Are reciprocal changes a consequence of "ischemia at a distance" or merely a benign electric phenomenon? A PTCA study

Relation of collateral circulation with reciprocal changes in patients with acute ST-elevation myocardial infarction

OBJECTIVE

Acute STEMI is often accompanied by reciprocal ST-segment depression (RC) occurring in opposite leads, whose significance has been debated for decades. The possible role of collateral circulation in promoting RC in acute STEMI has not been identified. So our aim to find the relationship between collateral circulation and RC in STEMI patients treated with primary percutaneous intervention (PPCI).

METHODS

The study included 112 pts. with acute STEMI underwent PPCI. The patients divided in to 2 groups: Group (A):66 pts. with RC, Group (B):46 pts without RC. All patients subjected to history taking, ECG [localization of infarction & RC], CKMB level, transthoracic echo [LVEF%], coronary angiography &PPCI to culprit artery and assess number of diseased vessels, site of occlusion, collaterals, TIMI flow pre and post PCI.

RESULTS

Patients in group A with RC had shorter time to door, P < 0.001; more frequent inferior infarctions, P < 0.001; had higher CKMB level, P < 0.001; higher LVEDD, P < 0.001; LVESD, P < 0.001and lower LVEF, P = 0.004; had multi vessel diseases P = 0.02, increase incidence of RCA as a culprit artery <0.001 compared to patients with no RC. Patients with RC had significantly higher incidence of proximal LAD occlusion, distal RCA and distal LCX compared to patients without RC. The percentage of change was 61.2 ± 12.35% for ST elevation and 50.5 ± 10.87% for reciprocal ST depression post PCI with significance difference between them, t = 3.035P = 0.0023.There was no significant correlation between collateral circulation and RC. We found four significant independent predictors of RC. They were inferior infarction (P = 0.024), RCA as a culprit vessel, (P = 0.034), low EF, (P = 0.007) and multi-vessel disease, (P = 0.022).

CONCLUSION

There is no correlation between concomitant RC and presence of collateral vessels in acute STEMI patients. So the pathogenesis of reciprocal ST-segment changes result from an interplay of ischemia at distance due to multi-vessel CAD and benign mirror electrical changes not caused by collateral circulation diverting blood to ischemic area from non-diseased artery.

Clinical Significance of Reciprocal ST-segment Changes in Patients With STEMI: A Cardiac Magnetic Resonance Imaging Study

INTRODUCTION AND OBJECTIVES

We sought to determine the association of reciprocal change in the ST-segment with myocardial injury assessed by cardiac magnetic resonance (CMR) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).

METHODS

We performed CMR imaging in 244 patients who underwent primary PCI for their first STEMI; CMR was performed a median 3 days after primary PCI. The first electrocardiogram was analyzed, and patients were stratified according to the presence of reciprocal change. The primary outcome was infarct size measured by CMR. Secondary outcomes were area at risk and myocardial salvage index.

RESULTS

Patients with reciprocal change (n=133, 54.5%) had a lower incidence of anterior infarction (27.8% vs 71.2%, P < .001) and shorter symptom onset to balloon time (221.5±169.8 vs 289.7±337.3min, P=.042). Using a multiple linear regression model, we found that patients with reciprocal change had a larger area at risk (P=.002) and a greater myocardial salvage index (P=.04) than patients without reciprocal change. Consequently, myocardial infarct size was not significantly different between the 2 groups (P=.14). The rate of major adverse cardiovascular events, including all-cause death, myocardial infarction, and repeat coronary revascularization, was similar between the 2 groups after 2 years of follow-up (P=.92).

CONCLUSIONS

Reciprocal ST-segment change was associated with larger extent of ischemic myocardium at risk and more myocardial salvage but not with final infarct size or adverse clinical outcomes in STEMI patients undergoing primary PCI.

Reciprocal ST-Segment Changes in Myocardial Infarction: Ischemia at Distance Versus Mirror Reflection of ST-Elevation

BACKGROUND

Reciprocal ST-depression in the electrocardiograms (ECGs) of patients with ST-elevation myocardial infarction (STEMI) results from either true ischemia at a distance via collateral circulation diverting blood to the infarcted region or an electrical phenomenon that results from a mirror reflection of ST-elevation. We aimed to identify the role of reciprocal ECG changes in predicting collateral circulation to the infarcted area determined angiographically.

METHODS

In a retrospective study, ECG and angiography of 53 STEMI patients admitted to SUNY Upstate Medical University in 2014 were reviewed independently by experts blinded to the results of ECG and coronary angiography.

RESULTS

Reciprocal changes (RC) in ECG were present in 41 patients (77%) and on angiography, 14 patients (26%) exhibited collateral vessels to the ischemic areas. No correlation was found between the presence of RC and collateral circulation (P = 0.384), or between the depth of reciprocal ST-depression and the degree of the collateral circulation (P = 0.195). However, 84% of patients without collaterals exhibited resolution of RC after successful percutaneous coronary intervention (PCI) (P = 0.036), suggesting that the ST depressions that resolved after reperfusion were directly caused by the culprit vessel. Patients without RC presented late after symptom onset (9.25 versus 3.83 hours, P = 0.004), also suggesting time related resolution.

CONCLUSIONS

RC had no relation to or predictive value for collaterals on angiography. Among late presenting patients, RC were less frequent. Thus, reciprocal ST-depression may represent subendocardial ischemia from the primary coronary event or simply an electrical phenomenon, rather than ischemia at distance from impaired collateral circulation.

