Inferior Infarction Group Research Articles

Right Ventricular Myocardial Infarction : Presentation and Acute Outcomes

Right Ventricular Infarction (RVI) complicating inferior wall myocardial infarction (MI) is common and associated with significant morbidity and mortality. We try to systematically assess the incidence, clinical presentation and in hospital outcomes of right ventricular myocardial infarction in a tertiary-care set up. This study was a descriptive, cross sectional observational series of consecutive patients with RVMI. All patients with acute inferior myocardial infarction (n=100) were enlisted. RVMI was diagnosed by ≥1mm ST elevation in lead V4R in right sided electrocardiogram. RVI occurred in 31% (n=31) of patients of acute inferior infarctions. Patients with isolated inferior myocardial infarction served as controls (n=69). Echocardiography was performed within 24 hours of admission. From both groups, 51% were qualified for thrombolysis. The incidence of hypotension (96.7%), cardiogenic shock (64.5%), bradycardia and heart block were much higher in RVI than in inferior myocardial infarction. Clinically manifest RV dysfunction (raised jugular venous pulse, hypotension and tricuspid regurgitation) and right ventricular dilatation detected by echocardiography was seen in a variable number of patients. In hospital mortality rate was significantly higher (n=13, 41.9%) in right ventricular infarction group than in inferior myocardial infarction group (n=2, 2.9%)TAJ 2012; 25: 42-46

Significance of reciprocal ST segment depression in ST elevation myocardial infarction

BackgroundThe significance of reciprocal ST segment depression during acute myocardial infarction has been an area of debate, whether it is a sign of multivessel disease, ischemia at a distance or merely a benign electrical phenomenon. ObjectiveTo study the relation between the presence of reciprocal ST segment depression in ST elevation myocardial infarction, extent of coronary artery disease & left ventricular systolic function. Patients and methodsA prospective, controlled study involving 200 ST elevation myocardial infarction patients (100 inferior, 100 anterior), each group was sub-grouped into 2 subgroups according to the presence of reciprocal ST segment depression or absence: in anterior STEMI group we had subgroup A1 with RSTD (41 patients) and subgroup A2 without RSTD (59 patients) while in inferior STEMI group each subgroup (B1 and B2) consisted of 50 patients. Echocardiography & coronary angiography were done for all patients. ResultsPatients with reciprocal ST segment depression showed a significant lower mean Left ventricular ejection fraction compared to those without (37+3% vs 53+5% P<0.001, anterior ST elevation myocardial infarction subgroups) & (47+4% vs 60+3% P<0.001, inferior ST elevation myocardial infarction subgroups). Higher incidence of multivessel disease was found in subgroups with reciprocal ST segment depression (80.5% vs 49.2%, P<0.001 in anterior ST elevation myocardial infarction) & (60% vs 20%, P<0.001 in inferior ST elevation myocardial infarction). The mean modified gensini score was higher in subgroups with reciprocal ST segment depression (64.2+12.6 vs 30.2+6.6, P<0.001 in anterior infarction group) & (36.2+10.6vs 20.4+4.2, p<0.001 in inferior infarction group). ConclusionReciprocal ST segment depression in acute myocardial infarction was associated with significant LV systolic dysfunction & greater extent of coronary artery disease.

N-terminal probrain natriuretic peptide in patients with acute coronary syndrome .

