774-5 Effect of Cardiac Translation on Measurement of Left Ventricular Wall Velocities: Implications for Doppler Imaging of Myocardium

Doppler imaging of the myocardium is a new application which has the potential to record myocardial velocities. These recorded velocities, however, include cardiac motion independent of ventricular contraction. A measured myocardial velocity, therefore, represents the net vector of contraction, translation, and rotation. To determine the effects of cardiac translation on myocardial velocities, 2-dimensional (2D) and M-mode echocardiographic recordings were obtained in 10 normal subjects. The average anteroseptal (AS) and posterior wall (PW) velocities were measured by 2D echo directed M-mode in the centerline of the parasternal short-axis view. Translation was measured from 2D echo cine-loop display as the displacement of the epicardial junction of the right ventricular free wall and interventricular septum during systole. The average translational velocity is reported as the component of the displacement vector parallel to the M-mode beam (+=toward transducer). The AS and PW velocities (cm/sec) displayed in the table represent net measured velocities, which include the translational vector.ResultsASPWTranslationMean±SD3.2±0.54.5±1.1+1.3±0.6Range2.4 to 4.03.4 to 6.9-l.4 to+2.4In 8/10 subjects the velocity vector was positive. The mean percent error in the M-mode derived velocities due to translation was 41% for the AS wall and 31% for the PW.Conclusions1) As measured by 2D echocardiography, the magnitude of the translational vector is significant when compared to the M-mode derived myocardial velocities. 2) The relative error demonstrated in the measured velocities may be further modified when applied in two dimensions, due to the angle of incidence of the Doppler beam. 3) New techniques for measuring myocardial velocities, such as Doppler imaging of the myocardium, should incorporate algorithms which correct for the translational vector

Doppler color flow “proximal isovelocity surface area” method for estimating volume flow rate: Effects of orifice shape and machine factors

AbstractPreviously described Doppler color How mapping methods for estimating the severity of valvular regurgitation have focused on the distal jet. In this study, a newer Doppler color flow technique, focusing on the flow proximal to an orifice, was used. This method identifies a proximal isovelocity surface area (PISA) by displaying an aliasing interface. Volume flow rate (cm3/s) can be calculated as PISA (cm2) × aliasing velocity (cm/s). For planar circular orifices, a hemi-elliptic model accurately approximated the shape of PISA.Clinically, however, orifice shapes may be noncircular. In vitro flow experiments (n = 226) using orifices of various shapes (ellipse, square, triangle, star, rectangle) were performed. Volume flow rate calculated using a hemi-elliptic model for PISA was accurate, with average percent differences from actual flow rate = +4.3% for a square, −4.2% for a triangle, −4.7% for a star, −4.5% for an ellipse and −2.8% for a rectangle. However, average percent differences for calculated volume flow rates using a hemispheric model for PISA shape ranged from −11.6% (square) to −34.8% (rectangle).In addition, to evaluate whether PISA is influenced by machine factors, in vitro studies (n = 83) were performed. For a volume flow rate of 13 liters/min, the color aliasing radius was not affected by: 1) system gain(radius = 9.9 mm at −20 dB versus 10.4 mm at +20 dB); 2) wall filter(10.8 mm at high versus 11.2 mm at tow); 3) frame rate(11.2 mm at 6/s versus 10.6 mm at 22/s); 4) transmit power(10.3 mm at high versus 10.1 mm at low); and 5) packet size(10.6 mm at 4 samples/line versus 10.5 mm at 8 samples/line). The aliasing radius was lower at higher aliasing velocities. However, the calculated volume flow rate was not affected by changes in aliasing velocity.It is concluded that differences in planar orifice shape do not affect volume flow rate calculated using a hemi-elliptic model. Furthermore, changes in machine factors do not alter volume flow rate calculated using the PISA method. The PISA method may have advantages over previous Doppler color flow methods in calculating volume flow rate and may be useful clinically in estimating valvular regurgitant or shunt volume

Increased left ventricular mass is a risk factor for the development of a depressed left ventricular ejection fraction within five years The Cardiovascular Health Study

