QRS prolongation on the signal-averaged electrocardiogram versus ST-segment changes on the 12-lead electrocardiogram: which is the most sensitive electrocardiographic marker of myocardial ischemia?

ECG-based signal analysis technologies for evaluating patients with acute coronary syndrome: a systematic review

BACKGROUND/OBJECTIVES

Timely identification of cardiac ischemia is critical in patients with acute coronary syndrome (ACS). The first test is often the standard, resting 12-lead ECG. Given its limitations, signal analysis enhancements have been proposed. We summarize the published evidence for commercially available ECG-based signal analysis technologies.

METHODS

This is a systematic review of the English-language published literature.

RESULTS

Published evidence meeting inclusion criteria was available for two devices: PRIME ECG and LP 3000. Meta-analysis of eight studies estimated a 68.4% sensitivity (95% CI, 35.1%-89.7%) and 91.4% specificity (CI, 83.6%-95.7%) for the PRIME ECG, compared with 40.5% sensitivity (CI, 19.6%-65.5%) and 95.0% specificity (CI, 87.9%-98.0%) for the standard 12-lead ECG.

CONCLUSIONS

Existing evidence is insufficient to confidently inform the appropriate use of ECG-based signal analysis technologies for detecting ischemia or infarct in ACS. Further research is needed to determine in what circumstances, if any, these devices might precede, replace, or add to the standard ECG in test strategies for detecting ischemia or infarct in ACS.

A new electrocardiographic marker of myocardial reperfusion in patients with acute ST-segment elevation myocardial infarction treated with primary percutaneous intervention: the value of QRS duration

AIMS

Although ischaemia-induced QRS complex changes have been described previously, their relation with reperfusion status is not clear. We aimed to investigate the relation of QRS duration with reperfusion at tissue level compared to myocardial blush in patients with acute myocardial infarction who underwent successful primary percutaneous coronary angioplasty.

METHODS AND RESULTS

One hundred and forty-eight patients were enrolled. Based on the post-angioplasty myocardial blush grade (MBG), patients were divided into reperfusion (grades 2 and 3) and impaired reperfusion (grades 0 and 1) groups. Although the two groups did not differ in terms of admission QRS duration (81±17 vs. 79±15 msec, p=0.473), the patients in the impaired reperfusion group had a significantly longer QRS duration both at immediate post-angioplasty (78±18 vs. 68±17 msec, p=0.001) and at the 60th minute ECG (77±17 vs. 60±17 msec, p<0.001). Patients in the impaired reperfusion group revealed significantly less narrowing of QRS duration in the post-angioplasty 60th minute ECG (6±5 vs. 20±5 msec, p<0.001) when compared to the patients in the reperfusion group. After adjusting all variables, QRS narrowing in the 60th minute ECG was determined as an independent electrocardiographic predictor of reperfusion (OR:1.39, 95% CI: 1.25-1.54, p<0.001).

CONCLUSIONS

We demonstrated that QRS duration is a strong indicator of myocardial reperfusion status.

Relationship of admission QRS duration and changes in QRS duration with myocardial reperfusion in patients with acute ST segment elevation myocardial infarction (STEMI) treated with fibrinolytic therapy

BACKGROUND

Although ischemia induced QRS complex changes have been described previously, their relationship with impaired reperfusion, which is known to be associated with poor clinical outcomes, is not clear.

