Regional Myocardial Abnormalities Research Articles

Losartan improves regional left ventricular systolic and diastolic function in patients with hypertension: accurate evaluation using a newly developed color-coded tissue doppler imaging technique

BackgroundAngiotensin II receptor antagonists have recently been accepted as antihypertensive therapy. Tissue Doppler imaging (TDI) has been developed as a noninvasive tool to assess quantitatively regional myocardial motion abnormalities. This study was designed to determine whether our newly developed technique of color-coded TDI may be a useful means of quantifying the improvement in regional left ventricular (LV) myocardial contractility and relaxation after treatment with losartan in patients with hypertension. Methods and resultsLosartan (50 to 100 mg) was administered for 6 months to 37 previously untreated patients with essential hypertension. Averaged myocardial velocity profiles (MVPs) for color-coded TDI were recorded in the ventricular septum and LV posterior wall before and after treatment. Peak myocardial velocities and peak myocardial velocity gradients (MVGs) in the LV walls were determined during systole and early diastole. The plasma concentration of transforming growth factor (TGF)-β1 also was measured in all patients. Blood pressure and plasma TGF-β1 level decreased after initiation of losartan therapy. The LV mass index and LV meridional end-systolic wall stress also decreased after treatment with losartan. LV geometry changed from a pattern consistent with concentric hypertrophy to normal geometry in 10 patients and to a pattern consistent with concentric remodeling in 5 patients, and from concentric remodeling to normal geometry in 5 patients after treatment with losartan. The ratio of early to late diastolic filling for the transmitral flow velocity increased after losartan treatment. The peak systolic and early diastolic myocardial velocities and MVGs in the ventricular septum and LV posterior wall increased after treatment with losartan, although the values 6 months after treatment with losartan were still lower than those in normal individuals. There were good correlations between changes in plasma TGF-β1 level and changes in systolic and early diastolic MVGs 6 months after losartan. However, there were no significant correlations between changes in the systolic blood pressure and LV end-systolic wall stress and changes in the TDI parameters. ConclusionLosartan improves regional LV function in patients with hypertension. Our newly developed averaged MVP and MVG measurements may be useful for accurately evaluating regional LV myocardial contractility and relaxation in these patients.

Prediction of cardiac risk prior to elective abdominal aortic surgery: role of multiple gated acquisition scan.

Debate continues regarding the value of cardiac testing before major vascular surgery. Studies looking at whether a low radioisotope left ventricular ejection fraction (LVEF) could reliably predict postoperative cardiac events have produced conflicting results. Technetium-99m multiple gated acquisition (MUGA) scanning was employed in 122 patients undergoing elective abdominal aortic aneurysm surgery to estimate the resting LVEF and to detect regional or global myocardial wall motion abnormalities (WMAs). Adverse cardiac outcomes were predicted using logistic regression analysis. Among this group of patients, 20 did not proceed to surgery for a variety of reasons, and 102 underwent surgical repair. More than half of the patients (55%) had a history of cardiac disease. The mean +/- SD LVEF was 55.5% +/- 11.1%. Altogether, 31 patients had WMAs, and 21 had both WMAs and an abnormal LVEF (< or = 50%). Altogether, 20 cardiac complications were encountered in 17 patients (17%). Logistic regression analysis identified four significant predictors of cardiac complications: history of cardiac disease [odds ratio (OR) 10.43; 95% confidence interval (CI) 1.3 and 80.5], the presence of WMAs (OR 10.1, CI 1.4 and 74.6), additional procedures (OR 12.1, CI 1.4 and 103.0), and reoperation during the postoperative period (OR 6.4, CI 1.4 and 30.4). This is the largest reported British series of cardiac testing using MUGA scans prior to abdominal aortic reconstruction. Only the presence of WMAs (not the resting LVEF) was useful for predicting postoperative cardiac events. A history of cardiac disease, additional procedures, and reoperation during the postoperative period also place a patient at high risk for cardiac complications. A normal LVEF is by no means reassuring that a patient is at low risk of suffering an adverse cardiac outcome.

