ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The long-term effect of percutaneous and oral estrogen replacement therapy on blood pressure, plasma renin substrate, and serum estrogens was examined in a 2 year placebo-controlled study with 110 early postmenopausal women. The women were allocated to four treatment groups: (1) oral cyclical combination of 2 mg estradiol valerate and cyproterone acetate, (2) oral placebo, (3) percutaneous 17,β-estradiol, supplemented by 200 mg oral progesterone during the second year, or (4) percutaneous placebo cream. Systolic and diastolic blood pressure remained unchanged in both hormone treatment groups, whereas the diastolic blood pressure tended to increase in both placebo groups. Plasma renin substrate increased during oral treatment with estradiol, but remained unchanged with percutaneous estradiol. No correlation was found between blood pressure and plasma renin substrate. During percutaneous administration of estradiol, the serum concentrations of estrone and estradiol continued to rise after 3 months and reached a plateau at 6 months of therapy. Serum estrone but not estradiol showed the same pattern during oral estradiol therapy. No further changes in any of the measured variables were observed in the women treated with percutaneous estradiol after addition of cyclical oral progesterone. We conclude that both oral and percutaneous treatment with estradiol may provide protection against the age-related increase in diastolic blood pressure observed in early postmenopausal women, and that the metabolic steady state is not attained until after 3 months of estradiol therapy.

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

An atrial pacing model of functional 2: 1 block was used in 10 patients to investigate for the first time the electrophysiologic properties of the human atrioventricular node during intermittent conduction. By varying the terminal portion of the 2: 1 atrial train and using the extrastimulus technique, we characterized atrioventricular nodal (AVN) conduction and refractoriness after five different methods of AVN activation: a conducted beat (method I), a conducted beat with omission of the prior blocked beat (method II), a blocked beat (method III), a blocked beat “converted” to one that conducts by omission of the prior conducted beat (method IV), and finally, 1: 1 conduction at twice the cycle length of the 2: 1 train (control method V). Observed AVN conduction times obeyed the following relationship: method I> method II> method V, indicating a cumulative effect of concealed penetration by the blocked beats. During 2: 1 block, the AVN effective refractory period (ERP) altemated with a mean beat-to-beat difference of at least 100 msec, due mostly to marked ERP abbreviation during AVN activation by method III (vs both 2: 1 train cycle length and activation by method V). Concealed penetration by the blocked beat prolonged AVN ERP for the propagated beat (vs that with methods II and V), but to a lesser extent than conduction time was increased. Moreover, the AVN recovery curve with method I was displaced upward and to the right compared with that with methods II to V. We conclude that: (1) During functional 2: 1 AVN block in man there are dramatic beat-to-beat oscillations in the ERP, which partly reflect longitudinal heterogeneity of AVN refractoriness. (2) The greater prolonging effect of prior concealment on AVN conduction time vs ERP for the propagated beats suggests that electrotonically mediated increased AVN step delays induced by a blocked beat may abbreviate subsequent action potential duration while still retarding recovery of excitability. (3) In general, during Wenckebach cycles the progressive rightward and upward shift of the AVN recovery curve may actually begin with the “recovered” postblock beat.

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

We tested the hypothesis that different subsets of ischemia-induced wall motion disorders are characterized by specific patterns of abnormal regional left ventricular systolic function. Regional contraction was quantitatively assessed from two-dimensional echocardiograms by an automated integrative analysis considering the time course of wall motion during the entire contraction sequence in 20 patients with chronic myocardial infarction, in 13 patients with impending myocardial infarction (<2 hr after the onset of symptoms), and in nine patients during transient myocardial ischemia. Wall motion abnormalities were detected in all patients by the integrative analysis. In contrast, the sensitivity for detecting wall motion abnormalities was 80% during chronic infarction, 77% during impending infarction, and 56%C during transient ischemia if only end-diastolic and end-systolic frames were compared for assessment of overall regional systolic function. There were distinct differences in the time course of abnormal wall excursion between the three groups. Chronic infarction was characterized by a monophasic contraction pattern, with abnormal synergy in regional contractile events occurring predominantly during early systole. In contrast, transient ischemia caused predominantly mid-to-late systolic abnormal synergy followed by late systolic shortening corresponding to a polyphasic contraction pattern. During impending infarction, an intermediate temporal contraction pattern was present with both early and mesosystolic abnormal synergy. The asynergy ratio for the timing of regional contractile events–calculated by relating the extent of mid-to-late systolic asynergy to the extent of early-to-mid systolic asynergy–differentiated the contraction patterns of all patients with transient ischemia (asynergy ratio 3.9 ± 2.2, mean ± SD) from those with chronic myocardial infarction (0.28 ± 0.24; p<.001) and was significantly lower (p<.05) in patients with impending infarction (0.89 ± 0. 38) in comparison with those with transient ischemia. Impending myocardial infarction was associated with a significantly (p<.05) larger degree of functional abnormality than chronic infarction. We conclude that there is a hierarchy of levels of ischemia-induced impairment in left ventricular systolic function: ischemic injury in man first manifests itself as asynchronous polyphasic wall motion rather than any change in amplitude of wall excursion. Our results strongly suggest the need for a comprehensive analysis of the entire contraction sequence to evaluate the functional benefits of any interventions aimed at salvage of acutely ischemic myocardium in man.

