ACS was conducted by ischemia detection in provocative tests or presence of significant obstructions in coronary angiography. Statistical analysis used Student's t test and chi square.
Results: Dynamic EKG changes occurred in 2.78% of cases with a male predominance (70.2%) and mean age was 68.3+15,8y. The occurrence of ACS was significantly higher in patients with dynEKG (91.2% vs 19.8%; p<0.001). There was clear predominance of ST-Elevation ACS in dynEKG group (68.4% vs 1.8%; p<0.001) and similar distribution of non ST-Elevation ACS between dynEKG group and other ptes (22.8% vs 15.9%, p=0.58). The positive predictive value (PPV) and negative predictive value (NPV) for ECG Alt were: 91% and 81.2%.
Conclusion: Dynamic EKG changes are rare; however, its presence is closely associated with the occurrence of ACS, especially ST-Elevation ACS with high PPV and NPV. Strategies to increase the detection of dynEKG may represent a breakthrough in ACS stratification in emergency.