ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Primary dissecting aneurysm of a coronary artery is a rare form of acute coronary arterial obstruction.A review of 24 cases, including two observed by the authors, indicates that this condition tends to occur (1) in the young adult, (2) in the female more commonly than the male, and (3) relatively commonly in the postpartum state.The clinical manifestations take the form either of sudden death or acute myocardial infarction. In the latter situation, there is the potential for overcoming the coronary arterial obstruction by a surgical bypass procedure.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

The effects of exercise in combined aortic stenosis and insufficiency were evaluated in 10 patients by pressure measurements and the measurement of forward (QF) and regurgitant (QR) flows by simultaneous upstream and downstream sampling using indocyanine green. While heart rate increased, systolic aortic valve pressure gradient (mean, 37 ± 9 mm Hg) did not change. Increased QF(mean, 4.54 ± 0.34 at rest and 6.89 ± 0.42 liters/min with exercise,P< 0.001) was balanced by decreased QR(means, 4.09 ± 1.02 and 2.33 ± 0.71 liters/min,P< 0.02), and total flow did not change significantly. Although diastolic regurgitant period declined, total diastolic seconds per minute decreased by only 6%, while calculated systemic resistance decreased by 30%. Left ventricular systolic and aortic pressures increased, while left ventricular end-diastolic pressure and diastolic aortic valve gradients were unchanged. Mean systolic aortic valve area, calculated by utilizing total valve flow, was 1.8 ± 0.3 cm2in both states.Thus, exercise reduces regurgitant fraction in mixed aortic lesions as in pure aortic insufficiency. This observation confirms the necessity of measuring total valve flow in evaluation of mixed valve lesions. Reduced regurgitation primarily reflects an altered relationship of peripheral resistance to backflow resistance. While the stenotic valve is demonstrated to behave as a fixed systolic orifice, the diastolic aortic orifice area cannot be calculated from the Gorlin equation as it does not account for peripheral resistance.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Six children, aged between 3 and 19 years, with congenital complete heart block without associated cardiac disease were studied by His bundle electrography. All were symptomatic with resting ventricular rates over 40 beats/min, and electrocardiograms that showed a normal axis and QRS complex. His bundle to ventricular activation was within the normal range in all and the block was proximal to the bundle of His. Ventricular and atrial pacing did not result in retrograde or antegrade conduction. All the patients were thought to have a lesion proximal to the site where the bundle of His potential was recorded and, therefore, were unlikely to develop symptoms or require treatment.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Because a great majority of patients with chronic complete heart block have bilateral bundle-branch lesions, it becomes important to recognize earlier degrees of bilateral bundle-branch block. The H-V interval in the His bundle electrogram during unilateral bundle-branch block reflects the conduction primarily through the contralateral bundle branch, and thus the His bundle electrogram in bundle-branch block (BBB) provides information regarding the functional status of the contralateral bundle branch in addition to helping in the localization of defects elsewhere in the conduction system.His bundle electrograms were obtained in 20 patients with BBB and 13 patients without BBB. The following results were obtained from this study: (1) Prolonged P-R interval in the absence of BBB indicated delayed conduction through the A-V node. (2) Prolonged P-R interval in the presence of BBB indicated delayed conduction through the contralateral bundle branch or through the A-V node, or both. (3) Delayed conduction through the contralateral bundle branch in BBB occurred in the presence of a normal P-R interval and could only be detected by demonstrating a prolonged H-V time in the His recording. (4) In alternating BBB the His recording clearly demonstrated that the changing P-R interval was related to varying conduction through the bundle branches. (5) Finally, it has been demonstrated that the Wenckebach (Mobitz type I) type of decremental conduction can occur in the bundle branches or Purkinje system as well as in the A-V node.It is concluded that His bundle electrograms provide valuable information concerning the nature and management of conduction disturbances in patients with bundle-branch disease.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

His bundle potentials were recorded in 50 children. Eight had normal hearts, 11 had ventricular septal defects, seven had the tetralogy of Fallot, seven had secundum atrial septal defects, and eight had pulmonary valve stenosis. There were miscellaneous defects in nine children. Ages ranged from 2 weeks to 14 years. Two intervals were measured on recordings: (1) from the initial atrial activity (P′) to the His bundle potential (H), the P′-H interval, and (2) from H to the initial ventricular activity (V), the H-V interval. The H-V interval lengthened with age. The P′-H and H-V intervals did not differ significantly when different cardiovascular lesions were compared.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Atrial pacing was performed in 10 patients with various degrees of aortic valvular stenosis (AVS) and the hemodynamics were compared to eight normal subjects. Similar maximum heart rates (135 ± 6/min) in each group resulted in no significant complications or symptoms and no changes in cardiac output or transvalvular pressure difference while stroke work (SW) and volume and left ventricular end-diastolic pressure (LVEDP) declined. A postpacing overshoot in LVEDP (control, 14 ± 2; postpacing, 25 ± 3 mm Hg;p= 0.01) which occurred in the cases of AVS probably reflects a decrease in myocardial compliance. Pacing ventricular function curves relating induced changes in SW and LVEDP were generally steeper in patients with AVS than in the normal subjects and were definitely abnormal in three of the former. Pulsus alternans induced in two patients was associated with abnormal myocardial function while the control LVEDP level was not a good indication of the functional response of the myocardium.Atrial pacing appears to be beneficial in the preoperative evaluation of the patient with AVS when exercise stress may be dangerous because of the possibilities of inducing arrhythmias, syncope, and sudden death. It permits precisely controlled evaluation for preoperative and postoperative comparison.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

Weight reduction programs usually improve the exercise capacity of patients with chronic exogenous obesity. However, the reversibility of left ventricular hypertrophy and dysfunction associated with obesity is unknown. Accordingly, an analysis was made of hemodynamic data obtained by cardiac catheterization and standard chest roentgenograms in nine markedly obese patients before and after weight loss of 39 to 84 kg (24 to 55% of control weight) over periods of 4 to 34 months. In each case body oxygen uptake (360 to 297 ml/min), blood volume (7.8 to 6.1 liters), cardiac output (7.9 to 6.2 liters/min), and arteriovenous oxygen difference (4.6 to 4.0 vol. %) were significantly reduced after weight loss. Systemic arterial pressure declined (102 to 87 mm Hg) while systemic vascular resistance changed insignificantly (1,067 to 1,141 dynes-sec-cm-5). In seven subjects comparable chest roentgenograms before and after weight reduction revealed decrease in the cardiothoracic ratio, suggesting a reduction in left ventricular dimensions. These results have been interpreted as indicating that the circulatory effects of gross obesity are largely reversible with weight loss. Despite reductions in left ventricular stroke work, stroke volume, and cavity size at rest, the average left ventricular filling pressure rose with exercise to a comparable and abnormal level (20 mm Hg) both before and after weight loss. Thus, evidence of left ventricular dysfunction persisted, suggesting that myocardial hypertrophy and reduced ventricular compliance did not regress significantly with weight loss over periods as long as 3 years.

ISSN:0009-7322    

出版商:OVID    

年代:1972

数据来源: OVID