Reliability of resolution of ST-segment elevation after coronary reperfusion in predicting myocardial salvage in anterior wall acute myocardial infarction

Resolution of ST-segment elevation (ST resolution) after reperfusion therapy has been shown to correlate with improved left ventricular (LV) function in patients with acute myocardial infarction (AMI). However, not all patients with ST resolution have preserved LV function. We evaluated the clinical significance of ST resolution in 129 patients with anterior wall AMI who underwent successful coronary recanalization within 6 hours after symptom onset by studying the relation to myocardial blush grade, another angiographic marker of myocardial reperfusion. A reduction of > or =50% in ST-segment elevation after recanalization was defined as ST resolution. Ninety-eight patients had ST resolution and 31 patients did not. Patients with ST resolution were subdivided into 2 groups according to myocardial blush grade after recanalization: 67 patients with blush grade 2 or 3, and 31 with blush grade 0 or 1. The QRS score after recanalization was higher (5.9 +/- 1.9 vs 3.4 +/- 2.0, p <0.01) and predischarge LV ejection fraction was lower (39 +/- 8% vs 57 +/- 9%, p <0.01) in patients with blush grade 0 or 1 than in those with blush grade 2 or 3. However, the QRS score after recanalization and the predischarge LV ejection fraction were similar in patients who had ST resolution with blush grade 0 or 1 and in those without ST resolution. Our findings suggest that ST resolution after recanalization does not consistently predict myocardial salvage in patients with anterior AMI.     

Persistent ST-segment elevation after primary stenting for acute myocardial infarction: its relation to left ventricular recovery

BACKGROUND: Early restoration of coronary artery patency in acute myocardial infarction (AMI) has been linked to improvement in survival. However, early recanalization of an occluded epicardial coronary artery by either thrombolytic agents or percutaneous transluminal coronary angioplasty (PTCA) does not necessarily lead to left ventricular (LV) function recovery. HYPOTHESIS: The aim of this study was to evaluate the relation between persistent ST elevation shortly after primary stenting for acute myocardial infarction (AMI) and LV recovery. METHODS: Thirty-one patients with primary stenting for AMI were prospectively enrolled. To evaluate the extent of microvascular injury, serial ST-segment analysis on a 12-lead electrocardiogram recording just before and at the end of the coronary intervention was performed. Persistent ST-segment elevation (Persistent Group, n = 11) was defined as > or = 50% of peak ST elevation and resolution (Resolution Group, n = 20) was defined as < 50% of peak ST elevation. Echocardiography was performed on Day 1 and 3 months after primary stenting. RESULTS: At 3 months, infarct zone wall-motion score index (WMSI, 2.1 +/- 0.6 vs. 2.7 +/- 0.3, p < 0.05) was smaller in the Resolution Group than in the Persistent Group, whereas wall motion recovery index (RI, 0.4 +/- 0.3 vs. 0.1 +/- 0.2, p < 0.05) and ejection fraction (58 +/- 5 vs. 43 +/- 10%, p < 0.05) were larger in the Resolution Group than in the Persistent Group. The extent of persistent ST elevation (% ST) shortly after successful recanalization of the infarct-related artery was significantly related to RI at 3 months (r = -0.4, p < 0.05). However, time to reperfusion was not related to RI at 3 months. There was also significant correlation between corrected TIMI frame count and %ST (r = 0.4, p < 0.05). CONCLUSIONS: Persistent ST-segment elevation shortly after successful recanalization (> or = 50% of the peak value), as a marker of impaired microvascular reperfusion, predicts poor LV recovery 3 months after primary stenting for AMI.     

Effects of reperfusion on left ventricular ejection fraction and volume after acute myocardial infarction.

