Significance of spontaneous normalization of negative T waves in infarct-related leads during healing of anterior wall acute myocardial infarction

Transient deep and giant negative T waves in dogs with myocardial injury

INTRODUCTION

Although transient deep and giant negative T waves (NTWs) may develop during myocardial injury (MI) in humans, no data exist on this repolarization abnormality in canine MI. Therefore, this study aimed to describe the occurrence of transient deep/giant NTWs in dogs with MI.

ANIMALS, MATERIALS AND METHODS

Medical records were retrospectively searched to identify dogs with MI and transient deep/giant NTWs. Signalment, history, and selected diagnostic test results were reviewed. Data analysis was descriptive.

RESULTS

Six cases were diagnosed with MI associated with deep (n = 1) and giant (n = 5) transient NTWs. Myocardial injury was classified as acute in all cases and was due to snake envenomation (n = 3), sepsis (n = 2), and systemic inflammatory response syndrome (n = 1). At the time of deep/giant NTWs identification, all dogs had elevated cardiac troponin I and ≥1 echocardiographic abnormality of the left ventricular structure and/or function. Moreover, all dogs with giant NTWs had prolonged QT intervals. After the MI resolution, T-wave polarity and QT-interval duration became normalized in all dogs. Moreover, left ventricular morphological and functional parameters were completely normalized in four dogs. In contrast, ventricular echogenicity remained heterogeneous in two dogs, despite otherwise normalized ventricular parameters. Five dogs were still alive at the conclusion of the study.

CONCLUSIONS

Transient deep/giant NTWs may develop in dogs with acute MI and T-wave polarity changes seem to occur synchronously with the evolution of myocardial damage. Moreover, transient deep/giant NTWs seem associated with a favorable prognosis in canine MI.

Persistent T-wave inversion predicts myocardial damage after ST-elevation myocardial infarction

BACKGROUND

Persistent T-wave inversion (PTI) after ST-elevation myocardial infarction (STEMI) is associated with worse clinical outcome; however, the underlying mechanism between PTI and poor prognosis is incompletely understood. We sought to investigate the relationship between PTI and myocardial damage assessed by cardiac magnetic resonance (CMR) following STEMI.

METHODS

In this prospective observational study, we included 142 consecutive revascularized STEMI patients. Electrocardiography to determine the presence and amplitude of PTI and pathological Q-waves was conducted 4months after infarction. CMR was performed within 1week after infarction and at 4months follow-up to evaluate infarct characteristics and myocardial function.

RESULTS

Patients with PTI (n=103, 73%) showed a larger acute (21[11-29] vs. 6[1-13]%; p<0.001) and chronic infarct size (IS) (14[8-19] vs. 3[1-8]%; p<0.001) and more frequently microvascular obstruction (59 vs. 33%; p=0.02). The association between PTI and chronic IS remained significant (odds ratio: 9.02, 95%CI 3.49-23.35; p<0.001) after adjustment for pathological Q-wave and other IS estimators (high-sensitivity cardiac troponin T and C-reactive protein, N-terminal pro B-type natriuretic peptide, culprit vessel, pre-interventional TIMI flow). The value of PTI amplitude for the prediction of large chronic IS>11% (AUC: 0.84, 95%CI 0.77-0.90) was significantly higher compared to Q-wave amplitude (AUC: 0.72, 95%CI 0.63-0.80; p=0.009); the combination of PTI with pathological Q-wave (Q-wave/T-wave score) led to a net reclassification improvement of 0.43 (95% CI 0.29-0.57; p<0.001) as compared to PTI alone.

CONCLUSIONS

PTI following STEMI is independently and incrementally associated with more extensive myocardial damage as visualized by CMR. An electrocardiographic score combining PTI with pathological Q-wave allows for a highly accurate IS estimation post-STEMI.

