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Biomedical subjects

Roberto M Lang

Publications and source records attributed to Roberto M Lang.

At least 73 records · Page 4Linked to original sources
PubMed2004

Harmonic imaging for endocardial visualization and myocardial contrast echocardiography during transesophageal echocardiography.

BACKGROUND: Although harmonic imaging (HI) improves endocardial visualization and is necessary for myocardial perfusion imaging, it has yet to be implemented in transesophageal echocardiography. Our goal was to determine whether HI implemented in a prototype transesophageal echocardiography probe improved endocardial visualization and allowed perfusion imaging. METHODS: In 23 patients, fundamental and harmonic images were obtained in the transgastric short-axis (TSAX) and midesophageal 4-chamber views, and reviewed for endocardial visualization by 3 readers blinded to imaging mode. In 14 additional patients, perfusion imaging was performed in the TSAX view during contrast infusion. RESULTS: HI improved overall endocardial visualization, most noticeably in the anterior and lateral segments (P <.004) in the TSAX view, and in the lateral segments (P <.01) in the midesophageal 4-chamber view. The salvage rate was 8.3% in the TSAX view and 12.6% in the midesophageal 4-chamber view. Myocardial perfusion was consistently confirmed in the inferior (86%), posterior (100%), and lateral (79%) segments, but rarely in the septal (21%), anteroseptal (0%), and anterior (14%) segments. CONCLUSION: Use of HI with transesophageal echocardiography improves endorcardial visualization and allows partial assessment of myocardial perfusion.

Coronary Circulation↗
PubMed2004

Acute pancreatitis mimicking myocardial infarction: evaluation with myocardial contrast echocardiography.

Acute pancreatitis has frequently been reported to be associated with transient electrocardiography changes mimicking myocardial infarction despite normal epicardial coronary arteries. Although these reports generally have not included simultaneous assessment of myocardial function, 1 previous report has documented suggestive electrocardiography changes associated with a transient regional wall-motion abnormality but normal epicardial coronary arteries. Although the origin of these findings is poorly understood, suggested mechanisms have included electrolyte abnormalities, a vagally mediated reflex, coronary vasospasm, and myonecrosis as a result of the release of pancreatic proteolytic enzymes. We report a case of acute pancreatitis with electrocardiography changes and a regional wall-motion abnormality despite normal epicardial coronary arteries. Myocardial contrast echocardiography performed in this patient to evaluate the coronary microcirculation allows further insight into the mechanism of these findings.

Adult↗
PubMed2004

Age dependency of the Tei index of myocardial performance.

Despite its clinical use as a sensitive measure of left ventricular performance, little is known about whether the Tei index is influenced by aging. We determined the Tei index in 141 subjects without cardiovascular disease (age 16-78 years). There were statistically significant variations in ejection time, isovolumic relaxation time, and the Tei index with aging. There was a moderate linear correlation between isovolumic relaxation time and age (r = 0.49, P <.001) and the Tei index and age (r = 0.33, P <.001). This investigation demonstrated that when assessing myocardial performance in patients using this index, age-normalized values should be used.

Adolescent↗
PubMed2004

Automated quantitative assessment of wall motion in patients with poor acoustic windows.

BACKGROUND: No technique exists for objective evaluation of left ventricular wall motion in contrast-enhanced images. We tested a new technique for quantification of regional fractional area change using contrast-enhanced power modulation imaging with color kinesis. METHODS: The feasibility of this technique for detecting acute ischemia was first tested in 11 pigs. Next, the accuracy for detecting resting wall-motion abnormalities was determined in 52 patients requiring contrast and compared with conventional interpretation of 2-dimensional images by inexperienced readers. Expert interpretation of 2-dimensional images served as the gold standard. RESULTS: In pigs, coronary occlusion resulted in reversible hypokinesis and reduced regional fractional area change. In patients with poor acoustic windows, this technique's accuracy for quantitative detection of resting wall-motion abnormalities was 86% compared with 81% for conventional interpretation by inexperienced readers (P <.01). CONCLUSIONS: Regional wall motion can be accurately assessed using color-encoded power modulation imaging for patients requiring contrast. This technique may prove a useful diagnostic aid to echocardiographers of varying levels of experience.

Animals↗
PubMed2004

Non-invasive assessment of mitral valve area during percutaneous balloon mitral valvuloplasty: role of real-time 3D echocardiography.