Influence of the extent of coronary atherosclerotic disease on ST-segment changes induced by ST elevation myocardial infarction

The accuracy of the admission electrocardiogram (ECG) in predicting the site of acute coronary artery occlusion in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel disease is not well known. This study aimed to assess whether the presence of multivessel coronary artery disease (CAD) modifies the artery-related ST-segment changes in patients with acute coronary artery occlusion. We reviewed the admission ECG, clinical records, and coronary angiography of 289 patients with STEMI caused by acute occlusion of left anterior descending (LAD; n = 140), right (n = 118), or left circumflex (LCx; n = 31) coronary arteries. All patients underwent primary percutaneous coronary reperfusion during the first 12 hours. The magnitude and distribution of artery-related ST-segment patterns were comparable in patients with single (n = 149) and multivessel (n = 140) CAD. Occlusion of proximal (n = 55) or mid-distal (n = 85) LAD artery induced ST-segment elevation in leads V1 to V5, but only the proximal occlusion induced reciprocal ST-segment depression in leads II, III, and aVF (p <0.001). Proximal and mid-distal occlusion of right (n = 45 and 73, respectively) or LCx (n = 15 and 16) coronary artery always induced ST-segment elevation in leads II, III, and aVF and reciprocal ST-segment depression in leads V2 and V3. ST-segment elevation in lead V6 >0.1 mV predicted LCx artery occlusion. In conclusion, patients with STEMI with single or multivessel CAD have concordant artery-related ST-segment patterns on the admission ECG; in both groups, reciprocal ST-segment depression in LAD artery occlusion predicts a large infarct. Subendocardial ischemia at a distance is not a requisite for the genesis of reciprocal ST-segment changes.

Serial analyses of ventricular late potentials in patients with reciprocal ST segment changes during acute myocardial infarction

The aim of this study was to determine whether successful reperfusion may alter substrate that is responsible for late potentials in the presence or absence of reciprocal ST segment changes (RC). The study population consisted of 50 patients (27 with RC and 23 without RC) with anterior acute myocardial infarction (AMI) undergoing successful thrombolytic therapy (TT). The presence of reciprocal changes was defined as ST-segment depression >1 mm, measured 80 ms after the J point in at least 2 leads other than those reflecting the infarct on admission ECG. All patients were evaluated with coronary angiography at predischarge. Signal averaged ECG (SAECG) recordings were obtained before and 10 days after TT. Baseline characteristics, SAECG findings, and angiographic data were similar between the groups. The only different baseline finding was the time from symptom onset to TT (204 +/- 150 minutes for patients with RC vs 312 +/- 174 minutes for patients without RC. P = 0.021). After TT, RMS values improved in patients with RC (from 35 +/- 17 microV to 43 +/- 14 microV, P = 0.038) and LAS and RMS were significantly better in this group. However, patients without RC did not show any changes in SAECG parameters after TT. LV ejection fraction (10th day) was better in patients with RC (45 +/- 11% vs 39 +/- 6%, P = 0.014). The frequency of ventricular arrhythmias during the hospitalization period was also similar between the groups. Reciprocal ST depression that regresses simultaneously with the infarction related ECG changes after TT in anterior AMI seems to be related to the time that has elapsed since the symptom onset. The improvement in SAECG parameters after TT in these patients is probably the result of earlier reperfusion leading to less myocardial damage.

Electrocardiographic diagnosis of acute myocardial infarction: Current concepts for the clinician

BACKGROUND

Over the past 2 decades, the 12-lead electrocardiogram has attained special significance for the diagnosis and triage of patients with chest pain because timely detection of myocardial injury and a rapid assessment of myocardium at risk proved pivotal to implementing effective reperfusion therapies during acute myocardial infarction. However, this wealth of information could still be underutilized by clinicians who may restrict their diagnostic quest in patients with chest pain to the more classic electrocardiographic signs.

METHODS

The medical literature on electrocardiographic manifestations of acute myocardial infarction was extensively reviewed.

RESULTS

The widespread utilization of both coronary angiography and methods to determine myocardial function and metabolism in patients with acute myocardial infarction over the last 10 years has provided the means for rigorous comparisons with electrocardiographic information. We summarize these electrocardiographic signs and patterns in terms of their relevance to the clinician to help reduce the incidence of "nondiagnostic electrocardiograms" and improve timely decision-making.

CONCLUSIONS

The electrocardiogram continues to be an invaluable tool in the initial evaluation of patients with chest pain. The plethora of data currently available on electrocardiographic changes correlating with myocardial injury allows clinicians to make faster and better decisions than ever before.

Usefulness of ST-segment depression in non-infarct-related electrocardiographic leads in predicting prognosis after thrombolytic therapy for acute myocardial infarction

This study investigated both the in-hospital and long-term prognostic significance of ST-segment depression in non-infarct-related leads in patients who received thrombolytic therapy after acute myocardial infarction (AMI). We evaluated 221 consecutive patients who were admitted with their first AMI and underwent thrombolysis. Patients were followed for an average of 31 months and were classified into 3 groups: group 1 included 51 patients with persistent ST-segment depression, group 2 had 97 patients with transient ST-segment depression, and group 3 consisted of 73 patients without ST-segment depression (absent). Group 1 had significantly worse long-term survival during follow up by Kaplan-Meier analysis (55%) versus group 2 (81%) and group 3 (94%) (p = 0.0004) and higher event rates. This prognostic significance seemed to be maintained in both the anterior and inferior wall AMI groups. Multivariate analysis, using the Cox model, showed that Killip class, in-hospital left ventricular ejection fraction, and the persistence of ST-segment depression on the predischarge electrocardiogram (group 1) were independent predictors of survival. ST-segment depression in non-infarct-related leads on the predischarge electrocardiogram is an independent risk factor for worse long-term survival after anterior as well as inferior AMI treated with thrombolytic therapy.