|
| ||
|
|
||
Cardiac Motion (cardiac + motion)
Selected AbstractsEmergency Department Echocardiography Demonstrates Large Pericardial Effusion and Pendulous Cardiac Motion in Patient with Shortness of Breath and Electrical AlternansACADEMIC EMERGENCY MEDICINE, Issue 7 2008Chandler Hill MD No abstract is available for this article. [source] Effect of an Electronic Control Device Exposure on a Methamphetamine-intoxicated Animal ModelACADEMIC EMERGENCY MEDICINE, Issue 4 2010Donald M. Dawes MD Abstract Objectives:, Because of the prevalence of methamphetamine abuse worldwide, it is not uncommon for subjects in law enforcement encounters to be methamphetamine-intoxicated. Methamphetamine has been present in arrest-related death cases in which an electronic control device (ECD) was used. The primary purpose of this study was to determine the cardiac effects of an ECD in a methamphetamine intoxication model. Methods:, Sixteen anesthetized Dorset sheep (26,78 kg) received 0.0 mg/kg (control animals, n = 4), 0.5 mg/kg (n = 4), 1.0 mg/kg (n = 4), or 1.5 mg/kg (n = 4) of methamphetamine hydrochloride as a slow intravenous (IV) bolus during continuous cardiac monitoring. The animals received the following exposures in sequence from a TASER X26 ECD beginning at 30 minutes after the administration of the drug: 1) 5-second continuous exposure, 2) 15-second intermittent exposure, 3) 30-second intermittent exposure, and 4) 40-second intermittent exposure. Darts were inserted at the sternal notch and the cardiac apex, to a depth of 9 mm. Cardiac motion was determined by thoracotomy (smaller animals, , 32 kg) or echocardiography (larger animals, > 68 kg). Data were analyzed using descriptive statistics and chi-square tests. Results:, Animals given methamphetamine demonstrated signs of methamphetamine toxicity with tachycardia, hypertension, and atrial and ventricular ectopy in the 30-minute period immediately after administration of the drug. Smaller animals (n = 8, , 32 kg, mean = 29.4 kg) had supraventricular dysrhythmias immediately after the ECD exposures. Larger animals (n = 8, > 68 kg, mean = 72.4) had only sinus tachycardia after the exposures. One of the smaller animals had frequent episodes of ventricular ectopy after two exposures, including runs of delayed onset, nonsustained six- to eight-beat unifocal and multifocal ventricular tachycardia that spontaneously resolved. This animal had significant ectopy prior to the exposures as well. Thoracotomy performed on three smaller animals demonstrated cardiac capture during ECD exposure consistent with previous animal studies. In the larger animals, none of the methamphetamine-intoxicated animals demonstrated cardiac capture. Two control sheep showed evidence of capture similar to the smaller animals. No ventricular fibrillation occurred after the exposure in any animal. Conclusions:, In smaller animals (32 kg or less), ECD exposure exacerbated atrial and ventricular irritability induced by methamphetamine intoxication, but this effect was not seen in larger, adult-sized animals. There were no episodes of ventricular fibrillation after exposure associated with ECD exposure in methamphetamine-intoxicated sheep. ACADEMIC EMERGENCY MEDICINE 2010; 17:436,443 © 2010 by the Society for Academic Emergency Medicine [source] Near-Infrared Spectroscopy for Plaque CharacterizationJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 6 2008SERGIO WAXMAN M.D. A near-infrared (NIR) spectroscopy catheter-based system has been developed for intracoronary detection of lipid-rich plaques, capable of scanning an artery through blood and during cardiac motion. The lipid-rich plaque chemometric algorithm was validated in an ex vivo study using coronary artery specimens from autopsy hearts. A parallel clinical study was performed to demonstrate safety of the system in patients and the similarity of spectra acquired in vivo to data from the ex vivo study. Proof of spectral similarity between data obtained in patients and data from autopsy specimens is required to demonstrate the applicability of the algorithm to patients, in whom tissue for analysis is not available. A preliminary analysis in an unblinded cohort of patients from the clinical study reported promising results. The final results of the clinical study will be submitted for publication. The potential clinical value of this NIR spectroscopy device is discussed. [source] Assessment of a Novel Angiographic Image Stabilization System for Percutaneous Coronary InterventionJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2007ANDREW J. BOYLE M.B.B.S., Ph.D. Background: Optimization of coronary images for percutaneous coronary intervention (PCI) remains