Journal of the American College of Cardiology
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J. Am. Coll. Cardiol. · Dec 1998
Risk factors for clinically important adverse events after protamine administration following cardiopulmonary bypass.
The purpose of this study was to determine risk factors for adverse events following protamine administration after cardiopulmonary bypass. ⋯ Immunologic factors are important in predisposing individuals to protamine reactions, and a substantial proportion of patients are at considerably increased risk Strategies to reduce the risk of protamine-associated events are needed.
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J. Am. Coll. Cardiol. · Dec 1998
Comparative StudyVariation of anatomic valve area during ejection in patients with valvular aortic stenosis evaluated by two-dimensional echocardiographic planimetry: comparison with traditional Doppler data.
Flow variations can affect valve-area calculation in aortic stenosis and lead to inaccuracies in the evaluation of the stenosis. Knowing that transvalvular flow varies normally within one beat, we designed this study to assess the response of the valve to intrabeat variation of flow during systole. Results were compared with flow-derived measurements. ⋯ Our observations reveal striking differences between the dynamics of normal and stenotic valves. Surprisingly, Doppler-derived mean-valve area correlated better with maximal-anatomic area than with mean-anatomic area in patients with aortic stenosis. Discrepancies between duration of flow and valve opening could explain this phenomenon.
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J. Am. Coll. Cardiol. · Dec 1998
Comparative StudyComparison of mitral inflow and superior vena cava Doppler velocities in chronic obstructive pulmonary disease and constrictive pericarditis.
This study was conducted to determine whether Doppler recording of superior vena cava flow velocities can differentiate chronic obstructive pulmonary disease from constrictive pericarditis in patients with a respiratory variation of > or = 25% in mitral inflow E velocity. ⋯ Despite a similar respiratory variation in mitral E wave velocities, mitral inflow variables in chronic obstructive pulmonary disease are less restrictive compared with those in constrictive pericarditis. More importantly, patients with chronic obstructive pulmonary disease show a marked increase in inspiratory superior vena cava systolic forward flow velocity, which is not seen in patients with constrictive pericarditis.
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J. Am. Coll. Cardiol. · Dec 1998
"Stunning" of the left atrium after spontaneous conversion of atrial fibrillation to sinus rhythm: demonstration by transesophageal Doppler techniques in a canine model.
This study compared left atrial and left atrial appendage contraction velocities in sinus rhythm before and after a brief period of atrial fibrillation in a canine model. ⋯ Even brief (60 min) periods of atrial fibrillation in normal canine hearts result in marked depression of global left atrial systolic function and regional left atrial (left atrial appendage) systolic function upon resumption of sinus rhythm. This "mechanical stunning" of left atrial systolic function appears to be more profound and of longer duration for the left atrial appendage compared with the left atrium as a whole, which may predispose the appendage to blood stasis and thrombus formation. Chronic models of atrial fibrillation need to be developed to examine the impact of longer periods of atrial fibrillation upon the magnitude and duration of postconversion left atrial "stunning."