Impairment of BMIPP accumulation at junction of ventricular septum and left and right ventricular free walls in hypertrophic cardiomyopathy. (25/768)

Myocardial scintigraphy using 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) reveals a high incidence of reduced accumulation of the tracer in patients with hypertrophic cardiomyopathy (HCM). This defect is thought to reflect impairment of myocardial fatty acid metabolism. In this study, the distribution of BMIPP defects was characterized and correlated with the clinical features of patients with HCM. METHODS: Thirty patients with asymmetric septal hypertrophy (ASH) were examined. Regional BMIPP accumulation was evaluated. Each region was normalized to the accumulation in the nonhypertrophic lateral region, which was represented as 100% on each bull's-eye map. The corresponding thallium accumulation for, each region was then used to correct for the partial-volume effect. RESULTS: BMIPP accumulation was significantly less in the septal portion of the anterior wall (As), the septal portion of the posterior wall (Ps) and the apex than in the lateral segments. BMIPP defects were significantly more frequent in the As, Ps and apical segments (20.0%, 20.0% and 33.3%, respectively) and were present in the As or Ps segments in 8 patients (27%). The patients with BMIPP defects in the As or Ps segments had a more frequent family history of HCM or sudden death and severe cardiac dysfunction. CONCLUSION: BMIPP defects occur predominantly in the As and Ps segments in some patients with ASH, which is often associated with severe cardiac dysfunction. The distribution of BMIPP defects may contribute to the classification of HCM and the assessment of its severity.  (+info)

Morphology and significance of the left ventricular collagen network in young patients with hypertrophic cardiomyopathy and sudden cardiac death. (26/768)

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a primary cardiac disease with a diverse clinical spectrum, in which many of the abnormal structural and pathophysiologic features are consequences of inappropriate left ventricular hypertrophy. METHODS: We analyzed the amount, distribution and structure of the cardiac collagen network in transmural sections of the ventricular septum (thickness 17 to 40 mm, mean 25 mm) in 16 previously asymptomatic children and young adults with HCM (11 to 31 years of age, mean 20 years) who died suddenly. The morphologic appearance and volume fractions of interstitial (matrix) and perivascular (adventitial) collagen were analyzed with polarization microscopy and computerized videodensitometry in picrosirius red-stained sections. Findings were compared with 16 structurally normal hearts, 5 with systemic hypertension and 6 infants who died of HCM. RESULTS: Adults and young children with HCM had an eightfold greater amount of matrix collagen compared with normal controls (14.1 +/- 8.8% vs. 1.8 +/- 1% of the tissue section; p < 0.0001), and a threefold increase compared with patients with systemic hypertension (4.5 +/- 1.3%; p < 0.001) and infants with HCM (4.0 +/- 2.4%; p < 0.001). Compared with normal controls and hypertensives, adults and young children (and infants) with HCM showed increased numbers and thickness of each collagen fiber component of the matrix (perimysial coils, pericellular weaves and struts), which were often arranged in disorganized patterns. In HCM patients, the amount of collagen was not a consequence of other clinical, demographic and morphologic disease variables. CONCLUSIONS: Left ventricular collagen matrix in young, previously asymptomatic patients with HCM who died suddenly is morphologically abnormal and substantially increased in size. The enlarged matrix collagen compartment is present in HCM at an early age, further expands during growth, is partially responsible for increased ventricular septal thickness and likely represents a primary morphologic abnormality in this disease. These findings support the view that the complex HCM disease process is not confined to sarcomere protein abnormalities, but also involves connective tissue elements.  (+info)

Three-dimensional systolic strain patterns in the normal human left ventricle: characterization with tagged MR imaging. (27/768)

PURPOSE: To present a database of systolic three-dimensional (3D) strain evolution throughout the normal left ventricle (LV) in humans. MATERIALS AND METHODS: In 31 healthy volunteers, magnetic resonance (MR) tissue tagging and breath-hold MR imaging were used to generate and then detect the motion of transient fiducial markers (ie, tags) in the heart every 32 msec. Strain and motion were calculated from a 3D displacement field that was fit to the tag data. Special indexes of contraction and thickening that were based on multiple strain components also were evaluated. RESULTS: The temporal evolution of local strains was linear during the first half of systole. The peak shortening and thickening strain components were typically greatest in the anterolateral wall, increased toward the apex, and increased toward the endocardium. Shears and displacements were more spatially variable. The two specialized indexes of contraction and thickening had higher measurement precision and tighter normal ranges than did the traditional strain components. CONCLUSION: In this study, the authors noninvasively characterized the normal systolic ranges of 3D displacement and strain evolution throughout the human LV. Comparison against this multidimensional database may permit sensitive detection of systolic LV dysfunction.  (+info)

Effects of ramipril on cardiac gene transcription levels of angiotensin II receptors after myocardial infarction. (28/768)

AIM: To study the early changes of cardiac angiotensin (Ang) II receptor gene transcription after myocardial infarction (MI) in rats chronically treated with the angiotensin-converting enzyme (ACE) inhibitor ramipril. METHODS: MI was induced by left anterior descending coronary artery ligation in rats and sham-operated rats were used as control. Rats were treated daily with ramipril (1 mg.kg-1) or water, initiated 1 wk before surgery. Quantitative RT-PCR was applied to determine the Ang II receptors AT1, AT2 receptor gene mRNA levels in the non-infarcted myocardium. RESULTS: AT1 and AT2 mRNA levels increased time point-dependently in the cardiac septum after MI reaching a peak on d 1. There was no significant difference of the myocardial AT1 and AT2 receptor mRNA levels between the ramipril-treated and water-treated rats after MI. CONCLUSION: The AT1 and AT2 receptor gene transcription in the non-infarcted myocardium was associated with the process of cardiac remodeling after MI but not affected by ACE inhibition.  (+info)