difficult due to cardiac motion throughout the respiratory and cardiac cycles. We tested a novel system to stabilize angiographic images at the region of interest in order to assist during PCI. Methods: Patients undergoing PCI to the right coronary artery (RCA) (group 1, n = 22) or complex PCI (group 2, n = 16) were prospectively enrolled and the angiographic image sequences of patients who died suddenly of confirmed or presumed stent thrombosis following PCI (group 3, n = 16) were retrospectively reviewed. All image sequences were analyzed off-line by three cardiologists before and after image stabilization for accuracy of stent placement, presence of residual edge dissection, and adequacy of procedural outcome. Results: Image stabilization was successful in 100% of cases in a mean time of 95 ± 71 seconds and was considered to be helpful in 13.6% of group 1, in 18.3% of group 2, and in 10% of group 3 cases. There was good correlation between observers with a kappa statistic of 0.85 to 1.0 for all observations. However, there was no difference in the reviewers' opinions of stent placement, presence of edge dissection, or adequacy of procedural result when comparing the standard angiographic views and the stabilized images. In particular, no previously unrecognized edge dissections were apparent in group 3 with stabilized display. Conclusion: Image stabilization centered on the region of interest was considered helpful in a small subset of patients, particularly the complex PCI patients. However, no differences in objective parameters could be demonstrated. [source] Direct monitoring of coronary artery motion with cardiac fat navigator echoesMAGNETIC RESONANCE IN MEDICINE, Issue 2 2003Thanh D. Nguyen Abstract Navigator echoes (NAVs) provide an effective means of monitoring physiological motion in magnetic resonance imaging (MRI). Motion artifacts can be suppressed by adjusting the data acquisition accordingly. The standard pencil-beam NAV has been used to detect diaphragm motion; however, it does not monitor cardiac motion effectively. Here we report a navigator approach that directly measures coronary artery motion by exciting the surrounding epicardial fat and sampling the signal with a k -space trajectory sensitized to various motion parameters. The present preliminary human study demonstrates that superior-inferior (SI) respiratory motion of the coronary arteries detected by the cardiac fat NAV highly correlates with SI diaphragmatic motion detected by the pencil-beam NAV. In addition, the cardiac fat navigator gating is slightly more effective than the diaphragmatic navigator gating in suppressing motion artifacts in free-breathing 3D coronary MR angiography (MRA). Magn Reson Med 50:235,241, 2003. © 2003 Wiley-Liss, Inc. [source] Cardiac diffusion MRI without motion effectsMAGNETIC RESONANCE IN MEDICINE, Issue 1 2002Jiangang Dou Abstract We present a method for diffusion tensor MRI in the beating heart that is insensitive to cardiac motion and strain. Using a stimulated echo pulse sequence with two electrocardiogram (ECG) triggers, diffusion-encoding bipolar gradient pulses are applied at identical phases in consecutive cardiac cycles. In this experiment, diffusion is encoded at a single phase in the cardiac cycle of less than 30 ms in duration. This encoding produces no phase shifts for periodic motion and is independent of intervening strains. Studies in a gel phantom with cyclic deformation confirm that by using this sequence we can map the diffusion tensor free of effects of cyclic motion. In normal human subjects, myocardial diffusion eigenvalues measured with the present method showed no significant change between acquisitions encoded at maximum contractile velocity (peak) vs. at myocardial standstill (end-systole), demonstrating motion independence of in vivo diffusion measurements. Diffusion tensor images acquired with the present method agree with registered data acquired with a previous cardiac diffusion MRI method that was shown to be valid in the normal heart, strongly supporting the validity of MRI diffusion measurement in the beating heart. Myocardial sheet and fiber dynamics measured during systole showed that normal human myocardial sheet orientations tilt toward the radial during systole, and fiber orientations tilt toward the longitudinal, in qualitative agreement with previous invasive studies in canines. These results demonstrate the technique's ability to measure myocardial diffusion accurately at any point in the cardiac cycle free of measurable motion effect, as if the heart were frozen at the point of acquisition. Magn Reson Med 48:105,114, 2002. © 2002 Wiley-Liss, Inc. [source] | ||||||||||