摘要:

NO Abstract

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTThe analysis of plasma kinetics of the sympathetic neurotransmitter norepinephrine can be used to estimate sympathetic nervous “activity” (integrated nerve firing rate) for the body as a whole and for individual organs. In 12 patients with cardiac failure (left ventricular ejection fraction 10 % to 39 %), the mean arterial plasma norepinephrine concentration was 557 + 68 pg/ml (mean SE) compared with 211 + 21 pg/ml in 15 subjects without heart failure (p < .002). The difference was due to both increased release of norepinephrine to plasma (indicating increased “total” sympathetic activity) and reduced clearance of norepinephrine from plasma. The increase in sympathetic activity did not involve all organs equally. Cardiac (32 ± 9 vs 5 ± 1 ng/min; p <.002) and renal (202 ± 45 vs 66 ± 9 ng/min; p = .002) norepinephrine spillover were increased by 540% and 206%, respectively, but norepinephrine spillover from the lungs was normal. Adrenomedullary activity was also increased in the patients with heart failure, whose mean arterial plasma epinephrine concentration was 181 + 38 pg/ml compared with 71 ± 12 pg/ml in control subjects (p < .02). There is marked regional variation, inapparent from measurements of plasma norepinephrine concentration, in sympathetic nerve activity in patients with congestive heart failure. The finding of increased cardiorenal norepinephrine spillover has important pathophysiologic and therapeutic implications.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTFifty-one patients with uncomplicated transposition of the great arteries (TGA) and normal pulmonary pressure who were 10 to 20 years old and 69 normal subjects matched for age were studied by M mode echocardiography. Left ventricular internal dimensions and posterior wall thickness showed positive correlation with the body surface area in the TGA as well as in the control groups. Values for these parameters in the TGA group were generally smaller than those in the normal population. Septal thickness of patients with TGA (5.9 ± 1 mm) was also smaller than that in the control group (6.6 ± 1 mm) (p < .0 1). Septal motion was normal in 1 1 patients with TGA and paradoxical in 19 patients in this group. In the other 21 patients the septum was flat. The following systolic time intervals of the left ventricle were found for patients with TGA: preejection period (PEP) 64 + 11 msec, ejection time (ET) 310 + 37 msec, and PEP/ET 0.21 ± 0.04. These values were significantly different from those of the right ventricle for the normal population: PEP 77 + 12 (p < .01), ET 327 + 25 (p < .05), and PEP/ET 0.24 + 0.03 (p < .01). Shortening fraction and mean velocity of circumferential fiber shortening (49 + 7% and 1.6 + 0.3 circ/sec, respectively) were also significantly higher (p < .01) in patients with TGA than in the control group (33 + 4% and 1. 1 + 0.2 circ/sec). These data should help achieve reliable quantitative and qualitative interpretations of echocardiograms of patients with TGA.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTIn a new study controlled for many factors, we reconfirmed the relationship of higher blood pressure to alcohol use. This relationship was slightly stronger in men, whites, and persons 55 years of age or older. A slight increase in blood pressure appeared in men who drank one to two drinks daily, and a continuous increase occurred at all higher drinking levels among white men who had constant drinking habits. Among women, an increase occurred only at three or more drinks daily. The data suggest complete regression, beginning within days, of alcohol-associated hypertension upon abstinence. Blood pressure showed minor differences with beverage preference: those who preferred liquor had higher adjusted mean blood pressure than those preferring wine or beer. The results of this study contribute to the likelihood that the alcohol-blood pressure association is causal. Smoking, coffee use, and tea use showed no association with higher blood pressure. Systolic pressure showed a positive relationship to total serum calcium and an inverse relationship to serum potassium, but diastolic pressure showed little relationship to these blood constituents; the explanations include a possible direct effect on regulation of blood pressure.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTReversible myocardial depression, manifested by ventricular dilatation and decreased ejection fraction, is common in human septic shock. A proposed mechanism, based on animal studies, is myocardial ischemia resulting from inadequate coronary blood flow. Coronary flow observations have not been reported for human septic shock. To determine whether myocardial depression in human septic shock is associated with reduced coronary flow, thermodilution coronary sinus catheters were placed in seven patients with septic shock for measurements of coronary flow and myocardial metabolism. Four of the seven patients developed myocardial depression. These patients had coronary flow similar to or higher than that of control subjects and similar to that of the other three patients, who did not develop myocardial depression. None of the patients had net myocardial lactate production. In general, compared with values in control subjects, the oxygen content difference (arterial minus coronary sinus) was narrowed, and the fractional extraction of arterial oxygen was diminished. This pattern of disordered coronary autoregulation is analogous to the pattern of arteriovenous shunting in other organs in patients with septic shock. The preservation of coronary flow, the net myocardial lactate extraction, and the increased availability of oxygen to the myocardium argue against global ischemia as the cause of myocardial depression in human septic shock.