Ronald B. Himelman

Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava

To evaluate a simple noninvasive means of estimating right atrial (RA) pressure, the respiratory motion of the inferior vena cava (IVC) was analyzed by 2-dimensional echocardiography in 83 patients. Expiratory and inspiratory IVC diameters and percent collapse (caval index) were measured in subcostal views within 2 cm of the right atrium. Parameters were correlated with RA pressure by flotation catheter within 24 hours of the echocardiogram (38 were simultaneous). Correlations between RA pressure (range 0 to 28 mm Hg), expiratory and inspiratory diameters and caval index were 0.48, 0.71 and 0.75, respectively. Of 48 patients with caval indexes less than 50%, 41 (89%) had RA pressure greater than or equal to 10 mm Hg (mean +/- standard deviation, 15 +/- 6), while 30 of 35 patients (86%) with caval indexes greater than or equal to 50% had RA pressure less than 10 mm Hg (mean 6 +/- 5). Sensitivity and specificity for discrimination of RA pressure greater than or equal to or less than 10 mm Hg were maximized at the 50% level of collapse. Thus, IVC respiratory collapse on echocardiography is easily imaged and can be used to estimate RA pressure. A caval index greater than or equal to 50% indicates RA pressure less than 10 mm Hg, and caval indexes less than 50% indicate RA pressure greater than or equal to 10 Hg.

Noninvasive evaluation of pulmonary artery pressure during exercise by saline-enhanced Doppler echocardiography in chronic pulmonary disease.

To determine the feasibility of noninvasive determination of right ventricular systolic pressure (RVSP) during a graded-exercise protocol, saline contrast-enhanced Doppler echocardiography of tricuspid insufficiency was performed in 36 patients with chronic lung disease and 12 normal controls. In the patients with chronic pulmonary disease, symptom-limited, incremental supine bicycle exercise and pulse oximetry were performed on and off high-flow oxygen. Technically adequate Doppler studies were initially obtained in 20 patients (56%) at rest and 14 (39%) on exercise; these numbers increased to 33 (92%) and 32 (89%), respectively, after enhancement with agitated saline (both p less than 0.001). In 10 patients with chronic lung disease who had simultaneous hemodynamic monitoring during exercise, the correlation between Doppler and catheter measurements of pulmonary artery systolic pressure was close (r = 0.98). Among controls, RVSP increased from 22 +/- 4 at rest (mean +/- SD) to 31 +/- 7 mm Hg at peak exercise. In patients with chronic lung disease, RVSP increased from 46 +/- 20 to 83 +/- 30 mm Hg (both p less than 0.001 vs. controls). Despite normal resting values for RVSP in 28% of study patients, nearly all showed abnormal increases in RVSP during supine bicycle exercise. Increases in RVSP during exercise were greatest in patients who showed oxyhemoglobin desaturation. The short-term administration of oxygen significantly blunted the increase in RVSP during exercise. Saline contrast-enhanced Doppler evaluation of tricuspid insufficiency seems a potentially valuable noninvasive method of determining the exercise response of RVSP in patients with chronic pulmonary disease.

Left atrial volume determination by biplane two-dimensional echocardiography: Validation by cine computed tomography

Left atrial (LA) volume measurements have been made by the application of the method of discs (modified Simpsons rule) to orthogonal biplane atrial echocardiographic images. Validation of the technique has been suboptimal due to deficiencies of the reference standard, levophase angiography. To define the accuracy of echocardiography, we compared LA end-systolic volume by echocardiography in 27 patients with volumes by cine computed tomography (Cine CT), a highly accurate and validated method of measuring cardiac chambers. Echocardiographic tracings were made in the apical long-axis two- and four-chamber views. In patients with atria less than 300 ml, 14 had echoes performed prospectively, with optimization of LA size, while the remaining 10 were analyzed retrospectively. The volume of each slice was calculated and was then summated to obtain total volume. The correlation coefficient between two-dimensional echocardiography and Cine CT was r = 0.98, and it was r = 0.82 when patients with atria greater than 300 ml (n = 3) were excluded. Echocardiography underestimated Cine CT measurements by 23%. The slope of the prospective group was closer to unity than the slope of the retrospective group (p less than 0.001), and the correlation with Cine CT was slightly better for the prospective group (r = 0.88 versus r = 0.77). LA volume by two-dimensional echocardiography correlates closely with Cine CT, a more accurate method of volume determination, and gives valid measurements of LA volume. Efforts to maximize LA size during scanning limit inaccuracies of echocardiographic measurements of the left atrium.