To observe the changes and evaluate the significance of serum N-terminal probrain natriuretic peptide (NT-proBNP) levels in patients with acute coronary syndrome and to discuss its clinical significance and relationship with the severity of disease. Serum NT-proBNP levels were determined rapidly by using the triage BNP test for 98 consecutive patients with coronary heart disease (CAD) admitted to the hospital from March 2013 to December 2013; the correlation between the concentration of NT-proBNP and the degree of severity of the disease was analyzed. The levels of NT-proBNP in the acute myocardial infarction (AMI) group were higher compared with unstable angina pectoris (UAP), stable angina pectoris (SAP), and control groups, and the levels of NT-proBNP in UAP were higher compared to the SAP and control groups. Levels of NT-proBNP in the extensive anterior wall infarction group were higher compared to that of the inferior or anteroseptal wall infarction groups: p<0.05; the levels of NT-proBNP in the inferior wall and posterior wall infarction group were higher compared with the inferior wall infarction group and anteroseptal wall infarction group: p<0.05; the levels of NT-proBNP in the multi-vessel group were higher than those in the single-vessel group: p<0.05. The BNP level was positively correlated with age, heart rate, creatinine kinase-myocardial band (CK-MB), cardiac troponin T (cTnT), and blood urea nitrogen (BUN), whereas it was negatively correlated with left ventricular ejection fraction (LVEF). NT-proBNP is related to the lowering of left ventricular ejection fraction and the severity of myocardial ischemia. .

Clinical analysis of 30 cases of cardiac rupture in patients with acute myocardial infarction

ObjectiveTo analyse the characteristics, early diagnosis, and the suitable therapy of cardiac rupture (CR) in patients with acute myocardial infarction (AMI).Methods1526 consecutive cases of AMI from March 2002 to March...

E0432 An essential role of serum B-type natriuretic peptide in patients with acute inferior myocardial infarction

ObjectiveTo investigate the relationship between the level of serum B-type natriuretic peptide (BNP) and right ventricular infarction in patient s with acute inferior myocardial infarction (AIMI).MethodThe serum BNP level was...

Right Ventricular Myocardial Infarction: Presentation and Acute Outcomes

Acute inferior wall myocardial infarction can be complicated by right ventricular myocardial infarction (RVMI), and the excess mortality cannot be fully explained by mechanical reasons. The authors try to systematically assess the incidence, clinical presentation and early outcomes of right ventricular infarction in a tertiary-care setup. Their study was a prospective observational series of consecutive patients with RVMI. All patients with acute inferior myocardial infarction (n=135) were enlisted. RVMI was diagnosed by > or = 1 mm ST elevation in lead V(4R) in a right-sided electrocardiogram. Right ventricular (RV) infarction occurred in 37% (n=50) of patients with acute inferior infarctions. Patients with isolated inferior infarction served as controls (n=85). Echocardiography was performed within 24 hours of admission. From both groups, 66% qualified for thrombolysis. The incidence of hypotension-bradycardia and heart blocks requiring pacing support was much higher in right ventricular infarction (n=21) than in inferior infarction (n=13). Clinically manifest RV dysfunction (raised jugular venous pulse [JVP], hypotension, tricuspid regurgitation) and right ventricular dilation detected by echocardiography were seen in only 13 patients. The in-hospital mortality rate was significantly higher (n=8, 16%) in right ventricular infarction group than in inferior infarction group (n=3, 3.5%). Right ventricular infarction was seen in a third of inferior myocardial infarctions (IMIs), but hemodynamically evident right ventricular dysfunction occurred in only a tenth of acute IMIs. Nevertheless, the acute in-hospital mortality rate of patients with right ventricular infarction was much higher than in those with inferior infarction owing to arrhythmic and mechanical complications.

Relationship between infarction location and size to QT dispersion in patients with chronic myocardial infarction.

The relationship between the location and size of an infarction and QT dispersion was investigated in 84 Japanese patients with chronic myocardial infarction (54 with anteroseptal infarction and 30 with inferior infarction). The control group consisted of 23 subjects without ischemic heart disease (13 normal subjects and 10 hypertensive patients). Corrected QT dispersion (maximum corrected QT interval minus minimum corrected QT interval: QTc dispersion), was significantly larger in the anterior infarction group than in the control group (69.9+/-21.5 msec vs 53.0+/-17.6 msec), while the inferior infarction group showed no significant difference from control subjects. QTc dispersion was significantly greater in the patients with large anterior infarcts than in those with small anterior infarcts (80.5+/-20.5 msec vs 61.9+/-18.8 msec). In patients with chronic myocardial infarction, QT dispersion is influenced by the infarct location and size. Accordingly, interpretation of QT dispersion data should take these factors into consideration.