AbstractObjectivesOur aim in this study was to determine whether increased left ventricular mass (LVM) is a risk factor for the development of a reduced left ventricular ejection fraction (LVEF).BackgroundPrior studies have shown that increased LVM is a risk factor for heart failure but not whether it is a risk factor for a low LVEF.MethodsAs part of the Cardiovascular Health Study, a prospective population-based longitudinal study, we performed echocardiograms upon participant enrollment and again at follow-up of 4.9 ± 0.14 years. In the present analysis, we identified 3,042 participants who had at baseline a normal LVEF and an assessment of LVM (either by electrocardiogram or echocardiogram), and at follow-up a measurable LVEF. The frequency of the development of a qualitatively depressed LVEF on two-dimensional echocardiography, corresponding approximately to an LVEF <55%, was analyzed by quartiles of baseline LVM. Multivariable regression determined whether LVM was independently associated with the development of depressed LVEF.ResultsBaseline quartile of echocardiographic LVM indexed to body surface area was associated with development of a depressed LVEF (4.8% in quartile 1, 4.4% in quartile 2, 7.5% in quartile 3, and 14.1% in quartile 4 [p < 0.001]). A similar relationship was seen in the subgroup of participants without myocardial infarction (p < 0.001). In multivariable regression that adjusted for confounders, both baseline echocardiographic (p < 0.001) and electrocardiographic (p < 0.001) LVM remained associated with development of depressed LVEF.ConclusionsIncreased LVM as assessed by electrocardiography or echocardiography is an independent risk factor for the development of depressed LVEF

Endothelial function and urine albumin levels among asymptomatic Mexican-Americans and non-Hispanic whites

<p>Abstract</p> <p>Background-</p> <p>Mexican-Americans (MA) exhibit increases in various cardiovascular disease (CVD) risk factors compared to non-Hispanic Whites (NHW), yet are reported to have lower CVD mortality rates. Our aim was to help explain this apparent paradox by evaluating endothelial function and urine albumin levels in MA and NHW.</p> <p>Methods-</p> <p>One hundred-five MA and 100 NHW adults were studied by brachial artery flow-mediated dilatation (FMD), blood and urine tests. Participants were studied by ultrasound-determined brachial artery flow-mediated dilatation (FMD), blood and urine tests, at a single visit.</p> <p>Results-</p> <p>Despite higher BMI and triglycerides in MA, MA demonstrated higher FMD than did NHW (9.1 ± 7.3% vs. 7.1 ± 6.3%, p < 0.04). Among MA, urinary albumin was consistently lower in participants with FMD ≥ 7% FMD versus < 7% FMD (p < 0.006). In multivariate analyses in MA men, urinary albumin was inversely related to FMD (r = -0.26, p < 0.05), as were BMI and systolic blood pressure. In MA women, urinary albumin:creatinine ratio was an independent inverse predictor of FMD (p < 0.05 ).</p> <p>Conclusion-</p> <p>To our knowledge, this is the first study to analyze, in asymptomatic adults, the relation of MA and NHW ethnicity to FMD and urine albumin levels. The findings confirm ethnic differences in these important subclinical CVD measures.</p

A case of fatal ephedra intake associated with lipofuscin accumulation, caspase activation and cleavage of myofibrillary proteins

Ephedra, a herb reported to suppress appetite and stimulate the sympathetic nervous system as well as cardiac performance, has recently been related to several adverse events, including seizure, stroke, hypertension, myocardial infarction, and sudden death. Here, we describe the case of a 45‐year‐old woman who died of cardiovascular collapse while taking ephedra. Tissue analysis revealed non‐specific degenerative alterations in the myocardium (lipofuscin accumulation, basophilic degeneration and vacuolation of myocytes, as well as myofibrillary loss), associated with myocyte apoptosis, caspase activation, and extensive cleavage of miofibrillary proteins α‐actin, α‐actinin, and cardiac troponin T. Healthcare professionals are therefore urged to warn their patients about the risk of serious adverse effects, which may follow ephedra intake.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102708/1/ejhf2004-09-012.pd

Incidence of post myocardial infarction left ventricular thrombus formation in the era of primary percutaneous intervention and glycoprotein IIb/IIIa inhibitors. A prospective observational study

