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

The Significance of Equipment Availability and Anesthesia Educational Conferences to Decision-Making for EKG Lead V5 Abnormalities

Introduction To predict postoperative myocardial infarction rates in patients who undergo noncardiac surgery, the Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management recommends assessment of brain natriuretic peptide (BNP) in certain patients. Serial troponins are measured if the BNP level is elevated. In certain cases, Revised Cardiac Risk Index (RCRI) alone does not perform well, for example, during vascular surgery. Cardiac events occur in 20% of all vascular surgery patients. The odds ratio for such events is 9.2 if ST segments were depressed by 1 mm intraoperatively (relative to the PR interval) within the first 48 hours postoperatively. Increasing the number of cables and pads from three to five for electrocardiogram (EKG) increases the sensitivity from around 30% to over 80% for ischemic events relative to a formal EKG stress test, and then the monitor continuously displays not only lead II but also lead V5. Methods Our hypothesis was that raising awareness about diagnostic and therapeutic options to reduce the risk of postoperative myocardial infarction would increase the use of five pads. We conducted open-ended surveys at six hospitals to assess the reasons for choosing three pads. In our university hospital practice, we measured a cross-sectional incidence of using three pads before and, once again, a month after an intervention during a single morning. Several resident conferences encouraged the use of five pads. Education included weekly lectures and informal discussions with other staff during surgery, demonstrating that using five pads allows interrogation of an entire 12-lead EKG. In comparison, three pads only allow viewing three leads. Results At baseline, only three pads were available in 96% of our 23 operating rooms. Five cables were available in eight of those surgeries, but two were taped off to the side. Surveys unveiled scarcity of equipment and, more importantly, disempowerment (i.e., knowing how to diagnose or when to treat ischemia). After several conferences, the prevalence of equipment availability of only three pads fell to 47%. Conclusions Education enumerated details of recognizing ischemic configurations of ST depression. Next, education revealed methods to interrupt the progression of ischemia to infarction such as elevated blood pressure and hematocrit, reducing heart rate, and calling a cardiology consultant if the anesthesiologist wishes to draw serial troponins. Barriers to implementing an enhanced recovery after surgery (ERAS) pathway began with a need for more access to manage stress tests or optimize blood pressure medications after a preoperative anesthesia evaluation. The intraoperative barrier was knowing what to do if ST depression occurs. Therefore, we began raising awareness by encouraging the addition of an element of a future ERAS pathway, adding a cost of only $1 to monitor lead V5. Future ERAS pathways can include preoperative stress tests and consults, as found in published guidelines.

Angiographic Complete versus Clinical Selective Incomplete Percutaneous Revascularization in Heart Failure Patients with Multivessel Coronary Disease

Background

Patients with multivessel disease (MVD) often pursue complete revascularization (CR) during percutaneous coronary intervention (PCI) to improve prognosis. However, angiographic CR is not always feasible and is associated with some procedure-related complications in heart failure (HF) patients with MVD. Clinical selective incomplete revascularization (IR) may be reasonable for these high-risk patients, but its role in long-term outcomes remains uncertain.

Methods

Six hundred patients with HF and MVD submitted to PCI were enrolled. Major adverse cardiac events (MACEs) were defined as a composite of recurrent myocardial infarction, any revascularization, and all-cause mortality at 5 years.

Results

During a mean follow-up period of 3.7 ± 1.9 years, there was no significant difference in 5-year MACEs between selective IR and successful angiographic CR in HF patients with MVD. However, patients who failed CR had a significantly greater incidence of 5-year MACEs than those in the other two groups (failed CR: 46.4% vs. selective IR: 27.7% vs. successful CR: 27.8%, p < 0.001).

Conclusions

Long-term outcomes of selective IR were comparable with those of successful angiographic CR in HF patients with MVD. However, patients that failed CR showed 2.53-fold increased risk of MACEs compared to patients undergoing either selective IR or successful angiographic CR. A more comprehensive planning strategy should be devised before PCI in HF patients with MVD.

Correlation of Reciprocal Changes and QRS Amplitude in ECG to Left Ventricular Dysfunction, Wall Motion Score and Clinical Outcome in First Time ST Elevation Myocardial Infarction

INTRODUCTION

Electrocardiogram (ECG) is the simplest tool for diagnosing ST Elevation Myocardial Infarction (STEMI). We can use a12 lead ECG for prognostication purposes also.

AIM

The aim of the study was to find out the role of ECG as a prognostic marker in terms of clinical outcome and wall motion abnormality.