Hyperkalemia masked by pseudo-stemi infarct pattern and cardiac arrest

Background

Hyperkalemia is a common electrolyte abnormality and has well-recognized early electrocardiographic manifestations including PR prolongation and symmetric T wave peaking. With severe increase in serum potassium, dysrhythmias and atrioventricular and bundle branch blocks can be seen on electrocardiogram. Although cardiac arrest is a worrisome consequence of untreated hyperkalemia, rarely does hyperkalemia electrocardiographically manifest as acute ischemia.

Case presentation

We present a case of acute renal failure complicated by malignant hyperkalemia and eventual ventricular fibrillation cardiac arrest. Recognition of this disorder was delayed secondary to an initial ECG pattern suggesting an acute ST segment elevation myocardial infarction (STEMI). Emergent coronary angiography performed showed no evidence of coronary artery disease.

Conclusions

Pseudo-STEMI patterns are rarely seen in association with acute hyperkalemia and are most commonly described with patient without acute cardiac symptomatology. This is the first such case presenting concurrently with cardiac arrest. A brief review of this rare pseudo-infarct pattern is also given.

Negative T wave in ischemic heart disease: a consensus article

BACKGROUND

For many years was considered that negative T wave in ischemic heart disease represents ischemia and for many authors located in subepicardial area.

METHODS

We performed a review based in the literature and in the experience of the authors commenting the real significance of the presence of negative T wave in patients with ischemic heart disease.

RESULTS

The negative T wave may be of primary or secondary type. Negative T wave observed in ischemic heart disease are of primary origin, therefore not a consequence of abnormal repolarization pattern. The negative T wave of ischemic origin presents the following characteristics: (1) are symmetrical and of variable deepness; (2) present mirror patterns; (3) starts in the second part of repolarization; and (4) may be accompanied by positive or negative U wave. The negative T wave of ischemic origin may be seen in the following clinical settings: (1) postmyocardial infarction due to a window effect of necrotic zone and (2) as a consequence of reperfusion in case of aborted MI when the artery has opened spontaneously, or after fibrinolysis, PCI, or coronary spasm.

CONCLUSION

Acute ongoing ischemia do not cause negative T wave. This pattern appears when the ongoing ischemia is vanishing or in the chronic phase. In all these cases the cause of negative T wave is not located in the subepicardial area. Furthermore, positive exercise testing is expressed by ST depression never by isolated negative T wave. There are many circumstances that may present negative T wave outside ischemic heart disease and that have been discussed in this paper.

Prominent T wave in V2 with respect to V6 as a sign of lateral myocardial infarction

BACKGROUND

In the absence of confounding electrocardiographic features, a prominent R wave in leads V1-V2 reflects a lateral myocardial infarction (MI). We hypothesized that repolarization abnormalities in V1-V2 could also reflect a lateral MI.

METHODS

We retrospectively selected a group of 57 patients with a recent or previous first Q-wave MI involving left ventricular (LV) inferior and/or lateral wall at contrast-enhanced cardiac magnetic resonance (CMR). The location and extent of the MI at CMR were compared with electrocardiographic features.

RESULTS

The infarction was located in the inferior wall in 12 patients (21%), in the lateral wall in 8 (14%), and in both walls in 37 patients (65%). Infarct size corresponded to 16.8 (SD 9.0%) of LV myocardium. Infarct extent in the inferior and lateral wall (8.3%, SD 7.2% vs. 8.4%, SD 7.5% of LV myocardium) did not differ significantly. Using multiple linear regression analysis, inferior Q-waves and inferior negative T waves were directly associated with infarct extent in the inferior wall (p = 0.014 and p = 0.010, respectively). A prominent R wave in V1 and a prominent anterior T wave (expressed by the T wave amplitude in V2 minus its amplitude in V6) were directly associated with MI extent in the lateral wall (p = 0.008 and p = 0.018), while inferior negative T waves were negatively associated (p = 0.006).

CONCLUSIONS

In patients with MI of the inferior and/or lateral wall, a prominent T wave in V2 with respect to V6 reflects greater infarct extent in the lateral wall.

Upright T waves in lead aVR are associated with cardiac death or hospitalization for heart failure in patients with a prior myocardial infarction

The aim of the present study was to clarify the prognostic significance of upright T waves (amplitude > 0 mV) in lead aVR in patients with a prior myocardial infarction (MI). We retrospectively examined 167 patients with a prior MI. The primary end point was cardiac death or hospitalization for heart failure. During a follow-up period of 6.5 ± 2.8 years, 34 patients developed the primary end point. A Kaplan-Meier analysis showed a lower primary event-free rate in patients with upright T waves in lead aVR than in those with nonupright T waves in lead aVR (P = 0.001). Univariate Cox proportional hazards regression analyses showed that age, gender, chronic kidney disease, anterior wall MI, upright T waves in lead aVR, left ventricular ejection fraction, loop diuretic use, and spironolactone use were significantly associated with the primary end point. A multivariate Cox proportional hazards regression analysis selected age [hazard ratio (HR) 1.10, 95% confidence interval (CI) 1.05-1.16, P < 0.001], upright T waves in lead aVR (HR 3.10, 95% CI 1.23-7.82, P = 0.017), and loop diuretic use (HR 4.61, 95% CI 1.55-13.67, P = 0.006) as independent predictors of the primary end point. In conclusion, the presence of upright T waves in lead aVR is an independent predictor of cardiac death or hospitalization for heart failure in patients with a prior MI. The analysis of T-wave amplitude in lead aVR provides useful prognostic information in patients with a prior MI.

Associations of positive T wave in lead aVR with hemodynamic, coronary, and left ventricular angiographic findings in anterior wall old myocardial infarction

BACKGROUND

No information is available on the clinical significance of a positive T wave in lead aVR in myocardial infarction (MI). Accordingly, in the present study, we sought to clarify the associations of the positive T wave in lead aVR with hemodynamic, coronary angiographic, and left ventriculographic findings in anterior wall old MI.

METHODS

We examined 122 patients with anterior wall old MI who underwent diagnostic or follow-up cardiac catheterization including coronary angiography and left ventriculography. The patients were classified into the following 2 groups: patients with a positive (≥ 1mm) T wave in lead aVR (n=20, group A) and those without (n=102, group B).

RESULTS

Group A had higher pulmonary arterial, pulmonary capillary wedge, and left ventricular (LV) end-diastolic pressures and a lower cardiac index than group B. The prevalence of a long left anterior descending coronary artery (LAD) was higher in group A than in group B (60% vs 30.4%, p=0.01), and none of group A patients had an LAD that did not reach the apex. Group A had a lower LV ejection fraction than group B (36.4 ± 11.6% vs 48.4 ± 12.7%, p<0.001).

CONCLUSIONS

The positive T wave in lead aVR is related to severely reduced cardiac function, with an LAD wrapping the apex, in anterior wall old MI. Further studies are needed to clarify whether the positive T wave in lead aVR is associated with an adverse outcome in patients with anterior wall old MI.

Event-free survival in patients after an acute coronary event with exercise-induced normalization of the T-wave

BACKGROUND

Risk stratification of patients with unstable angina or non-Q-wave myocardial infarction (MI) is an unresolved clinical problem. The prognostic value of T-wave normalization (TWN) during exercise has not been studied in this group of patients.

HYPOTHESIS

Event-free survival in clinically stable patients after an acute coronary event without ST-segment elevation can be predicted by the presence of exercise-induced TWN.

METHODS

Sixty-five patients (43 men and 22 women, mean age 62+/-10 years) entered the study. The diagnosis of unstable angina and non-Q-wave MI was made in 40 and 25 patients, respectively. A treadmill exercise test was performed in all patients after clinical stabilization. The patients were divided into three groups: those with negative baseline T waves and exercise-induced TWN (Group 1); those with negative baseline T waves, but without TWN (Group 2); and those with positive baseline T waves (Group 3). The patients were followed up for 6 months.

RESULTS

During follow-up, serious cardiovascular complications occurred in 15 (23%) patients. These included exacerbation of ischemic heart disease (14 patients) and acute MI (1 patient). Event-free survival was greater in patients in Group 1 (95%) than in those in Group 2 (68%, p < 0.034) or Group 3 (71%, NS). Among all patients studied, exercise-induced TWN was predictive of event-free survival with a sensitivity of 38% and a specificity of 93%.

CONCLUSIONS

In clinically stable patients after an acute coronary event without ST-segment elevation, exercise-induced TWN is a specific but n ot sensitive predictor of event-free survival after 6 months.

Electrocardiographic Markers of Reperfusion in ST-elevation Myocardial Infarction

The outcome of patients who fail to reperfuse with thrombolytic therapy or percutaneous coronary intervention (PCI) for ST-elevation acute myocardial infarction (STEMI) may be improved with additional pharmacologic and mechanical interventions such as rescue PCI or intravenous glycoprotein IIb/IIIa infusion. The standard 12-lead ECG is the most commonly available and suitable tool for routine bedside evaluation of the success of reperfusion therapy for STEMI. This article reviews and discusses the current data on the four ECG markers for prediction of the perfusion status of the ischemic myocardium: ST-segment deviation, T-wave configuration, QRS changes, and reperfusion arrhythmias.

Ischemia-induced ST-segment elevation: classification, prognosis, and therapy

The standard 12-lead electrocardiogram (ECG) remains the most useful tool for the diagnosis, early risk stratification, triage, and guidance of therapy in patients with acute coronary syndromes. However, the initial and the terminal part of the QRS complex, the ST segments, and the T waves are influenced by anatomical and metabolic factors such as the "myocardium at risk" and "severity" and "duration" of ischemia. Moreover, there are complex interactions between all these factors. The ECG can identify potential candidates for reperfusion therapy as well as the completeness and success of reperfusion, whereas it can also identify those patients who will have no benefit from reperfusion because of either late arrival or nonischemic etiologies of ECG changes. These patients may have a "pseudo" ST-elevation acute myocardial infarction (STEAMI) or "pseudo-pseudo" STEAMI. The presence of Q waves and additional ST-segment depression and T-wave inversion on the admission ECG in patients with STEAMI may provide us information regarding the potential myocardial reserves, and various ECG scoring systems are in current use for that purpose. The pattern and timing of changes in Q waves, ST segment, and T waves may all be markers of the patency status of the infarct-related artery. We review and discuss each of the dynamic ECG variables during ischemia and reperfusion: the initial QRS (Q and R waves), the terminal QRS (Sclarovsky-Birnbaum score), the ST segment, and the T waves.

Electrocardiogram of acute ST-elevation myocardial infarction: the significance of the various "scores"

The Electrocardiogram has extensively been used for evaluation and triage of patients with acute chest pain. The clinician admitting a patient with ST elevation acute myocardial infarction should be able to estimate the size and location of the ischemic area at risk, how much of the ischemic myocardium has already undergone irreversible necrosis by the time of presentation, and the "severity of ischemia" (or what is the rate of progression of necrosis as long as ischemia continues). The electrocardiographic variables that are used to make these estimates are the initial portion of the QRS (Q and R waves), the terminal portion of the QRS (the S waves and the J-point), the ST segment, and the configuration of the T waves. This editorial discuss the ability to predict each of the "physiological" parameters using the above mentioned electrocardiographic variables.

Determinants of persistent negative T waves and early versus late T wave normalisation after acute myocardial infarction

OBJECTIVE

To determine whether persistent versus early or delayed T wave normalisation of negative T waves after acute myocardial infarction is determined by the myocardial state, the treatment strategy, or both.

DESIGN

127 consecutive patients with a first acute myocardial infarction and > or = 2 negative T waves on the 24-36 hour ECG were studied. They underwent dobutamine stress echocardiography and coronary angiography during the first week. ECG was recorded at hospital discharge and at a mean (SD) of 4 (1) months.

SETTING

University hospital.