BACKGROUND: In the last decade, multiple studies depicted discrepancies between mitral valvular orifice area (MVA) measurements obtained with the pressure half-time (PHT) method and invasive methods during the immediate post-percutaneous mitral valvuloplasty (PMV) period. Our aim was to assess the accuracy of Real-Time 3D echo (RT3D) to measure the MVA in the immediate post-PMV period. The invasively determined MVA was used as the gold standard. METHODS AND RESULTS: We studied 29 patients with rheumatic mitral stenosis from two centres (27 women; mean age 48.2+/-11.3 years), all of which had underwent PMV. MVA was calculated before and after PMV using the PHT method, 2D echo planimetry, RT3D echo planimetry and invasive determination (Gorlin's method). The RT3D MVA assessment showed a better agreement with the invasively derived MVA before and in the immediate post-PMV period (Bland-Altman analysis: Average difference between both methods and limits of agreement: 0.01 (-0.31 to 0.33) cm(2) and -0.12 (-0.71 to 0.47) cm(2)) before and immediately after the PMV, respectively. CONCLUSIONS: RT3D is a feasible and accurate technique for measuring MVA in patients with RMVS. It has the best agreement with the invasively determined MVA, particularly in the immediate post-PMV period.

Adult↗
PubMed2004

Secondary coronary artery vasospasm promotes cardiomyopathy progression.

Genetic defects in the plasma membrane-associated sarcoglycan complex produce cardiomyopathy characterized by focal degeneration. The infarct-like pattern of cardiac degeneration has led to the hypothesis that coronary artery vasospasm underlies cardiomyopathy in this disorder. We evaluated the coronary vasculature of gamma-sarcoglycan mutant mice and found microvascular filling defects consistent with arterial vasospasm. However, the vascular smooth muscle sarcoglycan complex was intact in the coronary arteries of gamma-sarcoglycan hearts with perturbation of the sarcoglycan complex only within the adjacent myocytes. Thus, in this model, coronary artery vasospasm derives from a vascular smooth muscle-cell extrinsic process. To reduce this secondary vasospasm, we treated gamma-sarcoglycan-deficient mice with the calcium channel antagonist verapamil. Verapamil treatment eliminated evidence of vasospasm and ameliorated histological and functional evidence of cardiomyopathic progression. Echocardiography of verapamil-treated, gamma-sarcoglycan-null mice showed an improvement in left ventricular fractional shortening (44.3 +/- 13.3% treated versus 37.4 +/- 15.3% untreated), maximal velocity at the aortic outflow tract (114.9 +/- 27.9 cm/second versus 92.8 +/- 22.7 cm/second), and cardiac index (1.06 +/- 0.30 ml/minute/g versus 0.67 +/- 0.16 ml/minute/g, P < 0.05). These data indicate that secondary vasospasm contributes to the development of cardiomyopathy and is an important therapeutic target to limit cardiomyopathy progression.

Animals↗
PubMed2004

Cardiovascular changes in preeclampsia.

The cardiovascular system undergoes a host of changes in association with the development of preeclampsia, which ultimately lead to the classic low cardiac output-high systemic vascular resistant state. A newer hypothesis suggests that exaggeration of the normal for pregnancy hyperdynamic, low-resistance state commencing in early gestation is responsible for the genesis of the clinically apparent vasoconstrictive disease in late pregnancy. Such events may also lead to the vascular damage that persists into later life. In preeclampsia, cardiac contractility is preserved but both steady and pulsatile arterial load are increased inappropriately, failing to decrease as would occur in normal pregnancy, involving both conduit and small vessels. Abnormal adaptive mechanisms may be secondary to changes in vascular tone or vascular wall elements, and may have future implications for a woman later in life.

Blood Circulation↗
PubMed2004

The role of still-frame parametric imaging in magnetic resonance assessment of left ventricular wall motion by non-cardiologists.

BACKGROUND: Cardiac magnetic resonance (MR) images are often reviewed by non-cardiologists who are not trained in the interpretation of regional left ventricular (LV) function. We hypothesized that the use of still-frame parametric MR images of wall motion could aid in the assessment of regional LV function. METHODS: Dynamic, electrocardiogram-gated, steady-state free precession (FIESTA) short-axis images were obtained in 6 to 10 slices in 18 consecutive patients. Each loop was used to automatically generate a still-frame image, in which each pixel is assigned a value equal to the amplitude of cyclic variation in local intensity, resulting in higher intensity in pixels that change between blood and tissue during the cardiac cycle. The dynamic images were reviewed by an expert cardiologist who provided gold standard grades for regional wall motion and by four radiologists. Then the radiologists reviewed and graded the same MR images in combination with parametric images. Grades assigned to each segment in the two sessions were compared with the gold standard. RESULTS: According to expert interpretation, 6 patients had normal wall motion, and 12 had wall motion abnormalities. Parametric images showed a bright band in the area spanned by endocardial motion, with reduced brightness and thickness in areas of hypokinesis. The agreement between the radiologists' grades and the gold standard significantly improved by adding parametric images (from 77% to 81%), which also resulted in reduced interobserver variability (from 52% to 33%). CONCLUSIONS: Still-frame parametric images aid in the assessment of regional wall motion by non-cardiologists who are required to interpret cardiac images.

Female↗
PubMed2004

Atypical cardiac myxomas.

Atypical cardiac myxomas are a rare occurrence and may present with a variety of clinical manifestations depending on the morphology and location. We present three cases of myxomas located atypically on the left atrial appendage ridge, chordae of the mitral valve, and right atrium. Echocardiography plays a prominent role in the diagnosis and follow-up of these patients.

Adult↗
PubMed2003

Thyroid hormone resistance in the heart: role of the thyroid hormone receptor beta isoform.

Several cardiac genes possess thyroid hormone (TH) response elements regulated by TH receptors. Mutation in TR-beta gene causes the human syndrome of resistance to TH, which is characterized by elevated serum concentration of T(4) and T(3) and variable degrees of insensitivity to TH. It is unclear, however, whether a mutant TR-beta could function as a dominant negative in the heart when expressed from the endogenous locus. A well-described resistance to TH (Delta337T) was either introduced into germline of mice (KI-mut) or expressed as a transgene in the heart using a cardiac-specific promoter (KS-mut). Mice were studied at baseline, after 5-propyl-2-thiouracil (PTU) or after PTU and T(3) treatment (PTU + T(3)). PTU + T(3) treatment significantly increased left ventricular mass in all groups compared with baseline measurements, although the increase in left ventricular mass was significantly less in KI-mut animals. Baseline heart rates (HRs) were similar in wild-type (WT) and KI-mut but were lower in KS-mut animals. After TH deprivation (PTU), HR decreased in WT and KI-mut animals; similarly, HR increased in WT and KI-mut after PTU + T(3). In contrast, HR in KS-mut animals did not change after either treatment. Except for cardiac hypertrophy, the presence of a germline TR-beta mutation had surprisingly little effect on cardiac function.

Animals↗
PubMed2003

Use of echocardiography for the phenotypic assessment of genetically altered mice.

Transgenic mice displaying abnormalities in cardiac development and function represent a powerful new tool for understanding molecular mechanisms underlying normal cardiovascular function and the pathophysiological bases of human cardiovascular disease. Complete cardiac evaluation of phenotypic changes in mice requires the ability to noninvasively assess cardiovascular structure and function in a serial manner. However, the small mouse heart beating at rates in excess of 500 beats/min presents unique methodological challenges. Two-dimensional and Doppler echocardiography have been recently used as effective, noninvasive tools for murine imaging, because quality images of cardiac structures and valvular flows can be obtained with newer high-frequency transthoracic transducers. We will discuss the use of echocardiography for the assessment of 1) left ventricular (LV) chamber dimensions and wall thicknesses, 2) LV mass, 3) improved endocardial border delineation using contrast echocardiography, 4) LV contractility using ejection phase indices and load-independent indices, 5) vascular properties, and 6) LV diastolic performance. Evaluation of cardiovascular performance in closed chest mice is feasible in a variety of murine models using Doppler echocardiographic imaging.

Animals↗
PubMed2003

Percutaneous closure of a ruptured sinus of Valsalva aneurysm using the Amplatzer Duct Occluder.

Sinus of Valsalva aneurysms are rare congenital anomalies. When they rupture, they can lead to the development of biventricular failure as a result of systemic-pulmonary shunting. Surgical repair has been the traditional treatment for these aneurysms. We present a case of a 54 year old man in whom a ruptured sinus of Valsalva aneurysm was successfully closed using a catheter-based approach with the Amplatzer Duct Occluder.

Aortic Aneurysm↗