The bottom line syndrome. Hypertrophic cardiomyopathy revisited.
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Biomedical subjects
Publications and source records attributed to J M Criley.
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Changes in ejection fraction (EF) and segmental wall motion (SWM) have been shown to be sensitive indicators of left ventricular (LV) function. This information is only obtainable by contrast angiography or gated blood pool scans. Gated studies assume a fixed geometry for the LV for EF determinations, are lengthy and limited primarily to the LAO projection. We correlated contrast and Tc-99m pertechnetate angiograms by singl pass radioisotope angiography (immediately preceding the contrast study) in 12 patients. EF was calculated from the LV time/activity curve and values ranged from .21 to .72. Angiographic correlation yielded r = 0.97. Regional LV wall motion was evaluated by dividing a summated cardiac cycle into 16 frames and dynamically and sequentially displaying these frames. Regional wall motion evaluation of four LV quadrants correlated well with angiography (r = 0.97). For quantitation these images were divided into four anterior and four inferior segments and the areas of respective segments were compared and expressed as a shortening fraction. SWM compared favorably with angiographic determinations (r ranged from 0.70 to 0.99). Thus, single pass radioisotopic determinations of EF and SWM in the RAO projection correlated well with the angiographic values and provide essential quantitative information of LV function otherwise unobtainable at the bedside.
Transvenous right ventricular pacemaker catheters were implanted in 18 mongrel dogs for periods of 2 to 18 months (average 4.9 months). Heart block was produced in 15 of these dogs by injection of 37 per cent formaldehyde into the interatrial septum. In the other three dogs which served as controls, no heart block was produced and no electrical stimulation was applied to the implanted catheters. After the animals had been put to death, gross and microscopic examination of the hearts revealed four categories of morphological changes: (1) connective tissue sheath formation around the catheters, (2) endocardial papillary thickening, (3) interatrial septal changes, and (4) myocardial damage. Changes 1, 2, and 4 occurred in one or more intracardiac locations in all 18 dogs. Change 3 occurred only in the 15 dogs in which heart block was produced. The most striking histologic findings were areas of cartilagenous metaplasia in endocardium an underlying myocardium and areas of marked cellular proliferation of the endocardial cells both in the endothelium and underlying stroma. Chronic implantation of transvenous intracardiac pacemaker catheters in dogs consistently produces morphologic changes which may interfere with cardiac and pacemaker function and may hinder attempts to remove nonfunctional or unneeded catheter electrodes. The changes observed appear to be related to the presence of foreign material per se and not external electrical stimulation of the heart.
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Technetium-99m pyrophosphate (PPi) is currently considered the best scanning agent for the diagnosis of acute myocardial infarction. False-positive scans have been reported in association with unstable angina, alcoholic cardiomyopathy, and ventricular aneurysms. In this study, 86% of patients (12/14) with either calcific aortic or mitral valvular heart disease had positive PPi cardiac scintiscans and the location of the PPi uptake was limited to the calcific valve in all (9/9) of the patients who underwent valve replacement surgery. Six patients with valvular disease without radiologic evidence of calcium had negative PPi heart images. Three of these patients had surgical valve replacement, and in none was there increased uptake in the resected valve. Seventy-five percent of the patients with calcified aortic valves had localization of the PPi activity to the area of the aortic valve, whereas 50% of the patients with calcified mitral valves showed a diffuse pattern of uptake on the cardiac image. In vitro demonstration of increased radioactivity in surgically removed cardiac valves warrants the conclusion that Tc-99m PPi is taken up by calcified heart valves. We conclude that while PPi heart scanning is a sensitive indicator of acute myocardial infarction, false-positive scans can occur in the presence of calcific valvular disease, due to localization of PPi in the calcified portion of the valve.