Clinical significance of perioperative Q-wave myocardial infarction: The Emory Angioplasty versus Surgery Trial

Objective: The primary end point of the Emory Angioplasty versus Surgery Trial was a composite of three events: death, Q-wave infarction, and a new large defect on 3-year postoperative thallium scan. This study examines the clinical significance of Q-wave infarction in the surgical cohort (194 patients) of the Emory trial. Methods: Twenty patients (10.3%) with Q-wave infarctions were identified: 13 patients had inferior Q-wave infarctions and seven patients had anterior, lateral, septal, or posterior Q-wave infarctions (termed anterior Q-wave infarctions). Results: In the inferior Q-wave infarction group, postoperative cardiac catheterization (at 1 year or 3 years) in 11 patients revealed normal ejection fraction (ejection fraction >55%) in 10 (91%), no wall motion abnormalities in 10 (91%), and all grafts patent in 10 (91%). In the anterior Q-wave infarction group, postoperative catheterizatiOn in six patients revealed normal ejection fractions in five (83%), no wall motion abnormalities in three (50%), and all grafts patent in three (50%). Average peak postoperative creatine kinase MB levels were as follows: no Q-wave infarction ( n = 174) 37 ± 43 IU/L, inferior Q-wave infarction 40 ± 27 IU/L, and anterior Q-wave infarction 58 ± 38 IU/L. Mortality in the 20 patients with Q-wave infarctions was 5% (1/20) at 3 years; in patients without a Q-wave infarction it was 6.3% (11/174) ( p = 0.64). Of 17 patients with a Q-wave infarction who underwent postoperative catheterization, 11 (65%) had a normal ejection fraction, normal wall motion, and all grafts patent with an uneventful 3-year postoperative course. Conclusions: The core laboratory screening of postoperative electrocardiograms, particularly in the case of inferior Q-wave infarctions, appears to identify a number of patients as having a Q-wave infarction with minimal clinical significance. Q-wave infarction identified in the postoperative period seems to be a weak end point with little prognostic significance and therefore not valuable for future randomized trials. (J T horac C ardiovasc S urg 1996;112:1447-54)

Comparison of secretion pattern between A-type and B-type natriuretic peptides in patients with old myocardial infarction

The present study was designed to compare the secretion patterns of two cardiac hormones--A-type (atrial) and B-type (brain) natriuretic peptides--from the ventricles in patients with old myocardial infarction. Plasma levels of these two natriuretic peptides are increased, and their secretion from the ventricles is augmented, in patients with congestive heart failure. We measured the plasma levels of these two types of natriuretic peptides at the aortic root and the anterior interventricular vein in 42 patients with old myocardial infarction (anterior in 22 and inferior in 20) and 18 control subjects. The difference between the plasma levels of both A- and B-type natriuretic peptide in the anterior interventricular vein and aortic root was significantly greater in the groups with anterior and inferior infarction than in the control group (A-type [mean +/- SD] 380 +/- 290 and 247 +/- 205 pg/ml in the infarction groups vs. 11 +/- 14 pg/ml; B-type 497 +/- 445 and 75 +/- 73 pg/ml vs. 23 +/- 16 pg/ml, respectively). The difference between the plasma levels of each peptide at the anterior interventricular vein and aortic root had a significant negative linear correlation with left ventricular ejection fraction in both groups with infarction. The slope of the regression line of the arteriovenous difference of B-type natriuretic peptide at the anterior interventricular vein was significantly steeper in the anterior than in the inferior infarction group (left ventricular ejection fraction -12.801 vs. -1.891, p < 0.01). These results indicate that 1) the secretion of A- and B-type natriuretic peptide from the left ventricular increases in proportion to the severity of left ventricular dysfunction, and 2) secretion of B-type natriuretic peptide is much greater from the infarct than from the noninfarct region, suggesting that the regional ventricular wall stretch caused by infarction strongly stimulates secretion of B-type natriuretic peptide.