MATERIALS AND METHODS

It was a prospective study done in PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India, from January 2014 to September 2014. Patients aged above 18 years admitted with first episode of ST EMI as per the inclusion and exclusion criteria were recruited for the study. Presence of reciprocal changes and QRS amplitude was measured from ECG. Presence of Left Ventricular Dysfunction (LVD) and wall motion score were calculated from ECG along with clinical outcome during first follow up visit. Statistical analysis was done using SPSS software. Probability was calculated using chi-square test, independent t-test and ANOVA analysis.

RESULTS

A total of 120 patients were recruited for the study of which six were excluded based on the exclusion criteria. Among 114 patients analysed, 55 had reciprocal changes; 38 of them developed LVD which was statistically significant (p=0.002). Of the 78 patients with Anterior Wall Myocardial Infarction (AWMI), 35 had reciprocal changes; 15 (42.9%) of them had NYHA Class 1 symptoms, 14 (40%) had Class II and 4 (11%) had class III symptoms at follow up. The association was statistically significant (p=0.001). Similar statistically significant association was found in patients with Inferior Wall Myocardial Infarction (IWMI) who had reciprocal changes and NYHA symptoms at follow up (p=0.004). The mean wall motion score in patients with AWMI and reciprocal changes was 24.83 ± 4.1; whereas, without reciprocal changes was 23.98 ± 3.6; the association was not statistically significant. The mean QRS amplitude of all patients with LVD was 33.25 ±16.34. The association between QRS amplitude and LVD was not statistically significant. The overall mean wall motion score was 24.86 ± 3.91. The association between QRS amplitude and wall motion score was statistically significant (r value = 0.210). The association between QRS amplitude and wall motion score was statistically significant when we analysed AWMI (r= -0.147, p=0.199) and IWMI (r= -0.359, p=0.031) separately.

CONCLUSION

ECG can be used as a tool for prognostication in acute STEMI. The presence of reciprocal changes in the ECG can signify poorer outcome on follow up. Lower QRS amplitude can be used as a predictor of larger infarct.

Prognostic impact of Q waves on presentation and ST resolution in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention

Q waves can develop early in infarction and indicate infarct progression better than symptom duration. ST resolution (STR) is a predictor of reperfusion success. Our aim was to assess the prognostic impact of Q waves on presentation and STR after primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction. The combined end point was of mortality and adverse cardiovascular events (MACE; death, repeat myocardial infarction, or heart failure). Q waves on presentation (Q wave, n = 332; no Q wave, n = 337) was associated with significantly less mean STR, greater incidence of akinetic, dyskinetic, or aneurysmal regional wall motion, lower left ventricular ejection fraction, and worse in-hospital and 1-year MACEs (1 year 24% vs 8.2%, p <0.001). In addition, Q waves on presentation compared to no Q waves were associated with worse 1-year MACE regardless of infarct presentation in < or =3 hours, infarct location, and adequate STR (> or =70%). Q waves on presentation and inadequate STR (<70%), but not symptom duration, were independent predictors of MACE by multivariable analysis (adjusted hazard ratios of 2.7 and 2.4 for Q waves and STR, respectively). Compared to group A (no Q waves on presentation with STR), patients in group B (no Q waves with inadequate STR), group C (Q waves with STR), and group D (Q waves with inadequate STR) had hazard ratios of 3.0, 3.6, and 7.7, respectively (p <0.05) for the occurrence of MACE. In conclusion, assessment of Q-wave status on presentation and STR immediately after PPCI provides a simple and early clinical predictor of outcomes in ST-elevation myocardial infarction.

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.

Feasibility and applicability of paramedic-based prehospital fibrinolysis in a large North American center

BACKGROUND

Although considered the highest level of evidence and critical-to-test novel therapies, clinical trials are unrepresentative of the "real world" as they lack a true patient denominator, which limits general applicability of results. Accordingly, in conjunction with the Assessment of the Safety and Efficacy of a New Thrombolytic Regimen 3+ trial, we evaluated a comprehensive contemporary cohort of patients with ST segment elevation myocardial infarction (STEMI) to investigate: feasibility, applicability, safety, and efficacy of de novo paramedic-based prehospital fibrinolysis (PHF) program.

METHODS

Prospective observational comparative cohort of all patients with STEMI encountered during the Assessment of the Safety and Efficacy of a New Thrombolytic Regimen 3+ enrollment period. Time-to-treatment, systematic electrocardiographic (ECG) analysis, peak creatine kinase, inhospital clinical events, and mortality were assessed.

RESULTS

During the 22-month study period, 1095 patients with STEMI were admitted to hospital; 46% (119/258) of eligible patients received PHF (< or = 6 hours of symptom onset by ambulance). Paramedics contacted the study physician 3.6 times per week: 33% (119/357) of patients enrolled, and ECG transmission failure is 6%. Time-to-treatment was reduced with PHF versus inhospital (1 hour 43 minutes vs 2 hours 38 minutes; P < .001). Despite higher baseline Thrombolysis in Myocardial Infarction Scores and greater ECG territory at risk (ST), prehospital patients achieved more favorable outcomes: peak creatine kinase (1413 vs 1549 U/L; P = .122), Q wave at discharge (56.3% vs 70.7%; P = .003), and intracranial hemorrhage (0% vs 0.8%; P < 1.0), respectively. Inhospital mortality for PHF versus inhospital patients was 3.4% versus 4.8% (P = .627), with an adjusted odds ratio of 0.60 (confidence interval, 0.19-1.87).

CONCLUSION

Feasibility and applicability of PHF was demonstrated with a substantial reduction in treatment delay and favorable clinical outcomes. Extending the unrealized potential of paramedic-based PHF programs in North America is feasible and desirable.

Transient ischemic attack with infarction: A unique syndrome?

It is debated whether transient symptoms associated with infarction (TSI) are best considered a minor ischemic stroke, a subtype of transient ischemic attack (TIA), or a separate ischemic brain syndrome. We studied clinical and imaging features to establish similarities and differences among ischemic stroke, TIA without infarction, and TSI. Eighty-seven consecutive patients with TIA and 74 patients with ischemic stroke were studied. All underwent diffusion-weighted imaging on admission. Symptom duration and infarct volume were determined in each group. Thirty-six patients (41.3%) with TIA had acute infarct(s). Although TIA-related infarcts were smaller than those associated with ischemic stroke (mean, 0.7 vs 27.3 ml; p < 0.001), there was no lesion size threshold that distinguished ischemic stroke from TSI. In contrast, the symptom duration probability density curve was not broad, but instead peaked early with only a few patients having symptoms for longer than 200 minutes. The probability density function for symptom duration was similar between TIA with or without infarction. The in-hospital recurrent ischemic stroke and TIA rate was 19.4% in patients with TSI and 1.3% in those with ischemic stroke. TIA with infarction appears to have unique features separate from TIA without infarction and ischemic stroke. We propose identifying TSI as a separate clinical syndrome with distinct prognostic features.

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.

Estimation of myocardial cell damage on the basis of mean electrocardiographic voltage and anatomical left ventricular mass

Left ventricular mass (LVM) as assessed by magnetic resonance imaging (MRI, LVM(MRI)) and electrocardiographic (ECG) voltage reflect different pathological features. We hypothesized that ECG voltage is related to the electrical potential of cardiac muscle cells (electrical LVM) and to anatomical LVM as evaluated by MRI, and that the divergence between electrical LVM and anatomical LVM reflects the degree of myocardial damage. Because adipose tissue has high electrical resistance, we previously found a very strong correlation between body-fat-corrected mean ECG voltage (Vfm) and LVM as estimated by echocardiography in patients with essential hypertension. In this study we compared LVM(MRI), Vfm, the ratio of Vfm x 10(2)/LVM(MRI), and the results of 99mTc tetrofosmin scintigraphy in patients with and without myocardial infarction (MI). We studied 33 patients without Ml and 26 patients with Ml. Vfm significantly correlated with LVM(MRI) in patients without MI (r=0.71, p<0.01). The ratio of Vfm x 10(2)/LVM(MRI) apparently reflected the relation between electrical LVM and anatomical LVM. Vfm x 10(2)/LVM(MRI) in patients with MI was smaller than that in patients without MI (0.98+/-0.28 vs. 1.42+/-0.29, p<0.01). Vfm x 10(2)/LVM(MRI) decreased as 99mTc score increased (r=-0.66, p<0.01). Our results indicate that Vfm is a useful index of electrical LVM and that Vfm x 10(2)LVM(MRI) reflects the electrical potential of the viable myocardium in total anatomical LVM.

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.

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.

Influence of previous aspirin treatment and smoking on the electrocardiographic manifestations of injury in acute myocardial infarction

OBJECTIVE

To examine demographic and clinical characteristics of patients with acute myocardial infarction in order to identify factors affecting the electrocardiographic evolution of injury.

METHODS

Prospective cohort study of 1399 consecutive patients with a first myocardial infarction. Baseline clinical data associated with ST elevation and Q wave development were identified and 12 month survival was estimated.

RESULTS

Smoking had complex effects on the evolution of injury, increasing the odds of ST elevation (odds ratio (OR) 1.61; 95% confidence interval (CI) 1.08 to 2.36), but reducing the odds of Q wave development (OR 0.69, 95% CI 0.49 to 0.96). The effects of previous aspirin treatment were more consistent with reductions in the odds of ST elevation (OR 0.57, 95% CI 0.35 to 0.94) and Q wave development (OR 0.53, 95% CI 0.34 to 0. 84). ST elevation and Q wave development were both associated with an adverse prognosis, with estimated 12 month survival rates of 80. 6% (95% CI 78.2% to 83.1%) and 80.0% (95% CI 77.5% to 82.5%), respectively, compared with 86.5% (95% CI 81.2% to 91.9%) and 89.9% (95% CI 86.2% to 93.7%) for patients without these ECG changes.