The effects of reperfusion on left ventricular (LV) function and volume were studied in patients with evolving acute myocardial infarction (AMI). We analyzed the LV ejection fraction and volume in patients who had been admitted within 24 h of the onset of their first AMI with culprit lesion of #6, #7 and #1 (American Heart Association classification). Sixty-five patients (Re group) received successful reperfusion therapy within 6 h after the AMI. The other 60 patients (Oc group), who were admitted from 6 to 24 h after the AMI, received conservative therapy. Patients with re-obstruction of the culprit lesion after reperfusion therapy were excluded from the Re group. Patients with spontaneous recanalization following conservative therapy were excluded from the Oc group. The LV ejection fraction (LVEF), LV end-systolic volume index (LVESVI), and LV end-diastolic volume index (LVEDVI) were measured using a modified Dodge's formula by left ventriculography performed 4 weeks after the AMI. LVEF in the Re group was significantly greater than in the Oc group (57 +/- 12 vs 49 +/- 11%) (mean +/- SD, p less than 0.01). LVESVI in the Re group was significantly smaller than in the Oc group (30 +/- 13 vs 38 +/- 16 ml/m2, p less than 0.01). Although LVEDVI was not significantly different between the 2 groups, in patients with a responsible coronary lesion of segment #6, LVEDVI in the Re group was significantly smaller than in the Oc group (67 +/- 14 vs 77 +/- 18 ml/m2, p less than 0.05). Although LVEF and LV volume correlated in both groups, the correlation was weak (r = 0.40-0.42), suggesting that LV volume was not dependent solely on LV functional recovery. The incidence of ventricular aneurysm in the Re group was significantly lower than in the Oc group (15.4 vs 45.0%, p less than 0.01). Multivariate analysis selected reperfusion of the responsible coronary artery as one of the factors significantly associated with a reduction of LVEDVI, LVESVI, an improvement of LVEF, and a decrease in the rate of aneurysm formation. In summary, our results indicated that reperfusion improved EF, reduced LV volume, and decreased the rate of aneurysm formation as compared to non-reperfusion, which suggests that reperfusion therapy is beneficial for both functional recovery and ventricular remodeling.     

Impact of the magnitude of the initial ST-segment elevation on left ventricular function in patients with anterior acute myocardial infarction.

BACKGROUND: In the percutaneous coronary intervention (PCI) era, the impact of initial ST-segment elevation magnitude on left ventricular (LV) function in patients with acute myocardial infarction (AMI) remains unclear. METHODS AND RESULTS: In the present study, 239 patients with total occlusion and 81 patients with spontaneous reperfusion within 12 h of their first anterior AMI were evaluated. The sum of ST-segment elevation (SigmaST) was measured in leads I, aV(L) and V(1-6) shortly before angiography. Predischarge LV ejection fraction (LVEF) was obtained at 15+/-5 days. In total occlusion, the predischarge LVEF was significantly lower in patients with SigmaST >/=10 mm than in those with SigmaST <10 mm (51+/-14% vs 57+/-14%, p<0.01). However, in spontaneous reperfusion, there was no significant difference between patients with ST >/=10 mm and those with SigmaST <10 mm (61+/-13 vs 62+/-14 %, p=NS). Predischarge LVEF significantly correlated with SigmaST in total occlusion (r=-0.25, p<0.01), but not in spontaneous reperfusion (r=0.03, p=NS). CONCLUSION: The results suggest that initial SigmaST is an important predictor of LV function in patients with total occlusion, but not in those with spontaneous reperfusion.     

Clinical implications of serial changes in ST-segment elevation after reperfusion in patients with anterior acute myocardial infarction.

BACKGROUND: In patients with acute myocardial infarction (AMI), the relationship of serial changes in ST-segment elevation after reperfusion to left ventricular (LV) function remains unclear. METHODS AND RESULTS: The study group comprised 164 patients with reperfused anterior AMI within 6 h of symptom onset. The sum of ST-segment deviation was calculated on admission (SigmaST-admission), and 1 h (SigmaST-1 h) and 24 h (SigmaST-24 h) after reperfusion. ST resolution was defined as a reduction in SigmaST-1 h of > or =50% as compared with SigmaST-admission. Patients were classified into 3 groups: group A, 82 patients with ST resolution in whom SigmaST-1 h > or = SigmaST-24 h; group B, 37 patients with ST resolution in whom SigmaST-1 h < SigmaST-24 h; group C, 45 patients without ST resolution. Peak creatine kinase were higher in groups B and C than in group A (4,578+/-2,176, 4,236+/-2,638, 2,222+/-1,926 mU/ml, p<0.01). At 6 months follow-up, the LV ejection fraction were lower in groups B and C than in group A (53+/-8, 54+/-12, 62+/-9%, p<0.01). CONCLUSIONS: An increase in ST-segment elevation 1-24 h after reperfusion, despite ST resolution, is associated with a larger infarction and poorer LV function in patients with reperfused anterior AMI.     

