Experimental determination of the effect of progressive sharp-angle spinal deformity on the spinal cord.

Neurological deficit is a serious though not well-known complication associated with spinal deformity. Sharp-angle kyphosis may be congenital, traumatic, degenerative, infectious, or iatrogenic in origin. Many kyphotic deformities are underestimated, thus leading to severe neurological deficit. In order to determine exactly what procedures of angulation the patients should undergo to stabilize the spine, which are major operations, the authors analyzed in an experimental model the effects of progressive sharp angulation on the anatomy of spinal canal and cord. We found that sharp anterior angulation of 50 degrees causes anterior-posterior stenosis and the dura will touch the spinal cord. At 90 degrees of angulation, the spinal cord will be squeezed and the pressure in the canal will be double what it was initially, probably leading to ischemia. The experimental confirmation (determination) of these angulations allows the physician in charge to define early in the treatment program when a surgical stabilization procedure should be included, before the angulation causes any neurological damage.

Anomalous inferior vena cava with azygos continuation.

Five patients who underwent cardiac catheterization at three separate institutions during a period of 6 years were found to have anomalous inferior vena cava with azygos continuation. Although it is not uncommon to detect this defect in pediatric patients with congenital heart disease, it may be an unusual finding for an angiographer who works primarily with adults. This article serves as a reminder of the existence of this potentially confusing anomaly, usually associated with other congenital cardiac abnormalities.

Correlation between the position of transducers and mitral valve gradient in mitral stenosis.

To assess the severity of mitral stenosis related to the level of transducers, the mitral valve gradient using pulmonary wedge and left ventricle was obtained from 15 patients. The mitral gradient was obtained with both transducers at mid chest level. Then, the level of each transducer was realigned with the catheter tip in the pulmonary capillary wedge and in the left ventricle using lateral fluoroscopy and the mitral gradient was re-measured. At the mid chest level, the mean mitral valve gradient was 14 +/- 6.2 mm Hg with a mitral valve area of 1.3 +/- 0.6 cm2. With the adjusted level of transducers, the mitral valve gradient was 18.7 +/- 6.8 mm Hg with a valve area of 1.0 +/- 0.5 cm2. The difference was that the level of catheter tip in the wedge was 3.5 cm below the mid chest level and the one in the left ventricle was 2.5 cm higher than the mid chest level. This result suggested that the mitral valve gradient obtained at mid chest level underestimated the severity of mitral stenosis.

Intravenous adenosine (adenoscan) versus exercise in the noninvasive assessment of coronary artery disease by SPECT.

Fifteen patients at a mean age of 58 underwent adenosine and maximal exercise thallium SPECT imaging. All scans were performed 1 week apart and within 4 weeks of cardiac catheterization. SPECT imaging was performed after the infusion of 140 micrograms/kg/min of adenosine for 6 minutes. Mean heart rate increment during adenosine administration was 67 +/- 3.7 to 77 +/- 4.1. Mean blood pressure was 136 +/- 7.2 to 135 +/- 6.2 systolic and 78 +/- 1.8 to 68 +/- 2.6 diastolic. No adverse hemodynamic effects were observed. There were no changes in PR or QRS in intervals. Five stress ECGs were ischemic. No ST changes were observed with adenosine. Although 68% of the patients had symptoms of flushing, light-headedness, and dizziness during adenosine infusion, symptoms resolved within 1 minute of dosage adjustment or termination of the infusion in all but one patient, who required theophylline. Sensitivity for coronary artery detection was 77% and specificity 100%. Concordance between adenoscans and exercise thallium scintigraphy was high (13/15 = 87%). In two patients, there were minor scintigraphic differences. The authors conclude that adenosine is a sensitive, specific, and safe alternative to exercise testing in patients referred for thallium imaging and may be preferable to dipyridamole.

Atrial natriuretic peptide response to ionic and nonionic contrast left ventriculography.

