Inferior Myocardial Infarction Patients Research Articles

Right Atrial and Right Ventricular Function Assessed by Speckle Tracking in Patients with Inferior Myocardial Infarction.

In patients with inferior myocardial infarction (MI), involvement of the right chambers has a prognostic impact. The objective of this study was to evaluate the influence of left ventricular (LV) inferior wall MI in the right atrial (RA), and right ventricular (RV) longitudinal strain (LS) by 2D speckle tracking echocardiography (STE). 60 consecutive patients who underwent myocardial perfusion (MP) gated SPECT for chest pain were included. We studied 30 patients with LV inferior MI and 30 control subjects with normal MP. RV ejection fraction was measured by 3D transthoracic echocardiography, RV-free wall LS and RA reservoir, contraction, and conduit phases strain were analyzed by 2D speckle tracking echocardiography (STE). The median age in the LV inferior MI was 65 (54-70) years, 27% had a transmural myocardial infarction and 47% had residual myocardial ischemia, most of them, mild (36.7%). RV-free wall LS (-26.1 vs -30.3, p 0.01), RA LS-reservoir phase (31.5 vs 56.2, p 0.01), and RA-conduit phase LS (12.5 vs 35, p = 0.01) were significantly lower in the LV inferior MI patients compared to control subjects. In a logistic regression model, the MI of the LV reduced the 3D ejection fraction of both ventricles, mitral regurgitation, and pulmonary hypertension were associated with a decrease in RV LS and RA LS. This study shows that RV free wall LS, RA peak strain (reservoir phase), and RA conduit phase strain were significantly lower in patients with LV inferior MI vs control individuals. Subclinical extension to the RV in the inferior MI of the LV and its role in the longitudinal strain of RA could be determined using speckle tracking echocardiography.

Long-Term Outcomes in Acute Inferior Myocardial Infarction Patients with Right Ventricular Myocardial Infarction

Objective: To evaluate the prognostic influence of the presence of right ventricular myocardial infarction (RVMI) on patients with acute inferior myocardial infarction (MI) in the contemporary reperfusion era. Methods: A total of 9,308 patients with acute inferior MI were included from the prospective, nationwide, multicenter China Acute Myocardial Infarction Registry, including 1,745 (18.75%) patients with RVMI and 7,563 (81.25%) patients without RVMI. The primary outcome was all-cause mortality. The secondary outcome was major adverse cardiac and cerebrovascular event (MACCE) defined as a composite of all-cause mortality, recurrent MI, revascularization, stroke, and major bleeding. Results: There were no significant differences between acute inferior MI patients with or without RVMI in all-cause mortality and MACCE. Acute inferior MI patients with RVMI was associated with higher risks of in-hospital atrial-ventricular block (5.8% vs 3.1%; adjusted OR: 1.39; 95% CI: 1.06 to 1.84; P=0.0187) and two-year revascularization (10.3% vs 8.1%; adjusted HR: 1.21; 95% CI: 1.01 to 1.45; P=0.0418) relative to patients without RVMI. Primary percutaneous coronary intervention (PCI) and thrombolysis were all independent predictors to decrease both in-hospital and two-year all-cause mortality. For patients who received timely reperfusion, RVMI involvement did not increase all-cause mortality, whereas for those who did not undergo reperfusion treatment, RVMI involvement significantly increased all-cause mortality (20.3% vs 15.7%; HR: 1.34; 95% CI: 1.10 to 1.63). Conclusion: RVMI involvement did not increase all-cause mortality for acute inferior MI patients in contemporary reperfusion era, whereas the risk of all-cause mortality was increased for patients with no reperfusion treatment.

Evaluation of right ventricular dyssynchrony in patients with acute inferior myocardial infarction and its relation with mortality.

