Cardiovascular diseases最新文献

To determine the usefulness of R-wave amplitude changes during exercise testing for the diagnosis of coronary artery disease (CAD) and to understand the discrepancies that have been described in the literature regarding their value, we studied two groups of patients by means of electrocardiographic (EKG) treadmill testing and coronary arteriography. Group I was composed of 149 patients who were studied prospectively. The specificity of R-wave changes measured from preexercise to immediately postexercise (SRV(5)) was 81%, but that of R-wave changes measured from preexercise to peak exercise (URV(5)) was 46%. A group of 156 patients (Group II) evaluated retrospectively showed a high specificity for the SRV(5) (84%) and poor specificity for the URV(5) (39%). The sensitivity of the SRV(5) was 38% in Group I and 42% in Group II. Therefore, if measured during the immediate postexercise period and not at peak exercise, changes in R-wave amplitude may be of value in the diagnosis of coronary artery disease by electrocardiographic exercise testing.

Computerized fluoroscopy (CF) allows visualization of any segment of the arterial vascular system with intravenous injection of small volumes of standard iodinated contrast media. Because it avoids the risk of arterial puncture and the need for hospitalization, this technique is safer and more economical than standard arteriography. Because of these advantages, CF is likely to expand the role of arteriography in the clinical management of vascular disease. Computerized arteriographic imaging requires an intravenous power injection of 40 to 60 cc of iodinated contrast media. Immediately after injection, six to ten fluoroscopic images (1/15 sec duration) are obtained at 1.5-sec intervals. The first image serves as a mask from which subsequent images are serially subtracted by means of a digital video image processor. The sequence of different images is contrast enhanced and stored on a video disk. Video images are converted to hard copy arteriography with a standard multiformat camera. Technical failures (<5%) may result from patient motion, inadequate peripheral venous access, or extravasation of contrast media. Nearly 600 computerized intravenous arteriograms have been performed in 240 patients with peripheral vascular disease. Qualitative com-parisons with standard arteriograms suggest a close correlation between these two imaging techniques. Computerized fluoroscopy allows the identification of atheromatous plaque ulceration, stenoses, occlusions, and aneurysms. This method has been used to visualize the aortic arch and its branches, the cervical and intracranial vessels, the abdominal aorta, and arteries of the extremities. Computerized fluoroscopy has great potential as a method for safe, simple diagnostic screening and assessment of the postoperative patient.

Echocardiograms of 30 patients with a normally functioning Ionescu-Shiley pericardial xenograft valve in the aortic position were analyzed to delineate the ultrasonic patterns produced by this bioprosthesis. The pericardial leaflets were recorded as thin, discrete echoes that were similar in configuration to the native aortic valve. Maximum systolic excursion of the anterior and posterior leaflets was 19 +/- 0.22 mm (standard deviation.) The presence of multiple echoes produced by the titanium frame was the major technical limitation to echocardiographic imaging of valve motion.

Three cases of severe disc variance and erosion of the Teflon-disc Beall mitral valve prosthesis (Models 103 and 104) are reported. In two patients, the Beall mitral valves were excised and replaced with two Björk-Shiley mitral valves. The remaining patient did not survive, and at autopsy, the lens was found at the aortic bifurcation level. Because of this potentially lethal complication, careful follow-up of patients with Beall mitral valve prostheses (Models 103 and 104) is recommended.

The use of radiofrequency as a means of synchronization and stimulation does not necessitate an external lead, and thus has allowed the construction of an implantable device for long-term treatment of reentry tachycardias. The device is used along with Amiodarone therapy and can be triggered by the patient himself.

A 20-year-old woman had received a 22-mm Lillehei-Kaster prosthesis at the age of 16 for progressive mitral valve stenosis. She was asymptomatic for 4 years, when dyspnea on exertion, orthopnea and paroxysmal nocturnal dyspnea recurred. Operation was undertaken and a thrombus of recent origin was found extending from the posterior aspect of the prosthetic ring to the posterior left atrial wall. The sewing skirt was covered with neoendothelium and the valve orifice was not compromised; however, the hinge mechanism on the ventricular surface was overgrown with a dense fibrotic pannus that limited the normal 80 degrees excursion of the tilting disc to 15 degrees. This marked limitation of disc motion produced the equivalent of severe mitral stenosis. The Lillehei-Kaster valve was excised and replaced with a #27 Björk-Shiley prosthesis. The patient improved, and she remains asymptomatic 1 year after surgery.

Arteriographic examination of the coronary, cerebral, and peripheral circulatory systems is the ultimate diagnostic technique for the identification and quantification of atherosclerotic occlusive disease. In the past, hospitalization has been required for this invasive procedure. Recently, however, the concept of outpatient catheterization and arteriography has become a reality. To investigate the integrity, safety, and cost-effectiveness of our outpatient invasive procedures laboratory, we analyzed our experience with 254 cardiac catheterizations and 174 peripheral arteriograms performed during a 20-month period. There were no deaths or major complications. Minor complications (11%) included bleeding from the cutdown site, nausea, numbness, and allergic reactions. Two patients with arrhythmias required cardioversion. Nine patients (2%) were transferred to the hospital for observation or immediate surgery due to the nature of their atherosclerotic lesions. This study reveals (1) the technical quality, safety, indications, and contraindications for outpatient catheterization and arteriography; (2) the enthusiastic patient acceptance of outpatient invasive diagnostic studies; (3) the economic impact of these procedures on escalating health-care costs; and (4) the potential for outpatient catheterization and arteriography on a broad scale.

From January 1958 through December 1979, 1572 patients underwent surgery for left ventricular aneurysm (LVA) in our institution. The series included 1365 men and 207 women, with a ratio of 6.5:1. Ages ranged from 25 to 79 years, with a mean of 54.7 years. Most patients were in NYHA functional Class III or IV, and all had sustained at least one documented myocardial infarction. During the first decade, LVA resection alone was performed, but after the advent of aortocoronary bypass (ACB) surgery, the majority of patients underwent ACB along with LVA resection. Some required additional septoplasty, mitral valve replacement, annuloplasty, or aortic valve replacement. In all groups, the mortality was higher for women than for men. Early deaths were due primarily to acute or progressive myocardial failure secondary to recurrent myocardial infarction. Follow-up information for 6 months to 8 years was obtained by means of questionnaires submitted to patients and referring physicians. Of 475 patients who underwent LVA resection and ACB and who responded, 92.2% were either improved or asymptomatic.