Transient Increase in ST-segment Changes at Time of Reperfusion in Acute Myocardial Infarction Treated by Coronary Angioplasty

PURPOSE: The clinical significance of early ST-segment re-elevation, a so called òreperfusion peakó in patients with acute myocardial infarction (AMI) treated with thrombolysis is unclear. We examined the incidence and significance of early ST-segment re-elevation immediately upon reperfusion in patients undergoing percutaneous transluminal coronary angioplasty (PTCA) where the time of reperfusion can be precisely established. METHODS: Thirty-two patients (6 women, 26 men, age 61.5 +/- 10.2 years) with an AMI, admitted less than four hours after the onset of chest pain, were included. Twenty-four patients were treated with primary PTCA and eight with rescue PTCA. Computerized on-line vectorcardiography was used for continuous ischemia monitoring. A reperfusion peak was defined as an increase in ST-vector magnitude (ST-VM) of > 50 μV, starting within two minutes after the re-opening of the infarct-related coronary artery and followed by an immediate decrease in the ST segment. RESULTS: Primary success was achieved in all treated patients. Twenty of the patients (63%) developed a reperfusion peak. ST-VM before coronary angiography was significantly larger (p = 0.004) and peak enzyme levels were higher (p = 0.014) in patients who developed a reperfusion peak. Thrombolytic treatment prior to rescue angioplasty, time to reperfusion, target vessel, presence of collaterals or medication on admission did not differ significantly between the groups. CONCLUSION: The occurrence of a reperfusion peak during the minutes after the onset of reperfusion is a common finding in patients with AMI treated at an early stage with angioplasty. There is a relationship with the occurrence of a reperfusion peak and the extent of the initial ST deviation (presumably reflecting the myocardium at risk) and peak enzyme levels. The importance of a reperfusion peak for clinical outcome and prognosis is so far not known.     

Transient increase in ST-segment elevation immediately after reperfusion in acute myocardial infarction]

The significance of transient increase in ST-segment elevation immediately after reperfusion in acute myocardial infarction (AMI) was assessed by 12-lead electrocardiography. The study population consisted of 18 patients with initial anterior AMI, whose totally-occluded left anterior descending arteries were reperfused within 6 hours after the onset of symptoms. The ST-segment elevation was defined as that of more than 0.2 mV in the V3 lead immediately after reperfusion. Collateral circulation, timing of reperfusion, CPK release, left ventricular ejection fraction and mean % 201Tl uptake in the infarct regions were compared between patients with and without ST elevation. Eleven patients (61%) had ST-segment elevation (0.61 +/- 0.29 mV). Well-developed collaterals were observed in 43% of patients without ST-segment elevation (p < 0.05) but not in those with ST elevation. ST-segment elevations were accompanied by delays in timing of reperfusion (3.7 +/- 1.2 hrs vs 2.5 +/- 0.9 hrs, p < 0.05), higher peak CPK values (6,190 +/- 3,156 IU/l vs 3,222 +/- 2,053 IU/l, p < 0.05) and lower mean % 201Tl uptake (54.2 +/- 11.4% vs 73.9 +/- 11.3%, p < 0.01). We concluded that transient increase in ST-segment elevation immediately after reperfusion may relate to poorly-developed collaterals and prolongation of ischemia; i.e., severe ischemia before reperfusion, and therefore may reflect myocardial reperfusion injuries.     

Reperfusion phenomenon is a strong predictor of left ventricular remodeling after acute myocardial infarction.

BACKGROUND:Many clinicians have seen the reperfusion phenomenon, a paradoxical response that includes a transient increase of chest pain, additional ST-segment elevation or ventricular arrhythmias immediately after coronary reperfusion, in patients with acute myocardial infarction (AMI). The aim of the present study was to investigate the impact of this phenomenon during coronary reperfusion on left ventricular (LV) remodeling in patients with AMI. METHODS AND RESULTS: One hundred and thirty-eight consecutive patients with a first anterior-wall AMI, undergoing coronary reperfusion treatment within 24 h of onset were prospectively evaluated for reperfusion phenomenon and followed up with scheduled evaluations of LV function and morphology with left ventriculography for 1 year. Of the 138 enrolled patients, 77 underwent serial left ventriculography at the acute, subacute and 1-year phases. Of these 77 patients, 39 demonstrated the reperfusion phenomenon. The LV end-diastolic volume index significantly increased from the acute to subacute phase and to the 1-year phase, but was unchanged in the 38 patients without reperfusion phenomenon. In multivariate analysis, reperfusion phenomenon was the only determinant of LV dilatation after AMI. CONCLUSIONS: Reperfusion phenomenon was a strong predictor of LV remodeling after reperfusion therapy for AMI.     