The aim of this study was to evaluate right ventricle (RV) dyssynchrony and its relation with mortality using speckle-tracking echocardiography (STE) in patients with acute inferior myocardial infarction (IMI). One hundred and fifty-eight consecutive patients with acute IMI treated with primary percutaneous coronary intervention, and 44 healthy subjects were included. RV myocardial involvement (RVMI) was defined as an elevation >1mm in V1 or V4R and/or the presence of a culprit lesion at the proximal portion of the first RV marginal branch after reviewing coronary angiography. Patients were followed for 3years to determine the cardiovascular mortality. Overall, 70 patients with IMI had RVMI. IMI patients had significantly higher RV peak systolic longitudinal strain dyssynchrony (PLSSD) index, lower peak longitudinal systolic strain (PLSS), longer time to PLSS, and time to PLSS differences compared to healthy controls while the patients with RVMI had significantly worse values compared to patients without RVMI and healthy controls. Twenty-seven patients (17.1%) died within 2years. RVMI was more prevalent in mortality group, and they had significantly higher RV PSSD index, whereas they had lower RV free wall PLSS and longer time to PLSS differences. Receiver operating characteristics (ROC) analysis revealed that a RV PLSSD index>65ms predicted mortality with a sensitivity of 88.9% and specificity of 71.8% in IMI patients. Intra- and inter-ventricular dyssynhcrony may develop in patients with acute IMI, especially in those with RV involvement, which might have a negative effect on the prognosis of these patients.

Clinical, procedural and long-term outcome of ischemic VT ablation in patients with previous anterior versus inferior myocardial infarction

BackgroundOutcome of ischemic VT ablation may differ between patients with previous myocardial infarction (MI) in relation to infarct localization.MethodsWe analyzed procedural data, acute and long-term outcomes of 152 consecutive patients (139 men, mean age 67 ± 9 years) with previous anterior or inferior MI who underwent ischemic VT ablation at our institution between January 2010 and October 2015.ResultsMore patients had a history of inferior MI (58%). Mean ejection fraction was significantly lower in anterior MI patients (28 ± 10% vs. 34 ± 10%, p < 0.001). NYHA class and presence of comorbidities were not different between the groups. Indication for the procedure was electrical storm in 43% of patients, and frequent implantable cardioverter defibrillator (ICD) therapies in 57%, and did not differ significantly between anterior and inferior MI patients. A mean of 3 ± 2 VT morphologies were inducible, with a trend towards more VT in the anterior MI group (3.1 ± 2.2 vs. 2.6 ± 1.9, p = 0.18). Procedural parameters and acute success did not differ between the groups. During a mean follow-up of 3 ± 2 years, more anterior MI patients had undergone a re-ablation (49% vs. 33%, p = 0.09, Chi-square test). There was a trend towards more ICD shocks in patients with previous anterior MI (46% vs. 34%). After adjusting for risk factors and ejection fraction, multivariable Cox regression analyses showed no significant difference in mortality (p = 0.78) and cardiovascular mortality between infarct localizations (p = 0.6).ConclusionClinical characteristics of patients with anterior and inferior MI are similar except for ejection fraction. Patients with inferior MI appear to have better outcome regarding survival, ICD shocks and re-ablation, but this appears to be related to better ejection fraction when compared with anterior MI.

Precordial ST Segment Depression on Admission Electrocardiogram as a Simple Noninvasive Tool for Predicting Coronary Artery Disease Complexity in Patients with Inferior Myocardial Infarction