RESULTS

T wave normalisation was observed in 88 patients (early at discharge in 19 and delayed at four months in 69). Early T wave normalisation was associated with sustained contractile reserve during dobutamine stress (13 of 19 (68%)), whereas delayed T wave normalisation was observed mainly in patients with an ischaemic response (49 of 69 (71%)). The persistence of negative T waves was associated with an ischaemic response (21 of 39 (54%)) or persistent akinesis (17 of 39 (44%)). Among patients with an ischaemic response to dobutamine, in-hospital elective angioplasty was an independent determinant of delayed T wave normalisation (39 of 49 v 4 of 21 patients with persistent negative T waves at four months, p < 0.0001).

CONCLUSIONS

Early T wave normalisation is associated with dobutamine induced, sustained improvement indicating myocardial stunning. Delayed normalisation is observed mainly in patients with ischaemic myocardium who have undergone revascularisation. Persistent negative T waves correspond to either extensive necrosis or non-revascularised, jeopardised myocardium.

Relation of T-wave inversion in Q-wave acute myocardial infarction to myocardial viability on resting rubidium-82 and 18-fluoro-deoxyglucose positron emission tomography imaging

T-wave inversion in areas of Q-wave myocardial infarction has been advocated as a predictor of myocardial viability. However, the predictive value of this electrocardiographic finding in distinguishing viable from nonviable muscle is not fully defined. Thus, we correlated electrocardiographic Q waves and a measure of T-wave inversion with the results of rubidium-82 (Rb-82) and 18-fluoro-deoxyglucose-positron emission tomography (FDG-PET) imaging at rest. We analyzed 35 Q-wave myocardial infarct regions in 25 patients. Nineteen of the 35 (54%) were judged viable by Rb-82/FDG-PET. Using the Novacode T-wave score, T-wave inversion was present in 11 of 19 regions (58%) with viability and 5 of 16 regions (31%) without viability. Thus, neither Q waves nor T-wave inversion can accurately predict myocardial viability in patients with Q-wave myocardial infarction.

Normalization of negative T waves in the chronic stage of Q wave anterior myocardial infarction as a predictor of myocardial viability

We investigated whether spontaneous normalization of negative T waves (TWN) on infarct-related ECG leads (IRLs) in the chronic phase of Q wave anterior myocardial infarction (MI) could be a predictor of residual viability in infarct areas. We prospectively studied 35 patients (age 60 +/- 8.6 years) in the chronic phase of Q wave anterior MI. Spontaneous TWN (group A, n = 23) were defined as negative T waves that became upright (> or =0.15 mV) in > or =2 IRLs. The presence of negative T waves (group B, n = 12) was defined as symmetric or biphasic negative T wave of > or =0.15 mV. All patients underwent same-day rest 201Tl-stress (99m)Tc sestamibi dual-isotope myocardial perfusion SPECT and 24-hour 201Tl reinjection imaging for ischemia and viability analysis. On scintigraphic examination, ischemic or viable myocardial segments were found in 18 patients (78%) with TWN and 4 patients (33%) of group B (p = 0.013). The use of TWN as a parameter had a marked influence on the sensitivity (82%), specificity (62%), positive (78%) and negative (67%) predictive values and accuracy (74%) of the diagnosis of viable myocardium. If we add the criterion of positive T waves in aVR with negative T waves to our criteria, we found that sensitivity (90%), positive (80%) and negative (80%) predictive values and accuracy (80%) increased. The results of our study suggest that analysis of TWN on IRLs is an accurate marker of residual viability and/or persistent peri-infarct ischemia in patients in the chronic stage of Q wave anterior MI, and therefore optimizes the diagnostic and therapeutic strategies after MI.

