ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Quantitation of myocardial volumes, mass, and ejection fractions was performed in a group of 26 patients (10 of whom were infants less than 2 years old) with normal left ventricles and in a separate group of 13 children with intrinsic myocardial disease and clinical decompensation. All patients were studied by use of biplane cineangiocardiography, and volumes were determined by the area-length method. Left ventricular end-diastolic volume in "normal" infants below 2 years of age was 44.8 ± 8.5 cc/m2, and it was 71.4 ± 8.0 cc/m2in older normal children (P<0.001), ages 3 to 16 years. Left ventricular ejection fraction also was different in the younger normals: 0.76 ± 0.07 versus 0.63 ± 0.05 in older normals (P<0.001). Left ventricular mass and left atrial maximal volume were not significantly different in normal infants and older children, averaging 81.7 ± 10.0 g/m2and 33.6 ± 10.1 cc/m2, respectively. All patients in the cardiomyopathy group had significant elevations of left ventricular end-diastolic volume and mass, and the ejection fraction was reduced in all patients except one infant with severe mitral insufficiency. Five infants with chronic left ventricular failure and no mitral insufficiency had normal left atrial maximal volumes. Left atrial maximal volumes were increased significantly in six patients with myocardial disease, all of whom had mitral insufficiency. These results emphasize the potential value of the quantitative estimation of left heart volume and provide normative base-line data for left heart volume and mass parameters in both infants and children.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Quantitative angiocardiographic techniques have been used to determine left ventricular volume and mass in 100 patients with isolated aortic valve disease. The patients were divided into three groups: aortic stenosis (AS), 22 patients; aortic regurgitation (AR), 38 patients; and combined stenosis and regurgitation (AS+AR), 40 patients. The distribution of left ventricular volume and mass and their relationship to standard intracardiac pressure and flow determinations are presented for each group in order to define the hemodynamic and functional characteristics of the left ventricle in these patients. Mean values for end-diastolic volumes (EDV) in the three groups were AS=85 ml/m2, AS+AR=143 ml/m2and AR=197 ml/m2. Mean values for ejection fraction (EF=SV/EDV) were similar in the three groups, AS=61%, AR= 55%, AS+AR=58%.Left ventricular mass (LVM) was smaller in AS, mean=167 g/m2, and similar in AR, mean=232 g/m2, and AS+AR, mean=235 g/m2. Left ventricular filling pressure (LVEDP) was correlated with EDV in AS, r=0.45,P<0.05, and AS+AR, r=0.51,P<0.001, but not in AR. A similar relationship was seen between LVEDP and EF. The arteriovenous oxygen difference correlated well with EF in AS, r=−0.76.P<0.001. This relationship was weaker in AS+AR, r= −0.45,P<0.01, and AR, r=−0.45,P<0.01. Correlations were also present between increased LVM and elevated LVEDP and increased LVM and decreased EF in patients with AS and AS+AR.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Eleven patients with muscular subaortic stenosis were studied by use of combined right and transatrial septal left heart catheterization. A variety of stimulating maneuvers were performed to induce or increase the functional outflow tract obstruction; 150 &mgr;g/kg of propranolol was administered intravenously, and the stimulating maneuvers were repeated. Outflow obstruction was latent (present only with stimulation) in four patients, labile (present intermittently at rest) in five patients, and persistent and severe in two patients. Propranolol abolished or significantly decreased the spontaneous variations in outflow obstruction occurring at rest, during the enhanced gradient in the post-exercise state, and during variations induced by isoproterenol infusion. The outflow obstruction induced by inhalation of amyl nitrite, the Valsalva maneuver, and premature ventricular contractions was only inconsistently prevented. Long-term oral propranolol therapy has been of significant symptomatic benefit in all the patients with latent or labile outflow obstruction and is considered the treatment of choice in these groups. In one patient with persistent outflow obstruction, an increase in symptoms occurred when oral propranolol was administered, and the drug was discontinued. Evidence is presented to support the concept of a cycle of obstruction and hypertrophy in the natural history of this disease. This vicious cycle might be prevented by propranolol.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