Precordial ST Segment Depression on Admission Electrocardiogram&#x0D; as a Simple Noninvasive Tool for Predicting Coronary Artery Disease Complexity&#x0D; in Patients with Inferior Myocardial Infarction&#x0D; &#x0D; Jaya Suganti, Anggia Chairuddin Lubis, Abdullah Afif Siregar, Andika Sitepu, Cut Aryfa Andra,&#x0D; Ali Nafiah Nasution, Harris Hasan&#x0D; &#x0D; Department of Cardiology and Vascular Medicine, Faculty of Medicine University of Sumatera Utara, &#x0D; Haji Adam Malik General Hospital, Medan, Indonesia&#x0D; &#x0D; &#x0D; Background: Whether a precordial ST segment depression (PSTD) is merely a benign electrical phenomena or a sign of multivessel coronary artery disease (MVCAD) in inferior myocardial infarction (MI) remains unclear. The objective of this study is to analyze the complexity of coronary artery disease (CAD) in inferior MI patients with PSTD and to investigate whether PSTD can be used as a predictor of MVCAD in inferior MI.&#x0D; Methods: Patients with inferior MI were divided into two groups based on the presence of PSTD on admission ECG and were compared based on the patient’s coronary artery complexities.&#x0D; Results: A total of 215 patients with inferior MI were found in this study period, with 102 patients meet the inclusion and exclusion criteria. Patients with PSTD had a higher incidence of MVCAD and SYNTAX score. Further analyzes showed PSTD on admission ECG was an independent predictor of MVCAD in inferior MI [45 (66%) vs 23 (34%); OR 4.097; 95% CI 1.638-10.247; p=0.003).&#x0D; Conclusion: In daily clinical practice, PSTD on admission ECG may serve as a simple noninvasive tool for predicting MVCAD or a more complex CAD in inferior MI.&#x0D; &#x0D; Keywords: Precordial ST Segment depression, inferior myocardial infarction, SYNTAX score&#x0D;

Evaluation of right atrial volumes and functions by real-time three-dimensional echocardiography in patients after acute inferior myocardial infarction.

Right ventricle (RV) involvement causes acute systolic and diastolic functional alterations in the RV in patients after inferior myocardial infarction (IMI), which may result in an increase in left ventricle (LV) end-diastolic and right atrial (RA) pressure. In our study, we sought to evaluate RA volumes and mechanical functions using real-time three-dimensional echocardiography (RT3DE) in IMI patients with or without RV involvement. Ninety-six consecutive patients with IMI (mean age: 59.7±10.2years, 60 female) were included. RV myocardial involvement (RVMI) was defined as the presence of a culprit lesion at the proximal portion of the first RV marginal branch in coronary angiography. The study population was divided into two groups: IMI (58.3%) and IMI+RVMI (41.7%). Patients were evaluated using conventional two-dimensional echocardiography (2DE) and RT3DE. In RT3DE measurements, IMI+RVMI patients had significantly higher RA phasic volumes and worse conduit mechanical function. A receiver operating characteristic (ROC) curve analysis revealed that an RT3DE RA maximum volume (Vmax) index>27.9mL/m2 was an independent predictor of RV involvement in patients after acute IMI, with a sensitivity of 80.0% and a specificity of 89.3%. Right ventricle involvement may cause an increase in RA phasic volumes and deterioration of conduit function in patients with acute IMI.

The diagnostic and prognostic value of right ventricle systolic and diastolic function in inferior myocardial infarction patients

Background: Inferior myocardial infarction (MI) with right ventricular (RV) involvement will increase mortality and morbidity. Data of systolic and diastolic RV function in inferior ST-segment elevation MI (STEMI) are useful to predict the RV involvement. Aims: To evaluate the prognostic and diagnostic significance of RV systolic and diastolic function compared to RVMI diagnostic criteria by electrocardiography in inferior MI patients.Methods: Consecutive patients with first, acute, inferior STEMI were prospectively assessed. The RVMI was defined as an ST-segment elevation ≥ 0.1 mV in lead V4R. Echocardiography was performed within 24 hours of the inferior STEMI symptoms. We assessed the RVMI diagnostic criteria in inferior MI patients using echocardiography.Results: Out of 31 patients (mean age 56.39 ± 9.02 years), RVMI by electrocardiography and echocardiography was found in 18 (37%). Moreover, multivariate analysis showed that two variables — RV systolic and diastolic function, were independent predictors of RVMI in inferior MI patients. Sensitivity and specificity of the RV systolic function were 94.4% and 69.2%, respectively, while RV diastolic functions were 44% and 76.9%, respectively.Conclusion: RV systolic function predict RVMI with relatively high sensitivity and specificity. RV diastolic function predicts RVMI with relatively low sensitivity but with high specificity.

Clinical and echocardiographic factors associated with mitral plasticity in patients with chronic inferior myocardial infarction.

