Gary E. Lane

Current Results and New Developments of Coronary Angiography With Use of Contrast-Enhanced Computed Tomography of the Heart

Electron beam computed tomography (EBCT) is the reference standard for x-ray-based tomographic imaging of the heart because of its high temporal resolution, but it is available in only a few centers. Quantification of coronary calcium is the most widely recognized use of EBCT for cardiac imaging. This technique requires no contrast media and provides an accurate assessment of overall plaque burden in the coronary tree; however, it does not directly identify or localize coronary stenoses. Multislice spiral (helical) CT (MSCT) is a new technology that provides images of the beating heart in diagnostic quality under many circumstances and may facilitate the broader application of cardiac and coronary CT. Currently, for imaging of the heart, much more experience exists with EBCT than with MSCT. Contrast-enhanced CT coronary angiography (CTCA) can be done with EBCT or MSCT to obtain images of the major branches of the coronary tree and to define luminal narrowing. Studies at experienced centers performed with small numbers of patients show that sensitivity, specificity, and negative predictive value are good with CTCA in the assessment of obstructive coronary artery disease, but CTCA remains an investigational technique for these applications. Computed tomographic coronary angiography can be clinically useful for assessing coronary artery bypass graft patency and congenital coronary abnormalities.

Imaging of Congenital Coronary Anomalies With Multislice Computed Tomography

OBJECTIVE To describe a single-center experience of using retrospectively gated multislice computed tomographic (MSCT) coronary angiography for imaging congenital coronary anomalies. PATIENTS AND METHODS We retrospectively reviewed the clinical information and imaging studies for 9 patients diagnosed as having congenital coronary anomalies on invasive, selective coronary angiography between February 2001 and October 2003 at the Mayo Clinic in Jacksonville, Fla. Two experienced observers classified by consensus the origin and proximal course of the abnormal coronary arteries as seen on MSCT. RESULTS In 1 patient, MSCT showed a normal but extremely anterior origin of the right coronary artery from the right aortic sinus of Valsalva. In the other 8 patients, the origin and course of 4 anomalous right coronary arteries, 2 anomalous left circumflex coronary arteries, and 2 single coronary arteries were recognized easily on MSCT. CONCLUSION Similar to electron beam computed tomography and magnetic resonance imaging, widely available MSCT can characterize the proximal course of congenitally abnormal coronary arteries and thus aid in clinical decision making for patients with such anomalies.

Image Quality in a Standardized Algorithm for Minimally Invasive Coronary Angiography with Multislice Spiral Computed Tomography

Purpose To report our experience with a standardized approach to pharmacologic heart rate control and image postprocessing for computed tomographic coronary angiography (CTCA) with multislice computed tomography (MSCT). Method Two experienced observers used transaxial tomograms and maximum-intensity projections to classify coronary segments (12 per patient, 135 consecutive patients) for degree of stenosis. One factor affecting image quality was identified for each segment that could not be assessed. Results Nine patients (7%) were excluded for technical reasons. Of 1,512 segments from 126 patients, 1,086 (72%) were assessable (8.6 per patient). Of 300 segments from 25 patients who also had selective coronary angiography, CTCA was able to assess 211 (70%) and detected significant disease in 27 (82% sensitivity, 96% specificity, 73% positive predictive value, and 97% negative predictive value). Vessel caliber, heart rate, and Agatston score were associated with inability to assess 426 coronary segments (28%). Conclusion Heart rate and Agatston score are important predictors of the ability to assess proximal and midcoronary segments by CTCA with MSCT.

Unruptured Noncoronary Sinus of Valsalva Aneurysm: Preoperative Characterization by Transesophageal Echocardiography

We describe a patient with a large unruptured sinus of Valsalva aneurysm that was discovered incidentally. Transesophageal echocardiography was used to characterize the aneurysm preoperatively, and was helpful intraoperatively in assessment of the degree of native aortic valvular regurgitation after repair. The use of transthoracic echocardiography, contrast echocardiography, Doppler echocardiography, and transesophageal echocardiography are discussed in this condition.

