Circulation
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An inspiratory decline in systolic arterial blood pressure exceeding 10 mm Hg has been used clinically to identify hemodynamically significant pericardial effusions. Recently, the echocardiographic sign of right ventricular diastolic collapse (RVDC) has been shown to occur early in the course of cardiac tamponade in association with a hemodynamically important decline in cardiac output. This study was undertaken to compare the relative merits of pulsus paradoxus and the onset of RVDC in the early detection of cardiac tamponade in an unanesthetized canine preparation. ⋯ None of the dogs had RVDC when the pericardial space was empty, but all dogs showed RVDC during cardiac tamponade. We found that RVDC was strongly related to all of the cardiac parameters evaluated (intrapericardial pressure, cardiac output, aortic blood pressure, heart rate, and stroke volume) and provided information on each that was independent of that provided by pulsus paradoxus. Furthermore, RVDC appeared to be more strongly related to most cardiac parameters than was pulsus paradoxus and to be more sensitive and specific than pulsus paradoxus in detecting changes in intrapericardial pressure early in cardiac tamponade.
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The failure of the blood pressure to fall during the late strain pase of the Valsalva maneuver in patients with heart failure may result from the left ventricle operating on a flat portion of its function curve or from maintenance of left ventricular volume despite decreased systemic venous return. To test these possibilities, we studied the effect of the Valsalva maneuver (40 cm H2O for 15 sec) on left ventricular volume in 12 normal subjects with a mean left ventricular ejection fraction of 0.65 +/- 0.07 (+/- SD) and in eight patients with nonischemic cardiomyopathy, evidence of pulmonary congestion, and a mean left ventricular ejection fraction of 0.23 +/- 0.09. Left ventricular volume and right ventricular area were determined by apical two-dimensional echocardiography. ⋯ In normal subjects it decreased from 9.3 +/- 1.5 to 5.6 +/- 1.6 cm2 (p less than .001) and in patients it decreased from 13 +/- 2.2 to 10 +/- 2.9 cm2 (p less than .001). In normal subjects, left ventricular end-diastolic volume decreased from the control level during the Valsalva maneuver, and this was apparent in both the four-chamber (96 +/- 21 to 68 +/- 18 ml, p less than .01) and two-chamber views (97 +/- 15 to 56 +/- 20 ml, p less than .01). In the patients, left ventricular end-diastolic volume was not significantly different from control in either view (199 +/- 70 to 195 +/- 78 and 214 +/- 77 to 218 +/- 86 ml, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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To define the morphologic features of the left ventricle after ventricular septal myotomy-myectomy and to elucidate the structural changes associated with a postoperative reduction in the pressure gradient, 28 patients with obstructive hypertrophic cardiomyopathy were studied with M mode and qualitative and quantitative two-dimensional echocardiography. Nine patients with a marked reduction in the pressure gradient (no or small, less than or equal to 25 mm Hg, residual basal gradient) demonstrated a marked reduction in septal thickness after surgery (23 +/- 6 to 13 +/- 4 mm; p less than .01), a concomitant increase in septal to mitral valve distance (20 +/- 2 to 30 +/- 5 mm; p less than .005), and a loss or substantial decrease in the magnitude of systolic anterior motion of the mitral valve. Two-dimensional echocardiographic results demonstrated an increase of over 100% in the cross-sectional area of the left ventricular outflow tract at onset of systole (2.2 +/- 0.6 to 5.5 +/- 3 cm2; p less than .01). ⋯ Furthermore, the postoperative left ventricular outflow tract area was significantly smaller in patients with residual basal gradients (3.0 +/- 1 cm2) than that in patients with no residual gradient (5.5 +/- 3 cm2; p less than .05). Ten patients with only provocable subaortic gradients after operation showed postoperative left ventricular outflow tract dimensions intermediate between those in patients with either residual basal gradient or no residual gradient. On the basis of this echocardiographic assessment of septal myotomy-myectomy, we conclude that abolition or reduction of the subaortic gradient after operation in patients with obstructive hypertrophic cardiomyopathy is largely the consequence of surgical enlargement of the left ventricular outflow tract area.
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We analyzed long-term follow-up data accumulated during an 8 year study of survivors of prehospital cardiac arrest. All patients included in this study were primary entrants via community-based rescue systems; patients who were tertiary referrals (survivors of cardiac arrest from other hospitals) were not included in this analysis. In the group of 61 patients entering our study between 1975 and 1980, with a follow-up to 1983, there have been a total of 24 deaths (39%). ⋯ Life table analysis demonstrated a 10% rate of recurrence of cardiac arrest in the first year, with a 5% per year rate in each of the subsequent 3 years. Left ventricular ejection fractions at entry were not significantly different between survivors (mean = 45.3 +/- 13.6%) and nonsurvivors (mean = 37.6 +/- 12.6%), and the severity of ejection fraction abnormality at entry did not correlate with time to death in the nonsurvivors. However, ejection fraction was significantly lower in patients who died from causes other than recurrent cardiac arrest than in those who died of cardiac arrest (24.5 +/- 9.1% vs 42.7 +/- 9.2%; p less than .002).(ABSTRACT TRUNCATED AT 250 WORDS)
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We evaluated the accuracy of a noninvasive method for estimating right ventricular systolic pressures in patients with tricuspid regurgitation detected by Doppler ultrasound. Of 62 patients with clinical signs of elevated right-sided pressures, 54 (87%) had jets of tricuspid regurgitation clearly recorded by continuous-wave Doppler ultrasound. ⋯ Adding the transtricuspid gradient to the mean right atrial pressure (estimated clinically from the jugular veins) gave predictions of right ventricular systolic pressure that correlated well with catheterization values (r = .93, SEE = 8 mm Hg). The tricuspid gradient method provides an accurate and widely applicable method for noninvasive estimation of elevated right ventricular systolic pressures.