Ischaemic mitral regurgitation (IMR) is consequence of left ventricular (LV) remodelling after myocardial infarction. In some cases, the mitral valve enlarges to compensate for LV remodelling and tenting, improving its coaptation; a process termed 'plasticity'. We sought to identify clinical and echocardiographic factors associated with plasticity in patients with chronic inferior myocardial infarction (CII). This study included 91 revascularized CII patients and 46 controls. Plasticity and IMR severity were evaluated by 2D transthoracic echocardiography. Compared with controls, CII patients were older (59 vs. 25 years) and mostly men (80% vs. 46%), both P < 0.001. Chronic inferior myocardial infarction patients also had significant LV remodelling: larger LV volumes, larger mitral tenting areas, larger coaptation depths, longer mitral leaflets and chords, and worse mitral regurgitation (all P ≤ 0.03). Of 91 CII patients, 60 had mitral plasticity (longer anterior and posterior leaflets and longer posterior chords, all P < 0.001), despite not exhibiting significantly larger LV volumes, tenting area or coaptation depth, when compared with patients with no plasticity. Contralateral (anterior) papillary muscle-to-annulus length tended to be increased in CII plasticity patients (P = 0.05). Also they had less moderate and severe IMR (both P < 0.04) compared with non-plasticity CII patients. Multivariate analysis demonstrated independent associations between plasticity and smoking [odds ratio (OR) 0.03, 0.002-0.57; P = 0.019], duration of type-2 diabetes (OR 1.19, 1.007-1.42; P = 0.04) and haemoglobin (OR 2.17, 1.25-3.76; P = 0.005). Mitral plasticity results in less moderate and severe IMR. Longer time-duration of diabetes mellitus and higher haemoglobin level are independently associated with mitral plasticity, while smoking independently associates with no plasticity. Increased anterior papillary muscle-to-annulus length in CII patients with plasticity suggests complex LV remodelling mechanisms are involved in plasticity.

High-risk inferior myocardial infarction: Can speckle tracking predict proximal right coronary lesions?

It is important to diagnose right ventricular (RV) infarction in the setting of acute inferior myocardial infarction (MI). We aimed to improve the diagnostic accuracy of RV infarction and identify a high-risk subset of inferior MI patients with proximal RCA lesions. We tried to find the link between speckle tracking and coronaries in high risk inferior infarction METHODS: This study included 68 patients within 24 hours of first acute inferior MI. Group 1 (n = 49) isolated inferior MI; group 2 (n = 19) inferior and RV MI. echocardiography for RV free wall longitudinal strain (FWLS), RV fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), RV myocardial performance index (MPI) and peak systolic velocity (S'). Group 2 had higher MPI by tissue Doppler and 2D-RV average FWLS, whereas RV FAC, S', and TAPSE were lower (P < 0.001). In group 1, 14.4% had a significant proximal RCA lesion with impaired RV function. RV average FWLS at a cutoff value ≥ - 19.7% can predict proximal RCA culprit lesion with 91.7% sensitivity and 70.5% specificity, which was detected as an independent predictor in multivariate logistic regression (odds ratio: 37.75, P = 0.036). 2D RV average FWLS at a cutoff of ≥ - 19.7% is a useful added tool for diagnosis of RV involvement and an independent predictor to rule in proximal RCA culprit lesion in inferior-wall MI patients in the emergency department.

Comparison of In-hospital Major Adverse Cardiovascular Events in Patients of Acute Inferior Myocardial Infarction With or Without Precordial ST Segment Depression