Myocardial damage after successful thrombolysis is associated with the duration of ST re-elevation at reperfusion

The purpose of this study was to investigate the significance of ST re-elevation at reperfusion using strict criteria for patient inclusion and exclusion. Twenty-nine patients who had a first anterior infarction with single-vessel disease, successful recanalization by intracoronary thrombolysis (ICT) with urokinase, and an angiographically confirmed patent infarct-related artery after 4 weeks, were divided into three groups according to the deviation of the ST segment at reperfusion: Group A, 10 patients with sustained ST re-elevation; Group B, 10 patients with transient ST re-elevation; and Group C, 9 patients with ST reduction. Left ventricular (LV) function was evaluated from cineventriculograms performed in the 30° right anterior projection 4 weeks after ICT. LV ejection fraction and regional wall motion of the infarct area, evaluated by the centerline method (SD/chords), were significantly lower in Group A (44 ± 10%, -3.2 ± 0.4) than in Group B (61 ± 9%, -1.9 ± 0.7) and Group C (60 ± 5%, -2.0 ± 0.4) (p < 0.01). Peak creatine kinase (CK) activity was significantly higher in Group A (5848 ± 2112 IU) than in Group B (2485 ± 1254 IU) and Group C (1889 ± 1525 IU) (p < 0.05). These data suggest that a sustained ST re-elevation at reperfusion was strongly associated with marked LV dysfunction and higher peak CK activity. It was concluded that sustained, not transient, ST re-elevation associated with successful reperfusion indicates extensive myocardial damage.     

Cardioprotective effects of magnesium sulfate in patients undergoing primary coronary angioplasty for acute myocardial infarction.

BACKGROUND: Experimental evidence indicates that magnesium sulfate may have potential cardioprotective properties as an adjunct to coronary reperfusion. The present study was designed to examine the hypothesis that magnesium might have beneficial effects on left ventricular (LV) function and coronary microvascular function in patients with acute myocardial infarction (AMI). METHODS AND RESULTS: The study population of 180 consecutive patients with a first AMI (anterior or inferior) underwent successful primary coronary intervention. Patients were randomized to treatment with either intravenous magnesium (magnesium group, n=89) or normal saline (control group, n=91). Pre-discharge left ventriculograms were used to assess LV ejection fraction (LVEF), regional wall motion (RWM) within the infarct-zone and LV end-diastolic volume index. The Doppler guidewire was used to assess coronary flow velocity reserve (CFVR) as an index of coronary microvascular function. Magnesium group subjects showed significantly better LV systolic function (LVEF 63+/-9% vs 55+/-13%, p<0.001; RWM: -1.01+/-1.29 SD/chord vs -1.65+/-1.11 SD/chord, p=0.004), significantly smaller LV end-diastolic volume index (63+/-17 ml/m(2) vs 76+/-20 ml/m(2), p<0.001), and significantly higher CFVR (2.95+/-0.76 vs 2.50+/-0.99, p=0.023) than controls. CONCLUSION: Magnesium sulfate as an adjunct to primary coronary intervention shows favorable functional outcomes in patients with AMI.     

Noninvasive detection of coronary artery patency using continuous ST-segment monitoring

Continuous ST-segment Holter recordings were analyzed from 46 patients with acute myocardial infarction (AMI) receiving intracoronary streptokinase (SK) during the first 48 hours of hospitalization. Changes in ST deviation and the time periods of these changes were quantitated and correlated with angiographic evidence of reperfusion. Thirty-six patients had total occlusion of the infarct vessel and 10 had subtotal occlusion. Of the 36 vessels that were totally occluded, 19 were reperfused and 17 were not. In patients in whom reperfusion was successful, an ST steady state was achieved 55 +/- 32 minutes after SK administration. In patients in whom it was not successful, a steady state was achieved in 219 +/- 141 minutes (p less than 0.001). Achievement of steady state within 100 minutes after SK reperfusion indicated successful reperfusion with 89% sensitivity and 82% specificity. All patients with subtotal occlusion achieved an ST steady state before SK infusion. No patient with total occlusion achieved a steady state before SK. Achievement of ST steady state before SK infusion was 100% sensitive and 100% specific for subtotal occlusion at initial angiography. Continuous, quantitative ST-segment analysis is a sensitive and specific noninvasive technique for following coronary artery patency during AMI.     

