Predictive Value of Serial ECGs in Patients with Suspected Myocardial Infarction

The electrocardiogram (ECG) is an important diagnostic tool for patients with suspected acute myocardial infarction (AMI). Current guidelines recommend serial ECGs in case of persisting symptoms. We aimed to analyze the predictive value of ischemic ECG-signs in patients with suspected AMI. Patients presenting to the emergency department with suspected AMI were included. All patients with ST-elevation AMI were excluded from analyses. Patients received 12-lead-ECG and high-sensitive Troponin T (hs-TnT)-measurement at admission and after 3 h. Four groups were defined: no ischemic signs in either ECG; new ischemic signs in the second ECG; resolved ischemic signs in the second ECG; and persistent ischemic signs in both ECGs. Patients were followed for 2 years to assess the composite endpoint of all-cause-mortality, AMI, and coronary revascularization. Using a 30-day landmark analysis, a Cox regression with ischemic signs as the variable of interest, adjusted by cardiovascular risk factors, was calculated. Of 1675 patients, 1321 showed no ischemic signs, in 25 new-, in 92 resolved- and in 237 patients, persistent ischemic signs were documented. Patients with persistent ischemic signs had significantly worse outcomes, compared to those without. Compared to no ischemic signs, adjusted hazard ratios for the combined endpoint were 0.81 (95% CI 0.20, 3.31; p-value = 0.77) for new-, 0.59 (95% CI 0.26, 1.34; p-value = 0.21) for resolved-, and 1.47 (95% CI 1.102, 2.13; p-value = 0.041) for persistent ischemic signs. In patients with suspected AMI, persistent ischemic ECG-signs are predictive of a higher rate of all-cause-mortality, AMI, and revascularization.

Future Cardiac Events in Patients with Ischemic ECG Changes during Adenosine Infusion as a Myocardial Stress Agent and Normal Cardiac Scan

Background: We sought to determine the prognostic importance of adenosine-induced ischemic ECG changes in patients with normal SPECT myocardial perfusion images. Methods: We performed a retrospective analysis of 765 patients undergoing adenosine MPI between January 2013 and January 2015. Patients with baseline electrocardiographic (ECG) abnormalities and/or abnormal scan were excluded. Results: Overall, 67 patients (8.7%) had ischemic ECG changes during adenosine infusion in the form of ST depression of ≥1mm. Of these, 29 (43% [3.8% of all patients]) had normal MPI (positive (+) ECG group). An ageand sex-matched group of 108 patients with normal MPI without ECG changes served as control subjects (negative (-) ECG group). During a mean follow-up of 33.3 ± 6.1 months, patients in the +ECG group had no significantly more adverse cardiac events than those in the –ECG group. One (0.9%) patient within the negative ECG group had a nonfatal MI (0.7% annual event rate after a negative MPI). A case only was admitted due to heart failure in the (-) ECG group) that proved to be secondary to pulmonary cause and not of CAD. A case in this (+) ECG group admitted as a CAD that ruled out by coronary angiography. Conclusion: Patients with normal myocardial perfusion scintigraphy in whom ST-segment depression develops during adenosine stress test appear to be with no increased risk for future cardiac events compared with similar patients without ECG evidence of ischemia.