Substance P distribution and effects in the canine epicardial coronary arteries

Substance P (SP), a vasoactive neuropeptide detected in animal and human hearts has been reported to increase coronary blood flow in animals. However, no data are available on SP effects on epicardial coronary arteries, the site of coronary disease. To determine the amount and distribution of SP and its action in the large coronary vessels, we studied two groups of dogs. One group was anesthetized for collecting three 1 cm segments of the circumflex coronary artery (CX) and left anterior descending artery (LAD) through a left thoracotomy. These segments represented proximal (I), middle (II), and distal (III) portions of the two arteries. Concentrations (ng/g) of SP-like immunoreactivity (SP-LI) were determined by radioimmunoassay. SP-LI was present in LAD (I: 1.17 +/- 0.20, II: 1.08 +/- 0.36, III: 1.14 +/- 0.25) and CX (I: 1.44 +/- 0.38, II: 1.51 +/- 0.47, III: 0.70 +/- 0.20). SP differences among segments of LAD and segments I and II of CX were not significant, but there was a significant difference between segment III of CX and the others. In the second group of closed chest anesthetized dogs, we examined the effects of intracoronary SP infusion before and during administration of serotonin (5HT). LAD and CX artery responses (% area change) to SP and to SP plus 5HT were examined using quantitative coronary angiography. Intracoronary 133Xe in saline provided coronary flow data. SP infusion produced significant vasodilation in segment II (15% area increase) and III (17%) during the highest dose (1 microgram/min). The three SP doses infused with 5HT (0.05 mg/min) did not produce vasodilation, although LAD segment III constriction from 5HT was abolished during the highest dose of SP infusion. The presence of SP, and its dilatory effect on the coronary arteries, suggests a role in maintaining vasodilator tone in the coronary arteries.

Quiescent left atrial myxoma

Copyright ,c’ 1994 by Mosby-Year Book, Inc. 0002.8703/94/

Cardiac tamponade due to low-volume effusive constrictive pericarditis in a patient with uncontrolled type II autoimmune polyglandular syndrome

3.00 + 0 4/4/63613 has not appreciably enhanced the understanding of the natural history of this disorder. The potentially sudden, devastating nature of the complications of this tumor mandates prompt surgical excision once the diagnosis is made.4 The documentation of the growth rate of myxoma has been limited primarily to observation of recurrent tumors after a prior excision.5 Recently, it has been suggested that primary intracardiac myxomas grow at a rapid rate.6-8 We report a patient who had documentation of a left atrial myxoma by echocardiography over an interval of more than 2 years. A 72-year-old man presented for general examination at the Mayo Clinic in July 1992. He was free of symptoms except for a mild resting tremor, which had been present for several years. His medical history was remarkable for benign colon polyps and prostate cancer, diagnosed in 1989, for which he received radiotherapy. He also gave a history of an abnormal echocardiogram performed in March 1990 as part of a general examination by another physician, which he reported showed evidence of a possible left atria1

Indomethacin attenuates the constriction of canine epicardial coronary arteries to acetylcholine in the absence of endothelium: Contribution of platelets to vasoconstriction in vivo

Abstract Type II autoimmune polyglandular syndrome (APS), a relatively common endocrine disorder, includes primary adrenal insufficiency coupled with type 1 diabetes mellitus and/or autoimmune primary hypothyroidism. Autoimmune serositis, an associated disease, may present as symptomatic pericardial effusion. We present a case of a 54-year old male with APS who developed pericarditis leading to cardiac tamponade with a subacute loculated effusion. After urgent pericardiocentesis intrapericardial pressure dropped to 0, while central venous pressures remain elevated, consistent with acute effusive constrictive pericarditis. Contrast computerized tomography confirmed increased pericardial contrast enhancement. The patient recovered after prolonged inotropic support and glucocorticoid administration. He re-accumulated the effusion 16 days later, requiring repeat pericardiocentesis. Effusive–constrictive pericarditis, an uncommon pericardial syndrome, is characterized by simultaneous pericardial inflammation and tamponade. Prior cases of APS associated with cardiac tamponade despite low volumes of effusion have been reported, albeit without good demonstration of hemodynamic findings. We report a case of APS with recurrent pericardial effusion due to pericarditis and marked hypotension with comprehensive clinical and hemodynamic assessment. These patients may require aggressive support with pericardiocentesis, inotropes, and hormone replacement therapy. They should be followed closely for recurrent tamponade.

Improved Detection of Silent Cardiac Ischemia With a 12-Lead Portable Microprocessor-Driven Real-Time Time Electrocardiographic Monitor

This study was designed to evaluate the in vivo effect of acetylcholine on endothelial-damaged canine epicardial coronary arteries and the potential contribution of platelets to those acetylcholine-induced responses. Changes in left anterior descending artery cross-sectional area were determined by quantitative angiography in the closed chest anesthetized dog. Baseline cross-sectional area of the left anterior descending artery was not changed by removal of the endothelium by balloon-tipped catheter. Increased constrictor tone produced by prostaglandin F2 alpha was comparable in endothelium-intact and endothelium-removed vessels, supporting an endothelium-independent mechanism for prostaglandin F2 alpha in vivo. Acetylcholine produced anterior descending artery vasodilation with the endothelium intact; a comparable maximal dilator response was also obtained in the presence of increased constrictor tone (prostaglandin F2 alpha). In contrast, acetylcholine produced vasoconstriction of the anterior descending artery when the endothelium was removed. To evaluate the mechanism of acetylcholine-induced vasoconstriction in endothelium-removed vessels, the same protocol was completed in the presence of the platelet inhibitor indomethacin. Indomethacin did not alter baseline cross-sectional area or the dilator response to acetylcholine in endothelium-intact vessels. In contrast, the constrictor response in endothelium-removed vessels was antagonized, and a dilator response comparable with that in endothelium-intact vessels was produced by acetylcholine. The results of this study provide an experimental basis for the observations in human studies in which apparently atherosclerotic vessels constrict in response to acetylcholine. Removal of the endothelium in vivo abolishes the dilator response to acetylcholine and converts the acetylcholine response to vasoconstriction or vasospasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Beat-by-Beat Aortic Valve Area Measurements Indicate Constant Orifice Area in Aortic Stenosis: Analysis of Doppler Data with Varying RR Intervals

OBJECTIVE To compare a microprocessor-driven real-time 12-lead electrocardiographic monitoring device with Holter monitoring for detection of ischemia. DESIGN Electrocardiographic monitoring was conducted in 110 patients at bed rest or undergoing surgical procedures. MATERIAL AND METHODS In three groups of patients, simultaneous monitoring with a 12-lead real-time device and a 2-channel Holter system was performed to detect ischemic episodes. The differences in the number of ischemic events and the total time of ischemia revealed by the two devices were analyzed statistically. RESULTS In patients with coronary artery disease, more ischemic ST-segment shifts were detected by the 12-lead device than by Holter monitoring (44 versus 16 events; P < 0.05). Total time of ischemia was also greater with the 12-lead device (879 versus 273 minutes; P < 0.05). Ischemia was detected by both techniques in 6 patients, only by the 12-lead device in 12, and only by Holter monitoring in 1. Neither device detected ischemia in control subjects. The 12-lead device had an advantage in detecting inferior ischemia, and it identified an additional 13 patients with unstable angina who had changes in T-wave polarity but did not exhibit ST-segment shifts. CONCLUSION The 12-lead real-time electrocardiographic monitoring device is superior to Holter monitoring in detecting and facilitating real-time identification of myocardial ischemia in patients at bed rest.