Spatial orientation of the vectorcardiogram in patients with myocardial infarction.

We studied the rotation angles on the each of 3 axes and the planarity and roundness of QRS loop when its plane was laid close to horizontal in 4 groups of patients. Thirty five had anterior myocardial infarction, 34 inferior infarction, 15 non Q wave inferior infarction, and 34 were normal subjects. The rotation angles of the QRS loop were significantly different from the controls, on the Y and Z axes in the anterior infarction group, on the Z axis in the inferior infarction group and on the X axis in the non Q wave inferior infarction group (p < 0.01). The planarity index in the inferior infarction group was significantly higher (p < 0.01) than in other groups. The significantly smallest value of the roundness index was noted in the anterior infarction group (p < 0.01). Significant features of the early segmental planarity indexes were shown in the non Q and Q wave inferior infarction groups (p < 0.01). We conclude that the rotation angles and the planarity and roundness indexes are characteristic parameters for the infarct group and may be useful for diagnosing myocardial infarction, which is difficult with electrocardiography and vectorcardiography.

Diagnosis of Recent Myocardial Infarction With Quantitative Backscatter Imaging: Preliminary Studies

Acute myocardial ischemia and chronic myocardial infarction may be recognized with ultrasound tissue characterization techniques because of myocardial acoustic changes caused by reduced perfusion and/or collagen deposition. Our purpose was to study the acoustic properties of recent myocardial infarction when the predominating pathologic finding was myocardial edema and leukocytic infiltration. We used a new quantitative backscatter imaging system to study 18 patients 9 +/- 5 days after myocardial infarction (eight patients with anteroseptal myocardial infarction and 10 with inferior myocardial infarction) and 20 normal subjects. The cyclic variation of relative integrated backscatter (end-diastolic minus end-systolic) was calculated from on-line measurements. Standard parasternal long- and short-axis and apical four- and two-chamber views were obtained. In the anteroseptal myocardial infarction group, the cyclic variation of relative integrated backscatter was lower in the septum (1.5 +/- 1.6 dB) than in the posteroinferior wall (3.2 +/- 1.2 dB); however, the sample size of only three patients (of eight patients imaged) in the latter group prevented statistical comparison. The cyclic variation of relative integrated backscatter in the infarcted septum was less than the measurement obtained in the septum of the control group (4.3 +/- 2.4 dB, p less than 0.05). In the inferior infarction group, the cyclic variation of integrated backscatter in the posteroinferior wall (1.8 +/- 1.7 dB) was not significantly different from the measurement obtained in the septum (3.7 +/- 3.6 dB); however, the cyclic variation in the posteroinferior wall was significantly less than that obtained in the control group posteroinferior wall (5.7 +/- 1.7 dB, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Inferior ST segment changes during acute anterior myocardial infarction: A marker of the presence or absence of concomitant inferior wall ischemia

The significance of inferior ST segment changes during acute anterior myocardial infarction was studied in 60 patients with acute anterior infarction who had angiographic visualization of the entire distribution of the left anterior descending artery after thrombolytic therapy with streptokinase. In 34 patients (Group 1) this artery supplied the anterior wall of the left ventricle up to or including the apex but did not reach the inferior wall; in 16 patients (Group 2) it continued beyond the apex onto the inferior wall of the left ventricle; and in 10 patients with prior inferior infarction (Group 3) it partially supplied the inferior wall of the left ventricle through collateral channels to an occluded right or dominant circumflex coronary artery. Consistent with this anatomy, evidence of inferior wall ischemia was significantly more frequent in Groups 2 and 3 than in Group 1 by thallium-201 scintigraphy (91 versus 7%) and by contrast left ventriculography (91 versus 13%). There was no difference in the magnitude of precordial ST segment elevation among the three groups but the inferior ST segment depression was significantly smaller in Groups 2 and 3 with concomitant inferior wall ischemia than in Group 1 (aVF: -0.5 +/- 0.7; -0.5 +/- 1.0; -1.8 +/- 0.8 mm, respectively; p less than 0.001) with 10 of the 26 patients in Groups 2 and 3 having an elevated or isoelectric ST segment in aVF compared with none of the 34 patients in Group 1 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Achievement of coronary artery patency by use of anisoylated plasminogen streptokinase activator complex in acute myocardial infarction.