Usefulness of Doppler myocardial imaging for identification of mutation carriers of familial hypertrophic cardiomyopathy

Because myocyte dysfunction and disarray are early abnormalities in hypertrophic cardiomyopathy (HC), we tested if Doppler myocardial imaging (DMI) could identify systolic and diastolic dysfunction in mutation carriers (MC) (genotype positive patients without hypertrophy, defined as phenotype negative after conventional screening tests). In a single family with a missense mutation in the myosin binding protein C gene (Arg 502 Gln) we identified 5 MCs; these subjects were asymptomatic and had normal physical examination, normal electrocardiogram, treadmill stress test, ambulatory Holter electrocardiogram, and normal conventional M-mode, 2-dimensional, and Doppler echocardiography. In each patient we performed a DMI study and measured the peak velocities of the systolic (S), rapid filling (E), and atrial contraction (A) waves in the 4 sides of the mitral annulus, in 8 left ventricular segments (apical views), in the tricuspid annulus, and in 2 right ventricular segments. These data were compared with those from 10 normal volunteers matched for sex, age, and body surface. Compared with the normal volunteers, the MCs had lower left ventricular systolic velocities and higher right ventricular systolic velocities; lower diastolic rapid filling velocities; higher or similar atrial contraction velocities; reduced E/A; lower percentage of annular sides and segments with E/A >1 and lower average number of sides and/or segments with E/A >1 per patient; similar right ventricular rapid filling velocities; and similar or higher atrial contraction wave velocities. Thus, DMI detects important left and right ventricular annular and regional myocardial contraction and relaxation abnormalities independently of the presence of hypertrophy, in HC. These results show that DMI is more sensitive than conventional echocardiography and establishes a new and highly accurate method for the noninvasive screening of MCs of the disease.

Tissue Doppler imaging in detection of myocardial dysfunction in survivors of childhood cancer treated with anthracyclines

The applicability of tissue Doppler imaging (TDI) was investigated for estimating cardiac function in long-term survivors of childhood cancer treated with anthracyclines. A total of 63 children (age range 7.8–17.3 y) underwent standard echo Doppler cardiographic studies of blood flow velocities, left ventricular dimensions and fractional shortening, followed by measurements of peak myocardial velocities and direction using the noninvasive tissue Doppler imaging (TDI) technique. All 63 were late survivors (median 7.1 y, range 3.5–13.5 y after end of therapy) who had received mean (± SD) cumulative dose of 242 (± 141) mg/m 2 of anthracyclines. The control group consisted of 160 healthy subjects (age range 4 to 17.9 y). Standard echo-Doppler anatomical parameters that were found significantly ( p < 0.01) different for the study group are: RV wall thickness (decreased); LV diameter (increased); and LV fractional shortening (decreased). Studied hemodynamic parameters were not found to be different between the two groups. Quantitative TDI parameters: peak late diastolic myocardial velocities, as well as transmyocardial systolic and diastolic velocity differences, were significantly lower in late survivors than in the healthy pediatric population ( p < 0.01). Qualitative local functional impairment of the movement of the left ventricular walls was detected in 20% of the patients. TDI might become a useful noninvasive method for detecting subclinical myocardial damage in apparently healthy children who received moderate doses of anthracyclines for treatment of childhood malignancy. Prospective studies with TDI for the detection of regional myocardial abnormalities are recommended.

Fusion imaging: combined visualization of 3D reconstructed coronary artery tree and 3D myocardial scintigraphic image in coronary artery disease.

In patients with coronary artery disease, coronary angiography is performed for assessment of epicardial coronary artery stenoses. In addition, myocardial scintigraphy is commonly used to evaluate regional myocardial perfusion. These two-dimensional (2D) imaging modalities are typically reviewed through a subjective, visual observation by a physician. Even though on the analysis of 2D display scintigraphic myocardial perfusion segments are arbitrarily assigned to three major coronary artery systems, the standard myocardial distribution territories of the coronary tree correspond only in 50-60% of patients. On the other hand, the mental integration of both 2D images of coronary angiography and myocardial scintigraphy does not allow an accurate assignment of particular myocardial perfusion regions to the corresponding vessels. To achieve an objective assignment of each vessel segment of the coronary artery tree to the corresponding myocardial regions, we have developed a 3D 'fusion image' technique and applied it to patients with coronary artery disease. The morphological data (coronary angiography) and perfusion data (myocardial scintigraphy) are displayed in a 3D format, and these two 3D data sets are merged into one 3D image. Seventy-eight patients with coronary artery disease were studied with this new 3D fusion technique. Of 162 significant coronary lesions, 120 (74%) showed good coincidence with regional myocardial perfusion abnormality on 3D fusion image. No regional myocardial perfusion abnormality was found in 44 (26%) lesions. Furthermore, the 3D fusion image revealed 24 ischemic myocardial regions that could not be related to angiographically significant coronary artery lesions. The results of this study demonstrate that our newly developed 3D fusion technique is useful for an accurate assignment of coronary vessel segments to the corresponding myocardial perfusion regions, and suggest that it may be helpful to improve the interpretative and decision-making process in the treatment of patients with coronary artery disease.

