Two-dimensional echocardiographic demonstration of restoration of normal wall motion after acute myocardial infarction

Increasing frame rate in ultrasound imaging by temporal morphing using tissue Doppler

The diagnostic value of echocardiographic images seems to diminish when the frame rate is low. In this work, morphing based on velocity information was used to improve the perceived smoothness of B-mode cine-loops with low frame rate. Based on an estimate of the velocity field calculated from B-mode speckle tracking and tissue Doppler measurements, morphed cine-loops with arbitrarily high frame rate were created. Morphing was applied to cardiac ultrasound cine-loops with apical insonation. The quality of the morphed data was evaluated by removing frames from duplex B-mode and tissue Doppler recordings, then replacing the removed B-mode frames with morphed ones. The decimated and morphed sequences were compared to the original ones. Wall motion scoring, a subjective evaluation technique for regional viability of the myocardium, was applied to data from 20 patients with varying pathology. Sixty cine-loops were scored twice, first with original data and later with morphed data. The results were compared for each recording, and the scorings were identical in the two cases for 94% of the segments. We conclude that much of the diagnostic value is retained in recordings with 15 frames per second when temporal morphing is applied.

Detection and quantification of dysfunctional myocardium by magnetic resonance imaging. A new three-dimensional method for quantitative wall-thickening analysis

BACKGROUND

Regional left ventricular dysfunction is a major consequence of myocardial ischemia, and its extent determines long-term prognosis. Accurate and reproducible analysis of left ventricular dysfunction is therefore useful for risk stratification and patient management.

METHODS AND RESULTS

Short-axis cardiac cine magnetic resonance (MR) imaging was performed in 25 patients after anterior myocardial infarction at 21 +/- 2.1 days after the acute onset. The MR images were analyzed with the use of a dedicated analytical software package (MASS version 1.0), which includes a modified centerline method and a new three-dimensional analysis approach. A database of 48 healthy volunteers was constructed to objectively depict myocardial dysfunction in the patients; this database was compared with enzymatically determined infarct size. The mean (+/-SEM) quantity of dysfunctional myocardium and enzymatically calculated infarct size equaled 24.0 +/- 3.0 and 22.3 +/- 2.9 g, respectively (P = .69). Enzymatically determined infarct size correlated strongly with left ventricular dysfunction determined by cine MR imaging (y = 0.90x + .92. P < .0001). Segments related to the distribution of the left anterior descending coronary artery showed a significantly lower percentage wall thickening in patients than did corresponding segments of 48 normal subjects (46.0 +/- 8.22% versus 87.1 +/- mean SEM, respectively; P < .001). The mean (+/-SEM) end diastolic wall thickness of the infarcted segment did not differ from that of corresponding normal segments (7.4 +/- 0.33 versus 7.5 +/- 0.15 mm; P = .75).

CONCLUSIONS

We conclude that the use of three-dimensional quantitative analysis of cine MR images accurately quantities the extent of regional left ventricular dysfunction in the infarcted heart. This method of analysis may be useful in assessing the effect of interventional therapies.

Influence of reperfusion induced by thrombolytic treatment on natural history of left ventricular regional wall motion abnormality in acute myocardial infarction

Although several studies have investigated left ventricular (LV) function after reperfusion interventions, it is still unclear whether benefits result from successful therapy or whether such benefits only reflect the natural history of a subgroup of patients with acute myocardial infarction (AMI). This study evaluates the unique effect of thrombolytic therapy on the natural history of regional LV wall motion dysfunction. One hundred seventy-six patients with AMI were studied: 82 patients (group A) underwent conventional treatment and 94 (group B) thrombolytic therapy. LV regional improvement, evaluated by changes in echo score between admission and predischarge examination, was present more frequently in group B (28%) than in group A (17%). Furthermore, improved patients in group B had higher admission echo scores (7.5 +/- 3.5 vs 6.3 +/- 3.1), a prevalence of anterior AMI (68 vs 30.1%) and a higher rate of coronary patency (92 vs 58% in patients who had no improvement). In group A patients the rate of coronary patency was similar in those who did (46.1%) and did not have (36.1%) improvement. Observations at 12 to 18 months showed similar data in group A patients and in group B patients without improvement, whereas a marginal additional improvement was observed in group B patients who had in-hospital improvement. These observations demonstrate that LV function recovery is more frequent and marked in treated than in untreated patients. Follow-up results suggest a prolonged beneficial effect of thrombolytic treatment on LV function. The highest rate of coronary patency in improved group B patients underline the role of reperfusion on natural history of LV dysfunction after AMI.