Anisoylated plasminogen streptokinase activator complex (APSAC) is a recently developed thrombolytic agent with high fibrin-binding potential and sustained release pharmacokinetics (plasma half-life 70 minutes). Following studies of its intracoronary use, the efficacy was examined, in an open study using coronary angiography, of a single bolus dose of 30U given intravenously to 94 patients within 6 hours (mean 2.97 hours) from the onset of symptoms of myocardial infarction. After thrombolytic therapy, patency of the left anterior descending artery was demonstrated in 32 of 42 patients with anterior infarctions (76%), and in 12 of 13 patients with circumflex (92%) and 28 of 36 with right coronary artery infarcts (78%) in the inferior infarction group. The overall incidence of reocclusion was 24%, which occurred within the first 12 days after hospitalisation. Successful thrombolysis was associated with rapid resolution of the acute ST segment change, and an early peak of creatine phosphokinase (CK) compared with patients whose vessels remained occluded. No major systemic bleeding complications were experienced. Single dose intravenous APSAC appears to be a highly effective and relatively safe thrombolytic agent which has the major advantage over other such agents of easier administration. This makes it suitable for use in district hospitals and in the community, as well as in specialised cardiac centres.

The daily profile of ventricular premature beats in the patients with ischemic heart disease.

To clarify factors affecting the prevalence of ventricular premature contraction (VPC) in patients with stable ischemic heart disease, daily profiles of VPC prevalence were studied in 92 patients using continuous 24-hour electrocardiographic recordings. VPCs in patient groups with effort angina and inferior infarction showed similar daily profiles. However, a significant relationship between VPC prevalence and heart rate was observed in inferior infarction group, while patients with resting angina exhibited another relationship between the two parameters. Higher prevalence rate of VPCs in the early morning in patients with resting angina suggested the contribution of cardiac autonomic nerve activity to the increased frequency of VPCs, while constant frequency of VPCs during the day in anterior infarction group provided no influences on heart rate, effort, and autonomic nerve activity on the VPC prevalence. Age, sex, left ventricular ejection fraction, and nitrates and diltiazem used for the treatment of angina pectoris did not affect the daily profile of VPC prevalence in any patient groups. These results indicated that the clinical and pathophysiological differences of ischemic heart disease, even in stable patients, showed the different distribution of VPC prevalence within a day which is due, in part, to the varied activities of cardiac autonomic nerves.

Prognostic significance of electrocardiographic site of infarction after correction for enzymatic size of infarction.

To assess whether the site of myocardial infarction is an independent prognostic indicator, the outcome of patients with anterior myocardial infarction was compared with that of patients with inferior infarction. A consecutive series of patients who had suffered their first myocardial infarction was analyzed (398 with anterior and 391 with inferior infarction). Patients with anterior myocardial infarction had a higher 1 year mortality than those with inferior infarction (18.3% vs 10.5%, p = .002). When patients were matched for infarct size determined by peak creatine kinase (CK) level expressed as a multiple of the upper limit of normal, those with anterior myocardial infarction tended to have a higher 1 year mortality than those with inferior infarction for all subgroups of peak CK. Early mortality (day 1 to 28 after myocardial infarction) was greater in the anterior than in the inferior myocardial infarction group (10% vs 6.4%, p = .03); this was most significant when peak CK was greater than four times normal (12.4% vs 7.0%, p = .04). Late mortality was also higher in the anterior (8.4% vs 4.1%, p = .04) than the inferior infarction group and this was most significant when peak CK was less than two times normal (15.2% vs 0%, p = .02) or greater than eight times normal (10.6% vs 4.1%, p = .04). Multivariate analysis with proportional-hazards regression confirmed the prognostic significance of location of infarction independent of peak CK level. Thus, infarct location was found to be a predictor of prognosis that is independent of infarct size based on peak CK levels.

Survival after hospital discharge in matched populations with inferior or anterior myocardial infarction

Prognostic differences between patients with anterior or inferior myocardial infarction are often related to such variables as previous infarction or the size of the myocardial infarct. We examined the determinants of mortality in 997 hospital survivors of acute Q wave infarction (anterior in 449, inferior in 548) who, although not preselected, were well matched with respect to age, sex and prior infarction or congestive heart failure. Additionally, there was no significant difference in peak serum creatine kinase (CK) between the groups with anterior and inferior infarction (1,459 +/- 1,004 versus 1,357 +/- 1,036). Among the patients with anterior infarction who died during the 1 year follow-up period, 56% died in the first 60 days after hospital discharge compared with 18% of those without inferior infarction (p less than 0.01). Survival curves then became nearly identical at 3 months, and remained so until 1 year when the total mortality rate was 10% for the anterior and 7% for the inferior infarction group (p = NS). Variables associated with heart failure during the hospital phase were more prevalent in anterior infarction, but rales above the scapulae during the hospital stay (p less than 0.0001) and ventricular gallop at the time of discharge (p less than 0.0001) were the top two predictors of 1 year mortality by both univariate and multivariate analysis in inferior infarction. Age (p less than 0.0001) and peripheral edema (p less than 0.0001) were the strongest predictors of mortality in anterior infarction. Previous infarction, although just as common in the group with anterior infarction, was present at 1 year in 48% of nonsurvivors of the group with inferior infarction compared with only 19% of survivors (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Relationships between single-vessel coronary artery obstructions and wall motion dysfunction analyzed by four computer-based methods

We analyzed regional wall motion in 238 patients by using cineangiograms recorded in the 30° right anterior oblique projection. The sample was divided into three groups: a normal group ( n = 71), a group with isolated obstruction of the left anterior descending coronary artery and previous anterior myocardial infarction ( n = 85), and a group with isolated obstruction of the right coronary artery and previous inferior myocardial infarction ( n = 82). Both anterior and inferior groups also had motion abnormality within the corresponding anterior or inferior wall as judged by the qualitative analysis of cineangiograms. Four quantitative methods were compared: a long axis method and a center of mass method using internal reference systems, a method derived from the Stanford model and an area-based method using external reference systems. Normal regional values were determined from the normal group to evaluate the specificity and sensitivity of the methods. The area-based method was the most sensitive in the anterior infarction group, whereas the center of mass method was the most sensitive in the inferior infarction group. We conclude that there is no evidence that any method, among those tested, is superior to others for every expected location of wall motion abnormality.

Right ventricular function evaluated by radionuclide angiography in acute myocardial infarction

Radionuclide angiographic studies were performed in 26 patients with a first myocardial infarction, 11 with anterior and 15 with an inferior location. Right ventricular (RV) and left ventricular (LV) ejection fractions (EF) were determined. Mean LVEF in anterior infarctions (33.2 ± 7.3) was lower than in inferior myocardial infarctions (59.9 ± 10.2) ( p < 0.001). Mean RVEF in the anterior infarct group was 41.3 ± 15.1 and in the inferior myocardial infarction group 33.7 ± 12.8 ( p = NS). RVEF was less than 40% in 11 of 15 (73%) with inferior and 7 of 11 (66%) with anterior myocardial infarction. The ratio of LVEF:RVEF was 0.84 ± 0.19 in the anterior and 2.13 ± 1.28 in the inferior myocardial infarction group ( p < 0.001). LVEF correlated with RVEF in patients with anterior infarcts ( r = 0.77, p < 0.05) but not in those with inferior myocardial infarction ( r = 0.14). RV regional wall motion abnormalities were observed in the inferolateral zones in 10 of 15 (66%) with inferior and in none of the 11 patients with anterior myocardial infarctions ( p < 0.001). Inferoseptal wall motion abnormalities were observed in 3 of 15 (20%) with inferior and 6 of 11 (56%) with anterior myocardial infarctions (p = NS). RV dysfuction in the inferior infarctions is probably an expression of primary RV dysfunction rather than secondary to LV dysfunction. RV dysfunction was proportional to LV dysfunction in the anterior infarction group and was ofter accompanied by RV septal contraction abnormalities.