Fast determination of regional myocardial strain fields from tagged cardiac images using harmonic phase MRI. (29/768)

BACKGROUND: Tagged MRI of the heart is difficult to implement clinically because of the lack of fast analytical techniques. We investigated the accuracy of harmonic phase (HARP) imaging for rapid quantification of myocardial strains and for detailed analysis of left ventricular (LV) function during dobutamine stimulation. METHODS AND RESULTS: Tagged MRI was performed in 10 volunteers at rest and during 5 to 20 microg(-1). kg(-1). min(-1) dobutamine and in 9 postinfarct patients at rest. We compared 2D myocardial strains (circumferential shortening, Ecc; maximal shortening, E(2); and E(2), direction) as assessed by a conventional technique and by HARP. Full quantitative analysis of the data was 10 times faster with HARP. For pooled data, the regression coefficient was r=0.93 for each strain (P<0.001). In volunteers, Ecc and E(2) were greater in the free wall than in the septum (P<0.01), but recruitable myocardial strain at peak dobutamine was greater in the LV septum (P<0.01). E(2) orientation shifted away from the circumferential direction at peak dobutamine (P<0.01). HARP accurately detected subtle changes in myocardial strain fields under increasing doses of dobutamine. In patients, HARP-determined Ecc and E(2) values were dramatically reduced in the asynergic segments as compared with remote (P<0.001), and E(2) direction shifted away from the circumferential direction (P<0.001). CONCLUSIONS: HARP MRI provides fast, accurate assessment of myocardial strains from tagged MR images in normal subjects and in patients with coronary artery disease with wall motion abnormalities. HARP correctly indexes dobutamine-induced changes in strains and has the potential for on-line quantitative monitoring of LV function during stress testing.  (+info)

Regional dysfunction correlates with myofiber disarray in transgenic mice with ventricular expression of ras. (30/768)

A hallmark of certain cardiac diseases such as familial hypertrophic cardiomyopathy is focal myofiber disarray. Regional ventricular dysfunction occurs in human subjects with hypertrophic cardiomyopathy; however, no direct evidence exists to correlate regional dysfunction with myofiber disarray. We used a transgenic mouse, which exhibits regional myofiber disarray via ventricular expression of the human oncogene ras, to investigate the relationship between myofiber disarray and septal surface strain. An isolated ejecting mouse heart preparation was used to record deformation of markers on the septal surface and to determine nonhomogeneous septal surface strain maps. Myofiber disarray made in histological tissue sections was correlated with gradients in surface systolic shortening. Significantly smaller maximum principal shortening was associated with disarray located near the right ventricle (RV) septal surface. There was also significantly smaller surface shear strain associated with disarray located either near the RV surface or at the midwall. Because surface shear is a local indicator of torsion, we conclude that myofiber disarray is associated with reduced septal torsion and reduced surface shortening.  (+info)

Left ventricular opacification during selective intracoronary injection of echocardiographic contrast in patients with hypertrophic cardiomyopathy. (31/768)

Percutaneous alcohol ablation of the interventricular septum via the first septal perforator branch of the left anterior descending artery can successfully treat dynamic left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy. Increasingly, echocardiographic contrast agents are used before alcohol injection to identify the perfusion bed of the septal perforator vessels. This study describes the unexpected opacification of the left ventricular cavity in three of five consecutive patients following selective injection of the first septal perforator with Optison. This case study demonstrates that direct communication between the first septal perforator vessel and the left ventricle is common, an observation that may have considerable relevance to the technique of alcohol septal reduction.  (+info)

Left ventricular outflow tract gradient decrease with non-surgical myocardial reduction improves exercise capacity in patients with hypertrophic obstructive cardiomyopathy. (32/768)

OBJECTIVES: This study was undertaken to evaluate mid-term clinical results of non-surgical myocardial reduction in patients with hypertrophic obstructive cardiomyopathy. METHODS: Twenty-five patients with left ventricular outflow tract obstruction (mean gradient of 84. 54+/-31.38 mmHg) and symptoms of dyspnoea, angina and/or syncope were treated with non-surgical myocardial reduction. The patients were followed-up for a mean period of 10.44+/-1.8 months. In all patients clinical examination with echocardiography was repeated after every 3 months of follow-up, and a symptom-limited treadmill test was repeated at the 6 month follow-up. Eighteen patients underwent simultaneous respiratory gas analysis. RESULTS: Clinical follow-up examinations were achieved in all 25 patients. Persistent left ventricular outflow tract gradient reduction was seen in 23 patients. Seventeen patients had a reduction of left ventricular outflow tract gradient >50% of baseline value. Twenty patients showed a clinical improvement from 2.8+/-0.5 up to 1.2+/-0.5 NYHA class (P<0.001). The clinical improvement was matched by an improvement in objective measures of exercise capacity in patients with significant left ventricular outflow tract gradient reduction. Exercise time increased from 571.9+/-192.2 to 703.5+/-175.4 s, P<0. 001, and peak VO(2)increased from 14.6+/-5.2 to 20.5+/-8.6 ml. kg(-1)min(-1), P<0.05. CONCLUSION: Significant left ventricular outflow tract gradient reduction with exercise capacity improvement was achieved in the majority of patients treated with non-surgical myocardial reduction. We recommend this method as an alternative to surgery for symptomatic patients with hypertrophic obstructive cardiomyopathy.  (+info)