摘要:

The duration of the systolic time intervals in nondigitalized patients with heart failure was determined from simultaneous fast speed recordings of the electrocardiogram, phonocardiogram, and carotid arterial pulsation. These were compared with the systolic time intervals corrected for heart rate and sex in 211 normal subjects. The failing left ventricle is characterized by a prolongation in the systolic pre-ejection period and a diminution in the left ventricular ejection time while total electromechanical systole remains relatively unaltered. Both components of the pre-ejection period, the Q-1 interval and the isovolumic contraction time, were prolonged. These alterations in the phases of systole occur in the absence of a measurable change in ventricular depolarization time. The prolongation in the pre-ejection period is well correlated with the reduced stroke volume and cardiac output in heart failure and is independently augmented by high levels of arterial pressure. The abbreviation in left ventricular ejection time is also correlated significantly with the stroke volume and cardiac output. It is postulated that a defect in the mechanical performance of the heart is responsible for the abnormal systolic time intervals in human heart failure.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

The hemodynamic effects of nitroglycerin on 20 patients with coronary arterial disease were assessed by using atrial pacing to invoke angina pectoris. This new technique also permitted study of the hemodynamics during pain without the interference of the effects of muscular exercise on the heart affected by coronary artery disease.The pain threshold of each patient was determined by successive pacing runs and the effects of nitroglycerin were evaluated both before and during the pacing up to the level of pain. With regard to the circulatory status at pain an abnormally elevated pulmonary capillary venous "wedge" pressure was an infrequent phenomenon. This difference from the data of studies in which muscular exercise is used is briefly discussed.Sublingual nitroglycerin decreased aortic, pulmonary arterial, right atrial, and pulmonary capillary venous pressures. Stroke volume and cardiac output were reduced and this reduction was accompanied by a compensatory rise in heart rate. Tension-time index was reduced and during pacing at identical rates never reached the level at which angina pectoris was experienced before nitroglycerin. End-diastolic heart size as estimated from conventional chest roentgenograms was reduced by nitroglycerin at every pacing step in all six patients studied by this method. The conclusions were that at all heart rates studied nitroglycerin (a) decreased atrial pressures, (b) decreased heart size, (c) caused peripheral vasodilatation, and (d) allowed the heart to be driven at a higher rate without production of anginal pain. These hemodynamic changes reflect a decreased oxygen requirement of the heart and are consistent with the pain-relieving properties of nitroglycerin.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Thirty-three patients with severe hypertension were treated with rapidly injected intravenous diazoxide. Renal function was measured in nine patients and four underwent cardiac catheterization during renal function studies. Diazoxide had a rapid, profound hypotensive effect. Average decrease in mean arterial pressure was 26%, with an average duration of 16 hours. Drug resistance was not observed. Renal function was not impaired despite maintenance of arterial pressure at or near normal levels. Decreased mean arterial pressure was associated with a decrease in systemic vascular resistance and left ventricular end-diastolic pressure while an increase in cardiac index and heart rate occurred. Urine volume was unchanged, whereas the glomerular filtration rate and the effective renal plasma flow increased but urinary sodium excretion decreased markedly.Intravenous diazoxide is a practical effective agent for treatment of all forms of severe hypertension.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Serial determinations of plasma volume and urinary sodium excretion were determined during saluresis in 20 hypertensive patients. Although the diuretics produced a decrease in plasma volume and an increase in urinary sodium excretion in all patients, there was no direct relationship between the decrease in plasma volume and the fall in arterial pressure. Concomitant administration of dextran solution prevented the reduction in plasma volume but did not prevent the fall in arterial pressure. Similarly, replacement of plasma volume with dextran solution at the peak of hypotension following the diuretics had no effect on the reduced arterial pressure. Concomitant administration of hypertonic saline solution with the diuretic prevented the fall in arterial pressure, and the replacement of urinary sodium loss at the peak of hypotension returned the arterial pressure to control values when the sodium administered exceeded the urinary sodium loss. It would seem that in the hypertensive sodium depleted state a direct relationship exists between arterial pressure and sodium balance. Thus, a positive sodium balance is associated with a rise in arterial pressure, whereas a negative sodium balance is associated with a fall in arterial pressure. The data suggest also that the decreased pressor response during saluresis is due more to the production of negative sodium balance than to a decrease in plasma volume.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Twenty-seven patients with arteriographically proved coronary artery disease, aged 27 to 59 years, were studied for abnormalities of lipid or carbohydrate metabolism. All patients were referred because of cardiac symptoms and none had any prior history of lipid or carbohydrate abnormality. Twenty-three patients were found to have some abnormality of carbohydrate or lipid metabolism, and four had none. Seventeen patients had an abnormal lipoprotein electrophoretic pattern, 12 had elevated serum cholesterol concentrations, and 15 elevated serum triglyceride values. Eighteen patients had an abnormality of carbohydrate metabolism, 11 as determined on standard glucose tolerance tests and seven on cortisone glucose tolerance tests. These abnormalities of carbohydrate and lipid metabolism were not related to age or ponderal-index ratio. This high incidence of carbohydrate and lipid abnormalities in association with coronary artery disease may be important in the pathogenesis of the vascular disease as well as management of these patients and their progeny.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