METHODS AND RESULTS

To investigate the relationship of QRS duration changes with myocardial reperfusion, we studied 165 acute myocardial infarction (MI) patients who were administered fibrinolytic therapy for reperfusion. For each patient, 12-lead electrocardiogram (ECG) with a paper speed of 50 mm/s was recorded on admission and repeated at the 60(th) and 90(th) min following fibrinolytic therapy. Based on the myocardial blush grades obtained from a control coronary angiography, patients were divided into reperfusion (grades 2, 3) and impaired reperfusion (grades 0, 1) groups. We detected impaired reperfusion in 74 patients. The patients in the impaired reperfusion group were older, more often diabetic, and had longer pain-to-needle intervals. They also had significantly longer QRS durations at admission compared to reperfusion group patients (91+/-11 vs 79+/-11 ms, p<0.001). Reperfusion group patients showed significantly greater resolution in QRS duration at the 90(th) min post fibrinolysis ECG (18+/-5 vs 5+/-4 ms, p<0.001). In regression analysis, the pain-to-needle time (odds ratio (OR): 0.55, 95% confidence interval (CI) 0.35-0.88, p=0.012), QRS duration on admission (OR: 0.80, 95% CI 0.67-0.97, p=0.021), and change in QRS duration at the post fibrinolysis 90(th) min ECG (OR: 2.43, 95% CI, 1.29-4.60, p=0.006) were determined as independent predictors of adequate reperfusion.

CONCLUSION

The present study, for the first time, has shown that admission QRS duration and post fibrinolysis 90(th) min QRS duration changes are related to tissue reperfusion in fibrinolytic administered acute MI patients.

Portable type signal-averaged electrocardiography with dipyridamole: a new and convenient method to detect patients with coronary artery disease and ischemia

BACKGROUND

Whether or not patients with coronary artery disease (CAD) could be easily detected at the bedside using dipyridamole stress was investigated using a portable type signal-averaged electrocardiography (portable SAECG).

METHODS AND RESULTS

The standard 12-lead QRS wave SAECG was performed at the bedside before and after dipyridamole stress in 30 patients with angiographically significant stenotic lesions, who had positive myocardial ischemia in the dipyridamole-thallium myocardial perfusion imaging (CAD group), and 33 patients with no significant stenotic lesions, who had negative imaging (control group). The filtered QRS duration (fQRSd) before and after dipyridamole stress was determined by the vector magnitude method and the difference (DeltafQRSd) was obtained. Furthermore, the DeltafQRSd was obtained using the multiphasic oscillation method, as well at the same standard 12-lead, and the maximal value of changes in fQRSd (MAX DeltafQRSd) between the 12 leads was determined. The DeltafQRSd was similar between 2 groups (p = 0.11). The MAX DeltafQRSd associated was significantly greater in the CAD group (p < 0.0001). When a cut-off value of MAX DeltafQRSd > or = 5 ms was used for the detection of CAD, the sensitivity and specificity were 97 and 94%, respectively.

CONCLUSION

The portable dipyridamole-stress SAECG easily detect CAD and myocardial ischemia at the bedside.

Usefulness of QRS duration in the absence of bundle branch block as an early predictor of survival in non-ST elevation acute myocardial infarction

To determine whether an increased QRS duration in the absence of bundle branch block (BBB) on the presenting electrocardiogram of patients with acute myocardial infarction (AMI) is associated with decreased survival, we retrospectively reviewed 781 consecutive patients admitted to the coronary care unit of our institution with AMI without BBB between 1988 and 1998. In patients with ST elevation AMI (n = 412), the groups with QRS duration > or =100 ms and <100 ms had similar survival. Conversely, in patients with non-ST elevation AMI (n = 369), in-hospital, 1-, 3-, and 5-year survival was 84.4%, 75.6%, 66.7%, and 52.2%, respectively, in the group with QRS > or =100 ms compared with 95.4%, 89.2%, 83.8%, and 74.3%, respectively, in the group with QRS <100 ms (p <0.01, log-rank test). In patients with non-ST elevation AMI, those with QRS duration > or =100 ms were more likely to be men, to have had a prior AMI that healed, to be in Killip class II, III, or IV, and to have lower ejection fraction than patients with QRS duration <100 ms. After adjusting for age, sex, prior AMI or stroke, heart rate, and Killip class on admission, QRS duration > or =100 ms was independently associated with in-hospital and overall mortality in patients with non-ST elevation AMI. QRS duration > or =100 ms in the absence of BBB is an independent predictor of increased mortality in patients with non-ST elevation AMI.