Visualization of regional myocardial depolarization by tangential component mapping on magnetocardiogram in children.

Tangential components to the body surface on magnetocardiography theoretically reflect regional myocardial current sources just below the gradiometer. The usefulness of tangential component mapping on magnetocardiography in determination of regional myocardial abnormalities has not been investigated in children. Twenty-six children with ventricular hypertrophy, including a child with a left ventricular diverticulum (aged 7 to 15), and age matched 22 healthy children (aged 7 to 15) were studied. Tangential components on magnetocardiography were measured using a newly-developed super-conducting quantum interference device system housed in a magnetically shielded room. Isomagnetic maps and current vector maps were constructed from the data obtained. The peak magnetic fields and current dipoles were demonstrated to be located at the interventricular septum initially, and then were shifted to the anterior and inferior walls of the left ventricle and to the right ventricular outflow tract, successively. In patients with right ventricular hypertrophy whose systolic right ventricular pressure was over 60 mmHg, the peak magnetic fields were located in the right half with rightward directed current vectors throughout ventricular depolarization. In patients with left ventricular hypertrophy, the maximal magnetic fields during depolarization were shifted to the hypertrophic site, showing significantly stronger forces than those in healthy children (35.5+/-11.7 pT vs 26.5+/-11.9 pT, p < 0.01). In a patient with left ventricular diverticulum, two discrete depolarizing current dipoles were visualized. The mean time required in measuring MCGs among all subjects was 10 minutes. The time course as well as the location of the regional electrical activities of the myocardium in children can be visualized, in a short time, as a two-dimensional projection to the frontal plane by tangential component mapping on magnetocardiography.

Wall-Motion Abnormalities Don't Always Mean Ischemia

Regional myocardial wall-motion abnormalities during chest pain are ordinarily thought to indicate myocardial ischemia. These American authors describe

Transthoracic Echo During Chest Pain in the ED

It's been known for some time that transthoracic echocardiography (TTE) can detect regional myocardial wall-motion abnormalities, which are sensitive,

Reversible Myocardial Contraction Abnormalities in Patients With an Acute Noncardiac Illness

Reversible myocardial contraction abnormalities are usually observed in patients with acute ischemic syndromes caused by coronary artery disease. In this study, we report the occurrence of reversible anterior-apical contraction abnormalities in patients with an acute noncardiac illness. This was a retrospective study of 22 patients with the following characteristics: (1) hospitalization for an acute noncardiac illness; (2) appearance of deep T-wave inversion in the precordial leads of the ECG; and (3) presence of an anterior wall motion abnormality on an echocardiogram. Standard clinical information was collected together with results of serial ECGs, echocardiograms, and coronary angiograms. The primary diagnoses for the 22 acutely ill patients included CNS injury (n=6); sepsis (n=3); acute pulmonary disease (n=3); drug overdose or metabolic abnormality (n=7); and post noncardiac surgery (n=3). An initial echocardiogram revealed an anterior apical wall motion abnormality. At follow-up, all patients had progressive improvement in anterior wall motion with return of normal wall motion in 16 patients (73%). All patients evolved deep T-wave inversion (average, 7.8 mm) and QT interval lengthening in the precordial leads. Coronary angiography revealed a significant stenosis in the likely culprit artery (left anterior descending) in only one patient. A reversible cardiac contraction abnormality of the anterior wall and apex of the left ventricle can complicate the clinical course of critically ill patients in the absence of significant coronary artery disease. This phenomenon is associated with striking T-wave inversion and QT interval lengthening. Mechanisms other than myocardial ischemia may lead to the occurrence of reversible regional myocardial contraction abnormalities.

Simultaneous dobutamine stress echocardiography and thallium-201 perfusion imaging for the detection of coronary artery disease.

To compare the diagnostic value of dobutamine stress echocardiography with dobutamine thallium-201 single-photon-emission computed tomography (SPECT) in detecting coronary artery disease, we performed both tests simultaneously on 93 patients who also underwent coronary arteriography. Dobutamine was infused at rates of 5, 10, 20, 30 and 40 microns/kg/min in 3-min stages. The left ventricle was divided into anteroseptal, posterolateral and inferior regions. Within each region, wall motion or perfusion abnormalities were classified as normal, ischemia or fixed defect. The response to stress was concordantly classified by both tests in 67 patients (72%, kappa = 0.48). Regional agreement for abnormalities was observed in 79% (kappa = 0.56) of the 279 regions analyzed. Dobutamine echocardiography detected 62 (93%) and thallium SPECT 60 (90%, p = NS) of the 67 patients with significant coronary artery disease (> or = 50% diameter stenosis). The specificity was 77 (20 of 26) and 81% (21 of 26), respectively. The accuracy was 88 and 87%, respectively. Combined the two tests gave a sensitivity of 97%, a specificity of 65% and an accuracy of 88%. The accuracy for detecting individual coronary stenosis with echocardiography was 83% for the left anterior descending artery, 84% for the right coronary artery and 73% for the left circumflex artery. With SPECT, it was 83, 87 and and 76%, respectively. In conclusion, dobutamine stress echocardiography and thallium SPECT provide a comparable accuracy for detection and localization of coronary artery disease, and for identification of regional myocardial abnormalities. Performing the two tests simultaneous is feasible but it adds limited value in detecting coronary artery disease.