Atrial natriuretic peptide (ANP) levels were measured prior to and at 1 and 5 minutes postcontrast left ventriculography with an ionic contrast agent (diatrizoate), and a nonionic agent (iopamidol) and the results were compared. Since ionic contrast agents have been found to cause an increase in left ventricular end-diastolic pressure (LVEDP) and nonionic agents have been found to have less of an effect on LVEDP, we investigated the response of ANP levels, which have been found to increase secondary to increased LVEDP (atrial pressure), with both agents. A group of 38 patients who were scheduled for left heart catheterization for suspected coronary artery disease was included (19 in each group) and blood samples for ANP levels were drawn from the left ventricles. At the same time, heart rate, LVEDP, and left ventricular systolic pressure (LVSP) were also measured. It was found that the LVEDP increased significantly for both agents at 1 minute postventriculography, but no further change occurred at 5 min. Heart rate increased significantly in the diatrizoate group at 1 minute with a return of heart rate to preventriculography levels at 5 min, while the ANP level and LVSP remained unchanged at 1 minute postventriculography with both agents but increased significantly at 5 min in the diatrizoate group only. This difference in ANP response is not correlated with the LVEDP. The response of ANP may be related to heart rate and/or LVSP.

An unusual case of pulmonary emboli.

The authors present an interesting case of pulmonary embolus serendipitously diagnosed during an evaluation for a presumed metastatic pulmonary nodule.

Aortic balloon valvuloplasty.

Fifty-eight patients with severe aortic stenosis underwent successful aortic balloon valvuloplasty. The mean aortic valve gradient was reduced from 65 +/- 22 to 32 +/- 13 mmHg with symptomatic improvement. The procedure is an effective palliative procedure for patients with high surgical risk.

Cavernous lymphohemangioendothelioma of the right atrium--a case report.

The authors report a successful resection of a rare cystic tumor in the right atrium, discovered in an asymptomatic patient with atrial fibrillation. The cystic nature of the tumor was characterized by two-dimensional echocardiogram preoperatively. The site of attachment and movement of the tumor were clearly shown by cine computed tomography preoperatively. The tumor contained numerous endothelium-lined cavernous channels and groups of red blood cells. These features are distinctly different from those of other cystic tumors.

Exercise first-pass radionuclide assessment of left and right ventricular function and valvular regurgitation in symptomatic mitral valve prolapse.

The changes in right ventricular (RV) and left ventricular (LV) function and in regurgitant fractions on first-pass exercise radionuclide angiography (RNA) were assessed in 29 consecutive patients with symptomatic mitral valve prolapse (MVP). The mean right ventricular ejection fraction (RVEF) was 35 +/- 8% at rest and 46 +/- 15% after exercise (p less than 0.001). The mean left ventricular ejection fraction (LVEF) was 62 +/- 11% at rest and 74 +/- 13% after exercise (p less than 0.001). Seven of 29 patients had an abnormal RV response and 6 had an abnormal LV response. Eight had abnormal wall motion after exercise. A total of 12/29 patients (41%) had one or more abnormalities. The mean left-sided regurgitant fraction before exercise was 27 +/- 17% in 21/29 patients (72%) and 31 +/- 21% after exercise (p = ns). An additional 5 patients (17%) developed left-sided regurgitation after exercise. These findings indicate that wall motion abnormalities and abnormal RVEF and LVEF responses to exercise occur in symptomatic MVP patients. In addition, 26/29 (89.6%) had left-sided regurgitation after exercise. Since the presence of a murmur did not correlate with the presence of mitral regurgitation by RNA, then symptomatic patients with MVP should have first-pass exercise RNA to assess the presence of regurgitation at rest and after exercise. Antibiotic prophylaxis is recommended in MVP patients with systolic murmurs or with regurgitation. Since patients without murmurs can have regurgitation, further study is necessary to determine the need for endocarditis prophylaxis in these patients.

Right to left interatrial shunting following balloon mitral valvuloplasty.

