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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The volume, velocity, and acceleration of ascending aortic blood were measured in man using a pulsed Doppler ultrasound instrument, with online spectral analysis and offline computer processing of velocity data. This system was firstly validated in a test rig capable of generating pulsatile flow of talc particles in water at physiological velocities and accelerations in a model aorta. Doppler measurements correlated well (r greater than or equal to 0.90) with simultaneous electromagnetic measurements of stroke volume, peak ejection velocity, and maximum acceleration in this rig. In vivo validation was performed firstly by comparing simultaneous Doppler and thermodilution cardiac output (Q) measurements; this yielded the following regression equation: Doppler Q = 0.90 X thermodilution Q + 0.03 litre.min-1, r = 0.92; n = 38. Beat by beat measurements were then validated against simultaneous invasive aortic blood velocity measurements made using a Mills electromagnetic cathetertip probe. When paced single beats of different size were compared within subjects the correlation coefficients between Doppler and electromagnetic measurements averaged 0.89 for stroke volume, 0.91 for peak ejection velocity, and 0.79 for maximum acceleration in five subjects. The absolute values for velocity and acceleration from the Doppler system differed significantly from the absolute values given by the electromagnetic system and this difference was not consistent between subjects. It is concluded that the Doppler system can non-invasively record relative changes in left ventricular ejection in man.
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PMID:Validation of beat by beat pulsed Doppler measurements of ascending aortic blood velocity in man. 331 63

Intracardiac defects such as atrial septal defect (ASD) and patent foramen ovale (PFO) are common forms of congenital intracardiac apertures which can be successfully closed percutaneously. Since the initial description of an atrial septal defect closure device in the mid 1970s by King and Mills, transcatheter closure of atrial septal defects and patent foramen ovale using various devices has now become an established practice in many centers. The left atrial appendage is a trabeculated remnant of the embryonic left atrium. This is an important source of emboli related to atrial fibrillation. Closure of the left atrial appendage is designed to reduce the risk of stroke in patients with atrial fibrillation. This article reviews the current indications and latest developments in catheter closure of PFO, ASD and left atrial appendage.
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PMID:Transcatheter closure of patent foramen ovale, atrial septal defect and left atrial appendage. 1920 22