Persistent negative T waves in the infarct-related leads as an independent predictor of poor long-term prognosis after acute myocardial infarction

This study sought to determine the long-term prognostic significance of persistent or transient negative T waves in infarct-related leads. After acute myocardial infarction (AMI), QRS and T wave alterations may resolve. No clinical study has investigated the prognostic importance of persistent versus transient negative T waves. We studied 147 consecutive patients with first AMI and >/=2 negative T waves in the infarct-related leads on the electrocardiogram. One hundred twenty patients developed Q waves. Patients were followed clinically for 60 +/- 21 months. T-wave normalization was observed early (before hospital discharge) in 34 patients and late (at 4 +/- 1 months) in 65. Thirty patients had Q-wave regression. Adverse outcome occurred in 57 patients. There were 23 hard events (cardiac death in 12 patients and nonfatal AMI in 11). Patients with early or late T-wave normalization had similar event-free survival curves that diverged rapidly from that of patients with persistent negative T waves, who had a worse outcome (p <0.0001). Patients with or without Q-wave regression had similar survival curves. Using multivariate Cox regression analysis, higher end-systolic volume (hazard ratio [HR] 1.01, p = 0.007), the presence of multivessel disease (HR 3.33, p = 0.009), and persistent negative T waves (HR 2.92, p = 0.024) predicted hard events. Persistent negative T waves 4 months after first AMI were independently associated with a worse outcome, whereas Q-wave regression has no long-term prognostic importance.

Myocardial damage and left ventricular dysfunction in patients with and without persistent negative T waves after Q-wave anterior myocardial infarction

Persistent T-wave inversions during the chronic stage of Q-wave myocardial infarction (MI) indicate the presence of a transmural infarction with a fibrotic layer pathologically. The aim of the present study was to examine the relation between left ventricular (LV) damage and changes in polarity of the T waves from the acute to chronic phase in patients with Q-wave anterior wall MI. We studied 140 patients with persistent T-wave inversions in leads with Q waves (negative T-wave group) and 158 patients with positive T waves (positive T-wave group) at 12 months after anterior MI. In the positive T-wave group, the precordial T waves reverted from a negative to a positive morphology < 3 months after MI in 21 patients (3 M-positive T-wave subgroup), 3 to 6 months in 52 patients (6 M-positive T-wave subgroup), and 6 to 12 months in 75 patients (12 M-positive T-wave subgroup). Ten patients had persistent positive T waves without initial T-wave inversion (persistent positive T-wave group). Wall motion index and LV dimension were higher and the wall thickness for the infarct area and LV ejection fraction were lower in the negative T-wave than in the positive T-wave groups, except the persistent positive T-wave group in the chronic stage (p < 0.0001). Wall motion in the infarcted area improved over the course of 1 year in the 3 M-, 6 M-, and 12 M-positive T-wave subgroups (p < 0.0001), but not in the persistent positive T-wave group. Among the patients with T-wave inversions after admission, those who had persistent negative T waves after 12 months had worse LV function. In patients with initial T-wave inversion, earlier normalization of the precordial T waves was associated with greater improvement in LV function. Patients with persistent positive T waves without initial negative T waves had poorer recovery of LV function than patients with persistent negative T waves. We conclude that the presence of inverted T waves in leads with abnormal Q waves 12 months after MI and the time required for T-wave normalization can be used to assess the degree of LV dysfunction.

The use of the electrocardiogram to identify epicardial coronary and tissue reperfusion in acute myocardial infarction

The standard 12-lead electrocardiogram (ECG) gives us crucial information concerning myocardial perfusion and the success of reperfusion therapy for ST elevation acute myocardial infarction. Continuous monitoring has advantages over repeated snapshot recordings. There are four electrocardiographic markers for prediction of the perfusion status of the ischemic myocardium: (1) ST-segment measurements, (2) T-wave configuration, (3) QRS changes, and (4) reperfusion arrhythmias. Complete and stable (> or = 70%) resolution of ST-segment elevation is associated with better outcome and preservation of left ventricular function than partial (30 to 70%) or no (<30%) ST-segment resolution. Early inversion of the T waves after initiation of reperfusion therapy is another marker of myocardial reperfusion and a good prognostic sign. Using standard 12-lead ECG, dynamic changes in Q-wave number, amplitude, and width; R-wave amplitude; and S-wave appearance are detected during reperfusion therapy. However, the significance of these changes has not been clarified. Reperfusion arrhythmias, especially bradycardia and accelerated idioventricular rhythm, are detected occasionally during reperfusion therapy, but the value of reperfusion arrhythmias as a marker of coronary artery patency is still debatable. Dynamic changes in the QRS complexes, ST segments and T waves occur during reperfusion therapy and the days after. Whereas changes in ST-segment amplitude have been extensively studied, the significance of QRS-complex and T-wave changes is less clear, and especially whether changes in the QRS complex and T wave may be complementary and additive to ST-segment monitoring. It has remained unclear whether electrocardiographic signs of reperfusion and reischemia should be used for therapeutic decision making in the clinical setting.