Detection of acute myocardial infarction with digital image processing of two-dimensional echocardiograms

We have previously described the ability of a computer-based image digitizing system to assess early textural changes in acute canine myocardial infarction. To determine whether this technique could be applied to human beings, we studied 12 patients with a first acute transmural myocardial infarction and five normal subjects. Two-dimensional echocardiograms were performed on days 1 and 8 in normal subjects and on days 1 (day of admission), 2, 3, 5, and 14 in the patient population. All recording parameters on the echocardiography machine were kept identical for serial studies. The mean period between hospitalization and first echocardiogram was 11.1 hours (range 4 to 20 hours). End-diastolic frames from the two-dimensional echocardiographic images were digitized and displayed on a monitor. The mean pixel intensity (MPI) (+/- SD) in the region of asynergy (area of myocardial infarction) and a normal area were determined. In normal volunteers, no significant change in MPI was noted between anteroseptal and lateral areas on two separate two-dimensional echocardiographic studies, which were performed 7 days apart (anteroseptal: MPI, 21.6 +/- 1.1 vs 21.8 +/- 0.4, p = not significant) and (lateral: MPI, 21.5 +/- 1.2 vs 21.4 +/- 1.4, p = not significant). In patients with myocardial infarction, a significant increase in MPI was noted on the first day of myocardial infarction between normal and infarcted myocardium (20.4 +/- 2.0 vs 24.3 +/- 2.3, p less than 0.05) and progressively increased thereafter until day 14 (20.5 +/- 1.7 vs 31.9 +/- 3.7, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Progressive changes in ventricular structure and function during the year after acute myocardial infarction

To investigate the long-term changes in left ventricular structure and function after myocardial infarction, 51 patients with a first myocardial infarction (17 anterior, 23 inferior, and 11 non-Q wave) were studied by two-dimensional echocardiography at the time of entry into the hospital, at 3 months, and 1 year after infarction. The left ventricular endocardial surface was reconstructed from these echocardiograms, and the endocardial surface area (ESA) index (in cm2/m2) and area of abnormal wall motion (AWM in cm2) were quantitated. Despite different trends in the ESA index between entry and 3-month values in those with and without early infarct expansion, a decrease in the ESA index from 3 months to 1 year was noted in anterior and non-Q wave infarctions (anterior with early expansion: 96.3 +/- 8.6 to 81.5 +/- 4.2 cm2/m2, p less than 0.05; anterior without early expansion: 59.7 +/- 2.0 to 54.7 +/- 2.0 cm2/m2, p less than 0.01; non-Q wave: 64.1 +/- 3.5 to 57.9 +/- 4.4 cm2/m2, p less than 0.01). The mean decline in ESA from 3 months to 1 year of 8.9 +/- 2.5 cm2 was independent of initial infarct size. Regional function, as represented by the area of AWM, was also improved but the timing of the improvement was related to the location and size of the infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Serial changes in left ventricular wall motion by two-dimensional echocardiography following anterior myocardial infarction

To evaluate the time course of spontaneous changes in wall motion following anterior infarction, we prospectively performed serial apical four-chamber two-dimensional echocardiography on 45 consecutive long-term survivors of initial transmural anterior infarction. Studies were performed on admission (1 +/- 1 days), 1 week after admission (6 +/- 2 days), at discharge (15 +/- 8 days), and at long-term follow-up (235 +/- 186 days). Ventricular size was expressed as end-diastolic area in square centimeters. Wall motion for this tomographic section was evaluated as the percent change in left ventricular area from end diastole to end systole (% LVA). Patients were grouped on the basis of significant differences for %LVA between the first and fourth studies. Group I (n = 14) had improved wall motion (23 +/- 5% to 38 +/- 9%); group II (n = 23) did not change (22 +/- 9% to 23 +/- 11%); and group III (n = 8) had worsened wall motion (28 +/- 6% to 18 +/- 7%). End-diastolic area did not change over the study period for groups I and II but increased significantly for group III (30 +/- 6 to 35 +/- 4 cm2, p less than 0.05). Most of the increase in end-diastolic area for group III was between the third and fourth study. The percent improvement (%IMP) in wall motion for patients in group I who did not have ventricular fibrillation outside the hospital expressed in days (t) following infarction fit an exponential curve (%IMP = 100-100e-(.108t) that predicts that 70% of eventual recovery will occur in the first 15 days post-infarction. We conclude that changes in left ventricular size and wall motion occur following anterior infarction with improvement or worsening occurring spontaneously in some patients. If improvement occurs, it should be evident within 2 weeks of infarction; infarct expansion in this select group of long-term survivors occurred primarily after discharge.

Preservation of left ventricular ejection fraction during percutaneous transluminal coronary angioplasty by distal transcatheter coronary perfusion of oxygenated Fluosol DA 20%

The cardioprotective efficacy of coronary perfusion during angioplasty was evaluated. Forty-two patients underwent transcatheter infusion of oxygenated Fluosol DA, 20% emulsion (FDA-20), a perfluorocarbon oxygen transport fluid, into the distal coronary artery during balloon inflations. Left ventricular function was continuously monitored by two-dimensional echocardiography, and left ventricular ejection fraction was quantitatively analyzed from the video record by an area-length method with a validated computer algorithm. Each patient had multiple nonperfused and perfused balloon inflations lasting more than 45 seconds. Nineteen of the 42 patients also received control solutions of oxygenated Ringer's lactate and nonoxygenated FDA-20. The ejection fraction of nonperfused sequences fell from a baseline value of 57 +/- 15% to 36 +/- 14% at 45 seconds of inflation time (p less than 0.0005). Falls of similar magnitude were seen in the lactated Ringer's and nonoxygenated FDA-20 perfused balloon inflations. The ejection fraction fall was associated with a 54% rise in end-systolic volume (p less than 0.0005) and a 4% rise in end-diastolic volume (p = ns) compared to baseline. Inflations perfused with oxygenated FDA-20 showed a 45-second, left ventricular ejection fraction of 53 +/- 13% (p = ns compared to baseline), which was significantly greater (p less than 0.0001) than the 45-second ejection fraction of the nonperfused, or control solution perfused sequences. Results indicate that the profound fall in ejection fraction occurring during percutaneous transluminal coronary angioplasty can be ameliorated by distal coronary perfusion with an oxygenated perfluorocarbon emulsion.

Influence of coronary artery bypass surgery on regional left ventricular wall motion: An intraopertive two-dimensional transesophageal echocardiographic study

Two-dimensional transesophageal echocardiography was used to evaluate the effect of coronary revascularization on regional myocardial function in 30 patients. Cross-sections at the level of the papillary muscles were obtained 15 minutes after intubation, 15 minutes after sternal closure, and 6 and 12 hours later, in the intensive care unit. Regional myocardial function of eight segmental areas was obtained using a floating axis system. The segments were allocated to one of four conditions, depending on baseline regional area ejection fraction (RAEF): condition I) RAEF < 0%; condition II) RAEF = 0% to 25%; condition III) RAEF = 26% to 50%; or condition IV) RAEF > 50% (normal). Compared to baseline values (postinduction), RAEF changed after sternal closure in condition I from -10.4% +/- 5.4% to 17.6% +/- 10.3% (P < .01), in condition II from 14.3% +/- 6.1% to 30.7% +/- 7.8% (P < .01), and in condition III from 35.0% +/- 6.1% to 50.4% +/- 6.3% (P < .01). In condition IV there was no significant change in RAEF. Further improvement of RAEF in conditions I, II, and III was not seen in the intensive care unit. Thus, preoperative normal regional myocardial function was not affected by coronary revascularization, and dysfunctioning myocardium frequently improved immediately after revascularization.

Relation of dyspnea to left ventricular wall motion disturbances in a population of 67-year-old men

Dyspnea, a potential early symptom of coronary artery disease and congestive heart failure, was evaluated to establish its relation to left ventricular wall motion abnormalities. A group of 67-year-old men, drawn from the general population of Gothenburg, Sweden, was studied. Acceptable studies by 2-dimensional echocardiography were obtained from 42 of 49 men with dyspnea of presumed cardiac origin, and from 45 randomly selected nondyspneic control subjects. Both groups originated from a random population sample of 644 men. All men with akinesia, not limited to the basal inferolateral segment, were dyspneic. Akinesia (inferolateral segment only) was found in 4 of 45 control subjects (9%). Six of 20 men (30%) with low-grade dyspnea and 5 of 5 men with the most severe grade of dyspnea had 1 or more akinetic segments. The severity of dyspnea was related to regional wall motion disturbances (as classified in 11 anatomic segments [p less than 0.02 to p less than 0.0001]) and to presence and number of akinetic segments (p less than 0.0001). The degree of dyspnea was correlated to anterior (p less than 0.0001) but not inferior akinesia. The regional wall motion disturbances measured by echocardiography still contributed significantly to the explanation of dyspnea when taking into account the presence or absence of clinical coronary artery disease determined from a 12-lead electrocardiogram, the history of angina pectoris and myocardial infarction, and the findings on chest x-ray films. Thus, presumed cardiac dyspnea is a sensitive marker of regional wall motion disturbances. Furthermore, the location of these disturbances may be of importance for the hemodynamic changes leading to cardiac dyspnea.