Journal of the American College of Cardiology
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J. Am. Coll. Cardiol. · Jan 1991
Comparative Study Clinical TrialThe flail mitral valve: echocardiographic findings by precordial and transesophageal imaging and Doppler color flow mapping.
To determine the echocardiographic and Doppler characteristics of mitral regurgitation associated with a flail mitral valve, precordial and transesophageal echocardiography with pulsed wave and Doppler color flow mapping was performed in 17 patients with a flail mitral valve leaflet due to ruptured chordae tendineae (Group I) and 22 patients with moderate or severe mitral regurgitation due to other causes (Group II). Echocardiograms were performed before or during cardiac surgery; cardiac catheterization was also performed in 28 patients (72%). Mitral valve disease was confirmed at cardiac surgery in all patients. ⋯ By Doppler color flow mapping, a flail mitral valve leaflet was also characterized by an eccentric, peripheral, circular mitral regurgitant jet that closely adhered to the walls of the left atrium. The direction of flow of the eccentric jet in the left atrium distinguished a flail anterior from a flail posterior leaflet. By transesophageal echocardiography with Doppler color flow mapping, the ratio of mitral regurgitant jet arc length to radius of curvature was significantly higher in Group I than Group II patients (5.0 +/- 2.3 versus 0.7 +/- 0.6, p less than 0.001); all of the Group I patients and none of the Group II patients had a ratio greater than 2.5.(ABSTRACT TRUNCATED AT 250 WORDS)
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J. Am. Coll. Cardiol. · Jan 1991
Comparative Study Clinical Trial Controlled Clinical TrialSuperiority of transesophageal echocardiography in detecting cardiac source of embolism in patients with cerebral ischemia of uncertain etiology.
The diagnostic yield of transesophageal and transthoracic echocardiography for identifying a cardiac source of embolism was compared in 79 patients presenting with unexplained stroke or transient ischemic attack. There were 35 men and 44 women with a mean age of 59 years (range 17 to 84); 52% had clinical cardiac disease. Both transthoracic and transesophageal echocardiograms were performed using Doppler color flow and contrast imaging. ⋯ The two techniques had a similar rate of identifying apical thrombus and mitral valve prolapse. Overall, transesophageal echocardiography identified abnormalities in 39% of patients with no cardiac disease versus 19% for transthoracic echocardiography (p less than 0.005). Thus, transesophageal echocardiography identifies potential cardiac sources of embolism in the majority of patients presenting with unexplained stroke.(ABSTRACT TRUNCATED AT 250 WORDS)
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J. Am. Coll. Cardiol. · Jan 1991
Influence of incremental changes in heart rate on mitral flow velocity: assessment in lightly sedated, conscious dogs.
To determine the effect of increasing heart rate on mitral flow velocity variables, the time constant of left ventricular isovolumic relaxation and the transmitral pressure gradient, 16 lightly sedated, conscious dogs were studied with Doppler echocardiography during incremental right atrial pacing (n = 16) or the administration of atropine (n = 8) or isoproterenol (n = 8). With increasing heart rate, similar changes were seen with all three interventions and included: 1) mitral flow velocity in early diastole and the early diastolic transmitral pressure gradient either changed minimally or did not change; 2) mitral flow velocity at the start of and as a result of atrial contraction progressively increased; 3) the "absolute" increase in mitral flow velocity and transmitral pressure gradient at atrial contraction demonstrated a biphasic response, initially decreasing as heart rate increased, but then increasing again when atrial contraction occurred in close proximity (less than 70 ms) to mitral valve opening; 3) mitral flow velocity at atrial contraction did not exceed mitral flow velocity in early diastole until atrial contraction was within 70 ms of mitral valve opening and the two velocity peaks were nearly fused; and 4) the largest transmitral pressure gradient and mitral flow velocity occurred at the fastest heart rates, when left atrial contraction preceded mitral valve opening. ⋯ However, for any given heart rate, mitral flow velocity variables and late diastolic pressure gradient can be markedly different, depending on whether atrial pacing, withdrawal of parasympathetic tone or sympathetic stimulation is the cause of the increase in heart rate. These differences among methods appear most related to their effect on PR interval and to a lesser extent the rate of letf ventricular isovolumic relaxation.(ABSTRACT TRUNCATED AT 400 WORDS)
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J. Am. Coll. Cardiol. · Jan 1991
Comparative StudyImplications of echocardiographically assisted diagnosis of pericardial tamponade in contemporary medical patients: detection before hemodynamic embarrassment.
Identification of suspected pericardial tamponade and the decision to perform invasive drainage of the pericardial space have historically been based on classic bedside findings. Two-dimensional echocardiography has improved detection of pericardial effusion, but it may be excessively sensitive in evaluation of patients for hemodynamic embarrassment. Therefore, 50 consecutive medical patients were examined who were identified by echocardiography to have probable tamponade (defined as the presence of right heart chamber collapse in the presence of a pericardial effusion) and who underwent combined right-sided cardiac catheterization and percutaneous pericardiocentesis. ⋯ Echocardiographically assisted diagnosis of pericardial tamponade in medical patients results in the identification of a substantial subset of patients with only subtle evidence of hemodynamic compromise. This subset of patients differs sharply from medical patients described in previous reports with classic tamponade. Although the patients can be managed by invasive catheter pericardiocentesis with few complications, the natural history and the optimal management strategy for this group are not resolved.