Evaluation and clinical use of early washout ratio of thallium-201 in normal and ischemic myocardium after dipyridamole-induced vasodilation using ring-type emission computed tomography.

Using newly developed ring-type emission computed tomography (SPECT), we investigated the washout ratio (WR) of T1-201 in the myocardium quantitatively with fast dynamic scanning after infusion of dipyridamole (0.57 mg/kg), and assessed the feasibility of early WR as a marker to detect coronary artery disease. Twenty-three patients with and 8 patients without coronary artery disease had serial SPECT images obtained every 5 min for 45 min and at 180 min after dipyridamole and subsequent T1-201 injection. The best appropriate transaxial slice was selected for WR analysis. Most appropriate diagnostic time was 25 min after infusion of T1-201 (WR-25). Normal WR-25 was 7.1 +/- 4.0%, 5.9 +/- 3.1% and 7.1 +/- 2.3% at the septum, anterior and lateral wall, respectively. Sensitivity, specificity and accuracy to identify coronary stenosis greater than 50% with a usage of abnormal WR-25, defined as WR-25 less than (mean of normals--1SD) in each region of inferest of the left ventricle (LV), were 96%, 100% and 97%, respectively. These results were better than those achieved by visual analysis (sensitivity 78%, specificity 100%, accuracy 84%). In patients with single as well as multivessel disease, the regional accuracy in assessing stenosis of more than 50% in the left anterior descending artery (LAD) and left circumflex artery (LCX) by WR-25 was 94% and 83%, respectively, which was significantly better than using visual methods (LAD 72% and LCX 50%; p less than 0.05). Thus, evaluation of early washout ratios (WR-25) after dipyridamole injection is a valuable method to increase sensitivity in assessing regional myocardial perfusion abnormality and is helpful in detection of ischemic heart disease, even with multivessel disease.

Cardiac output and regional myocardial contraction in anorexia nervosa

The study measured cardiac output and assessed regional myocardial contraction in 14 patients with anorexia nervosa, some of whom also had bulimia, and in 15 controls. The experimental and control groups were not significantly different in age or body surface area ( p = > 0.05). To evaluate regional myocardial contraction, 12 of 14 anorexia nervosa-bulimia (ANB) patients were studied in the acute phase and once serially at a mean interval of 1.5 years by assessing the movement of each left ventricular wall segment toward the center of the ventricle as imaged in the precordial short axis. Cardiac output was measured in the ascending aorta by pulsed Doppler for control subjects and for 13 ANB patients. Regional myocardial contraction was normal for all controls, but eight of 14 ANB patients showed regional myocardial contraction abnormalities. Between studies, four of these eight demonstrated improved regional myocardial contraction, three remained unchanged, and one was worse. Mean cardiac output was markedly reduced in ANB patients (2.6 L/min) compared to controls (4.5 L/min) ( p = < 0.001). The low cardiac output in ANB patients was reflected as reduced mean ascending aortic velocity/second (18.5 cm/s) compared to a mean of 22.8 cm/s for controls ( p = < 0.02). Mean ascending aortic area was slightly smaller for ANB patients. Mean peak ascending aortic velocity was significantly lower in ANB patients than in controls ( p = < 0.02). Mitral valve prolapse was seen during at least one examination in seven of 14 ANB patients (0/15 controls) and disappeared in two of three patients following hydration. We condlude that ANB patients may have significant long-term abnormalities in cardiac output and regional myocardial contraction.