ST-segment depression in lead aVR predicts predischarge left ventricular dysfunction in patients with reperfused anterior acute myocardial infarction with anterolateral ST-segment elevation.

BACKGROUND: Patients with an anterolateral acute myocardial infarction (AMI) have a worse prognosis, and those with additional inferolateral wall involvement might be higher risk because of more extensive area at risk. Lead -aVR obtained by inversion of images in lead aVR has been reported to provide useful information for inferolateral lesion. METHODS: We examined the relation between ST-segment deviation in lead aVR on admission electrocardiogram (ECG) and left ventricular function in 105 patients with an anterolateral AMI undergoing successful reperfusion < or = 6 hours after onset. Patients were classified according to ST-segment deviation in lead aVR on admission ECG: group A, 23 patients with ST elevation of > or = 0.5 mm; group B, 47 patients without ST deviation; and group C, 35 patients with ST depression of > or = 0.5 mm. RESULTS: There were no differences among the 3 groups in age, sex, or site of the culprit lesion. In groups A, B, and C, the peak creatine kinase level was 3661 +/- 1428, 4440 +/- 1889, and 6959 +/- 2712 mU/mL, and the left ventricular ejection fraction (LVEF) measured by predischarge left ventriculography was 54% +/- 9%, 48% +/- 7%, and 37% +/- 9%, respectively(P < .01). During hospitalization, congestive heart failure occurred more frequently in group C than in groups A or B (P < .05). ST-segment depression in lead aVR had a higher predictive accuracy than other ECG findings in identifying patients with predischarge LVEF < or = 35%. CONCLUSIONS: We conclude that in patients with an anterolateral AMI, ST-segment depression in lead aVR on admission ECG is useful for predicting larger infarct and left ventricular dysfunction despite successful reperfusion.     

Prediction of remote left ventricular volumes and functions after acute myocardial infarction with successful coronary intervention.

BACKGROUND: The scintigraphic perfusion defect size (DS) at 1 week after acute myocardial infarction (AMI) predicts remote left ventricular (LV) volumes and LV ejection fraction (LVEF). The present study examined whether LV volumes and LVEF 6 months after AMI may be better predicted by the combination of LV volumes and LVEF just after reperfusion, and DS at 1 week, after AMI in patients with Thrombolysis In Myocardial Infarction (TIMI) grade III reperfusion by percutaneous coronary intervention. METHODS AND RESULTS: In 48 patients with AMI and TIMI grade III reperfusion, quantitative gated SPECT (QGS) was performed just after reperfusion, and at 1 week and 6 months after AMI. LV end-diastolic volume index decreased (108+/-8 to 93+/-6 ml/m(2), p<0.05) and LVEF increased (44+/-3 to 50+/-2%, p<0.05) 6 months after AMI. In addition, they were better predicted by a combination of LV volumes and LVEF just after reperfusion and DS at 1 week after AMI. CONCLUSIONS: In AMI with TIMI grade III reperfusion, LV volumes and LVEF at 6 months after MI correlate with the values obtained just after reperfusion. Myocardial perfusion imaging combined with QGS at reperfusion may predict these late-phase parameters.     

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.     

Influence of reperfusion therapy on left ventricular remodeling after acute myocardial infarction

To determine the relation between reperfusion therapy and left ventricular function and remodeling after acute myocardial infarction (AMI), 75 consecutive patients with anterior AMI were studied. The patients were divided into four groups according to the reperfusion outcome and time to reperfusion from onset of MI: 12 patients with spontaneous reperfusion, 18 patients with early (less than 4th) successful reperfusion, 16 patients with late (greater than or equal to 4th) successful reperfusion and 29 patients with unsuccessful reperfusion. The right oblique left ventriculograms (LVG), which was performed early (n = 19) and late after infarction (n = 75) were analyzed to assess left ventricular (LV) volume and global and regional LV function. At the late examination, spontaneous early and late reperfused patients showed smaller LV volume (endo diastolic and endo-systolic volume index) than unsuccessfully reperfused patients LV volume was similar in both early and late reperfused patients. Spontaneous and early reperfused patients showed higher LV ejection fraction (EF) and better regional wall motion (RWM) than unsuccessfully reperfused patients. Both EF and RWM was similar in late and unsuccessfully reperfused patients at the late examination. Endo-diastolic and endo-systolic volume index increased significantly with time in patients with unsuccessful reperfusion (n = 10), as compared with the index found in the early examination. In patients with late reperfusion (n = 5), end-diastolic volume index increased with time, but end-systolic volume index was unchanged. RMW improved in patients with early reperfusion (n = 4), but was unchanged in patients with late and unsuccessful reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Early identification of impaired myocardial reperfusion with serial assessment of ST segments after percutaneous transluminal coronary angioplasty during acute myocardial infarction.