Reproducibility of quantitative two-dimensional echocardiography

In order to assess reproducibility of quantitative planimetry, three physicians trained in two-dimensional echocardiography performed five successive studies on one another over 2 weeks (30 total studies). Then each physician traced each study (90 total tracings) for left ventricular and atrial volumes and ejection fraction by means of a modification of Simpsons rule, and left ventricular mass and average wall thickness by means of a truncated ellipsoid formula. Calculation of intertechnician variability, intertracer variability, and 95% confidence limits showed that measurements of volumes were less reproducible than measurements of ejection fraction, average wall thickness, and mass. Mean intertracer variability of 15% exceeded mean intertechnician variability of 11%; this disparity was magnified in the subject who was technically difficult to image. Ninety-five percent confidence limits were: ejection fraction +/- 7%, average wall thickness +/- 9%, left ventricular mass +/- 12%, left ventricular end-diastolic volume +/- 11%, stroke volume +/- 14%, left ventricular end-systolic volume +/- 15%, and left atrial volume +/- 19%. Reproducible planimetry data can be obtained in normal hearts with the use of a protocol for quantitative imaging and planimetry.

Cardiac manifestations of human immunodeficiency virus infection: a two-dimensional echocardiographic study.

To determine the prevalence of cardiac abnormalities in patients with human immunodeficiency virus (HIV) infection, two-dimensional Doppler echocardiography was performed on 70 consecutive patients with HIV infection, including 51 with acquired immunodeficiency syndrome (AIDS), 13 with AIDS-related complex and 6 with asymptomatic HIV infection. Of the 70 patients, 36% were hospitalized and 64% were ambulatory at the time of evaluation. The average age was 37 years; 93% were homosexual men. Echocardiographic findings included dilated cardiomyopathy in eight patients (11%), pericardial effusions in seven patients (10%) (one with impending tamponade), pleural effusion in four patients (6%) and mediastinal mass in one patient (1%). Among the 25 hospitalized patients, echocardiographic abnormalities were noted in 16 (64%), whereas among the 45 ambulatory patients, the only abnormality noted was mitral valve prolapse in 3 patients (7%) (p less than 0.0001). Dilated cardiomyopathy was the only echocardiographic lesion more common in the 25 hospitalized patients than in 20 hospitalized control patients with acute leukemia. Symptoms of congestive heart failure responded to conventional therapy. Cardiac lesions were associated with active Pneumocystis carinii pneumonia and low T helper lymphocyte counts. Dilated cardiomyopathy of unknown origin may be more common than was previously recognized in hospitalized, acutely ill patients with AIDS, but is uncommon in ambulatory patients with HIV infection. Echocardiography should be considered in the evaluation of dyspnea in hospitalized patients with HIV infection, especially those with dyspnea that is out of proportion to the degree of pulmonary disease.

Severe pulmonary hypertension and cor pulmonale in the acquired immunodeficiency syndrome

Abstract Numerous cardiopulmonary manifestations of the acquired immunodeficiency syndrome (AIDS) have been reported. 1,2 We have previously found that dilated cardiomyopathy, pericardial effusion and pleural effusion are the most common cardiopulmonary lesions detected by echocardiography in hospitalized AIDS patients. 3 We have also noted evidence of mild to moderate pulmonary hypertension in patients with dilated cardiomyopathy and occasional patients with active Pneumocystis carinii pneumonia. 3 By necropsy studies, some AIDS patients with Pneumocystis carinii pneumonia or cytomegalovirus infection of the lung have had right ventricular dilatation in the absence of left ventricular dilatation or myocarditis. 2 Although pulmonary emboli, pulmonary infarction, venous thromboemboli and non-bacterial thrombotic endocarditis have also been demonstrated by autopsy in AIDS patients, cor pulmonale has not been reported previously.