A complication of balloon mitral valvuloplasty is development of left-to-right interatrial shunt. This report describes right-to-left interatrial shunting following balloon mitral valvuloplasty in a patient with mitral stenosis, tricuspid regurgitation and pulmonary hypertension.

Long-term follow-up by exercise radionuclide angiography of patients after valve replacement for aortic regurgitation.

The long-term effects of valve replacement for chronic isolated aortic regurgitation as assessed by first-pass exercise radionuclide angiography have never been reported. We studied 20 males and 5 females before, 15 months postoperatively, and from 29 to 109 (mean 62 +/- 21) months following valve replacement with exercise radionuclide angiography. Mean peak heart rate did not change for the three studies. Peak systolic blood pressure decreased from 201 +/- 42 mmHg to 185 +/- 24 mmHg at 15 months and further declined to 177 +/- 32 mmHg by the long-term study (p less than 0.03). The mean resting left ventricular ejection fraction improved from 44 +/- 15% preoperatively to 57 +/- 18% at 15 months (p less than 0.002) with no further improvement by the long-term evaluation. The postexercise ejection fraction improved from 42 +/- 13% preoperatively to 61 +/- 21% at 15 months (p less than 0.002) also with no change by the long-term study. The duration of exercise improved from 9.7 +/- 4.6 min to 11.9 +/- 3.4 min (p less than 0.03) at 15 months with no additional improvement long term. Improvement in resting and postexercise ejection fraction and in exercise duration is maximal at 15 months. Accuracy and cost containment suggest that assessment of the maximal change in ejection fraction by exercise radionuclide angiography after aortic valve replacement in asymptomatic patients be limited to the 15-month interval.

Preliminary experience in the use of ultrafast computed tomography to diagnose aortic valve stenosis.

Eight patients, mean age 72 years, with aortic valve stenosis were studied by ultrafast CT 1 day after cardiac catheterization. After injection of radiographic contrast material through a peripheral vein, two contiguous eight-level R wave-triggered cine mode scans in the short axis were acquired, starting above the aortic valve and continuing through the apex of the left ventricle. Seven of eight patients, all with calcified aortic valves, had a detectable central orifice. Catheterization-derived aortic valve areas were within 0.25 cm2 of the CT valve areas in six of seven. LV mass was measured by ultrafast CT in the eight patients with aortic valve stenosis (121.6 +/- 18.2 gm/m2) and was found to be significantly higher (p less than 0.0001) than that in a group of eight subjects with normal LV function, no history of hypertension, and normal ECGs (73.0 +/- 13.1 gm/m2). It is concluded that in selected cases ultrafast CT can contribute to the assessment of severity of calcific aortic stenosis by measurement of LV mass and valve area.

Single coronary artery: right coronary artery originating from distal left circumflex.

This report describes a patient with single coronary artery, in whom the right coronary artery originated from the distal left circumflex. However, this anomaly was not of clinical significance based on atypical nature of chest pain, negative thallium exercise test and absence of coronary obstruction.

Assessment of global and regional left ventricular function in ischemic heart disease using ultrafast computed tomography.

Contrast-enhanced ultrafast computed tomography (CT) of the left ventricle was done in the long axis and short axis within one day of cardiac catheterization in 14 males with ischemic heart disease and a mean age of 58 years. Imaging was R wave-triggered at 58-msec intervals (13/level). Left ventriculography was performed in 30 degrees right anterior oblique (RAO) and 60 degrees left anterior oblique (LAO) caudal 12 degrees. CT left ventricular ejection fraction was measured using a modified Simpson's reconstruction of end-systolic and end-diastolic slices. Catheterization left ventricular ejection fraction was measured by area-length method. Six left ventricular segments (septal, apex, anterior, lateral, inferior, and posterior) were scored by different paired observers as follows: dyskinesis (-1), akinesis (0), moderate-severe hypokinesis (1), mild hypokinesis (2), and normal (3). Correlations of left ventricular ejection fraction for catheterization vs. long-axis CT and short-axis CT were r = .83 and r = .86, respectively. Seven of eight patients with transmural myocardial infarction were identified on CT by akinetic/dyskinetic segments. Eighty-four segments were scored. There was agreement (normal vs. abnormal) in 76 (90%). CT detected 47 normal segments vs. 51 by catheterization (92%), 11 akinetic/dyskinetic segments (92%), and 14 hypokinetic segments vs. 21 (67%). Wall motion scores between CT and catheterization differed by greater than 1 in 6 of 84 segments (7%). Therefore, ultrafast CT can accurately assess global and regional left ventricular function.