An evaluation of the influence of sex upon cerebral atherosclerosis was carried out in 5,033 consecutive autopsies studied by a special well-standardized coding technique. A sex difference in frequency of cerebral atherosclerosis appears from the fourth to the sixth decade. During this period the percentage of female cases with no atherosclerosis lags behind the percentage of male cases by a 15-year period. After the sixth decade, the frequency of cerebral atherosclerosis increases more rapidly in females, so that beyond the age of 65 years the frequency of cerebral atherosclerosis is equal in the two sexes. Furthermore, younger males show a higher degree of cerebral atherosclerosis than females of the same age and a reverse trend appears in the oldest age groups. Diabetic females have more cerebral atherosclerosis than nondiabetic males, and beyond the fourth decade they have at least as much involvement as the diabetic males.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Of three patients with Shy-Drager syndrome, two presented with syncope related to exercise and, in all three, exercise stress clearly defined the element of orthostatic hypotension. Autonomic cardiovascular regulatory function was absent in two, but some residual autonomic function was present in the form of heart rate response in one patient who had milder postural hypotension. Hemodynamic studies were carried out with subjects supine and tilted 45° before and after exercise, following plasma volume expansion, and during the effects of isoproterenol and atropine. Despite disordered venoconstrictor responses demonstrated during exercise, hyperventilation, and after the Valsalva maneuver, decrease in central blood volume and right atrial pressure were not excessive with tilt, and total systemic vascular resistance remained essentially unchanged as did heart rate. Cardiac index may have decreased excessively (−24%), suggesting a cardiac component in production of hypotension. Absence of sympathetic cardiac effects, both chronotropic and inotropic, may play a significant role in orthostatic hypotension by limiting heart rate and preventing shift of the Frank-Starling curve to the left. Amelioration of postural effects by plasma volume expansion was noted along with increased cardiac output, stroke volume, and pulse pressure indicating that myocardial heterometric regulation was operative. Atropine had little effect, eliminating the possibility that parasympathetic depressor effects were responsible for postural hypotension. Exercise, by decreasing systemic vascular resistance even though venous return was adequate, produced hypotension even in recumbency and aggravated postural effects. Similarly, isoproterenol caused marked hypotension in supine subjects. Exercise, by reducing systemic vascular resistance, has a deleterious effect despite increased venous return and may precipitate postural symptoms. Exercise stress is of value in the evaluation of patients with syncope or cerebral ischemia secondary to autonomic dysfunction where orthostatic hypotension is of doubtful significance at rest.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

We studied 11 patients with spontaneous isorhythmic atrioventricular (A-V) dissociation occurring during cardiac surgery. The period of synchronization or accrochage was shown to result from retrograde capture of the atria by an A-V junctional rhythm. The P wave in leads II, III, and aVFwas biphasic (−, +) during the period of synchronization, with the initial negative portion of the P wave or the entire P wave often buried within the QRS complex. It was concluded that isorhythmic A-V dissociation occurs only during the period when the rhythm alternates between an atrial rhythm and an A-V junctional rhythm and results when either the dominant pacemaker slows or the latent pacemaker accelerates.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Aberrant ventricular conduction (AbC) was produced in 52 subjects, including 14 normal volunteers, by the introduction of atrial premature beats through a transvenous catheter electrode. Simultaneous standard electrocardiograms and vectorcardiogams permitted detailed analysis of configuration. Multiple patterns of AbC were produced in 29 of 52 subjects. The general categories and their frequency were as follows: right bundle-branch block without significant axis shift from control, 31; right bundle-branch block with left axis deviation, 27; left axis deviation, 14; inferior axis deviation, six; right bundle-branch block with inferior axis deviation, seven; and complete left bundle-branch block, six. These patterns were believed to depend on the location of isolated or combined functional block in the major pathways of the specialized conduction system, which include the right bundle branch, common left bundle branch, anterior division of the left bundle branch, and posterior division of the left bundle branch. The present study has documented the general varieties of AbC, their relevance to clinical cardiology, and the varieties most likely to cause diagnostic difficulty.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Isopotential body surface maps and the sequence of epicardial excitation were studied in children with three types of pure right ventricular hypertrophy; that is, secundum atrial defects, valvular pulmonic stenosis, and tetralogy of Fallot. Patients with similar types of hypertrophy demonstrated internal consistency as to the anatomy, sequence of epicardial excitation of the right ventricular free wall, and body surface potential distribution; however, these phenomena varied between the three groups for each type of hypertrophy. These studies indicate that diagnostic information is available on the body surface to distinguish: (1) right ventricular hypertrophy due primarily to dilatation (secundum atrial septal defects), (2) right ventricular hypertrophy with symmetrical increase in thickness throughout the right ventricle (valvular pulmonic stenosis with moderate to severe right ventricular hypertrophy), and (3) right ventricular hypertrophy proximal to infundibular narrowing (tetralogy of Fallot) from one another. The body surface events could be accounted for in part by the events measured at the epicardial surface.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID