Biomedical subjects
Publications and source records attributed to H C Smith.
We report the case of a patient in whom an aneurysmal coronary artery fistula was visualized with two-dimensional echocardiography. Subsequent contrast echocardiography, coronary arteriography, and surgery confirmed the location and nature of the lesion. Contrast echocardiography was superior to angiography in delineating the cardiac chamber into which the fistula emptied.
This report describes for the first time the successful use of transluminal balloon-catheter dilation (angioplasty) for high-grade basilar artery atherosclerotic stenotic lesions in two patients with frequent, severe, progressing symptoms that were unresponsive to anticoagulant therapy. Excellent angiographic and short-term clinical results have been obtained. These results and the relative frequency of these lesions justify further evaluation of this approach.
This is a report of the longest survival of a patient with Ebstein's anomaly. The patient had no cardiac symptoms until the age of 79 years, when he presented with severe tricuspid incompetence and congestive heart failure, from which he ultimately died. The diagnosis was established by utilizing two-dimensional sector echocardiography.
A patient with unruptured aneurysm of the sinus of Valsalva presented because of ventricular tachycardia refractory to medical therapy. The underlying problem was not suspected until cardiac catheterization. Once the aneurysm was repaired, the tachycardia was abolished; the patient required no antiarrhythmic drugs. Two points are emphasized: First, cardiac catheterization is often indicated early in cases of ventricular tachycardia without obvious cause. Second, recurrent ventricular tachycardia is a hitherto unreported but important complication of sinus of Valsalva aneurysm.
Two cases are presented to illustrate the diagnostic and therapeutic dilemma when an anomalous origin of the left coronary artery from the pulmonary artery occurs with a hemodynamically significant intracardiac lesion. Hemodynamic alterations resulting from the associated intracardiac lesion may obscure the clinical features of the coronary arterial abnormality, and the appearance of normal coronary arterial distribution with left ventricular or aortic root angiography may create a false impression of a normal origin of the coronary arterial supply. A high index of suspicion may be the only lead to the detection of an anomalous origin of the left coronary artery from the pulmonary artery in association with an intracardiac lesion. In addition to the intracardiac lesion known to be associated with coronary arterial abnormalities, the question of anomalous coronary supply should be raised by the finding of poor left ventricular function or mitral insufficiency after operation (unexplainable by other causes), by the development of poor myocardial function during cardiac catheterization or anesthesia, or by the significant enlargement of a coronary artery seen during left ventriculography or supravalvular aortography.
Two patients with hereditary telangiectasia (Osler-Weber-Rendu disease) and high-output congestive heart failure secondary to large hepatic arteriovenous malformations had preoperative heart catheterization and exploratory cardiotomy to correct presumed intracardiac left-to-right shunts at the atrial level. At operation, both patients had oxygen-enriched blood returning from the inferior vena cava. Subsequent hepatic angiography demonstrated large hepatic arteriovenous fistulas, and both patients underwent hepatic artery banding and ligation, with reduction of left-to-right shunting.
A virilizing, gonadotrophin-responsive adrenal cortical adenoma was removed from a 54-year-old woman. Following removal of the tumour, which contained and secreted androgens and estradiol, serum gonadotrophins rose to menopausal levels and the patient experienced menopausal symptoms. Pre-operative attempts to localize the source of androgens were unsuccessful.
Regional displacements of lung parenchyma due to respiratory movements at 1 G and 7 Gy were studied in anesthetized dogs in the left decubitus position in a water-filled respirator that provided control of respiratory volumes and rate and minimized inertial shifts in position and shape of the thorax and abdominal contents and related effects on the lungs. Inspiratory movements at 1 G were relatively uniform, although regional volume increased more in the nondependent (right) lung than in the dependent (left) lung. Regional functional residual capacity (FRC) increased in the nondependent lung and decreased in the dependent lung during exposures to 7 Gy. The greatest inspiratory increase in volume occurred near the midlung, where regional FRC changed the least during acceleration. The decrease in dependent and increase in nondependent lung volumes during acceleration are attributed to the increased weight and consequent downward displacement of the higher specific gravity mediastinal contents concomitantly with upward displacement of pulmonary gas, producing an exaggeration of the dependent-to-nondependent gradient in alveolar size.
The peak rate of systolic wall thickening (p +/- dTw/dt) in regions of the left ventricle (LV) was determined preoperatively by biplane roentgen videometry in 18 patients before and after sublingual administration of nitroglycerin (NTG) and 3-23 months (median 12) after aortocoronary bypass surgery. The regional LV response to NTG was a reliable predictor for postoperative improvement in regional wall dynamics after successful aortocoronary bypass grafting. The ejection fraction response to NTG or surgery will not predict the regional myocardial response to NTG or surgery, nor will the regional response predict the global response. Subendocardial myocardial infarction is another cause of unimproved regional myocardial function after NTG and aortocoronary bypass surgery.
The effect of stenosis of the left main and proximal anterior descending coronary arteries on anterior left ventricular wall dynamics was investigated in 70 patients with ischemic heart disease by the use of roentgen videometric analysis of left ventricular angiograms. In all patients with ischemic heart disease, mean values for peak rate of systolic wall thickening and diastolic wall thinning were significantly smaller than normal (P less than 0.01). In patients without infarction, there was no correlation between peak rate of systolic anterior wall thickening and stenosis of the coronary artery supplying it, but there was a significant reduction in peak rate of diastolic wall thinning (P less than 0.01) in patients with stenosis greater than 90%; this difference was not apparent at any lower degree of stenosis. This population could not be recognized by any other parameter of global or regional ventricular function; thus, diastole is more sensitive to regional left ventricular dysfunction than systole.
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The incidence of perioperative myocardial infarction (MI) was examined in 148 patients with known coronary artery disease (CAD) who underwent 226 noncardiac surgical procedures. In 168 operations in 99 patients who had prior coronary artery bypass grafting (CABG) there were no perioperative MI's whereas in the 49 patients who had not undergone prior CABG who underwent 58 noncardiac operations, there were three MI's (5 percent). The lower (p less than 0.02) incidence of perioperative MI in patients with CAD who had had prior CABG suggests a protective effect for subsequent noncardiac operation, which could not be explained by other differences in cardiac status between the groups. All three MI's occurred in patients with three-vessel CAD, evidence that this should be added to prior MI as a significant risk factor. The study indicates also that patients with prior CABG have less risk of MI during and following anesthesia and noncardiac operation than do patients without CABG who have had a previous MI.
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We characterized smooth muscle function in the rabbit vas deferens in vivo by means of a new strainometer. Intraluminal pressure was measured and smooth muscle tension in the wall was calculated. Our studies revealed a low baseline pressure, no spontaneous contractions, and a constant wall tension. Studies of the effect of vasectomy on in vivo smooth muscle function showed increased intraluminal pressure, diameter, and baseline wall tension, and development of spontaneous contractions with increased wall tension, intraluminal pressure, and diameter with each contraction.
We evaluated the smooth muscle response to the systemic administration of various vasoactive drugs and hormones in vivo in the rabbit vas deferens. Norepinephrine, epinephrine, and urecholine caused contractions of the vas deferens that caused it to shorten and thicken. Isuprel inhibited contractions that were initiated by obstruction of the vas deferens. Catecholamine depletion from guanethidine caused dilation of the vas deferens, increased intraluminal pressures spontaneous contractions, and a spermpacked lumen. The vas deferens in the immature rabbit showed normal response to norepinephrine and obstruction. Estrogen administration prevented the normal dilation and increased peristalsis observed with obstruction.
Thirty-one patients were assessed by the multiple-gated acquisition cardiac blood-pool isotope-imaging technique using radiolabeled albumin within 24 hours of biplane contrast ventriculography. Data from the imaging method were analyzed by a semiautomatic technique with computer-generated edge detection and background subtraction. An excellent correlation was observed between ejection fractions determined with multiple-gated isotope imaging and those obtained by biplane contrast ventriculography (r = 0.93), and the same was true for average ejection rates (r = 0.80). For assessment of wall motion with this imaging technique, the anterior and the left anterior oblique left ventricular views were divided into nine segments, and a score was assigned to each segment based on the degree of wall motion. The cumulative anterior and left anterior oblique scores correlated well with the score from biplane contrast ventriculography (r = 0.90), and in 94% of segments in the left anterior oblique projection the assessment with multiple-gated isotope imaging was the same as or varied by only one class from the assessment by biplane contrast ventriculography. The multiple-gated acquisition cardiac blood-pool isotope-imaging technique is thus a valuable noninvasive method for assessing left ventricular function as measured by ejection fraction, ejection rates, and wall motion.
The peak rate of systolic wall thickening (pdTw/dt) in regions of the left ventricle was determined by biplane roentgen videometry in 60 patients before and a median of 14 mo after aorto-coronary bypass graft surgery. The left ventricular ejection fraction, stroke volume, and end-diastolic volume and pressure did not change significantly after surgery in the presence of patent or occluded grafts (P greater than 0.05). Statistically significant increases occurred in the peak rate of systolic wall thickening regions supplied by patent bypass grafts, and significant decreases occurred in regions with occluded grafts (P less than 0.01). Of 42 preoperatively hypokinetic regions (pdTw/dt greater than 0 less than 5.0 cm/s) supplied by a patent graft, 30 improved by an average of 2.6 cm/s after operation; 18 returned to normal. Failure of 24 hypokinetic regions to improve to normal was associated with myocardial infarction in 11 or with late postoperative graft blood flows of less than 60 ml/min measured by videodensitometry, in 10. All seven preoperatively akinetic (pdTw/dt=0) or dyskinetic (pdTw/dt less than 0) regions did not improve after the operation despite the fact that, in five of the seven, coronary bypass flows were over 60 ml/min. All eight preoperatively hypokinetic regions supplied by coronary artery graft flows of less than or equal 40 ml/min failed to improve to normal after operation. All nine preoperatively hypokinetic regions supplied by coronary artery graft flows of over 60 ml/min improved to normal after surgery. Late postoperative coronary artery bypass graft flows, the functional status of the myocardium, the status and distribution of the native coronary circulation, and decreased regional function elsewhere in the ventricle must all be considered when regional left ventricular function is interpreted.
Echocardiography revealed a persistent large segment of dyskinesis of the posterolateral wall in a patient with clinical an enzyme evidence of acute myocardial infarction but without diagnostic electrocardiographic changes. A left ventricular angiogram confirmed the echocardiographic findings.