Evaluation of regional myocardial function in ischemic heart disease by echocardiography

Left Ventricular Thrombus in Myocardial Infarction After Successful Primary Percutaneous Coronary Intervention: Prevalence and Predictors-A Middle Eastern Single-Centre Experience

Background

Left ventricular thrombus (LVT) is a well-recognized complication of myocardial infarction that affects patient outcomes and warrants screening.

Methods

This retrospective study included 308 consecutive patients who presented with acute ST-elevation myocardial infarction and were treated with primary percutaneous coronary intervention.

Results

Early screening for LVT by echocardiography and cardiac magnetic resonance revealed the following: LVT (+) group (36 patients [11.7%]) and LVT (−) group (272 patients [88.3%]). The 2 powerful independent variables associated with LVT formation were left anterior descending–related infarct (odds ratio, 10.17; P < 0.0001) and severe left ventricular systolic dysfunction (odds ratio, 8.3; P = 0.0001). The lower the left ventricular ejection fraction, the higher the risk of LVT was. Multivessel coronary artery disease and the type of early invasive strategy (culprit lesion only vs complete revascularization) were not predictive of LVT. The impact of environment (i.e., hot climate, exercise) and dehydration on the risk of LVT formation is uncertain.

Conclusion

Early LVT formation is a frequent complication in acute ST-elevation myocardial infarction despite timely intervention. Its independent predictors are left anterior descending–related infarct and severe left ventricular systolic dysfunction. In patients with multivessel coronary artery disease, there was no significant difference between lesion-only culprits and complete revascularization in reducing the risk of LVT development. Further studies in larger numbers of patients are needed because of the uncertainties regarding the links between the biological effects of the environment and the risk of LVT formation.

Usefulness of multiaxis echocardiography in assessment of the left ventricle in ischemic heart disease. A review

Echoventriculography, a multiaxis M-mode echocardiographic technique, was developed to examine in detail the regional wall motions of the left ventricle. The basic technical aspects and limitations are described, and experience is reviewed on 263 healthy subjects or patients with ischaemic heart disease. The reliability in detecting site and size of asynergic segments was excellent as related to electrocardiographic and thallium scintigraphic sites of acute infarction, and with left ventricular cineangiograms in chronic coronary heart disease. The correlation with pathologic anatomic size of infarct in 24 consecutive patients was r = 0.88 (p less than 0.001) when expressed by a percentage of the left ventricular horizontal circumference. 94% of 111 infarcted segments were correctly detected by echo; only the posteroseptal and the most lateral regions remain out of the methodological range. The method separated old infarct scars from fresh necrosis. Decreasing echo contraction index correlated with increasing severity of coronary obstructions in 43 patients studied for coronary artery surgery. In 15 infarct patients the M-mode technique was more sensitive than two-dimensional echocardiography in recording asynergic segments or endocardial echoes. The multiple segmental echoventriculographic index decreased parallel with clinical severity of acute infarction (r = -0.79, p less than 0.001; 30 patients). There was a 88% (p less than 0.01) concordance between the reduction of the ST segments (-30%) and the recovery of the mechanical function in the ischaemic myocardial segments (+26%) after beta blockade with pindolol in 22 patients with acute infarction. Methylprednisolone showed no improvement. With dopamine the left ventricular size decreased markedly (p less than 0.0005). Echoventriculography thus seems to be very informative in evaluation of chronic or acute left ventricular dysfunction, despite the rather demanding nature of the technique in practice.

Quantification of left ventricular wall dysfunction by M-mode echocardiographic mapping in heart failure following acute myocardial infarction

Echocardiographic mapping was performed in 44 patients on arrival in hospital and day 2 following acute myocardial infarction (AMI). To evaluate left ventricular (LV) function the per cent deviation of the mean systolic wall velocity (PD-V) from the normal was measured from 16 LV segments. Adequate data were obtained from 89% of the segments. The number of hypokinetic segments was somewhat higher in anterior than inferior AMI, reaching significance (p less than 0.05) on day 2. Dyskinetic segments were also more common in patients with anterior infarction (p less than 0.001), who also had significantly higher enzyme maxima than patients with inferior AMI (p less than 0.01). Enzyme maxima correlated well with the sum of PD-V from all hypokinetic segments on day 1 (r = 0.79, p less than 0.01). Compensatory hyperkinesia was more common in inferior than anterior AMI (p less than 0.001). Global LV function, estimated by subtracting the number of hyper- from hypokinetic segments (score sigma S:Adj), was significantly related to heart failure (Killip classification) (p less than 0.01) and the respiratory rate (r = 0.71, p less than 0.01) in the acute phase as well as to heart failure during the first post AMI month (New York Heart Association classification).

Prediction of apical thrombus formation in acute myocardial infarction based on left ventricular spatial flow pattern

The predictive value of the left ventricular spatial flow pattern for thrombus formation was determined in 62 patients with acute myocardial infarction. A normal flow pattern by pulsed Doppler echocardiography was characterized by 1) simultaneous onset of blood motion at the mitral valve and apical level, and 2) a discontinuous Doppler signal along the lateral wall and interventricular septum. The flow pattern was assessed by these criteria, within 24 h after the onset of complaints and after 6 and 12 weeks. In 46 of the 62 patients, a normal flow pattern was found at the first examination; none of these 46 patients developed a thrombus during the study period. An abnormal flow pattern was seen at the first examination in 16 patients; this pattern normalized during follow-up in 6 patients, none of whom developed a thrombus. In the other 10 patients the abnormal flow pattern persisted, and 7 of these developed a thrombus. These findings suggest that a normal left ventricular flow pattern in the setting of acute myocardial infarction is not associated with subsequent thrombus formation. This observation may be of importance if anticoagulation is considered.

Quantitation of myocardial dyssynergy in closed-chest dogs by two-dimensional echocardiography

Myocardial infarction was produced in 29 anaesthetized mongrel dogs by a closed-chest coronary occlusion technique. A two-dimensional echocardiographic examination (2-D echo) was carried out just before occlusion and again 48 h after occlusion. Many cross-sectional images were recorded by a video-tape recorder. The applied site of the probe was fixed in an intercostal space and the direction of the ultrasonic beam was tilted stepwise from the basis to the apex. The animals were sacrificed at 49 hours after occlusion. The hearts were removed, quick frozen, sliced into radiating sections and stained with nitroblue tetrazolium (NBT). The outline of dyssynergy, including dyskinesis, akinesis or extreme hypokinesis, was traced with a tablet digitizer by two specialists. The three-dimensional image of dyssynergy in the left ventricular wall was reconstructed by a computer in spherical co-ordinates and assumed to be made of numerous triangular pyramids. The volume of dyssynergy was calculated quantitatively as the sum of volumes of these numerous triangular pyramids. The volume of dyssynergy seen in 2-D echo correlated well over a wide range with the volume of infarction determined by NBT staining.

Dialysis-associated ischemic heart disease: insights from coronary angiography

We reviewed the records of 44 dialysis patients who had undergone one or more coronary angiograms to determine the frequency with which symptomatic ischemic heart disease (IHD) and significant coronary artery narrowing coincided and to determine those factors which were associated with the coronary atherosclerotic process. Thirty-four patients were catheterized for angina pectoris or myocardial infarction. Of this group, 53% were found to have significant narrowing of coronary arteries. This group was older than the group with trivial or no coronary artery occlusion and their duration of dialysis was shorter. All the patients with significant coronary occlusion were white and the majority were adult males. Discriminant function analysis revealed that the presence of significant coronary artery occlusion could be predicted with high sensitivity and specificity by the following variables: older age, white race, male sex, the presence of symptomatic IHD prior to the onset of dialysis, increased total serum cholesterol, abnormal left ventricular wall motion, and reduced alkaline phosphatase. We also found that the occurrence of symptomatic IHD far exceeded the presence of significant atherosclerotic coronary artery narrowing. We suggest that this may result from several dialysis-associated alterations in oxygen delivery and myocardial oxygen consumption.

Improvement in regional ventricular function after percutaneous transluminal coronary angioplasty

We performed atrial pacing and radionuclide ventriculography in 12 patients before and after percutaneous transluminal coronary angioplasty (PTCA). Successful dilatation was achieved in 9 patients while in 3 the procedure was unsuccessful. Atrial pacing before PTCA showed ischemic dysfunction of the region supplied by the narrowed coronary artery. Regional ejection fraction decreased by 36 +/- 12% during rapid atrial pacing, while global left ventricular ejection fraction fell by 11 +/- 7% with a secondary increase in end-diastolic and end-systolic ventricular volume with the onset of ischemia. After successful PTCA, ischemic dysfunction was ameliorated or abolished. Measurements made at identical heart rates showed that both global and in particular regional left ventricular ejection fraction were significantly higher after successful angioplasty and did not fall during the stress of atrial pacing. There was no improvement in regional or global LV function in patients in whom angioplasty was not successful. The study showed that nuclear ventriculography with the stress of graded atrial pacing was a useful method for analysing the immediate results of coronary angioplasty and for studying its effects on regional myocardial function.