Background: The clinical implications of precordial ST segment depression (PSTD) during acute inferior myocardial infarction has been an area of debate, and still under investigation with conflicting results. Based on previous studies, the presence of PSTD defines a high risk subset of patients with acute inferior myocardial infarction due to a more extensive myocardial ischemia that lead to a higher incidence of major adverse cardiovascular events (MACE). Despite of these results, others still considered this ECG finding as a benign electrical phenomenon. The aim of this study is to compare the incidence of in-hospital MACE in patients of acute inferior myocardial infarction with or without PSTD and to know whether PSTD can be used as a predictor of in-hospital MACE in acute inferior myocardial infarction.Methods: A total of 96 acute inferior myocardial infarction patients admitted from December 2013-2015 at Cardiology Department of Haji Adam Malik General Hospital were retrospectively analyzed. Patients were divided into two groups based on the presence of PSTD on admission ECG. Bivariate and multivariate analyses were performed to study the association between PSTD and in-hospital MACE, p value&lt;0.05 was considered statistically significant.Results: The bivariate analysis showed that in-hospital MACE was significantly higher in patients of acute inferior myocardial infarction with PSTD than without PSTD (92% vs 8%, p&lt;0.001). On multiple logistic regression analysis, patients of acute inferior myocardial infarction with PSTD have a 5.4 fold increased risk of in-hospital MACE than patients without PSTD (OR 5.480; 95% CI 1.759-17.067, p=0.003).Conclusion: The presence of precordial ST segment depression on admission ECG in acute inferior myocardial infarction patients was associated with a higher in-hospital MACE and was an independent predictor of in-hospital MACE.

A Comparative Study of Rv Function in Anterior And Inferior Stemi

I. Introduction The prognosis of patients with acute myocardial infarction (AMI) is directly related to left ventricular (LV) function and size 1.2 Traditionally, the principal investigated target of clinicians is LV function, with little interest in the right ventricle.However, right ventricular (RV) dysfunction after AMI is also associated with increased risk of morbidity and mortality. 3-5 RV dysfunction has been associated with increased morbidity and mortality in patients with congenital heart disease, valvular disease, coronary artery disease, pulmonary hypertension, and heart failure. 6-8 Right Ventricle (RV) dysfunction may be primarily attributed to abnormality of RV myocardium or secondary to left ventricle (LV) dysfunction, as a consequence of Ventricular Interdependence between the two ventricles, as they are encircled by common muscle fibres, share a common septal wall and are enclosed within a common pericardium. 9 Early recognization of RV dysfunction is warranted but till today it remains a challenging task because of complex structure and asymmetric shape of RV. 10 Most of the previous studies have evaluated RV functions in patients of inferior myocardial infarction. There are only few studies available in literature evaluating RV function in anterior myocardial infarction. Therefore, in the present study conventional echocardiography combined with tricuspid annular plane systolic excursion [TAPSE Fractional area change(FAC), pulsed doppler and TDI were used to evaluate the effect of different infarction sites on RV functional changes in patients with first acute ST-elevation myocardial infarction (STEMI) without concomitant RV infarction.

Assessment of the right ventricular systolic function after acute right ventricular myocardial infarction in association with left ventricular inferior myocardial infarction by two-dimensional speckle tracking echocardiography

Objective To assess right ventricular (RV) systolic function in patients with acute right ventricular myocardial infarction (RVMI) in association with left ventricular inferior myocardial infarction (INFMI) by applying 2-dimensional (2D) speckle tracking imaging (STI) longitudinal strain (LS) and strain rate (LSr) parameters. Methods Seventeen consecutive patients diagnosed with INFMI in association with RVMI were included in our study, 21 INFMI patients without RVMI were also included to match the RVMI group. RVMI group and INFMI group were called acute myocardial infarction (AMI) group, all of them were diagnosed AMI the first time. Twenty-four chest pain patients admitted consecutively at the same time but with negative results in the selective coronary angiography were served as blank control. Echocardiography were performed within 48 hours. The RVLS parameters, which include LS and LSr, were then analyzed offline. Results The RV global LS (RVGLS), the LS of the basal and mid segments of the free wall and septum, the LSr of the basal and mid segments of the free wall were lower than control group in the AMI group (P<0.05). Compared to INFMI group, the RVGLS, the LS of the mid and apical segments of the free wall and the LSr of the mid segments of the septum were lower in the RVMI group (P<0.05). In the single parameter mode of ROC curve analysis, the diagnosis efficiency of RV free wall LS (RVFWLS) and RVGLS were higher than other parameters. The cut-off value of RVFWLS and RVGLS were -18.26% and -16.27% respectively (sensitivity were 100% and 100%, respectively, specificity were 65.5% and 72.4%, respectively). Conclusions The 2D-STI RVLS parameters precisely reflect the impaired RV systolic function in the INFMI and RVMI patients, the RV global systolic function are even worse when RVMI involved, mainly for the RV free wall. RVLS parameters are good predictors of RVMI which could provide more references for the early diagnosis and functional evaluation of RV in acute INFMI patients with RVMI. Key words: Echocardiography; Myocardial infarction; Ventricular function, right; Speckle tracking imaging