Mitral valvuloplasty is superior to valve replacement for preservation of left ventricular function: An intraoperative two-dimensional echocardiography study

To investigate the mechanism and time of onset of ventricular dysfunction after mitral valve replacement, 18 patients with pure, severe mitral regurgitation (of whom 10 underwent mitral valve repair and 8 standard mitral valve replacement with papillary muscle excision) were studied by intraoperative two-dimensional echocardiography immediately before and immediately after the operative procedure. No patient sustained a perioperative myocardial infarction or had any residual mitral regurgitation. Although preoperative hemodynamics were similar, postoperatively the patients with valve repair had a lower pulmonary capillary wedge pressure than did the patients with valve replacement (8.6 +/- 1.9 versus 14.4 +/- 7.5 mm Hg, p less than 0.04). Although intraoperative echocardiographic ejection fraction fell significantly after mitral valve replacement (0.64 +/- 0.11 to 0.40 +/- 0.09, p less than 0.0001), it was maintained after valve repair (0.44 +/- 0.20 to 0.49 +/- 0.16, p = NS). Additionally, regional myocardial contractile abnormalities in the anterior and posterior septum were detected immediately after the procedure by intraoperative echocardiography in the patients with valve replacement, but not in those with repair. These postoperative regional contractile abnormalities after papillary muscle resection have not been described previously. Resection of the papillary muscles may disrupt the muscle bundle alignment and induce contractile abnormalities remote from the excised muscle. This study demonstrated that significant global and regional ventricular dysfunction develops immediately after removal of the papillary muscles, whereas myocardial contractility is preserved in patients undergoing mitral valve repair. Therefore, with intraoperative echocardiography to assure minimal residual regurgitation, surgeons should attempt to preserve ventricular function by performing mitral valve reconstruction in patients with mitral regurgitation.

Effect of Pindolol on Neurosympathetic Responsiveness, Blood Flow Variability, and Conduction in Acutely Ischaemic Myocardium

The effects of a beta-adrenoceptor antagonist with partial agonist activity (pindolol) were assessed in the open-chest anaesthetised dog during 12-minute periods of left anterior descending coronary artery (LAD) occlusion and reperfusion before and after sympathetic stimulation. Regional myocardial catecholamine efflux, blood flow, and epicardial activation abnormalities were assessed in three groups. In a control group (n = 8), two periods of ischaemia resulted in reproducible intraexperimental changes in catecholamine responses, blood flow, conduction abnormalities, and arrhythmias. Intravenous (i.v.) pindolol (0.45 mg/kg before the second occlusion) reduced nerve-stimulated norepinephrine (NE) overflow from nonischaemic (NI) myocardium but did not modify overflow from ischaemic (I) myocardium either during ischaemia or reperfusion. At constant heart rate (atrial pacing, n = 8), pindolol reduced absolute blood flow to I and NI but had no effect on the ratio of endocardial/epicardial blood flow, arrhythmias, or activation abnormalities during occlusion. Following a reduction in heart rate of 32 +/- 6 beats/min (no pacing, n = 8), pindolol resulted in similar reduction in blood flow to I and NI but also increased the ratio of endocardial/epicardial flow and reduced both spontaneous arrhythmias and activation delay during occlusion. The acute effects of pindolol on conduction abnormalities, arrhythmias, and blood flow distribution in I are thus dependent on reduction in heart rate.

The clinical and prognostic significance of dipyridamole Tl-201 emission computed tomography in patients with dilated cardiomyopathy.

To clarify the clinical significance of regional myocardial perfusion abnormality of the left ventricle in dilated cardiomyopathy (DCM), 20 patients with DCM underwent dipyridamole Tl-201 emission computed tomography (ECT). The subjects were divided into 2 groups: group 1 had (n = 9) reversible defects and group 2 (n = 11) had persistent defects only. Group 2 patients significantly advanced heart failure and significantly poorer prognoses than group 1 (55% vs 11% in 2 years survival rate, p less than 0.05). The echocardiographic left ventricular end-diastolic dimension was larger in group 2 than group 1 (68.3 +/- 8.2 mm vs 61.9 +/- 4.0 mm, p less than 0.05) and % fractional shortening was smaller in group 2 than group 1 (18.0 +/- 4.5% vs 24.5 +/- 6.9%, p less than 0.05). Moreover, 12 of the 13 segments with reversible defect showed fairly well preserved left ventricular wall motion, whereas 35 of 58 segments with persistent defect had severely impaired wall motion (1/13 vs 35/58, p less than 0.01). Dipyridamole Tl-201 ECT demonstrated conclusively that the two types of defects (reversible and persistent) are useful to evaluate not only the abnormal myocardial perfusion but also myocardial damage and the prognosis in DCM.

Noninvasive detection of regional myocardial perfusion abnormality with 201Tl and 81Rb (author's transl)

Noninvasive detection of regional myocardial perfusion abnormality with 201Tl and 81Rb (author's transl)