Negative T waves shortly after ST-elevation acute myocardial infarction are a powerful marker for improved survival rate

BACKGROUND

Recent studies have reported that negative T waves in the setting of acute coronary events are associated with Thrombolysis In Myocardial Infarction flow grade 3 in the infarct-related artery and with improved parameters of ventricular function rather than with ischemia.

METHODS

Patients enrolled in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) angiographic substudy (ie, patients with acute infarction randomly assigned to one of 4 thrombolytic regimens who then underwent coronary angiography) were included in this study if they survived at least 24 hours and had no confounding electrocardiographic factors (n = 1505).

RESULTS

More patients had negative T waves develop (NT group, n = 938 [62%]) than not (PT group, n = 567 [38%]). Peak creatine kinase MB, time to thrombolysis, and randomization to accelerated alteplase were no different between the groups. Thirty days after admission, 12 patients in the NT group had died versus 25 patients in the PT group (1.3% vs. 4.4%; P <.001; odds ratio for negative T waves 0.28; 95% confidence interval 0.14-0.56). The difference persisted when only patients who survived at least 3 days were analyzed. After adjusting for relevant covariates (including presence of new Q waves in the follow-up electrocardiogram), negative T waves were an independent predictor for survival (P =. 007; odds ratio for negative T waves 0.38; 95% confidence interval 0. 18-0.78). Patients in the NT group were 35% more likely to have achieved patency of the infarct-related artery, although this difference was not statistically significant.

CONCLUSIONS

Negative T waves shortly after acute myocardial infarction treated with thrombolysis were markers for improved 30-day survival rate. This finding merits prospective testing.

The use of the electrocardiogram to identify epicardial coronary and tissue reperfusion in acute myocardial infarction

The standard 12-lead ECG gives us crucial information concerning myocardial perfusion and the success of reperfusion therapy for ST-elevation acute myocardial infarction. Continuous monitoring has advantages over repeated snapshot recordings. There are four electrocardiographic markers for prediction of the perfusion status of the ischemic myocardium: 1) ST-segment measurements; 2) T-wave configuration; 3) QRS changes; and 4) reperfusion arrhythmias. Complete and stable (> or = 70%) resolution of ST-segment elevation is associated with better outcome and preservation of left ventricular function than partial (30% to 70%) or no (< 30%) ST-segment resolution. Early inversion of the T-waves after initiation of reperfusion therapy is another marker of myocardial reperfusion and a good prognostic sign. Using standard 12-lead ECG, dynamic changes in Q-wave number, amplitude and width, R-wave amplitude and S-wave appearance are detected during reperfusion therapy. However, the significance of these changes have not been clarified. Reperfusion arrhythmias, especially bradycardia and accelerated idioventricular rhythm are detected occasionally during reperfusion therapy, but the value of reperfusion arrhythmias as a marker of coronary artery patency is still debatable. Dynamic changes in the QRS complexes, ST-segments and T-waves occur during reperfusion therapy and the days after. While changes in ST-segment amplitude have been extensively studied, the significance of QRS-complex and T-wave changes are less clear, and especially whether changes in the QRS-complex and T-wave may be complementary and additive to ST-segment monitoring. It has remained unclear whether electrocardiographic signs of reperfusion and re-ischemia should be used for therapeutic decision-making in the clinical setting.