Electrocardiographic changes after myocardial infarction as indicators of deranged regional left ventricular wall motion. A serial M mode echocardiographic mapping study

Electrocardiographic and echocardiographic findings were compared in 44 patients with a first transmural infarction. Each patient was investigated on days 1, 2, 10, and 360. The electrocardiogram was classified according to QRS and ST segment changes. Local left ventricular function was determined from mean systolic wall velocity measurements by an M mode echocardiographic mapping technique in 10 of 16 segments suitable also for electrocardiographic evaluation. Mean systolic wall velocity was corrected for differences in anterior and inferior wall motion. Wall motion was normal in segments without QRS or ST changes throughout the study. All segments with QRS or ST changes showed significantly lower corrected systolic wall velocity values during the acute stage. Segments with ST depression, alone or in combination with a minor Q wave, had corrected mean systolic wall velocity values similar to those of normal segments after one year. Segments with major Q waves and all segments with ST elevation showed reduced corrected mean systolic wall velocity values throughout the study. Segments with ST elevation, irrespective of Q waves, showed the most severely reduced wall motion with significantly lower corrected mean values than segments with minor or major Q waves without ST elevation on days 10 and 360. Thus when electrocardiograms are used for defining local left ventricular function, consideration must be given to the phase of illness, QRS morphology, and presence of ST segment elevation.

Left ventricular mural thrombi secondary to acute myocardial infarction: predisposing factors and embolic phenomenon

Twenty-five patients with acute myocardial infarction were examined for ventricular thrombi using two-dimensional echocardiography. Six of 10 patients (60%) with an anterior wall infarction had an apical or apical-septal thrombus within the first week of hospitalization. None of the fifteen patients with an inferior wall myocardial infarction had a mural thrombus. Although the size of infarction in the patients with a thrombus was not significantly larger than in those who had an anterior wall infarction without a thrombus (43% +/- 10% vs. 31% +/- 7%, P less than 0.1), the severity and extent of dyskinesia or akinesia were more marked in the former group. Left ventricular function as determined by the nuclear blood pool scan ejection fraction was also significantly less for the former group than for the latter group (21% +/- 6% vs. 40% +/- 11%, P less than 0.02). Three of six patients with an intracavitary thrombus on echocardiography had systemic embolic during their hospital course. Postinfarction ventricular thrombi tend to occur in those patients with an anterior wall myocardial infarction who have far advanced wall motion abnormalities of the affected area, and overall poor left ventricular function. Although the number of patients was small, the high incidence of systemic embolization in the infarction subjects with echocardiographically proven thrombi indicates that these patients are at increased risk for such events.

A comparison of conventional contrast ventriculography and digital subtraction ventriculography

We studied 46 patients with a history of transmural myocardial infarction or angiographic evidence of coronary artery stenosis with both conventional contrast ventriculography and digital subtraction ventriculography from May to September 1982. Urografin 76, 30 ml, was administered at a flow rate of 18 ml/s, by means of a catheter in the superior vena cava during digital subtraction ventriculography (DSV). Results of the latter were compared with conventional contrast ventriculograms. The correlation coefficient was r =0.938 (p less than 0.001) for determination of ejection fraction with both methods. The data in individual cases suggest that DSV is more sensitive than conventional contrast ventriculography in determination of severely reduced ejection fractions. The methods are practically identical in qualitative evaluation of disorders of regional wall motion in the anterolateral region, while DSV is more sensitive than conventional ventriculography in evaluating the apical region. Sensitivity was 85.7% when the two methods were compared in evaluation of the inferior region of the left ventricle. Both methods are identical in demonstration of severely deformed ventricles. Digital subtraction ventriculography may replace conventional contrast ventriculography in some of the situations discussed above.

Apex two dimensional echocardiography. Alternative approach to quantification of acute myocardial infarction

Apex echocardiography has been chosen as an approach to detect and quantify acute myocardial infarction because the usual parasternal acoustic windows are often occluded. Fifty-three patients were studied, all within 12 hours after the onset of symptoms of their first myocardial infarction. Three apical long axis views were obtained, that is the two and four chamber views, and the right anterior oblique equivalent or three chamber view. Satisfactory echocardiograms were obtained in 48 patients (91%). The individual apical views were divided into equal segments and the area of asynergy was estimated in each view. Left ventricular asynergy was present in all 48 patients. In 46 patients a positive correlation between the electrocardiogram and the echocardiogram was obtained, as far as infarct localisation was concerned. The estimated asynergic area correlated well with the peak value of the isoenzyme of creatine kinase (CK MB). Apex echocardiography is a reliable alternative method of detecting and quantifying myocardial infarction soon after the onset of symptoms.

Prevalence of regional left ventricular dysfunction in patients with coronary artery disease

Left ventricular (LV) wall motion was evaluated prospectively by M-mode echocardiography for 503 patients, and results were compared with cinearteriographic and ECG findings. M-mode results from 92 of the patients were also compared with two-dimensional echocardiographic (2D) and LV angiographic findings. Abnormal echo motion was found by M-mode in 89 percent of patients with ECG Q waves of infarction and in 61 percent of coronary artery disease (CAD) patients without Q waves. Thirty-four percent of CAD patients had normal wall motion on M-mode examination. More abnormalities were detected when patients were examined using both M-mode and 2D, because M-mode was more sensitive in detecting anterior lesions and 2D was more sensitive in detecting posterior lesions. Both M-mode and 2D showed a low incidence of false-positive diagnosis (less than 2 percent) for patients with normal findings at cardiac catheterization.

Detection and quantification of acute, isolated myocardial infarction by two dimensional echocardiography

Ninety consecutive patients with acute, isolated myocardial infarction were evaluated with two dimensional echocardiography. Satisfactory echocardiograms were obtained in 66 patients (73 percent). All patients were studied 2 to 12 hours after the onset of symptoms. Sixty patients had additional studies at 48 and 72 hours. Long axis views were obtained at the base, body and apex of the left ventricle. Five short axis views of the left ventricle were obtained at different levels from the cardiac base to the apex. The individual short axis views, corrected for the end-diastolic internal diameter of the left ventricle, were divided into equal segments and the area of asynergy in each view was estimated. Infarct localization was similar on electrocardiography and echocardiography in 62 of 66 patients. In two dimensional echocardiography in one patient. The results of an echocardiographic study in one patient were false negative. During the study period the individual asynergic area remained stable. The initial asynergic area correlated well (r = 0.87, p less than 0.01) with the peak value of the isoenzyme of creatine kinase (CK-MB), which occurred hours later. Thus, two dimensional echocardiography is a reliable method to localize and quantify, early after the onset of symptoms, the eventual extent of myocardial involvement in patients with acute, isolated infarction.

Echoventriculography in acute myocardial infarction. IV. Infarct size and reliability by pathologic anatomic correlations

A morphologic-echocardiographic comparison was carried out in 24 consecutive patients to determine the accuracy of multidirectional single-beam echocardiography in imaging the size and site of 22 fatal acute myocardial infarctions and of 2 postinfarction ventricular aneurysms treated surgically. Echocardiography never missed the infarction, regardless of whether the infarction was anterior or posterior. The correlation between the echocardiographic and pathologic anatomic extent of infarct, as expressed by a percentage of the left ventricular horizontal circumference, was r=0.88 (p less than 0.001). One hundred four of one hundred eleven infarcted segments (94%) were detected by echo; only the posterior septal and the most lateral segments of the left ventricle tended to remain out of range of the method. The regional asynergy at the center of the infarcted region was clearcut-systolic thickening was never seen and the systolic wall motion was paradoxical in 75% of the patients (mean, -20+/-2.0 mm). Analysis of the regional function from multiple sites characterized reduction of the left ventricular performance (p less than 0.0005) better than did the ejection fraction in the presence of asynergy. An old postinfarction scar was differentiated from the acute necrosis. Thus, segmental left ventricular akinesis or paradoxical motion as seen by multidirectional echocardiography permits noninvasively a reliable estimation of the extent of acute myocardial infarction.