CONCLUSIONS

The thrombogenicity of the blood may be a major determinant of infarct severity. Smoking increases thrombogenicity and the likelihood of ST elevation, but because coronary occlusion is relatively more thrombotic in smokers, responses to both endogenous and exogenous thrombolysis are better, reducing the risk of Q wave development. Previous aspirin treatment reduces thrombogenicity, protecting against ST elevation and Q wave development.

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.

Can the surface electrocardiogram be used to predict myocardial viability?

OBJECTIVE

To investigate whether QRS morphology on the surface ECG can be used to predict myocardial viability.

DESIGN

ECGs of 58 patients with left ventricular impairment undergoing positron emission tomography (PET) were studied. (13)N-Ammonia (NH(3)) and (18)F-fluorodeoxyglucose (FDG) were the perfusion and the metabolic markers, respectively. The myocardium is scarred when the uptake of both markers is reduced (matched defect). Reduced NH(3) uptake with persistent FDG uptake (mismatched defect) represents hibernating myocardium. First, the relation between pathological Q waves and myocardial scarring was investigated. Second, the significance of QR and QS complexes in predicting hibernating myocardium was determined.

RESULTS

As a marker of matched PET defects, Q waves were specific (79%) but not sensitive (41%), with a 77% positive predictive accuracy and a poor (43%) negative predictive accuracy. The mean size of the matched PET defect associated with Q waves was 20% of the left ventricle. This was not significantly different from the size of the matched PET defects associated with no Q waves (18%). Among the regions associated with Q waves on the ECG, there were 16 regions with QR pattern (group A) and 23 regions with QS pattern (group B). The incidence of mismatched PET defects was 19% of group A and 30% of group B (NS).

CONCLUSIONS

Q waves are specific but not sensitive markers of matched defects representing scarred myocardium. Q waves followed by R waves are not more likely to be associated with hibernating myocardium than QS complexes.

Pathophysiology of acute coronary syndromes leading to acute myocardial infarction

Acute coronary syndromes, including unstable angina, myocardial infarction, and sudden death, account for more than 250,000 deaths annually. They are the manifestation of a progressive atherosclerotic process, which culminates in the rupture of atherosclerotic plaques and the formation of mural thrombi. This article reviews recent and current research, which has shed light on key events and evolutionary processes leading to acute coronary syndromes. The article details the development of vulnerable plaques, factors that promote plaque rupture, and triggering events related to plaque rupture. Also discussed are sequelae of acute coronary syndromes, including Q wave and non-Q wave infarction and left ventricular remodeling.

Non-Q-wave versus Q-wave myocardial infarction after thrombolytic therapy: angiographic and prognostic insights from the global utilization of streptokinase and tissue plasminogen activator for occluded coronary arteries-I angiographic substudy. GUSTO-I Angiographic Investigators

BACKGROUND

Although the stratification of patients with myocardial infarction into ECG subsets based on the presence or absence of new Q waves has important clinical and prognostic utility, systematic evaluation of the impact of thrombolytic therapy on the subsequent development and prognosis of non-Q-wave infarction has been limited to date.

METHODS AND RESULTS

We examined 12-lead ECG, coronary anatomy, left ventricular function, and mortality among 2046 patients with ST-segment elevation infarction from the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries angiographic subset to gain further insight into the pathophysiology and prognosis of Q- versus non-Q-wave infarction in the thrombolytic era. Non-Q-wave infarction developed in 409 patients (20%) after thrombolytic therapy. Compared with Q-wave patients, non-Q-wave patients were more likely to present with lesser ST-segment elevation in a nonanterior location. The infarct-related artery in non-Q-wave patients was more likely to be nonanterior (67% versus 58%, P=.012) and distally located (33% versus 39%, P=.021). Early (90-minute, 77% versus 65%, P=.001) and complete (54% versus 44%, P<.001) infarct-related artery patency was greater among the non-Q-wave group. Non-Q-wave patients had better global (ejection fraction, 66% versus 57%; P<.0001) and regional left ventricular function (10 versus 24 abnormal chords, P=.0001). In-hospital, 30-day, 1-year, and 2-year (6.3% versus 10.1%, P=.02) mortality rates were lower among non-Q-wave patients.

CONCLUSIONS

The excellent prognosis among the subgroup of patients who develop non-Q-wave infarction after thrombolysis is related to early, complete, and sustained infarct-related artery patency with resultant limitation of left ventricular infarction and dysfunction.