The hemodynamic effects of physical training, three periods weekly for 1 to 2 months, after myocardial infarction were assessed in seven patients by cardiac catheterization at rest and during exercise. The training was followed by reduction in exercise heart rate and tension-time index as determined from brachial artery pressures. Stroke volume during exercise was enhanced. No significant change occurred in the heart volume. Left ventricular function was improved, and a significant increase in the rate of rise of right ventricular pressure occurred. These were interpreted as indicating myocardial hypertrophy, which probably through reduced compliance also accounted for increased ventricular filling pressures. Lactate in arterial blood was reduced during exercise without any change in the arteriovenous oxygen difference. Small and not significant changes occurred in vital capacity, forced expiratory volume, fasting blood sugar, and serum lipids.Concomitant with the hemodynamic changes exercise tolerance was improved. The data support the thesis that in some patients increased physical activity after myocardial infarction is followed by beneficial hemodynamic effects on the heart and possibly by increased coronary blood flow. The need for proper selection of patients and close medical supervision during training is illustrated and emphasized.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

An ectopic ventricular rhythm (IVR) with a rate of 60 to 100/min was detected in 36 of 100 consecutive patients with acute myocardial infarction by constant monitoring of the electrocardiogram. This mechanism was not apparent clinically and was usually transient, lasting 4 to 30 beats. It was frequently associated with inferior myocardial infarction and usually occurred during sinus bradycardia or the slow phase of sinus arrhythmia. Unlike true paroxysmal ventricular tachycardia (PVT), IVR did not progress to ventricular fibrillation and did not influence the prognosis adversely. Recognition of IVR is important in order to avoid unnecessary and perhaps dangerous treatment with cardiosuppressive drugs and electrical cardioversion.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

Paroxysmal ventricular fibrillation unassociated with heart block occurred in two patients with hypomagnesemia. In neither patient were other causes of the arrhythmia apparent. Temporary transvenous pacing successfully suppressed the episodes after drug therapy failed. Prolongation of the Q-T interval was a prominent electrocardiographic feature in both patients and is postulated to have resulted from a loss of intracellular potassium secondary to hypomagnesemia.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

The records of 56 patients with proved acute aortic dissection were studied for factors bearing on the applicability of vigorous drug therapy to reduce arterial pressure. Fourteen patients had an arterial pressure of 120 mm Hg systolic or less. Fifteen additional patients had evidence of occlusion of a major branch of the aorta. More than half of the 56 patients, therefore, could not have received antihypertensive drugs.The presence of a contraindication to drug therapy marked a patient for an early death. All 29 died within 2 weeks. Twelve of the 27 in whom no contraindications to drug therapy were observed survived more than 2 weeks and six survived more than a year even though none were placed on a vigorous antihypertensive regimen.Assessment of the efficacy of drug therapy of dissecting aortic aneurysm should take into account these facets of the natural history.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID

摘要:

The effects of intravenous isoproterenol upon the pressure-flow-volume relationships in the pulmonary vascular bed were studied in 34 patients and one normal subject during simultaneous right and transseptal left heart catheterization. In five patients with primary myocardial disease and in one normal subject, active pulmonary vasodilation was demonstrated by a significant increase in pulmonary blood volume (PBV) and a concomitant fall in pulmonary vascular distending pressure (PD). Infusion of the drug into 18 patients with mitral stenosis resulted in a concordant rise in PBV and PD, strongly suggesting passive distention of the pulmonary vascular bed. In contrast to the responses of these two groups of patients, isoproterenol infusion into 11 patients with aortic valve disease failed to change the PBV, but caused a significant decrease in PD.It is concluded that the response of different groups of patients to isoproterenol cannot be explained by a single mechanism. Multiple actions of the drug must be considered, including active pulmonary vasodilation, a positive inotropic action upon the heart, and bronchomotor effects.

ISSN:0009-7322    

出版商:OVID    

年代:1968

数据来源: OVID