To evaluate the relation between ST-segment analysis and microvascular reperfusion in patients with acute myocardial infarction (AMI), we studied 51 patients with first AMI who were successfully treated by percutaneous transluminal coronary angioplasty (PTCA). The lead showing the greatest ST-segment elevation on the 12-lead electrocardiogram (ECG) was serially investigated until 24 hours after PTCA. Successful reperfusion was determined by technetium-99m tetrofosmin single-photon emission computed tomography. Impaired reperfusion (group 1: < 4 change in the sum of the defect score from before to immediately after PTCA) was observed in 24 patients, and successful reperfusion (group 2) was observed in 27 patients. Although ST-segment elevation was reduced significantly at 30 minutes after PTCA in group 2 (2.2 +/- 1.4 to 1.7 +/- 1.3 mm, p = 0.01), there was no significant change in group 1 (1.9 +/- 1.9 to 2.4 +/- 1.7 mm). Ten of 14 patients (71%) with persistent ST-segment elevation (DeltaST > 0 mm change in ST segment from before to 30 minutes after PTCA > 0) were in group 1, whereas 23 of 37 patients (62%) with ST-segment resolution (DeltaST < or = 0) were in group 2. The sensitivity and specificity of persistent ST-segment elevation for predicting impaired microvascular reperfusion were 42% and 85%, respectively. Thus, persistent ST-segment elevation 30 minutes after primary PTCA was a highly specific electrocardiographic marker of impaired reperfusion in patients with AMI.     

ST-segment re-elevation and left ventricular expansion soon after acute anterior myocardial infarction.

The sum of ST-segment elevation (sigma ST on V2-4) was measured to evaluate ST-segment re-elevation during early convalescence in 57 patients with acute myocardial infarction. Following rapid ST-segment elevation resolution during the first 12 h, sigma ST again increased in many patients without signs of reinfarction or pericarditis, reaching a maximum approximately 5 days after onset. The magnitude of this re-elevation (delta sigma ST) was less than 0.3 mV in 30 patients (group A), and 0.3 mV or more in another 27 (group B). Based upon left ventriculography, the global ejection fraction in group B decreased significantly from 51 +/- 10% at the acute phase to 46 +/- 10% at the chronic phase. No such decreases were seen for group A. Regional ejection fraction in the infarcted portion improved significantly from 28 +/- 13% at the acute phase to 35 +/- 14% at the chronic phase in group A, but did not improve in group B. In addition, the non-infarcted portion in group B showed a significantly reduced regional ejection fraction. These results suggest that myocardial expansion of the infarcted portion may contribute to ST-segment re-elevation, an ominous sign of left ventricular dysfunction soon after acute myocardial infarction.     

Left ventricular remodeling after anterior wall acute myocardial infarction in modern clinical practice (from the REmodelage VEntriculaire [REVE] study group)

Left ventricular (LV) remodeling after acute myocardial infarction (AMI) has been well described in previous studies. However, there is a paucity of data on the incidence of and risk factors for LV remodeling in modern clinical practice that incorporates widespread use of acute reperfusion strategies and almost systematic use of "antiremodeling" medications, such as angiotensin-converting enzyme inhibitors and beta blockers. We enrolled 266 patients with anterior wall Q-wave AMI who had >or=3 segments of the infarct zone that were akinetic on echocardiography before discharge. Echocardiographic follow-up was performed 3 months and 1 year after AMI. LV volumes, ejection fraction, wall motion score index, and mitral flow velocities were determined in a blinded analysis at a core echocardiographic laboratory. Acute reperfusion was attempted in 220 patients (83%; primary angioplasty in 29% and thrombolysis in 54%). During hospitalization, 99% of patients underwent coronary angiography and 87% underwent coronary stenting of the infarct-related lesion. At 1 year, 95% of patients received an antiplatelet agent, 89% a beta blocker, 93% an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker, and 93% a statin. Echocardiographic follow-up was obtained in 215 patients. There was recovery in LV systolic function as shown by a decrease in wall motion score index and an increase in ejection fraction. There was a significant increase in end-diastolic volume (EDV; 56.4 +/- 14.7 ml/m2 at baseline, 59.3 +/- 15.7 ml/m2 at 3 months, 62.8 +/- 18.7 ml/m2 at 1 year, p <0.0001). LV remodeling (>20% increase in EDV) was observed in 67 patients (31%). Peak creatine kinase level, systolic blood pressure, and wall motion score index were independently associated with changes in EDV. In conclusion, recent improvements in AMI management do not abolish LV remodeling, which remains a relatively frequent event after an initial anterior wall AMI.     

再灌注心律失常对急性心肌梗死患者心肌细胞凋亡和左室重构的影响

目的探讨急性心肌梗死（AMI）患者再灌注心律失常（RA）、心肌细胞凋亡和左室功能的关系。方法156例经急诊再灌注治疗的AMI患者,分为RA组58例（24小时内出现RA）,非再灌注心律失常（Non．RA）组98例。应用ELISA方法,分别检测再灌注治疗成功后即刻、7天和2—4周血清细胞凋亡信号分子Fas／APO-1水平,并在1周、6个月和1年做心脏彩超,检测左室射血分数（LVEF）和左室舒张末期内径（LVEDD）。结果（1）RA组血管开通时间较Non-RA组晚,且前降支病变较Non-RA组发生率高（P〈0．05）。（2）再灌注治疗成功后即刻,RA组血清Fas／APO-1浓度明显高于Non-RA组[（13．82±4．36）μg/L与（8．19±3．56）μg/L,P〈0．05]。（3）再灌注治疗成功后第7天,两组患者血清Fas／APO-1浓度达高峰,2—4周时明显下降,与第7天比较差异有统计学意义[RA组（10．91±3．65）μg/L与（14．26±4．98）μg/L,P〈0．05;Non-RA组（4．69±1．87）μg/L与（12．19±3．25）μg/L,P〈0．01],且2—4周时RA组Fas／APO-1浓度明显高于Non．RA组[（10．91±3．65）μg/L与（4．69±1．87）μg/L,P〈0．01]。（4）AMI再灌注治疗成功后1周,RA组与Non-RA组比较,LVEF和LVEDD差异无统计学意义[LVEF（47．7±9．6）％与（49．2±8．9）％,P〉0．05;LVEDD（59．7±10．3）mm与（57．4±12．4）mm,P〉0．05]。（5）AMI再灌注治疗成功1年后,Non-RA组LVEF明显高于自身急性期和RA组[分别为（59．5±9．2）％、（49．2±8．9）％和（49．9±10．1）％,P〈0．05],LVEDD虽然无显著性变化（P〉0．05）,但有增加趋势。结论心肌缺血严重患者易发生RA,且与心肌缺血所诱发心肌细胞凋亡有关,影响左室功能的恢复,促进心室重构。     

Reliability of Q-wave formation and QRS score in predicting regional and global left ventricular performance in acute myocardial infarction with successful reperfusion

The frequency of electrocardiographic Q-wave formation and the relation of Q wave and QRS score to regional and global left ventricular (LV) performance were determined in 131 patients with acute myocardial infarction (AMI) receiving thrombolytic therapy. Thrombolytic therapy was successful in reperfusing the occluded infarct artery in 100 patients and was unsuccessful in 31. The number of patients who had 1 or more Q waves (88 vs 87%) and 2 or more Q waves (70 vs 74%) was similar. In contrast, normal wall motion was significantly more common in the infarct area in patients in whom reperfusion was successful (42 vs 15%, p less than 0.05). Total QRS scores were similar in patients in whom reperfusion was successful and in those in whom it was not (6.0 +/- 3.2 vs 6.4 +/- 4.2). Despite similar QRS scores, successfully treated patients had significantly higher LV ejection fraction (53 +/- 13% vs 46 +/- 15%, p less than 0.05). Thus, Q-wave formation after successful thrombolytic therapy for AMI is common but does not faithfully reflect regional or global LV performance. Electrocardiographic analysis alone is not a reliable method to assess efficacy of reperfusion therapy.