Cardiac consequences of renal transplantation: Changes in left ventricular morphology and function

To characterize changes in left ventricular morphology and function associated with renal transplantation, noninvasive cardiac evaluations were performed in 41 adults at the time of surgery and at follow-up. At the time of transplantation, 36 patients had undergone hemodialysis through a fistula for 2.3 +/- 2.5 years (mean +/- SD); their hematocrit level was 26 +/- 6% and systolic blood pressure was 151 +/- 19 mm Hg. Perioperatively, left ventricular hypertrophy was present in 93% of patients by echocardiography, but in only 37% by electrocardiography. Abnormal left ventricular diastolic function was present in 67% of patients and indicated a high risk for perioperative pulmonary edema. At follow-up (1.5 +/- 1.4 years), mean hematocrit level increased to 39 +/- 7%, systolic blood pressure decreased to 132 +/- 14 mm Hg and spontaneous closure of the fistula occurred in 13 patients. Left ventricular mass by echocardiography decreased from 237 +/- 66 to 182 +/- 47 g (p less than 0.001), a decrease of 23%. Left ventricular volumes and cardiac index also decreased significantly, reflecting the rapid resolution of a pretransplant high output state. Despite proportionate regression of left ventricular hypertrophy within months of transplantation, diastolic function did not improve. The significant regression of left ventricular hypertrophy that occurs after renal transplantation may help explain the improved cardiovascular survival of patients with a renal transplant over that of patients on long-term dialysis.

Septal Bounce, Vena Cava Plethora, and Pericardial Adhesion: Informative Two-Dimensional Echocardiographic Signs in the Diagnosis of Pericardial Constriction

To assess the diagnostic value of three different two-dimensional echocardiographic signs of pericardial constriction (early diastolic septal bounce, plethora of the inferior vena cava with blunted respiratory response, and pericardial adhesion), two independent observers retrospectively evaluated echocardiograms in 100 patients, 39 of whom had pericardial constriction, 15 had hemodynamically insignificant pericardial thickening, 16 had restrictive cardiomyopathy, and 30 had normal hearts. Causes of pericardial disease included cardiac surgery, malignancy, and uremia. Sensitivity and specificity of the three signs for constriction were 62% and 93% for septal bounce, 79% and 80% for vena cava plethora, and 79% and 90% for pericardial adhesion, respectively. The presence of either vena cava plethora or pericardial adhesion increased sensitivity, whereas the presence of both plethora and adhesion increased specificity. Between the two readers, septal bounce was the most consistent and pericardial adhesion the least consistent sign. False positive results included right ventricular pacing or left bundle branch block (septal bounce), postpericardiotomy (pericardial adhesion), and right heart failure (vena cava plethora). False negative results were often caused by technical problems with imaging. We conclude that these three two-dimensional echocardiographic signs are useful in differentiating pericardial constriction from hemodynamically insignificant pericardial thickening or restrictive cardiomyopathy.

The 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 echocardiography, the presence of a flail mitral valve leaflet was defined by the presence of abnormal mitral leaflet coaptation or ruptured chordae. Using these criteria, transesophageal imaging showed a trend toward greater sensitivity and specificity than precordial imaging in the diagnosis of flail mitral valve leaflet. 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)

Improved recognition of cor pulmonale in patients with severe chronic obstructive pulmonary disease

To compare sensitivity of clinical methods (physical examination, electrocardiogram, and chest radiograph) to echocardiography in the detection of cor pulmonale, and to determine the role of nocturnal oxygen desaturation in its development, 33 non-hypoxemic patients who had severe chronic obstructive pulmonary disease (COPD) were evaluated by clinical methods, echocardiography, and overnight ear oximetry. Compared to 25 age-matched control subjects, COPD patients had higher peak pulmonary systolic pressures by contrast-enhanced Doppler (40 +/- 13 versus 22 +/- 5 mm Hg, or 5.3 +/- 1.7 versus 2.9 +/- 0.7 kPa) and ratios of right to left ventricular volume (1.1 +/- 0.6 versus 0.6 +/- 0.1, both p less than 0.05). Defining cor pulmonale as pulmonary hypertension, right ventricular enlargement, or right ventricular hypertrophy, 25 COPD patients (75 percent) had cor pulmonale by echocardiography and 13 (39 percent) by clinical methods (p less than 0.05). Nocturnal desaturation was present in only 21 percent of patients. Echocardiographic measurements were similar between patients with emphysema and patients with bronchitis, and between patients with and without sleep desaturation. In patients who have severe COPD without waking hypoxemia, cor pulmonale is detected nearly twice as often by echocardiography as by clinical methods, but is usually not associated with sleep desaturation.