BACKGROUND: Before the widespread use of primary percutaneous coronary intervention (PCI) and glycoprotein IIb/IIIa inhibitors (GP IIb/IIIa) left ventricular (LV) thrombus formation had been reported to complicate up to 20% of acute myocardial infarctions (AMI). The incidence of LV thrombus formation with these treatment modalities is not well known. METHODS: 92 consecutive patients with ST-elevation AMI treated with PCI and GP IIb/IIIa inhibitors underwent 2-D echocardiograms, with and without echo contrast agent, within 24–72 hours. RESULTS: Only 4/92 (4.3%) had an LV thrombus, representing a significantly lower incidence than that reported in the pre-PCI era. Use of contrast agents did not improve detection of LV thrombi in our study. CONCLUSION: The incidence of LV thrombus formation after acute MI, in the current era of rapid reperfusion, is lower than what has been historically reported

What parameters affect left ventricular diastolic flow propagation velocity? in vitro studies using color m-mode doppler echocardiography

BACKGROUND: Insufficient data describe the relationship of hemodynamic parameters to left ventricular (LV) diastolic flow propagation velocity (Vp) measured using color M-mode Doppler echocardiography. METHODS: An in vitro LV model used to simulate LV diastolic inflow with Vp measured under conditions of varying: 1) Stroke volume, 2) heart rate (HR), 3) LV volume, 4) LV compliance, and 5) transmitral flow (TMF) waveforms (Type 1: constant low diastasis flow and Type 2: no diastasis flow). RESULTS: Univariate analysis revealed excellent correlations of Vp with stroke volume (r = 0.98), LV compliance (r = 0.94), and HR with Type 1 TMF (r = 0.97). However, with Type 2 TMF, HR was not associated with Vp. LV volume was not related to Vp under low compliance, but inversely related to Vp under high compliance conditions (r = -0.56). CONCLUSION: These in vitro findings may help elucidate the relationship of hemodynamic parameters to early diastolic LV filling

ACC/AHA/ACP-ASIM guidelines for the management of patients with chronic stable angina: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Management of Patients With Chronic Stable Angina)

The ACC/AHA Task Force on Practice Guidelines was formed to make recommendations regarding the diagnosis and treatment of patients with known or suspected cardiovascular disease. Ischemic heart disease is the single leading cause of death in the U.S. The most common manifestation of this disease is chronic stable angina. Recognizing the importance of the management of this common entity and the absence of national clinical practice guidelines in this area, the task force formed the current committee to develop guidelines for the management of patients with stable angina. Because this problem is frequently encountered in the practice of internal medicine, the task force invited the American College of Physicians-American Society of Internal Medicine (ACP-ASIM) to serve as a partner in this effort by naming four general internists to serve on the committee

ACC/AHA 2002 guideline update for the management of patients with chronic stable angina - Summary article: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients With Chronic Stable Angina)

"The American College of Cardiology (ACC)/American Heart Association (AHA) Task Force on Practice Guidelines regularly reviews existing guidelines to determine when an update or a full revision is needed. This process gives priority to areas in which major changes in text, and particularly recommendations, are merited on the basis of new understanding or evidence. Minor changes in verbiage and references are discouraged. The ACC/AHA/American College of Physicians-American Society of Internal Medicine (ACP-ASIM) Guidelines for the Management of Patients With Chronic Stable Angina, which were published in June 1999, have now been updated. The full-text guideline incorporating the updated material is available on the Internet (www.acc.orgor www.americanheart.org) in both a track-changes version showing the changes in the 1999 guideline in strike-out (deleted text) and highlighting (new text) and a “clean” version that fully incorporates all the changes. This summary article describes the 4 most important areas of change reflected in the update in a format that we hope can be read and understood as a stand-alone document. Interested readers are referred to the full-length version on the Internet to completely understand the location of these changes within the full-length guideline, as well as their proper context. The full-length guideline includes some additional changes that are not reflected in this summary article. All new references appear in bold-faced type; all original references appear in normal type. Although the primary focus of this guideline is on symptomatic patients, asymptomatic patients with known or suspected coronary disease are included in this update and are described in Section V.