Tricuspid annular motion in right coronary artery-related acute inferior myocardial infarction with or without right ventricular involvement

Tricuspid annular movement and velocities before and after thrombolytic therapy were investigated for the detection of right ventricular (RV) involvement in RCA (right coronary artery)-related acute inferior myocardial infarction (IMI). Patients with RCA-related acute IMI were evaluated for this pilot prospective cohort study. Annular movement was measured by TAPSE (tricuspid annular plane systolic excursion), and annular velocities were measured by tissue Doppler echocardiography. Data collected before and after thrombolysis and angiography. Diagnosis of RV myocardial infarction (RVMI) was defined by co-presence of electrocardiographic and angiographic criteria. Chi-square and Student's t-tests were used in statistical analysis. Thirty-one patients were included. Before thrombolysis, annular velocities and TAPSE were found significantly higher in patients without RVMI than in patients with RVMI. Comparison of tricuspid systolic velocity (Sa) and movement before and after thrombolytic therapy in patients without RVMI revealed no significant difference (21.6±2.1 mm vs. 21.8±2.0 mm p>0.05 and 136.1±8.8 mm/s vs. 137.5±9.0 mm/s p>0.05, for TAPSE and Sa respectively). Contrarily, in patients with RVMI, TAPSE and systolic velocity increased significantly after thrombolysis compared with pre-thrombolysis (16.2±2.0 mm vs. 17.6±1.8 mm p=0.001 and 110.0±12.6 mm/s vs. 113.08±12.7 mm/s p=0.027 for TAPSE and Sa respectively). Diastolic velocities did not change significantly after thrombolysis in patients with RVMI. Tricuspid annular movement and velocity measurement by echocardiography may contribute to echocardiographic diagnosis of RV involvement in RCA-related IMI. Patients without RVMI have significantly higher annular velocities and TAPSE than in patients with RVMI before thrombolysis. Only in IMI patients with RVMI, significant increases in TAPSE and Sa were observed after thrombolysis.

Right Ventricular Infarction and Tissue Doppler Imaging - Insights From Acute Inferior Myocardial Infarction After Primary Coronary Intervention -

Tissue Doppler imaging (TDI) data for acute inferior myocardial infarction (MI) patients who have received primary percutaneous coronary intervention (PCI) are sparse. One hundred and sixty-five patients received primary PCI for acute inferior MI were enrolled. Right ventricular infarction (RVI) was defined as a culprit lesion proximal to the right ventricular branch of right coronary artery (RCA). Echocardiograms and TDI were obtained within 6 h after primary PCI. The prevalence of multi-vessel disease in the RCA-P culprit group (50%) was higher than that in other groups (39% of RCA-D culprit, 43% of left circumflex artery (LCX) culprit). The myocardial performance index (MPI) of the lateral tricuspid annulus provides discriminatory power for identifying RVI, whereas systolic velocity (Sm) of the lateral tricuspid annulus does not. Lateral mitral annular MPI divided by the lateral tricuspid annular MPI is a reliable index for identifying a culprit lesion (>1.06 predicts culprit over LCX; <0.96 predicts culprit over RCA-P and RVI). Kaplan-Meier survival curves revealed that late cardiovascular events were more likely in RVI patients. However, multivariate Cox proportional hazards analysis revealed that the most important factor in hard events and all cardiovascular events was multivessel disease. TDI is useful for identifying RVI and culprit lesions in inferior MI patients received primary PCI. RVI itself isn't associated with 1-year hard events and all cardiovascular events.

Clinical Significance of Precordial ST Segment Depression in Acute Inferior Myocardial Infarction

Background and Objectives:To evaluate the clinical and prognostic significance of precordial ST segment depression in precordial leads on admission electrocardiogram (ECG) in acute inferior myocardial infarction treated with intravenous thrombolytic therapy. We analysed about clinical and angiographic characters. Materials and Method:ECG findings in 50 patients with acute inferior myocardial infarction were retrospectively studied with results of coronary angiography and clinical informations. We classified all patients in two group according to the admissional ECG. Twenty nine patients (Group A) had no or <1.0 mm ST depression in precordial lead and Twenty one patients (Group B) had ≥1.0 mm ST depression in two or more precordial (V1-V6) leads were included in this group. Results:In precordial ST segment depression in acute inferior myocardial infarction patients had higher plasma peak mean CK levels (1945±1419 vs 3547± 2728 IU/L, p=0.027) and lower LV ejection fraction (62±10% vs 53±11%, p=0.008) and lower left ventricle global chordal shortening (0.89±0.71 vs -1.39±0.94, p=0.046) and inferior wall chordal shortening (-1.68±1.11 vs -2.43±0.74, p=0.014) and higher Killip class (1.3±0.8 vs 2.4±1.4, p=0.002) than without precordial ST segment depression patients. Conclusion:In conclusion acute inferior myocardial infarction with precordial ST depression patients had more extensive myocardial damage with global and inferior left ventricle severe wall motion dysfunction. Therefore, this suggests a worse prognosis in acute inferior myocardial infarction with precordial ST depression than without precordial ST depression patients. We need more aggressive diagnosis and treatment in this patients to prevent extending myocardial damage. (Korean Circulation J 1999;29(3):285-291)

956-119 Inferior Wall Myocardial Infarction and Thrombolytic Therapy: An Appraisal of Clinical Heterogeneity and Indications for Treatment

Clinical trials to determine the efficacy of thrombolytic therapy trials consider all patients with acute inferior myocardial infarction (IMI) as a single group, but these patients have heterogeneous clinical characteristics. Stratification of IMI patients by the amount of myocardium at risk and the time to treatment should clarify the precise indications for thrombolytic therapy. This study is an independent secondary analysis of the TIMI II patient data available through the NHLBI. Clinical features were used to identify IMI subgroups in the TIMI II trial characterized by increased myocardium at risk. There were 861 patients with IMI who had one or more of the following markers for myocardium at risk: anterior ST depression, hypotension defined as a systolic blood pressure &lt; 100 mmHg, or advanced AV block. There were 455 patients with IMI who did not have any markers of increased myocardium at risk. The subgroups for each marker and the group without any marker were then stratified by time to thrombolysis and their outcomes were compared to historical controls with hypothesis tests and confidence intervals. Patients with IMI plus anterior ST depression, hypotension, or AV block who received thrombolysis had a highly statistically significant decre,1se in mortality (p &lt; 0.001) compared to historical controls. Patients with IMI plus hypotension or AV block had a significant decrease in mortality only up to 3 hours from onset of symptoms (p &lt; 0.05). In patients with simple 1MI, an insignificant relative reduction in mortality of 15.4% was seen from a baseline mortality of 2.5%. Consequently, thrombolytic therapy cannot be justified for all patients with IMI, but it is clearly indicated for IMI with anterior ST depression, advanced AV block, and hypotension. The decrease in mortality for patients with hypotension or AV block declines steeply over the first 3 hours. IMI with anterior or lateral ST elevation, right ventricular infarction, or new bundle-branch block is hypothesized to have the same benefit but could not be tested because the data was not available in the TIMI II database. To demonstrate significance of the relative reduction in mortality for patients with simple IMI would require 32,220 patients. For the individual patient with a simple inferior myocardial infarction, the essentially immaterial benefit of 15.4% relative reduction in mortality from a baseline mortality of 2.5% may not outweigh the risk of a hemorrhagic complication of therapy. In conclusion, IMI patients should be considered on an individual basis, with consideration given to the amount of myocardium at risk and the time to treatment.

Identification of best electrocardiographic leads for diagnosing anterior and inferior myocardial infarction by statistical analysis of body surface potential maps

In view of the increasing interest in quantifying and modifying the size of myocardial infarction (MI), it is important to look for clinically practical subsets of electrocardiographic leads that allow the earliest and most accurate diagnosis of the presence and electrocardiographic type of MI. A practical approach is described, taking advantage of the increased information content of body surface potential maps over standard electrocardiographic techniques for facilitating clinical use of body surface potential maps for such a purpose. Multivariate analysis was performed on 120-lead electrocardiographic data, simultaneously recorded in 236 normal subjects, 114 patients with anterior MI and 144 patients with inferior MI, using as features instantaneous voltages on time-normalized QRS and ST-T waveforms. Leads and features for optimal separation of normal subjects from, respectively, anterior MI and inferior MI patients were selected. Features measured on leads originating from the upper left precordial area, lower midthoracic region and the back correctly identified 97% of anterior MI patients, with a specificity of 95%; in patients with inferior MI, features obtained from leads located in the lower left back, left leg, right subclavicular area, upper dorsal region and lower right chest correctly classified 94% of the group, with specificity kept at 95%. Most features were measured in early and mid-QRS, although very potent discriminators were found in the late portion of the T wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of myocardial infarction on high-frequency QRS potentials.

Studies have shown that the number of high-frequency QRS notches increases after myocardial infarction (MI). To assess overall high-frequency (greater than 80 Hz) potentials more quantitatively, we adapted filtered and the root-mean-square (RMS) voltage of the residual (80-300 Hz) signal computed. High-frequency RMS values were significantly (p less than 0.01) greater in leads II, III and aVf in normal subjects (n = 12) than in patients with inferior infarction (n = 12). Similarly, high-frequency RMS values were higher (p less than 0.01) in leads V2 and V5 in normal subjects (n = 14) than in patients with prior anterior MI (n = 14). A reduction in high-frequency RMS values with inferior infarction was independently confirmed using Fourier analysis of the QRS in lead II. QRS notching in these subjects was also quantified by computing the number of baseline crossings of the first derivative (dV/dt). As predicted, notching was significantly greater (p less than 0.05) both with inferior MI (lead II) and anterior MI (lead V5). However, contrary to classic theory, the number of notches correlated negatively with direct measurements of high-frequency RMS voltage in lead II (r = -0.63) and lead V5 (r = -0.49). Positive correlations were obtained between high-frequency potentials and two new indexes that measure the amplitude of QRS dV/dt-peak-to-peak amplitude of dV/dt and RMS dV/dt. Using these indexes, absolute separation of inferior MI patients and normal subjects was obtained. We conclude that MI increases low-amplitude QRS notching but diminishes total high-frequency voltage, probably because of an overall decrease in electromotive potentials and slowing of ventricular conduction.

Incidence of 'Precordial ST-Segment Depression' in Acute Inferior Myocardial Infarction

Patients of acute inferior myocardial infarction, in addition to the ST segment elevation in inferior leads often have ST segment depression in the precordial leads. This study was performed to observe the incidence of these ‘reciprocal’ ST changes. One hundred consecutive acute inferior myocardial infarction patients were included in the study. They were further allocated to two electrocardiographic groups. Group 1 consisted of patients of acute inferior myocardial infarction with precordial ST segment depression &amp; Group 2 consisted of patients of acute inferior myocardial infarction without precordial ST segment depression. Among the 100 consecutive patients, a large number of patients were included in group 1 (76%). Significant number of patients of group 1 belonged to the age group of above 60 years compared to group 2 (27.6% vs. 4.2%; p &lt; .02). Conversely significantly higher number of younger patients ≤ 40 years belonged to group 2 (41.7% vs. 11.9%; p &lt; .01). Mean ST segment elevation (mm) was also significantly higher in group 1 than group 2 (4.07 ± 1.93 vs. 2 ± 0.78; p &lt;.001). The patients of acute inferior myocardial infarction thus show a significant number of ST segment depression in their precordial leads. In different studies these subset of patients showed increased morbidity and mortality. Key words: acute inferior myocardial infarction; precordial ST segment depression. DOI: 10.3329/uhj.v6i1.7185University Heart Journal Vol.6(1) 2010 pp.21-22