Diagnostic value of electrocardiogram and vectorcardiogram in postinfarction ventricular asynergy

The ability of ECG-VCG to predict the severity of postinfarction LV asynergy was evaluated in 152 patients with previous myocardial infarction who underwent left cineventriculography in the right anterior oblique view. Various ECG and VCG signs were examined in order to predict the existence of severe asynergy in general (dyskinesia or akinesia or severe hypokinesia) and of dyskinesia in particular. In patients with inferior myocardial infarction (Group A) persistent ST segment elevation was the only specific ECG sign (100%) of severe asynergy; it had a poor sensitivity (6.2%). Four frontal VCG signs (presence of terminal bite, y- greater than 0.18 mV, maximum early superior vector along x axis = MESV greater than or equal to 1.3 mV, duration of initial superior forces = DISF greater than 50 msec) increased the sensitivity of the ECG-VCG method to 75.8% while maintaining a 100% specificity. Regarding the diagnosis of dyskinesia, only the ECG sign of persistent ST segment elevation and the VCG sign of y- greater than or equal to 0.3 mV had a 100% specificity. The sensitivity of the ECG-VCG method was 33.3% (16.6% ECG and 16.6% VCG). In patients with anterior myocardial infarction (Group B), concerning the diagnosis of severe asynergy, the ECG signs of sigma ST greater than 3 mm in anterior leads; pathologic Q wave in four or more anterior leads (including D1 and aVL); and the presence of LAH or LAH + RBBB, had a 100% specificity and a good sensitivity (60.5%). The VCG sign of a narrow horizontal QRS loop increased the sensitivity of the ECG-VCG method to 71% while maintaining a 100% specificity. As for the diagnosis of dyskinesia, the ECG signs with a 100% specificity were sigma ST greater than or equal to 5 mm in anterior leads, a pathologic Q wave in more than five anterior leads (including I and a VL) and RBBB + LAH; these variables had a sensitivity of 48.3%. The VCG sign of a narrow horizontal QRS loop increased the sensitivity of the ECG-VCG method to 79.3% while maintaining a 100% specificity. In patients with inferior plus anterior myocardial infarction (Group A + B) the signs mentioned above for each group were evaluated, confirming a 100% specificity. Regarding the diagnosis of severe asynergy, the ECG signs had a sensitivity of 61.3%, while VCG increased the sensitivity of the ECG-VCG method to 90.3%.(ABSTRACT TRUNCATED AT 400 WORDS)

Re-evaluation of the vectorcardiographic criteria for inferior myocardial infarction. Correlation between vectorcardiograms and left ventriculograms.

In 72 patients satisfying the vectorcardiographic criteria described by Young et al, vectorcardiographic findings were compared between a group of patients with an inferior myocardial infarction and a false positive group to increase the specificity of the vectorcardiographic diagnosis of inferior myocardial infarction. The first group was composed of 18 cases, with angiographic findings of inferior myocardial infarction and the false positive group was composed of 54 cases which had no significant narrowing of coronary arteries. Vectorcardiographic parameters such as the angle between the X axis and maximal QRS vector, the duration of initial superior force, the maximal superior deviation (QY) and the maximal inferior deviation (RY) were analyzed and only QY and QY/RY showed statistically significant differences between the 2 groups. Of these two parameters, QY/RY indicated a more definite difference. In addition, the rate of false positive cases was reduced prominently if the criterion of QY/RY above or equal to 0.2 was added to the criteria of Young et al. The direction of the maximal T vector was downward in 2 cases (11%) in the inferior myocardial infarction group, but downward in 44 cases (81%) in the false positive group.