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTCatheter mapping during sinus rhythm was performed in 132 patients with coronary artery disease and 26 patients with congestive noncoronary cardiomyopathy. Each of the patients had a clinical history of one of the following: no ventricular arrhythmia, nonsustained ventricular tachycardia, cardiac arrest, or sustained ventricular tachycardia. The characteristics of the endocardial electrogram and other measured indexes of slow endocardial conduction were compared between patients with different types of disease and in different arrhythmia groups to determine if differences existed. The cardiomyopathic group had a higher percent of normal endocardial electrograms than the coronary artery disease group, with no evidence of slow endocardial conduction. The sustained ventricular tachycardia group exhibited a greater percent of abnormal endocardial electrograms and more evidence of slow endocardial conduction, distinguishing this group from the three other arrhythmia groups. We conclude the following: (1) The underlying electrophysiologic substrate varies in patients with different ventricular arrhythmias. It is therefore inappropriate to analyze all patients with ventricular arrhythmias as a single group. (2) Patients with congestive noncoronary cardiomyopathy, regardless of the type of their arrhythmia, have a relatively normal endocardium. Those patients with serious ventricular arrhythmias should not be considered candidates for surgery directed at removing abnormal endocardium.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTThrombolytic recanalization of the obstructed coronary lumen was studied in 32 patients receiving intracoronary streptokinase for 60 to 90 min during acute myocardial infarction. The process was viewed at high arteriographic magnification and was quantified with computer-assisted measurements from repeated single-plane views. The variability of the method for this application was 0. 15 to 0. 18 mm on minimum diameter estimates. Structural details were seen that are not commonly appreciated at conventional magnification. The recanalized lumen appears to form along an interface between the thrombus and the vessel wall, progressively enlarging its minimum arteriographic diameter to 0.65 0.24 mm (±+ 1 SD) at the end of the short-term infusion of streptokinase reflecting a final % stenosis of 77 10%. In nine infarct lesions found patent 5 + 3 weeks later, the recanalized lumen further improved an average of 0.34 mm in minimum diameter (p < .005) and 13% stenosis (p < .01). A thin film of contrast medium surrounding the obstructing thrombus faintly defined the boundaries of the original atherosclerotic lumen in all but two cases. The “original stenosis” measured 1.25 0.32 mm in minimum diameter and 56 14% stenosis when first visualized; it was unchanged throughout the course of infusion of streptokinase. In five patients catheterized 10 + 12 weeks before their infarction, the original stenosis averaged 1.15 0.22 mm in the preinfarct angiogram, as compared with 1.17 + 0.23 mm in its faintly defined form during thrombolytic therapy (p = NS). In 10 cases, this original lesion was less than a 50% stenosis, and in 21 cases less than 60%. These measurements permit an objective evaluation of the thrombolytic process; they demonstrate that mildto- moderate atherosclerotic coronary lesions are subject to acute thrombotic occlusion and that intracoronary streptokinase administered over 60 to 90 min only partially lyses the obstructing thrombus.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTIn patients with atherosclerotic coronary artery disease, cigarette smoking increases myocardial oxygen demand but may cause an inappropriate decrease in coronary blood flow and myocardial oxgyen supply. This study was performed to explore the mechanism of smoking-induced coronary vasoconstriction and, specifically, to determine if smoking causes an ct-adrenergically mediated increase in coronary artery tone. In 36 chronic smokers with coronary artery disease (27 men and nine women, 50 9 [mean + SD] years old), heart rate-systolic arterial pressure double product and coronary sinus blood flow (by thermodilution) were measured before and during smoking both before and after (1) normal saline (n = 5, control subjects), (2) an at-adrenergic-blocking agent, phentolamine, 5 mg (n 15), (3) a /3-adrenergic-blocking agent, propranolol, 0.1 mg/kg (n = 12), or (4) sodium nitroprusside, 0.4 to 0.8 g.g/kg/min, given in a dose sufficient to diminish systolic