Early and 1-year clinical outcome of patients' evolving non-Q-wave versus Q-wave myocardial infarction after thrombolysis. Results from The TIMI II Study

Validation of black blood late gadolinium enhancement (LGE) for evaluation of myocardial infarction in patients with or without pathological Q-wave on electrocardiogram (ECG)

Background

The pathological Q-wave (QW) is an important indicator of infarcted myocardial volume indicating a worse prognosis compared to non-Q-wave (NQW) infarctions. Traditional classification divides infarcts into transmural and non-transmural based on QW and NQW. This view has been challenged by the advent of late gadolinium enhancement (LGE) MR imaging. Conventional LGE (Conv-LGE) detection of subendocardial MI is limited by bright blood pool. Dark Blood LGE imaging (DB-LGE) nulls the blood pool improving the conspicuity and accuracy of detection of subendocardial infarcts. We hypothesize that improved detection of subendocardial enhancement with DB-LGE will result in improved correlation of electrocardiogram (ECG) and extent of infarction.

Methods

Sixty-four clinically confirmed infarction patients were enrolled in this prospective study. All the participants underwent cardiac MR imaging including conv-LGE and DB-LGE. Twelve-lead ECG were performed on the same day. The patients were divided into QW and NQW groups by one experienced cardiologist. MI quantitation was by MI% (the ratio of MI volume to whole myocardial volume) and transmural grading, compared using paired t-test and Wilcoxon-test, respectively. The image quality obtained by Conv-LGE and DB-LGE were evaluated according to the signal intensity ratio (SIR) and contrast-to-noise ratio (CNR).

Results

Fifty-six subjects were enrolled in the final analysis [23 (41%) QW and 33 (59%) NQW infarcts]. For the QW cohort, both sequences classified infarcts as transmural in 21/23 (91%) subjects and subendocardial in 2/23 (9%). For the NQW cohort, both sequences classified infarcts as transmural in 16/33 (48%) subjects and subendocardial in 17/33 (52%). Using BB-LGE there were significant differences in detecting subendocardial infarcts in QW and NQW cohorts (Z=-5.85, P<0.001). The MI% of QW group was greater than in NQW group (24.2±10.3 vs.15.9±9.8, P=0.003). Compared to Conv-LGE, BB-LGE provided higher CNR and SIR between infarcted myocardium and blood pool (6.3±2.6 vs. 2.1±1.3, P<0.001; 5.4±1.9 vs. 1.3±0.2, P<0.001). BB-LGE detected more subendocardial infarcted segments in the QW group and NQW group (Z=-4.24, P<0.001; Z=-5.57, P<0.001). The larger MI% was displayed in BB-LGE than in Conv-LGE in both QW group and NQW group (24.2±10.3 vs. 22.6±10.3, P<0.001; 15.9±9.8 vs.14.6±9.6, P=0.001).

Conclusions

Compared to conventional LGE, DB-LGE can provide more accurate detection and characterization of infarction in terms of transmurality and subendocardial extent. This is important for evaluating QW and NQW MIs. Due to nulling the high signal of blood pool, DB-LGE can effectively improve the identification of subendocardial MI which may be missed on conventional LGE. Therefore, in both QW and NQW MIs, DB-LGE detects more subendocardial MIs and larger MI% is found. This may facilitate more accurate quantitative MR assessment of both QW and NQW MIs and further empower LGE volume as a predictive biomarker.

Competing Risks of Cardiovascular Versus Noncardiovascular Death During Long-Term Follow-Up After Acute Coronary Syndromes

Background

Understanding the relative risk of cardiovascular versus noncardiovascular death is important for designing clinical trials. These risks may differ depending on patient age, sex, and type of acute coronary syndrome (ACS).

Methods and Results

IMPROVE‐IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial) was a randomized controlled trial of simvastatin plus either ezetimibe or placebo following stabilized ACS. Cause of death was adjudicated by an independent committee. We compared the cumulative incidence of cardiovascular and noncardiovascular death for patients with unstable angina/non‐ST‐segment elevation myocardial infarction (UA/NSTEMI) and ST‐segment elevation myocardial infarction (STEMI), in those <65 and ≥65 years old, and males and females, over 7 years of follow‐up. Of 18 131 patients, the presenting event was STEMI for 5190 (29%) and UA/NSTEMI for 12 941 (71%); 10 173 (56%) patients were <65 years old and 7971 (44%) were ≥65 years old at presentation. UA/NSTEMI patients were older than STEMI patients, with more cardiovascular and noncardiovascular risk factors. In STEMI patients, the cumulative incidence of cardiovascular death was higher for ∼4 years following the index event, after which noncardiovascular death predominated. In UA/NSTEMI patients, the cumulative incidence of cardiovascular death remained higher than noncardiovascular death over the full follow‐up period. Patients ≥65 years old and <65 years old had a higher incidence of cardiovascular death than noncardiovascular death over the entirety of follow‐up. Female patients had a higher incidence of cardiovascular death than noncardiovascular death for ∼6 years following the index event; male patients had a higher incidence of cardiovascular death than noncardiovascular death over the entirety of follow‐up.

Conclusions

Among post‐ACS patients enrolled in a long‐term clinical trial, the relative incidence of cardiovascular and noncardiovascular death differed based on type of ACS presentation and sex, but not age. These findings further delineate long‐term prognosis after ACS and should inform the design of future cardiovascular outcomes trials.

Prognostic implications of prominent R wave in electrocardiographic leads V1 or V2 in patients with acute coronary syndrome

Although the adverse prognosis of Q-waves on electrocardiogram (ECG) has been demonstrated, the prognostic significance of prominent R wave (PRW) in V1 or V2 across a broad spectrum of acute coronary syndrome (ACS) has not been specifically studied. In the Global Registry of Acute Coronary Events (GRACE) and the Canadian ACS Registry I ECG substudies, admission ECGs were analyzed in an independent core ECG laboratory. PRW was defined as R wave >40 to 50 ms in V1 or V2, R/S ≥1 in V1, or R/S ≥1.5 in V2. Among 11,895 patients with ACS, 495 (4.2%) had PRW; they were less likely to have a history of hypertension or heart failure and had lower GRACE risk scores, but a higher incidence of ST-segment depression (all p ≤0.001). Patients with PRW had similar rates of in-hospital death (2.8% vs 4.1%, respectively, p = 0.15) but lower rates of in-hospital heart failure (8.5% vs 15.2%, respectively, p = 0.02) and 6-month mortality (4.6% vs 8.4%, respectively, p = 0.004). In multivariable analyses, PRW was not a significant independent predictor of in-hospital mortality (adjusted odds ratio = 0.99, 95% confidence interval 0.55 to 1.8) or 6-month mortality (adjusted odds ratio = 0.70, 95% confidence interval 0.43 to 1.15). Among 4,418 patients who underwent coronary angiography, those with PRW had a higher prevalence of left circumflex artery disease (62.5% vs 49.5%, respectively, p = 0.01). In conclusion, across the broad spectrum of patients with ACS, PRW provides no significant additional prognostic utility beyond comprehensive risk assessment using the GRACE risk score. PRW is more frequently associated with left circumflex artery disease.

Clinical features of myocardial infarction in young Japanese patients

Clinical features and outcomes of acute myocardial infarction (AMI) in the young have been poorly investigated. The aim of this study was to investigate the clinical features and hospital outcomes of AMI in young Japanese. We conducted a case-control study. A total of 53 consecutive AMI patients whose age was ≤ 45 years old were assigned to the young group and 106 AMI patients whose age was > 45 years old were assigned to the non-young group. We compared the clinical features and hospital outcomes between the two groups. Compared with the non-young group, the young group was associated with male sex, hyperlipidemia, current smoking, being overweight, single vessel disease, and Killip class I on admission. There were no differences in the length of hospital stay or major adverse cardiac events between the groups. However, mortality and ventricular rupture were slightly lower in the young. In conclusion, young AMI patients had clinical characteristics different to those of the non-young patients. Compared to non-young patients, modifiable risk factors such as smoking, hyperlipidemia, and being overweight were associated with young AMI patients.

Early electrocardiographic findings and MR imaging-verified microvascular injury and myocardial infarct size

OBJECTIVES

This study investigated early electrocardiographic findings in relation to left ventricular (LV) function, extent and size of infarction, and microvascular injury in patients with acute myocardial infarction (MI) treated with percutaneous coronary intervention (PCI).

BACKGROUND

The electrocardiogram (ECG) is the most used and simplest clinical method to evaluate the risk for patients immediately after reperfusion therapy for acute MI. ST-segment resolution and residual ST-segment elevation have been used for prognosis in acute MI, whereas Q waves are related to outcome in chronic MI. We hypothesized that the combination of these electrocardiographic measures early after primary PCI would enhance risk stratification.

METHODS

We prospectively included 180 patients with a first acute ST-segment elevation MI to assess ST-segment resolution, residual ST-segment elevation, and number of Q waves using the 12-lead ECG acquired on admission and 1 h after successful PCI. The ECG findings were related to LV function, infarction size and transmurality, and microvascular injury as assessed with cine and gadolinium-enhanced cardiac magnetic resonance 4 +/- 2 days after reperfusion therapy.

RESULTS

Residual ST-segment elevation (beta = -2.00, p = 0.004) and the number of Q waves (beta = -1.66, p = 0.005) were independent ECG predictors of LV ejection fraction. Although the number of Q waves was the only independent predictor of infarct size (beta = 2.01, p < 0.001) and transmural extent of infarction (beta = 0.60, p < 0.001), residual ST-segment elevation was the only independent predictor of microvascular injury (odds ratio: 19.1, 95% confidence interval: 2.4 to 154, p = 0.005) in multivariable analyses. The ST-segment resolution was neither associated with LV function, infarct size, or transmurality indexes, nor with microvascular injury in multivariable analysis.

CONCLUSIONS

In patients after successful coronary intervention for acute MI, residual ST-segment elevation and the number of Q waves on the post-procedural ECG offer valuable complementary information on prediction of myocardial function and necrosis and its microvascular status.

Impact of chronic patency of infarct-related coronary artery on prevalence of myocardial ischemia during the pharmacologic and exercise stress test

BACKGROUND

Even late restoration of anterograde coronary flow may have beneficial effects on left ventricular function, electrophysiology, and survival in postinfarction patients.

HYPOTHESIS

The patency or occlusion of an infarct-related coronary artery in the chronic phase may also be associated with myocardial ischemia provoked by pharmacologic and physiologic stress tests.

METHODS

High-dose dipyridamole echocardiography test (DET) (up to 0.84 mg/kg over 10 min), exercise electrocardiography (EET), and coronary angiographic data in a group of 127 in-hospital patients who had survived an acute myocardial infarction were analyzed. Patients who had only angiographic evidence of infarct-related single artery disease (> or = 50% luminal diameter reduction) and no previous revascularization were enrolled in the study. DET and EET were performed (DET in all, EET in 118 patients) within 5 days before coronary angiography. Fifty-seven patients had total occluded infarct arteries (Group 1) with various degrees of collateral circulation (2.6 +/- 1.1 collateral score, by a 3 grading system), whereas the other 70 patients had patent infarct arteries (Group 2) with significant residual stenoses (82 +/- 13% diameter reduction).

RESULTS

The prevalence of rest angina or effort angina and topography of the infarct-related coronary artery did not differ between the two groups (all p = NS). There were more patients with Q wave in Group 1 than in Group 2 (72 vs. 57%, p = 0.08) compared with non-Q wave infarction (Group 1 = 28 vs. Group 2 = 43%, p = 0.08). Ischemia in the infarct-related artery territory detected by DET (defined as new wall motion dyssynergy or marked worsening of resting hypokinesia) was 61% in Group 1 and 41% in Group 2 (p = 0.025). EET was positive in 26 of 54 (48%) Group 1 and in 21 of 64 (33%) Group 2 patients (p = 0.09).

CONCLUSIONS

Patients with occluded infarct-related arteries have a higher prevalence of ischemia during DET and EET regardless of the presence of collateral flow. These results suggest that the presence of partial anterograde flow in the prolonged period could have a favorable influence on prevalence of residual ischemia in these patients.

Incidence and prognosis of non-Q-wave vs. Q-wave myocardial infarction following catheter-based reperfusion therapy

BACKGROUND

The clinical importance of classifying myocardial infarction (MI) into non-Q-wave (NQWMI) vs. Q-wave (QWMI) subsets is controversial and might depend on the therapeutic reperfusion strategy employed. The prognostic implications of NQWMI development following primary percutaneous coronary intervention (PCI) have not been reported.

AIM

To examine the incidence, determinants and prognostic implications of NQWMI vs. QWMI development following primary PCI.

DESIGN

The ACSIS Registry, a 2-month nationwide survey conducted biennially, prospectively collects data from all MI admissions in Israel.

METHODS

Outcomes were compared among patients managed by primary PCI who subsequently developed NQWMI vs. QWMI. Independent predictors of Q-wave development and 1-year mortality were determined by multivariate stepwise logistic regression analysis and Cox proportional hazard model, respectively.

RESULTS

Of 4537 MI patients with ST-segment elevation on admission, 1230 (27%) were treated with primary PCI. A discharge diagnosis of NQWMI was made in 259 (21.1%) patients. The baseline features and PCI strategies employed were similar among NQWMI vs. QWMI patients, though peak creatine kinase levels were higher (median 795 U/l vs. 1681 U/l, P = 0.0001) and severe left ventricular ejection fraction (LVEF) impairment (<40%) more frequent (22.6% vs. 43.9%, P < 0.0001), in the latter group. Mortality at 1-year was significantly lower in NQWMI vs. QWMI patients (3.9% vs. 10.8%, P log-rank = 0.001). By Cox proportional hazard analysis, NQWMI vs. QWMI was an independent predictor of freedom from 1-year mortality [HR = 0.34 (95% CI: 0.15-0.79), P = 0.01].

DISCUSSION

The diagnosis of NQWMI after primary PCI is associated with an excellent prognosis independent of established prognosticators, including LVEF.

C-terminal provasopressin (copeptin) is associated with left ventricular dysfunction, remodeling, and clinical heart failure in survivors of myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) is associated with left ventricular (LV) dysfunction and clinical heart failure. Arginine vasopressin is elevated in heart failure and the C-terminal of provasopressin (Copeptin) is associated with adverse outcome post-AMI. The aim of this study was to describe the association between Copeptin with LV dysfunction, volumes, and remodeling and clinical heart failure post-AMI.

METHODS AND RESULTS

We studied 274 subjects with AMI. Copeptin was measured from plasma at discharge and subjects underwent echocardiography at discharge and follow-up (median 155 days). Subjects were followed for clinical heart failure for a median of 381 days. Remodeling was assessed as the change (Delta) in LV volumes between echo examinations. Copeptin correlated directly with wall motion index score (WMIS) and inversely with LV ejection fraction (LVEF) at discharge (WMIS, r=0.276, P < .001; LVEF, r=-0.188, P=.03) and follow-up (WMIS, r=0.244, P < .001; LVEF, r=-0.270, P < .001) and with ventricular volumes at follow-up (LVEDV, r=0.215, P=.002; LVESV, r=0.299, P < .001). Copeptin was associated with ventricular remodeling; DeltaEDV; r=0.171, P=0.015, DeltaESV; r=0.186, P=.008. Subjects with increasing LVESV had higher levels of Copeptin (median 6.30 vs. 5.75 pmol/L, P=.012). Subjects with clinical heart failure (n=30) during follow-up had higher Copeptin before discharge (median 13.55 vs. 5.80, P < .001). In a Cox proportional hazards model, Copeptin retained association with clinical heart failure. Kaplan-Meier assessment revealed increased risk in subjects with Copeptin >6.31 pmol/L.

CONCLUSIONS

Copeptin is associated with LV dysfunction, volumes, and remodeling and clinical heart failure post-AMI. Measurement of Copeptin may provide prognostic information and the AVP system may be a therapeutic target in post-MI LV dysfunction.

Infarct size in primary angioplasty without on-site cardiac surgical backup versus transferal to a tertiary center: a single photon emission computed tomography study

BACKGROUND

Primary percutaneous coronary intervention (PCI) performed in large community hospitals without cardiac surgery back-up facilities (off-site) reduces door-to-balloon time compared with emergency transferal to tertiary interventional centers (on-site). The present study was performed to explore whether off-site PCI for acute myocardial infarction results in reduced infarct size.

METHODS AND RESULTS

One hundred twenty-eight patients with acute ST-segment elevation myocardial infarction were randomly assigned to undergo primary PCI at the off-site center (n = 68) or to transferal to an on-site center (n = 60). Three days after PCI, (99m)Tc-sestamibi SPECT was performed to estimate infarct size. Off-site PCI significantly reduced door-to-balloon time compared with on-site PCI (94 +/- 54 versus 125 +/- 59 min, respectively, p < 0.01), although symptoms-to-treatment time was only insignificantly reduced (257 +/- 211 versus 286 +/- 146 min, respectively, p = 0.39). Infarct size was comparable between treatment centers (16 +/- 15 versus 14 +/- 12%, respectively p = 0.35). Multivariate analysis revealed that TIMI 0/1 flow grade at initial coronary angiography (OR 3.125, 95% CI 1.17-8.33, p = 0.023), anterior wall localization of the myocardial infarction (OR 3.44, 95% CI 1.38-8.55, p < 0.01), and development of pathological Q-waves (OR 5.07, 95% CI 2.10-12.25, p < 0.01) were independent predictors of an infarct size > 12%.

CONCLUSIONS

Off-site PCI reduces door-to-balloon time compared with transferal to a remote on-site interventional center but does not reduce infarct size. Instead, pre-PCI TIMI 0/1 flow, anterior wall infarct localization, and development of Q-waves are more important predictors of infarct size.

The endocardial extent of reperfused first-time myocardial infarction is more predictive of pathologic Q waves than is infarct transmurality: a magnetic resonance imaging study

BACKGROUND

Historically, Q-wave myocardial infarction (MI) has been equated with transmural MI. This association have, however, recently been rejected. The endocardial extent of MI is another potential determinant of pathological Q waves, since the first part of the QRS complex where the Q wave appears reflects depolarization of subendocardial myocardium. Therefore, the aim of the present study was to test the hypothesis that endocardial extent of MI is more predictive of pathological Q waves than is MI transmurality and to investigate the relationship between QRS scoring of the ECG and MI characteristics.

METHODS

Twenty-nine patients with reperfused first-time MI were prospectively enrolled. One week after admission, delayed contrast-enhanced magnetic resonance imaging (DE-MRI) was performed and 12-lead ECG was recorded. Size, transmurality and endocardial extent of MI were assessed by DE-MRI. Q waves were identified with Minnesota coding and electrocardiographic MI size was estimated by QRS scoring of the ECG.

RESULTS

There was a significant difference between patients with and without Q waves with regard to MI size (P = 0.03) and endocardial extent of MI (P = 0.01), but not to mean and maximum MI transmurality (P = 0.09 and P = 0.14). Endocardial extent was the only independent predictor of pathological Q waves. Endocardial extent of MI was most strongly correlated to QRS score (r = 0.86, P<0.001) of the MI variables tested.

CONCLUSION

The endocardial extent of reperfused first-time acute MI is more predictive of pathological Q waves than is MI transmurality.

Comparative cost-effectiveness of anticoagulation with bivalirudin or heparin with and without a glycoprotein IIb/IIIa-receptor inhibitor in patients undergoing percutaneous coronary intervention in Sweden: a decision-analytic model

OBJECTIVE

This study modeled the comparative costs and effectiveness of anticoagulation with bivalirudin alone, heparin alone, and heparin combined with a glycoprotein IIb/IIIa-receptor inhibitor (GPI) in patients undergoing percutaneous coronary intervention (PCI) in Sweden.

METHODS

GPIs are prescribed for -40% to 50% of patients undergoing PCI in Sweden. However, because treatment practices vary between hospitals, the model analyzed a cohort in which different proportions of patients (0%-100%) would receive a GPI in addition to heparin and the remaining patients would receive heparin monotherapy. This mixed cohort was compared with a cohort treated with bivalirudin. Abciximab was used as the GPI comparator, as this is the only GPI currently approved in Sweden for patients undergoing PCI. Pooled data from 3 studies (REPLACE-2 [second Randomized Evaluation of PCI Linking Angiomax to Reduced Clinical Events], ESPRIT [European/Australasian Stroke Prevention in Reversible Ischaemia Trial], and EPISTENT [Evaluation of Platelet IIb/IIIa Inhibitor for Stenting]) were used as the source for the probabilities of myocardial infarction (MI), urgent revascularization (UR), major and minor bleeding (Thrombolysis in Myocardial Infarction study definitions), and death. Treatment costs associated with these complications were obtained from 4 Swedish hospitals, and official drug prices were obtained from the Swedish Pharmacopoeia. All costs were presented in 2006 Swedish kronor (SEK). The model was evaluated over a 30-day time frame from the perspective of a Swedish hospital. The modeled patient population was 63 years old, weighed 78 kg, and was 75% male.

RESULTS

Compared with a pattern in which heparin plus a GPI was used in 50% of all PCIs and heparin alone was used in the remaining 50%, bivalirudin treatment was associated with a significant reduction in all complications in the model (P < 0.05), including a mean of 18.2 fewer MIs, 1.6 fewer URs, 15.3 fewer bleeding events, and 1.3 fewer deaths per 1000 treated patients. Bivalirudin therapy also was associated with a significant reduction in total drug and health care costs per patient (SEK -1301; 95% Cl, -1367 to -1229). The benefit of bivalirudin was sensitive to the rate of GPI use: additional reductions in rates of MI, UR, and death were seen at lower rates of GPI use, and additional reductions in rates of bleeding and costs of drugs and health care utilization were seen at higher rates of GPI use.

CONCLUSIONS

In this model, anticoagulation with bivalirudin in patients undergoing PCI was cost-effective compared with heparin alone and heparin plus a GPI. In a hypothetical Swedish hospital unit using equal proportions of heparin alone and heparin plus a GPI, a switch to bivalirudin would reduce the risk of both ischemic events and bleeding events, resulting in savings in total drug and health care costs.

Biomarkers of cardiovascular damage

Acute coronary syndromes (ACS) are due to the rupture or erosion of atheromatous plaques. This produces, depending on plaque size, vascular anatomy and degree of collateral circulation, progressive tissue ischaemia which may progress to cardiomyocyte necrosis. This may then result in cardiac remodelling. Serum biomarkers are available which can be used for diagnosis of all of these stages. Markers to detect myocardial ischaemia at the pre-infarction stage are potentially the most interesting but also the most challenging. An ischaemia marker offers the opportunity to intervene to prevent progression to infarction. The problems with potential ischaemia markers are specificity and the reference diagnostic standard against which they can be judged. To date, only one, ischaemia-modified albumin(R), has reached the point where clinical studies can be performed. The measurement of the cardiac troponins, cardiac troponin T and cardiac troponin I, have become recognised as the diagnostic reference standard for myocardial necrosis. The sensitive nature of these tests has also revealed that myocardial necrosis is also found in a range of other clinical situations, highlighting the need to use all clinical information for diagnosis of acute myocardial infarction. The measurement of B-type natriuretic peptides can be shown to be diagnostic and prognostic in both ACS and detecting the sequelae of post-infarction myocardial insufficiency. The role of the B-type natriuretic peptides in detection of cardiac failure, both acute and chronic, is well defined but remains the subject of further studies, in ACS.

Biomarkers of Cardiovascular Damage and Dysfunction—An Overview

Acute coronary syndromes (ACS) are due to the rupture or erosion of atheromatous plaques. This produces, depending on plaque size, vascular anatomy and degree of collateral circulation, progressive tissue ischaemia which may progress to cardiomyocyte necrosis and subsequent cardiac remodelling. Cardiac biomarkers can be used for diagnosis and assessment of all of these stages. Markers to detect myocardial ischaemia at the pre-infarction stage are potentially the most interesting but also the most challenging. An ischaemia marker offers the opportunity to intervene to prevent progression to infarction. The challenges with potential ischaemia markers are specificity and the diagnostic reference standard for assessment. To date, only one, ischaemia modified albumin, has reached the point where clinical studies can be performed. The measurement of the cardiac troponins, cardiac troponin T and cardiac troponin I, has become the diagnostic standard as the biomarker of myocardial necrosis. The sensitive nature of troponin measurement has also revealed that myocardial necrosis is also found in a range of other clinical situations. This illustrates the need to use all clinical information for diagnosis of acute myocardial infarction. The measurement of B type natriuretic peptides can be shown to be diagnostic and prognostic for both acute ACS and detecting the sequelae of post infarction myocardial insufficiency. The role of the B type natriuretic peptides in detection of cardiac failure, acute and chronic, is well defined. Their role in ACS remains the subject of further studies.

Size and transmural extent of first-time reperfused myocardial infarction assessed by cardiac magnetic resonance can be estimated by 12-lead electrocardiogram

BACKGROUND

The ability of the 12-lead electrocardiogram (ECG) to quantify size and transmural extent of myocardial infarction (MI) is not fully explored. Q waves are still thought of as indicative of transmural MI despite that several studies have rejected this association. We hypothesized that size and transmural extent of acute MI indeed can be estimated by QRS scoring on the 12-lead ECG using delayed, contrast-enhanced magnetic resonance imaging (DE-MRI) as gold standard and that Q waves are not predictive of transmural MI.

METHODS

Twenty-nine patients with first-time reperfused MI were studied. Delayed, contrast-enhanced magnetic resonance imaging was performed and 12-lead ECG was recorded 8 +/- 1 days after the acute event. Myocardial infarction size and transmurality were determined by DE-MRI and compared with Selvester QRS score from the ECG recorded on the same day.

RESULTS

There was a good correlation (r = 0.79, P < .001) between MI size by QRS scoring and DE-MRI. As local MI transmurality increased as assessed by DE-MRI, the local QRS score increased progressively (P < .001). There was no significant difference in the number of Q-wave-related QRS points between nontransmural and transmural MI (1.8 +/- 0.6 vs 2.9 +/- 0.4, P = .14). The global QRS score, however, differed significantly (3.1 +/- 0.8 vs 5.1 +/- 0.6, P < .05).

CONCLUSION

QRS score is significantly related to both MI size and transmurality by DE-MRI in patients with first-time reperfused MI. Presence of Q waves, however, is not indicative of transmural MI in these patients. Thus, QRS scoring could potentially be used for diagnosing and characterizing MI in patients with suspected recent MI.

The Pathologic Basis of Q-Wave and Non-Q-Wave Myocardial Infarction

OBJECTIVES

The purpose of this study was to determine the pathologic basis of Q-wave (QW) and non-Q-wave (NQW) myocardial infarction (MI).

BACKGROUND

The QW/NQW distinction remains in wide clinical use but the meaning of the difference remains controversial. We hypothesized that measurement of total MI size and transmural extent by late gadolinium enhancement cardiovascular magnetic resonance (CMR) would identify the pathologic basis of QWs.

METHODS

A total of 100 consecutive patients with documented previous MI had electrocardiogram and CMR on the same day. Patients with acute MI within seven days were excluded. Left ventricular function and the size and transmural extent of MI were quantified in the three major arterial territories and correlated with the presence of QW.

RESULTS

Subendocardial MI showed QW in 28%. Transmural MI showed NQW in 29%. Of all MIs, 48% were at some point transmural, and 99% of these were at some point non-transmural. As MI size and number of transmural segments increased, the probability of QW increased (anterior: total size chi-square = 53, p < 0.0001, transmural extent chi-square = 36, p < 0.0001; inferior: total size chi-square = 16, p = 0.001, transmural extent chi-square = 10, p = 0.001). These findings did not hold for lateral MI. In a multivariate model, the transmural extent of MI was not an independent predictor of QW when total size of MI was removed. The QW/NQW classification was a good test for size of MI (area under receiver operating characteristic curve: anterior 0.90, inferior 0.77).

CONCLUSIONS

The QW/NQW distinction is useful, but it is determined by the total size rather than transmural extent of underlying MI.

MR imaging in ischemic heart disease

This article reviews the current MR imaging literature with respect to ischemic heart disease and focuses on the clinical practicalities of cardiac MR imaging today.

Does 24-hour ST-segment resolution postfibrinolysis add prognostic value to a Q wave? An ASSENT 2 electrocardiographic substudy

BACKGROUND

Both ST resolution and Q-wave development postfibrinolysis provide important prognostic insights in patients with acute myocardial infarction (MI). However, the relative contributions of these 2 factors to risk assessment have not been examined prospectively.

METHODS AND RESULTS

ST resolution and Q development were evaluated 24 to 36 hours (24-36 h) postfibrinolysis in ASSENT-2: 13,100 out of 16,949 patients who had both baseline and 24-36 h electrocardiograms free of confounders (left bundle branch block, ventricular rhythm, reinfarction before 24-36 h electrocardiograms) were included in this analysis. Q-wave MI evolved in 10,466 patients (79.9%) and 2634 patients (20.1%) had non-Q-wave MI at 24-36 h postfibrinolysis. Mortality rates at 1-year were 7.0% for patients with Q-wave MI and 5.8% for non-Q-wave MI patients, respectively (P =.046). Patients with Q-wave MI versus those without were less likely to have complete ST-segment resolution (49.1% vs 59.1%) and more likely to have partial (37.1% vs 27.8%) or no resolution (13.8% vs 13.1%) at 24 to 36 hours postfibrinolysis (P <.001). Mortality rates at 1 year for Q-wave MI with complete, partial, and no resolution were 5.2%, 8.1%, and 10.1%, respectively (P <.001), and for non-Q-wave MI with complete, partial, and no resolution were 4.5%, 7.6%, and 8.0% (P =.003).

CONCLUSION

These results demonstrate the additional prognostic significance of ST-segment resolution to Q-wave development at 24 to 36 hours after fibrinolysis.

Angiographic and clinical characteristics associated with the development of Q-wave and non-Q-wave myocardial infarction in the thrombolysis in myocardial infarction (TIMI) 14 trial

BACKGROUND

In the absence of thrombolytic therapy, patients with non-Q-wave myocardial infarction (MI) have previously been shown to have lower long-term mortality rates than patients with Q-wave MI. The goal of our study was to examine the angiographic and clinical differences between non-Q-wave MI and Q-wave MI in patients with ST elevation MI (STEMI) in the era of thrombolytic and combination therapy of thrombolytics plus glycoprotein IIb/IIIa inhibitors.

METHODS

Angiography was performed 90 minutes after thrombolytic administration in the Thrombolysis in Myocardial Infarction (TIMI) 14 trial. The development of a non-Q-wave MI was assessed on electrocardiogram performed at the time of hospital discharge. Angiographic findings were assessed at an angiographic core laboratory by blinded investigators.

RESULTS

The qualifying episode of ST elevation developed into a non-Q-wave MI in 36% of patients (315/878) and into a Q-wave MI in 64% of patients (563/878). In patients in whom non-Q-wave MI developed, the rate of TIMI grade 3 flow was higher, peak creatine kinase level was lower, mean left ventricular ejection fraction was greater, corrected TIMI frame counts (CTFCs) were lower (ie, faster blood flow), and chest pain duration after thrombolytic administration was shorter. Patients in whom non-Q-wave MI developed less frequently underwent a percutaneous coronary intervention (PCI), and when they did, they had faster post-PCI CTFCs and higher rates of post-PCI TIMI grade 3 flow. Patients in whom a non-Q-wave MI developed had lower rates of severe recurrent ischemia. There were no differences in 30-day or in-hospital mortality rates or recurrent MI between patients with Q-wave MI and patients with non-Q-wave MI.

CONCLUSION

After thrombolytic therapy in STEMI with or without abciximab, ejection fractions were higher, the duration of ischemia was shorter, and coronary blood flow at both 90 minutes and after PCI was faster in patients who sustained non-Q-wave MI than in patients who sustained Q-wave MI. No differences in mortality or recurrent MI rates were detected in patients who sustained a Q-wave MI and patients in whom a Q-wave MI did not evolve in the modern thrombolytic era.

Development and prognosis of non-Q-wave myocardial infarction in the thrombolytic era

BACKGROUND

Data on non-Q myocardial infarctions (MI) are derived primarily from prethrombolytic era studies. Previous trials demonstrated different development rates and none reported on clinical outcomes.

METHODS

Our goal was to determine the incidence and prognosis of non-Q-wave MI among patients with ST-segment elevation receiving thrombolysis. A retrospective analysis of 5 randomized controlled trials was made. The main outcome measures included rates of (1) transformation of ST-segment elevation to Q- and non-Q-wave MI and (2) inhospital and 1-year mortality and reinfarction among patients who subsequently develop a Q or non-Q MI postthrombolysis as compared to controls.

RESULTS

Non-Q wave development was greater among patients receiving thrombolysis versus placebo/control (3.1% absolute difference, 95% CI 1.2%-5.0%). Among patients receiving thrombolysis, those who developed a non-Q MI experienced significantly lower inhospital and 1-year mortality (absolute differences -3.8% [95% CI -5.2% to -2.4%] and -6.4% [95% CI -9.9% to -3.0%], respectively) and reinfarction (absolute differences -2.9% [95% CI -4.3% to -1.6%] and -3.5% [95% CI -6.1% to -0.9%], respectively) rates, compared with those who evolved a Q MI. Inhospital and 1-year mortality was also significantly lower when compared to placebo/control patients who developed a non-Q MI (absolute differences 4.6% [95% CI -8.2% to -1.1%] and -7.5% [95% CI -12.5% to -2.5%], respectively).

CONCLUSIONS

Patients receiving thrombolysis more often develop a non-Q-wave MI and have a better prognosis than either those who develop a Q MI postthrombolysis or a non-Q MI after standard medical therapy.

Ten year mortality in subsets of patients with an acute coronary syndrome

OBJECTIVE

To describe the mortality during the subsequent 10 years for subsets of patients hospitalised for suspected acute coronary syndrome.

PATIENTS AND METHODS

All patients who were admitted to the emergency department in one hospital during 21 months for chest pain or other symptoms raising suspicion of an acute coronary syndrome were registered. From this baseline population three subgroups were defined among those being hospitalised: patients who developed a Q wave acute myocardial infarction (AMI) (n = 306); patients who developed a non-Q wave AMI (n = 527); and patients who developed confirmed or possible myocardial ischaemia (unstable angina pectoris) (n = 1274). These three groups were compared in terms of 10 year mortality.

RESULTS

Patients who developed a non-Q wave AMI had the highest 10 year mortality (70.3%), significantly higher than those who developed a Q wave AMI (60.1%; p = 0.004) and those who had confirmed or possible myocardial ischaemia (50.1%; p < 0.0001). There was no difference between patients with confirmed and those with possible myocardial ischaemia (50.0% and 50.1%, respectively). After correction for dissimilarities in age, sex, and history the adjusted risk ratio for death in patients with a non-Q wave AMI compared with Q wave AMI was 1.01 (95% confidence interval (CI) 0.82 to 1.25). The corresponding risk ratio for death in patients with a non-Q wave AMI compared with confirmed or possible myocardial ischaemia was 1.91 (95% CI 1.64 to 2.23). There was also an imbalance in drug regimens among groups.

CONCLUSION

This study shows that in a non-selected population of patients hospitalised with a suspected acute coronary syndrome, the highest risk of death is found in those with a non-Q wave AMI and the lowest in those with confirmed or possible myocardial ischaemia. Thus, patients with a Q wave AMI have a long term mortality risk intermediate between the two fractions defined as having unstable coronary artery disease. However, adjusting these results for age and history of cardiovascular disease eliminated the observed difference in mortality between non-Q wave and Q wave AMI. Furthermore, an imbalance in drug regimens might have affected the outcome.

Pathophysiology of early coronary angioplasty with stenting on non-Q-wave vs Q-wave myocardial infarction

This study was undertaken to evaluate the pathophysiologic and clinical effects of the early application of percutaneous transluminal coronary angioplasty (PTCA) supported by stenting on non-Q-wave myocardial infarction (MI). Ninety-four patients with non-Q-wave MI and 316 patients with Q-wave MI were studied. Early PTCA with provisional stenting (40%) was performed in all of them. A history of MI (22% vs 12%, p=0.018), preinfarction angina < or = 24 hours before the onset of MI (60% vs 33%, p<0.001), and patent infarct-related vessels (83% vs 21%, p<0.001) were significantly more common in non-Q-wave MI than in Q-wave MI. As predictors of the occurrence of non-Q-wave MI, preinfarction angina (p=0.001) and previous MI (p=0.021) were significant variables. Clinical outcomes showed more improvement in in-hospital death (0.0% vs 5.0%, p=0.036) and long-term event-free curves for death and/or MI (p=0.035) in non-Q-wave MI than Q-wave MI when patients with previous MI were excluded. There was no significant difference in clinical outcome between the two groups when patients with previous MI were included. The high incidence of patent infarct-related vessels and preinfarction angina as well as the improved outcome obtained by early PTCA/stenting suggest instability of coronary occlusion and culprit coronary lesions in non-Q-wave MI. In conclusion, non-Q-wave MI constitutes a characteristic feature of MI induced by unstable coronary lesions, and early interventional therapies are presumed to result in improved outcomes by stabilizing the unstable culprit lesions.

Twenty-two year (1975 to 1997) trends in the incidence, in-hospital and long-term case fatality rates from initial Q-wave and non-Q-wave myocardial infarction: a multi-hospital, community-wide perspective

OBJECTIVES

The goal of this study was to examine long-term trends in the incidence, in-hospital and long-term mortality patterns in patients with an initial non-Q-wave myocardial infarction (NQWMI) as compared with those with an initial Q-wave myocardial infarction (QWMI).

BACKGROUND

Limited data are available describing trends in the incidence and mortality from an initial QWMI and NQWMI from a multi-hospital community-wide perspective.

METHODS

Our study was an observational study of 5,832 metropolitan Worcester, Massachusetts residents (1990 census = 437,000) hospitalized with validated initial acute MI in all greater Worcester hospitals during 11 annual periods between 1975 and 1997.

RESULTS

The incidence of QWMI progressively decreased between 1975/78 (incidence rate = 171/100,000 population) and 1997 (101/100,000 population). In contrast, the incidence of NQWMI progressively increased between 1975/78 (62/100,000 population) and 1997 (131/100,000 population). Hospital death rates were 19.5% for patients with QWMI and 12.5% for those with NQWMI. After controlling for various covariates, patients with QWMI remained at significantly increased risk for hospital mortality (adjusted odds ratio = 1.63; 95% confidence interval: 1.35, 1.97). While the hospital mortality of QWMI has progressively declined over time (1975/78 = 24%; 1997 = 14%), the in-hospital mortality for NQWMI has remained the same (1975/78 = 12%; 1997 = 12%). These trends remained after adjusting for potentially confounding prognostic factors. The multivariable adjusted two-year mortality after hospital discharge declined over time for patients with QWMI and NQWMI.

CONCLUSIONS

Despite impressive declines in the incidence, in-hospital and long-term mortality associated with QWMI, NQWMI is increasing in frequency and has the same in-hospital mortality now as it did 22 years ago.

Q-wave evolution of a first acute myocardial infarction without significant ST segment elevation

BACKGROUND

Some patients with acute myocardial infarction presenting without significant ST segment elevation develop a Q-wave infarction. It is unclear whether these patients can be identified from the admission electrocardiogram (ECG) and whether they differ in their in-hospital prognosis from those who retain a non-Q-wave myocardial infarction.

METHODS

In 432 consecutive patients admitted to our centre with a first acute myocardial infarction without Q waves and with ST segment amplitudes < or =0.1 mV on admission, we assessed the frequency, the electrocardiographic predictors and the short-term implications of a Q-wave evolution.

RESULTS

In 94 patients (22%), a Q-wave myocardial infarction evolved before hospital discharge (14 anterior, 26 inferior, six lateral, and 48 posterior). Minor anterior ST segment elevation was 36% sensitive and 95% specific in predicting anterior Q waves; minor inferior ST segment elevation, 42% and 89%, respectively, for inferior Q waves; and a maximal ST segment depression > or =0.2 mV in leads V2-V3 with upright T waves and without remote ST segment depression, 38% and 97%, respectively, for posterior R waves. Although patients with a Q-wave evolution had a greater creatinkinase MB peak than those retaining a non-Q-wave pattern (191+/-113 vs. 105+/-77 IU/l, respectively, P<0.001), they experienced a benign in-hospital course, with similar risk of severe complications after adjustment for the baseline clinical predictors than non-Q-wave patients.

CONCLUSIONS

About one fifth of patients with a first acute myocardial infarction without a significant ST segment elevation develop a Q-wave infarction and the admission ECG can help identify them. This evolution, however, is not associated with a worse in-hospital outcome.

Non-Q-wave myocardial infarction following thrombolytic therapy: a comparison of outcomes in patients randomized to invasive or conservative post-infarct assessment strategies in the Veterans Affairs non-Q-wave Infarction Strategies In-Hospital (VANQWISH) Trial

OBJECTIVES

We wished to determine the effect of post-infarct management strategy on event rates (death or recurrent nonfatal myocardial infarction [MI]) in patients who evolved non-Q-wave MI (NQMI) following thrombolytic therapy.

BACKGROUND

Patients who evolve NQMI following thrombolytic therapy are often considered to be at high risk and are frequently managed with routine early invasive testing despite a lack of data supporting improved outcome.

METHODS

The Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) study included 115 patients who evolved NQMI following thrombolytic therapy. We compared the event rates in patients randomized to routine early coronary angiography with those in patients randomized to a conservative strategy of noninvasive functional assessment, with angiography reserved for patients with spontaneous or induced ischemia.

RESULTS

During an average follow-up of 23 months, 19 of 58 patients (33%) randomized to the invasive management strategy died or suffered recurrent nonfatal MI, compared with 11 of 57 patients (19%) randomized to the conservative strategy (p = 0.152). Equivalent numbers of patients were subjected to revascularization (percutaneous transluminal coronary angioplasty or coronary artery bypass graft). There were more deaths in the invasive management group than in the conservative management group (11 vs. 2). Excess deaths could not be attributed to periprocedural mortality.

CONCLUSIONS

Overall event rates (death or recurrent nonfatal MI) are comparable with conservative and invasive strategies in patients who evolve NQMI following thrombolytic therapy. Mortality rate in patients managed conservatively is low (3.5%), and routine invasive management may be associated with an increased risk of death.

Electrocardiographic presentation of blacks with first myocardial infarction does not explain race differences in thrombolysis administration

BACKGROUND

Previous studies have suggested that thrombolysis is used less often in blacks than in whites. However, whether the greater prevalence of contraindications or less specific electrocardiographic manifestations of myocardial infarction (MI) account for this difference is unclear.

METHODS AND RESULTS

We studied 498 consecutive patients (32% blacks) with first MI. Initial electrocardiograms were analyzed, blinded to race and outcome, for ST-segment deviation and bundle branch block to determine eligibility for thrombolysis. The relation of electrocardiographic eligibility for thrombolysis and actual use of thrombolysis in both races was explored. Among blacks, 45% received thrombolysis compared with 66% of whites (P <.001). A similar proportion of blacks and whites were eligible for thrombolysis (59% and 66% respectively, P =. 116), but 62% of electrocardiography-eligible blacks were treated with thrombolysis compared with 75% of whites (P =.016). After accounting for eligibility for electrocardiography and other clinical variables likely to affect the decision to administer thrombolysis by means of conditional logistic regression, blacks were still less likely to receive thrombolysis (relative risk 0.73; 95% confidence interval 0.55 to 0.97).

CONCLUSIONS

We conclude that the differences in thrombolysis administration to blacks and whites are not accounted for by differences in electrocardiographic presentation or other measured variables. Unmeasured differences in clinical presentation of MI may explain racial differences in thrombolysis and merits further study.

Use of resources, quality of life, and clinical outcomes in patients with and without new Q waves after thrombolytic therapy for acute myocardial infarction (from the GUSTO-I trial)

Previous reports indicate that patients who do not develop Q waves after thrombolytic therapy are a different population with a better long-term survival than those who do develop Q waves. However, the use of resources, quality of life, and health status of this population have not been fully evaluated. Using data from the Economics and Quality of Life subset of the Global Utilization of Streptokinase and tPA for Occluded Arteries study, we examined 30-day and 1-year mortality, use of resources, and quality-of-life measures among 1,830 of 3,000 patients with acute myocardial infarction and ST-segment elevation treated with thrombolytic therapy. At hospital discharge, 555 patients (30.2%) had not developed Q waves. These patients had lower mortality than patients with Q waves at 30 days (1.6% vs 4.5%, p <0.01) and at 1 year (4.7% vs 6.8%, p <0.04). Recurrent chest pain and dyspnea were similar at 30 days and 1 year. Patients without Q waves had significantly more angiography and trends toward higher readmission, revascularization, and use of calcium antagonists at 30 days. Angiography, revascularization, readmission, and quality of life were equivalent from 30 days to 1 year, with no sign of late instability. Logistic regression analysis showed an association between in-hospital revascularization and better survival and quality of life at 1 year. Conversely, there was no association between in-hospital use of calcium antagonists and outcome to explain the lower mortality in non-Q-wave patients. The absence of Q waves after thrombolytic therapy is a marker of success, implying better prognosis and equivalent quality of life, use of resources, and health status than for patients with Q-wave acute myocardial infarction and no sign of long-term unstable clinical course.

The prognosis of a first Q-wave versus non-Q-wave myocardial infarction in the reperfusion era

PURPOSE

To compare the prognosis of patients with a first Q-wave versus non-Q-wave myocardial infarction (MI) in the reperfusion era.

METHODS

Patients with a first MI were compared according to type of infarct-Q-wave (n = 1,786) versus non-Q-wave (n = 722)-and by treatment with thrombolysis.

RESULTS

Patients with non-Q-wave MI were more likely to be female and to have undergone previous coronary revascularization. Their 30-day mortality rate was 7%, as compared with a rate of 9% among patients with Q-wave infarction (adjusted odds ratio [OR] = 0.6, 95% confidence interval [CI]: 0.4 to 0.9). However, the subsequent 30-day to 1-year mortality rates were similar in patients with Q-wave or non-Q-wave MI. Patients who were not treated with thrombolysis and who had a non-Q-wave MI had a lower 30-day mortality rate (OR = 0.6, 95% CI: 0.3 to 0.9) but a similar 30-day to 1-year mortality rate (hazard ratio [HR] = 1.5, 95% CI: 0.9 to 2.5) as compared with their counterparts who developed Q-wave infarction. Among thrombolysis-treated patients, 30-day (OR = 0.8, 95% CI: 0.4 to 1.5) as well as 30-day to 1-year (HR = 1.2, 95% CI: 0.5 to 3.0) mortality rates were similar between patients who developed either Q-wave or non-Q-wave MI.

CONCLUSIONS

Patients who received thrombolysis had similar early and late mortality rates after the index infarction regardless of whether they had a Q-wave or non-Q-wave MI. Conversely, among patients who were not treated with thrombolysis, patients with a non-Q-wave MI had lower early mortality rates but similar long-term mortality rates as those with Q-wave MI.

Non-Q wave myocardial infarction. Assessment and management of a unique and diverse subset

Acute cardiac events involving coronary symptoms, elevated enzyme levels, and electrocardiographic changes without the development of Q waves often result in higher rates of reinfarction and unstable angina than do more severe myocardial infarctions. The incidence of these non-Q wave events is on the rise, possibly because of earlier detection and treatment of heart disease. Familiarity with the characteristics and management of the condition, therefore, is more important than ever.

Unstable Angina

The recent availability of novel antiplatelet and antithrombin agents has revolutionized the therapeutic options for intermediate- and high-risk unstable angina (UA). Current guidelines recommend aspirin, unfractionated heparin (UFH), and antianginal therapy. Low-molecular-weight heparin (LMWH) and direct thrombin inhibitors have significant theoretical advantages and apparent clinical benefits compared with UFH and are good alternatives in selected patients. Glycoprotein (GP) IIb/IIIa receptor inhibition reduces the future risk of myocardial infarction (MI) and may reduce the incidence of death in patients with unstable angina. In particular, these drugs should be considered for use in combination with aspirin and UFH in patients undergoing an "early invasive" approach. Coronary revascularization plays an important role in high-risk patients and in those with refractory angina, but its routine application continues to be controversial. Issues regarding the use of LMWH in combination with GP IIb/IIIa inhibitors and during percutaneous transluminal coronary angioplasty (PTCA) are being addressed in clinical trials. Ideally, the incidence of serious cardiac events in patients with UA will continue to decrease with the ongoing search for potent drug combinations that achieve early control of intracoronary thrombosis.

Angiographic characteristics of infarct-related and non-infarct-related stenoses in patients in whom stable angina progressed to acute myocardial infarction

BACKGROUND

In patients with coronary artery disease, angiographic and postmortem studies have shown that coronary stenoses in infarct-related arteries often have complex morphology. It is not known whether in patients with multivessel disease stenosis morphology in non-infarct-related arteries is different from those of the infarct-related arteries.

METHODS AND RESULTS

In 24 consecutive patients we examined the angiographic characteristics of both the infarct-related stenoses and non-infarct-related stenoses before and after spontaneous acute myocardial infarction, by visual inspection and computerized edge detection of coronary angiograms. Before myocardial infarction, the severity of the infarct-related stenoses was <50% in 14 patients and > or =50% in 10 patients (p=not significant) and of non-infarct-related stenoses was <50% in 16 and > or=50% in 13. A significantly greater proportion of infarct-related stenoses with severity > or =50% progressed to non-Q-wave than to Q-wave myocardial infarction (71% vs 50%, p < 0.05). Before myocardial infarction, the percentage of concentric, eccentric, and irregular infarct-related stenoses was 8%, 13%, and 50%, respectively, whereas in the non-infarct-related stenoses it was 62%, 17%, and 21%, respectively (p < 0.01). A similar proportion of irregular morphology progressed to Q-wave or non-Q-wave myocardial infarction.

CONCLUSIONS

In patients with stable angina who had acute myocardial infarction develop, the infarct-related and non-infarct-related stenoses on average are similar in severity but different in morphology. Nonsevere stenoses more frequently progress to Q-wave than to non-Q-wave myocardial infarction.

Relation of von Willebrand factor to occurrence of Q waves and thrombolytic treatment in acute myocardial infarction

We measured the changes of plasma von Willebrand factor antigen and fibrinogen levels in patients with acute myocardial infarction treated with recombinant tissue plasminogen activator and patients not given fibrinolytic drugs. The von Willebrand factor levels are greater in patients with Q-wave than in patients with non-Q-wave myocardial infarction and are independent of thrombolytic treatment. Fibrinogen levels are depressed by thrombolytic treatment but are unrelated to the presence or absence of Q waves.

[Clinical prediction of the early prognosis in acute myocardial infarct]

Several clinical factors can influence the pathophysiology, clinical course and prognosis of acute myocardial by different means. Some of them may be easily detected through the history, physical examination or ECG in an early phase. The knowledge of these factors may help the therapeutic decision making of patients with myocardial infarction. The influence for the main clinical factors (age, sex, risk factors, cardiologic antecedents and evolutive findings) on the short-term prognosis of acute myocardial infarction is reviewed. An analysis of the likely mechanisms of the influence of these factors on infarct prognosis is also performed.

The electrocardiogram predicts one-year outcome of patients with unstable angina and non-Q wave myocardial infarction: results of the TIMI III Registry ECG Ancillary Study. Thrombolysis in Myocardial Ischemia

OBJECTIVES

We sought to determine the prognostic value of the admission electrocardiogram (ECG) in patients with unstable angina and non-Q wave myocardial infarction (MI).

BACKGROUND

Although the ECG is the most widely used test for evaluating patients with unstable angina and non-Q wave MI, little prospective information is available on its value in predicting outcome in the current era of aggressive medical and interventional therapy.

METHODS

ECGs with the qualifying episode of pain were analyzed in patients enrolled in the Thrombolysis in Myocardial Ischemia (TIMI) III Registry, a prospective study of patients admitted to the hospital with unstable angina or non-Q wave MI.

RESULTS

New ST segment deviation > or = 1 mm was present in 14.3% of 1,416 enrolled patients, isolated T wave inversion in 21.9% and left bundle branch block (LBBB) in 9.0%. By 1-year follow-up, death or MI occurred in 11% of patients with > or = 1 mm ST segment deviation compared with 6.8% of patients with new, isolated T wave inversion and 8.2% of those with no ECG changes (p < 0.001 when comparing ST with no ST segment deviation). Two other high risk groups were identified: those with only 0.5-mm ST segment deviation and those with LBBB, whose rates of death or MI by 1 year were 16.3% and 22.9%, respectively. On multivariate analysis, ST segment deviation of either > or = 1 mm or > or = 0.5 mm remained independent predictors of death or MI by 1 year.

CONCLUSIONS

The admission ECG is very useful in risk stratifying patients with non-Q wave MI. The new criteria of not only > or = 1-mm ST segment deviation but also > or = 0.5-mm ST segment deviation or LBBB identify high risk patients, whereas T wave inversion does not add to the clinical history in predicting outcome.

Acute myocardial infarction: clinical characteristics, management and outcome in a metropolitan Veterans Affairs Medical Center teaching hospital

OBJECTIVES

The influence of race and age on thrombolytic therapy, invasive cardiac procedures and outcomes was assessed in a Veterans Affairs teaching hospital. The influence of Q wave evolution on the use of invasive cardiac procedures and outcome was also assessed.

BACKGROUND

It is not well known how early revascularization procedures for acute myocardial infarction are delivered or influence survival in a Veterans Affairs patient population.

METHODS

From October 1993 to October 1995, all patients with myocardial infarction were identified by elevated creatine kinase, MB fraction (CK-MB) and one of the following: chest pain or shortness of breath during the preceding 24 h or electrocardiographic (ECG) abnormalities.

RESULTS

Racial groups were similar in terms of age, time to ECG, peak CK and length of hospital stay. Mortality increased with age (odds ratio [OR] 1.93, 95% confidence interval [CI] 1.33 to 2.81). A trend toward increased mortality occurred for race other than Caucasian. Patients meeting ECG criteria were given thrombolytic agents in 49% of cases, but age, comorbidity count and Hispanic race decreased the probability of thrombolytic use. Cardiac catheterization was performed more often after thrombolytic agents (OR 1.85, 95% CI 0.97 to 3.54), but less often in African-Americans (OR 0.59, 95% CI 0.35 to 1.02), older patients (OR 0.39, 95% CI 0.24 to 0.64) or patients with heart failure (OR 0.30, 95% CI 0.17 to 0.52). Patients evolving non-Q wave infarctions were older and had increased comorbidity counts and trends toward increased mortality. Angioplasty was chosen less for patients > or = 65 years old (p = 0.02); angioplasty and coronary artery bypass graft surgery were performed less in patients > or = 70 years old (p = 0.02). Patients treated invasively had lower mortality rates than those treated medically (p < 0.02).

CONCLUSIONS

The use of thrombolytic agents and invasive treatment plans declined with age, and mortality increased with age. Trends toward increased mortality occurred with non-Q wave infarctions and race other than Caucasian.

Thrombolysis and Q wave versus non-Q wave first acute myocardial infarction: a GUSTO-I substudy. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Arteries Investigators

OBJECTIVES

We assessed the outcomes of patients with a first myocardial infarction with ST segment elevation, with and without the development of abnormal Q waves after thrombolysis.

BACKGROUND

Prethrombolytic era studies report conflicting short-versus long-term mortality in the overall non-Q wave population, probably related to its heterogeneity.

METHODS

Patients with no electrocardiographic (ECG) confounding factors or evidence of previous infarction were included. Q wave infarction was defined as a Q wave duration > or = 30 ms in lead aVF; R wave > or = 40 ms in lead V1; any Q wave or R wave < or = 10 ms and < or = 0.1 mV in lead V2; or Q wave > or = 40 ms in at least two of the following leads: I, aVL, V4, V5 or V6. In-hospital clinical events and mortality at 30 days and 1 year were assessed.

RESULTS

No Q waves developed in 4,601 (21.3%) of the 21,570 patients. This group comprised more women and had a lower Killip class, lower weight and less anterior baseline ST elevation. The non-Q wave group had less in-hospital cardiogenic shock (2.1% vs. 3.3%, p < 0.0001), less heart failure (8.5% vs. 13.9%, p < 0.0001) and a trend toward less stroke (0.7% vs. 1.0%, p = 0.07) but an increased use of angioplasty (28% vs. 24%, p = 0.0001). The unadjusted mortality rate in the non-Q wave group was lower at 30 days (0.9% vs. 1.8%, p = 0.0001) and 1 year (2.7% vs. 4.2%, p = 0.0001), as was the adjusted 30-day mortality rate (4.8% vs. 5.3%, p < 0.0001).

CONCLUSIONS

Patients with no ECG confounding factors or evidence of previous infarction who do not develop Q waves after thrombolysis have a better 30-day and 1-year prognosis than patients with a Q wave infarction.

Von Willebrand factor in patients evolving Q-wave versus non-Q-wave acute myocardial infarction

We assessed the changes in plasma von Willebrand factor level concentration in 10 patients with Q-myocardial infarction and in six patients with non-Q-myocardial infarction who did not receive thrombolytic treatment. Concentrations of von Willebrand factor antigen were measured by an enzyme-linked immunoassay method in plasma samples obtained twice daily for 4 consecutive days. In patients with Q-wave myocardial infarction, a significant rise in von Willebrand factor antigen levels (P < 0.05) occurred after admission and persisted for 3 days. No significant changes were found in plasma concentration of fibrinogen. In conclusion, von Willebrand factor antigen levels were greater in patients with Q-wave compared to patients with non-Q-wave myocardial infarction.

"Inadvertent" thrombolytic administration in patients without myocardial infarction: clinical features and outcome

STUDY OBJECTIVES

Increasing pressure to deliver thrombolytic agents quickly to patients with suspected myocardial infarction (MI), along with expanded indications, may contribute to inappropriate administration of these agents, with potentially catastrophic results. We sought to identify the extent to which MI is ruled out in patients given thrombolytic therapy for acute MI and to characterize the clinical course and outcome in such patents.

METHODS

We studied 609 consecutive patients admitted to the CCU of an urban teaching hospital who were treated with thrombolytic agents for suspected acute MI between January 1986 and December 1993. In 35 (5.7%), MI was ruled out on the basis of persistently normal serum creatine kinase-MB isoenzyme levels. Hospital course and alternative diagnoses were established by means of chart review and database inquiry.

RESULTS

Patients in whom MI was ruled out were similar to those with MI with regard to baseline demographic and clinical features. Presenting ECGs in patients without MI were less likely to show Q waves (43 versus 64%, P < .02) but more likely to show left ventricular hypertrophy (26 versus 7%, P = .001) and nonspecific ST-segment and T-wave changes (54 versus 32%, P < .01) compared the ECGs of MI patients. Transient ST-segment elevation was detected in 51%. Hospital complications of patients without MI were similar to those of MI patients. No patient in whom MI was ruled out sustained a major hemorrhage. Final diagnoses of patients without MI included unstable angina (n = 20, 57%) undefined chest pain (n = 8, 17%) pericarditis (n = 3), pancreatitis (n = 2), esophagitis (n = 1), and aortic dissection (n = 1). Two patients died, one of aortic dissection and another of pericarditis.

CONCLUSION

In a consecutive series of CCU patients in whom MI was ruled after thrombolysis, we found no demographic or presenting clinical features to distinguish them from patients in whom MI was diagnosed. Transient ST-segment elevation potentially justifying thrombolytic therapy was present in more than half of the patients in whom MI was ruled out but may have represented transient coronary occlusion, coronary spasm, or other manifestations of unstable angina. In this study, patients in whom MI was ruled out had a high incidence of coronary disease and risk of in-hospital complications similar to that of patients with acute MI. Our findings support the rationale and safety of policies to rapidly and aggressively administer thrombolytic agents in the emergency department.