Eight patients undergoing coronary angiography were successfully resuscitated from ventricular fibrillation (VF), and three of these patients remained conscious and alert for 24 to 39 seconds after VF by coughing every one to three seconds. The mean aortic systolic pressure induced by cough was 139.7 mm Hg (+/- 3.8) and only 60.7 mm Hg (+/- 5.1) by external cardiopulmonary resuscitation (CPR). Cough-CPR, accomplished by abrupt, forceful coughing maintains consciousness by rhythmic compression of the heart, has several advantages over external CPR in the catheterization laboratory, and may be applicable to other situations where serious rhythm disturbances are recognized before unconsciousness occurs.
A method is described for obtaining left and right ventricular endocardial biopsies repeatedly over a period of 3-6 mo in the dog. The left ventricular endocardial biopsy technique consists of the placement of a catheter via the venous route across the atrial septum and into the left ventricle. The biopsy catheter is in turn placed within this transseptal catheter. Tissues obtained by this method were satisfactory for both light and electron microscopic examination. At postmortem examination, only minimal and insignificant damage existed at the biopsy site. Consequently, we recommend this technique for the study of progressive pathologic changes in the endocardium that occur during the course of an experiment which can be identified and quantified in comparison to the control state.
This is an updated and expanded planning and oprimal resource guideline for diagnostic examinations of the cardiovascular system. Catheterization-angiographic laboratories are described and detailed specifications given for radiologic and physiologic equipment. Case loads for maintaining safe and effective performance are recommended and complication rates discussed. An optimal location for the laboratory is defined and the status of affiliated laboratories reviewed. Professional staff qualifications, relationships and requirements are enumerated and recommendations are made for organization and administration of the services. There is a protocol for electrical safety and radiation protection and a data base for assessing case loads in hospitals within a community or region. This statement also defines optimal facility and equipment criteria for conventional chest x-rays and radiologic equipment requirements for cardiovascular surgical operating rooms and intensive care units.
Repeated rhythmic (every 1-3 sec.) coughs were documented to maintain consciousness up to 39 seconds in 3 patients developing ventricular fibrillation during coronary arteriography. The arterial pressure wave resulting from a cough exceeded that induced by external chest compression in 2 individuals in whom both techniques were employed and in 5 others treated by external compression alone. Cough-induced cardiac compression is self-performed, and compared to external chest compression is less likely to traumatize the chest wall or heart and can be performed in any position on any surface. It is recommended that patients undergoing coronary arteriography be previously trained to cough abruptly and repeatedly every 1-3 seconds. The potential for utilizing this technique in other areas (i.e., CCU, home) is less favorable than in catheterization-induced ventricular fibrillation, but it might be employed successfully in patients with premonitory symptoms of ventricular arrhythmias or Stokes-Adams seizures. The prior training of high risk individuals (and their spouses) to induce effective coughing in the victim might be lifesaving.
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In order to delineate further the function of the main pulmonary artery as a receptor site, a specially designed Laks triple-lumen balloon catheter was inserted transvenously and positioned in the main pulmonary artery. In six conscious nonsedated dogs, inflation of a balloon in the main pulmonary artery produced acute reversible pulmonary arterial hypertension; the pressure beyond the balloon increased from a mean of 21/6 mm Hg to 43/14 mm Hg (P less than 0,001). This observed pulmonary hypertension occurred at an amount of balloon inflation which produced an increase in right ventricular systolic pressure (P less than 0.001), but no significant change occurred in cardiac output (P greater than 0.05) or right ventricular end-diastolic pressure (P greater than 0.1). Left atrial and pulmonary artery wedge pressures did not change or decreased slightly (P greater than 0.1 and P greater than 0.1, respectively). The calculated pulmonary vascular resistance increased (P less than 0.001), while the calculated systemic vascular resistance did not chang (P greater than 0.04). Therefore, we postulate that distention of the main pulmonary artery in the conscious dog reflexly produces constriction of pulmonary arterioles, and possibly venules, due to excitation of receptors probably located in the wall of the pulmonary artery or possibly the right side of the heart, or both.
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