Clinical trial of the disposable transducer catheter.

We compared the intracardiac and intravascular pressures obtained by a conventional strain gauge transducer (CT) with a recently developed disposable high-fidelity transducer catheter (DT) during cardiac catheterization. CT was positioned at the patient's midchest level. The pressure measurements obtained by DT compared favorably with those of CT. Femoral arterial pressures by the two methods showed no statistical difference. Right heart pressures were similar using both transducers. However, right ventricular pressures by DT in five of eight patients were lower than that from CT. Higher pulmonary arterial pressures were noted in two of seven patients and higher pulmonary capillary wedge pressures were seen in four patients using DT compared to CT. None of these differences were of statistical significance. These pressure differences may be due to transducer position. Because the midchest position of CT does not precisely define the anatomic location of the cardiac chamber being studied, pressure measurements can be overestimated or underestimated. DT eliminates this problem, as well as overshooting and concern with air bubbles in the catheter system commonly associated with CT. Therefore DT may provide accurate hemodynamic measurements. It would appear to be useful regardless of patient position and may be useful in ambulatory hemodynamic determinations.

Development and application of transseptal left heart catheterization.

The recent interest in transseptal left heart catheterization affords an opportunity to review the development and application of this procedure. This review briefly follows the history of right and left heart catheterization to the development of the transseptal procedure. A detailed description of the technique of transseptal catheterization is provided, as well as the indications and contraindications to its use. A learning curve is associated with this technique and is inversely related to the complication rate of the transseptal approach. Physicians working in high volume catheterization laboratories may gain the experience to safely perform transseptal left heart catheterization on carefully selected patients.

Exercise radionuclide assessment of left ventricular function before and after coronary bypass surgery.

The effects of elective saphenous vein coronary artery bypass surgery on left ventricular ejection fraction were assessed by using exercise first-pass radionuclide angiography in 66 consecutive patients. All patients with left main coronary artery or concomitant valvular disease were eliminated from the study. Before surgery, 7 patients had normal postexercise left ventricular function (Group 1), 33 had normal resting left ventricular function with an abnormal response to exercise (Group 2), and 26 had an abnormal resting left ventricular ejection fraction with an abnormal response to exercise (Group 3). Following surgery, patients in all three groups had no change in mean resting left ventricular ejection fraction; however, patients in Groups 2 and 3 had significant improvement in mean postexercise left ventricular ejection fraction (p less than 0.0001 and p less than 0.0054 respectively), whereas patients in Group 1 did not. Previous studies reported improvement in postexercise ejection fraction in patients with reduced resting left ventricular function and with an ischemic response to exercise (Group 3). But this is the first study to confirm improvement in postexercise function in patients with normal resting function and an ischemic response to exercise (Group 2).

Analysis of the position of the left ventricular apex and base during systole.

The relative positions of the left ventricular apex and base in end-diastole (ED) and end-systole (ES) were determined in a group of normal individuals using cross-sectional echocardiography (group A) and in a group of patients with normal hemodynamics and angiographic parameters using cine-computed tomography (group B). In both groups no change was detected in the position of the epicardial aspect of the apex from ED to ES. The base moved in direction of the apex by 10.2% +/- 1.9% (mean +/- standard deviation) of the longitudinal dimension of the chamber in group A and by 12.9% +/- 5.1% in group B. In both groups the apical cavity was obliterated by the peri-apical walls. Apical obliteration is responsible for the apparent movement of the apical segment seen in cineventriculography.