arterial pressure by 15% (n 4). During the initial smoking period, rate-pressure product increased and coronary sinus blood flow was unchanged by smoking in all groups. After 30 to 75 min, saline, phentolamine, propranolol, or sodium nitroprusside was given, and measurements were repeated. In the control subjects, rate-pressure product and coronary sinus blood flow responded in a similar manner to that observed previously. In those receiving phentolamine, rate-pressure product was unchanged, but coronary sinus blood flow rose substantially with smoking (percent change + 2 + 15% during the first smoking period [before phentolamine] and +32 + 17% during the second smoking period [after phentolamine]; p <.01). In the 12 patients who received propranolol, rate-pressure product was unchanged, but coronary sinus blood flow fell with smoking (percent change + 5 + 14% during the first smoking period [before propranolol], -12 + 5% during the second smoking period [after propranolol]; p <.01). In those who received sodium nitroprusside, rate-pressure product fell slightly, and coronary sinus blood flow responded in a similar manner to that observed previously. Thus, smoking-induced coronary vasoconstriction is due to an ca-adrenergically mediated increase in coronary artery tone.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTPlatelets labeled with indium-I 11 have been used successfully as a marker of active thrombosis in man. To establish the diagnostic accuracy of platelet scintigraphy in comparison to contrast venography in the diagnosis of acute lower limb venous thrombosis, we evaluated 103 consecutive patients divided into two groups. Platelets were labeled by the indium-I 1 1 oxine method. Patients from group (n = 73, 56 had venograms) were asymptomatic and underwent platelet scintigraphy 1. 1 + 0.6 days (mean + 1 SD) after a major orthopedic procedure. Patients from group II (n = 30. all had venograms) were symptomatic and underwent platelet scintigraphy 1.2 + 1.7 days after venography. In group II, 15 patients with positive findings on contrast venography were treated with intravenous heparin; five others with positive venograms did not receive heparin until platelet scintigraphy was completed. Both platelet scintigraphy and contrast venography were evaluated by two blinded observers. Only studies with blinded agreement of both platelet scintigraphy and contrast venography were included in the analysis. Sensitivity and specificity of platelet scintigraphy for the whole limb were 93% and 97% in group I and 42% and 67% in group II. The lower sensitivity in group lI was most likely attributable to therapy with heparin. These results demonstrate that platelet scintigraphy, a test that permits imaging for up to five days after a single injection, correlates favorably with contrast venography in patients who have not received heparin and may be used as a surveillance test in high-risk patients. The role of platelet scintigraphy in acutely symptomatic patients requires further evaluation.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTImproved selection of patients with suspected sustained ventricular tachycardia (VT) for programmed ventricular stimulation is needed. To determine if frequency analysis detects patients in whom sustained VT might be induced, we first obtained fast-Fourier transforms (FFT) of signalaveraged electrocardiograms (ECGs) from 20 patients with spontaneous sustained VT (group I) and compared them with the results of programmed ventricular stimulation with single and double extrastimuli during two cycle lengths and burst pacing from two right ventricular sites. The FFT data were expressed as an area ratio that quantified the relative contributions of 20 to 50 Hz frequencies in the terminal QRS and ST segment. A logistic regression with inducibility as the dependent variable was used to help define area ratio values greater than 20 as abnormal. Sustained monomorphic VT was induced in 18 patients, each with an area ratio value greater than 20. Sustained VT was not induced in two patients, each with an area ratio value less than 20. FFT data were then compared prospectively with the results of programmed stimulation in 38 patients (group II) with nonsustained VT (12 patients) or syncope (26 patients) referred for electrophysiologic study. In none of the 26 patients in group II with normal FFT values was VT inducible. Sustained monomorphic VT was induced in five of 12 patients with abnormal FFT values. Thus, the results of FFT analysis correctly predicted the results of programmed ventricular stimulation in 88% of patients studied and in 82% of patients in group II with syncope or nonsustained VT. Moreover, all five patients in group II in whom sustained VT was induced were identified correctly. Results of multivariate analysis demonstrated that area ratio values were independent of other determinants of inducibility, including left ventricular ejection fraction and prior myocardial infarction. The approach developed offers promise for improving identification of patients in whom sustained VT will be induced during programmed ventricular stimulation.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID