Incidence and time course of left ventricular dilation in the early convalescent stage of reperfused anterior wall acute myocardial infarction.

The incidence and early process of left ventricular (LV) dilation in 52 patients with reperfused anterior wall acute myocardial infarction (AMI) were assessed. All patients achieved coronary reflow within 24 hours of the onset and had a patent infarct-related artery in the convalescent stage. Left ventriculography was performed at pre-reflow and 25 days (mean) later to determine LV end-diastolic volume (ml) with the area/length method. Short-axis echo images at the midpapillary muscle level were recorded at days 1, 7, 14, and 28 of the AMI. With use of the papillary muscles as the internal landmarkers, the LV wall was divided into the anterior and posterior segments, and length and thickness of each segment were determined. Among 52 patients, 10 (19%) had a > or = 20% increase in end-diastolic volume in the convalescent stage. Echocardiographic studies demonstrated that there were no significant changes in lengths and thicknesses of the anterior and posterior segments during follow-up study relative to his or her baseline value in 42 patients without LV dilation. In the patients with LV dilation, however, the anterior segment exhibited a mean increase of 25% in its length with a mean decrease of 21% in its thickness at day 7 relative to their baseline values, but no progressive expansion was observed after day 7. A mean increase of 7% in the posterior segment length without reduction in its thickness first became evident at day 28.(ABSTRACT TRUNCATED AT 250 WORDS)

Time course of functional improvement in stunned myocardium in risk area in patients with reperfused anterior infarction.

BACKGROUND: The beneficial effect of coronary reflow on myocardial salvage may be assessed more accurately than in previous studies if the size of risk area is taken into account, particularly because the size of risk area varies significantly among patients. In this study, the risk area was determined with myocardial contrast echocardiography to investigate the time course of functional recovery of postischemic myocardium within the risk area in patients with reperfused anterior myocardial infarction. METHODS AND RESULTS: The study population consisted of 21 patients with anterior myocardial infarction who achieved coronary reflow within 6 hours of onset by means of thrombolysis or coronary angioplasty. Myocardial contrast echocardiography was performed with the injection of hand-agitated Haemaccel (5 ml) into the right and left coronary arteries before coronary reflow, and the risk area was defined as the area of contrast perfusion defect in the apical long-axis view. The ratio of the endocardial length of abnormal contraction (dyskinesis/akinesis) segment to that of contrast defect segment (AS/CD) was determined at days 1, 2, 3, 7, 14, and 28 of reflow. Before reflow, the length of contrast defect correlated well with the segment length of dyskinesis/akinesis. The values for AS/CD in patients with successful reperfusion significantly and progressively decreased until day 14; 1.00 +/- 0.02 at day 1, 0.93 +/- 0.11 at day 2 (p < 0.05 versus day 1), 0.84 +/- 0.16 at day 3 (p < 0.05 versus day 2), 0.80 +/- 0.13 at day 7 (p < 0.01 versus day 2), 0.73 +/- 0.10 at day 14, and 0.72 +/- 0.10 at day 28. Greater improvement in function was obtained in patients reperfused within 4 hours than in those reperfused at > or = 4 hours (AS/CD at day 28, 0.64 +/- 0.12 versus 0.75 +/- 0.09, p < 0.05). CONCLUSIONS: Thus, a significant amount of myocardium, an average of 28% in segment length of the risk area, is salvaged in patients with reperfused anterior myocardial infarction. Major functional improvement seems to be achieved within 14 days of reflow.

Lack of myocardial perfusion immediately after successful thrombolysis. A predictor of poor recovery of left ventricular function in anterior myocardial infarction.

BACKGROUND: We investigated myocardial perfusion dynamics after thrombolysis and its clinical implications. METHODS AND RESULTS: We studied 39 patients with acute anterior myocardial infarction (AMI). Myocardial contrast echocardiography (MCE) was performed before and immediately after successful reflow with intracoronary injection of sonicated Ioxaglate. The average segmental score by two-dimensional echocardiography (graded 0, normal, to 3, akinetic/dyskinetic) and global ejection fraction (left ventricular ejection fraction, LVEF%) by left ventriculography were measured at 1 day and at 4 weeks after reflow. Hypokinesis in the infarct region was assessed by the centerline method and expressed in terms of standard deviations (regional wall motion [RWM]: SD/chord) of normal. Immediately after reflow, 30 of 39 patients (group A) showed significant contrast enhancement within the risk area. The other nine patients (23%, group B), however, showed the residual contrast defect in the risk area (myocardial no reflow). There were no significant differences in the elapsed time, angiographic collateral grade, and degree of residual stenosis between group A and group B. Before reflow, both groups exhibited similar levels of global and regional left ventricular function. Improvement in global (LVEF, average segmental score) and regional left ventricular function was greater in group A than in group B (average segmental score, 0.44 +/- 0.41 versus 0.97 +/- 0.36, p less than 0.01; LVEF, 56.4 +/- 13.4 versus 42.7 +/- 8.9, p less than 0.05; RWM, -1.87 +/- 0.85 versus -3.18 +/- 0.52, p less than 0.005). CONCLUSIONS: MCE demonstrates that angiographically successful reflow cannot be used as an indicator of successful myocardial reperfusion in AMI patients. The residual contrast defect in the risk area demonstrated immediately after reflow is a predictor of poor functional recovery of the postischemic myocardium.

[Contrast echocardiographic assessments of myocardial blood flow in acute myocardial infarction].

Clinical information on the regional myocardial blood flow in the post-ischemic myocardium has been limited. In the present study, we assessed the influence of early coronary reperfusion and coronary obstruction that remained after reperfusion on regional myocardial perfusion by myocardial contrast echocardiography. The study population consisted of 17 patients with acute myocardial infarction who underwent either successful PTCR or emergent PTCA within 6 hours after the onset of the symptom. Myocardial blood flow was visualized by selective injections of hand-agitated poly-gelin colloid solutions into the right and left coronary arteries before and after coronary reperfusion. Before coronary reperfusion, the area at risk for necrosis was defined as the area of contrast defects by the intracoronary injection of contrast medium. The size (severity) of this defect correlated with the anatomic distribution of the obstructed coronary artery. Immediately after emergent PTCA (mean residual stenosis = 25%), 2 of 10 patients still showed injected contrast medium, however, in the remaining 8 patients (80%), the contrast washout time in the risk area was 1.5 times (mean value) longer than that in the normal region. This indicated impairment of the microcirculation in the post-ischemic myocardium. Immediately after PTCR (mean residual stenosis = 89%, p < 0.01 vs PTCA), contrast enhancement was observed only in the peripheral region of the risk area; contrast defects at the center of this region were observed on contrast echocardiography after reperfusion for all patients. This showed that there was impairment of myocardial blood flow in the risk area, even after successful recanalization in patients undergoing PTCR.(ABSTRACT TRUNCATED AT 250 WORDS)

[Quantification of mitral regurgitation by Doppler color flow mapping: comparison of mitral regurgitant fraction and volume with Doppler measurements].

Color flow imaging of the regurgitant areas has been used to quantitate the severity of valvular regurgitation, however, the exact relationship between color flow areas and regurgitant volumes or fraction has not been clarified. This study was designed to determine whether measurements of jet flow areas and distances using color flow imaging are closely related to the regurgitant volume (MRV:ml/beat) and fraction (MRF: %). Doppler examinations were performed in 29 patients with mitral regurgitation (MR). The MR jet was depicted as the largest clearly definable flow disturbance on the echo images, and the maximal jet area (cm2) and length (cm) were measured. The MRV and MRF were obtained from the Doppler measurements of the transmitral flow (TMF) and the aortic flow (AF) as follows: MRV = TMF-AF, MRF = MRV/TMF x 100. The maximal jet area showed significant correlations with the MRV and MRF (r = 0.75 and 0.75, p < 0.01), and the maximal jet length showed even better correlations with the MRV and MRF (r = 0.82 and 0.80, p < 0.01), irrespective of the etiology of MR. Thus, both the maximal jet area and length obtained from color flow imaging can be simple and useful measurement methods for predicting the MRV and MRF.