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The aim of the present study was to elucidate the mechanisms of mitral regurgitation accompanying myocardial infarction. Severity and site of mitral regurgitation was evaluated by the real-time two-dimensional Doppler flow imaging technique in 81 patients with old myocardial infarction. The incidence of mitral regurgitation did not depend on the region of infarction. There was, however, a close relationship between the site of regurgitation and the region of infarction. In patients with mitral regurgitation spurting from the posteromedial area of the valve, the inferior wall was involved in infarction without exception and in some of these patients, the posteromedial papillary muscle was also found to be affected by myocardial infarction; in those with regurgitation spurting from the anterolateral area, the anterior wall showed asynergy. On the other hand in patients with mitral regurgitation spurting from the central area, the region of infarction varied. In these patients, however, the larger the diameter of the mitral anulus, the more severe the grade of regurgitation. The extent of asynergy was another factor related to the severity of mitral regurgitation. Both longitudinally and transversely, broad infarction leads to the enlargement of the mitral anulus. However, even if the mitral anulus is not so dilated, severe involvement of either commissural area results in severe mitral regurgitation from the same commissural side. Thus, there are two major causative factors of mitral regurgitation: (1) asynergy of the papillary muscle or the ventricle that results in mitral regurgitation located in the commissural area of the same side as asynergy, and (2) enlargement of mitral anulus, which results in regurgitation from the central area of the orifice. The mechanisms of mitral regurgitation unveiled in the present study will contribute much to the clarification of the concept of so-called papillary muscle dysfunction."

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

To assess the efficacy of magnetic resonance (MR) imaging in evaluating graft patency after coronary bypass surgery, 20 patients who had prior surgery (average 5.5 years, range 1.5 to 14) and recent cardiac catheterization because of chest pain were studied. No patient had surgical intervention or change in symptoms in the time interval between catheterization and MR imaging. These 20 patients had a total of 47 grafts, defined as proximal anastomoses: 20 to the left anterior descending or diagonal artery (LAD), 13 to the left circumflex artery marginal branches (LCX), and 14 to the right coronary artery or posterior descending artery (RCA). The patients underwent cardiac and respiratory gated MR scans in a 0.5 tesla magnet with an echo time of 22 msec and two repetitions in a 128 × 256 matrix. In-plane resolution was 2.7 mm. Every patient had a scan in the transaxial plane and some underwent scanning in the sagittal and coronal planes as well. A graft was considered patent by MR when a signal-free lumen was visualized in an anatomic position consistent with that of a bypass graft, had a lumen larger than the native vessels, was seen on more than one slice, and was seen at a level higher than that of the native vessels. If a known graft was not seen it was considered occluded. The scans were interpreted by consensus of two physicians aware of the operative but not the cardiac catheterization data. Twenty-six of 29 patent grafts and 13 of 18 occluded grafts were correctly classified (sensitivity 90%, specificity 72%). Eighteen of 20 (90%) LAD grafts, 11 of 14 (79%) RCA grafts, and 11 of 13 (85%) LCX grafts were correctly classified. When the results from three patients with technically poor studies because of poor cardiac gating were excluded, the overall sensitivity and specificity were 92% and 85%, respectively. This study demonstrates the high sensitivity and moderate specificity of MR for evaluating the patency of coronary artery bypass grafts, particularly LAD grafts.

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The transstenotic pressure gradient recorded during coronary angioplasty (PTCA) reflects the dynamic relationship that exists between coronary blood flow and the effective crosssectional area of the arterial lumen. An apparent relationship between the dynamic behavior of the pressure gradient and subsequent acute vessel closure was observed in our catheterization laboratory. We therefore examined the usefulness of the pressure gradient trend in predicting acute complications after 463 attempted PTCA procedures. Two pressure gradient trend patterns were identified: (1) a rising trend pattern identified by an increasing pressure gradient in the interval after deflation of the angioplasty, and (2) a stable trend pattern identified by a constant or decreasing pressure gradient. The incidence of acute vessel closure (17% vs 4%, p.0001), emergency CABG (5.6% versus 1%, p<.05), and myocardial infarction (13% versus 2%, p<.0001) after the PTCA procedure was significantly higher among patients with rising trend patterns when compared with patients with stable trend patterns. Multivariate analysis identified independent predictors for an acute closure event as a rising trend pattern (p<.001), post-PTCA gradient (p<.05), and post-PTCA percent diameter stenosis (p<.02). Independent predictors for emergency coronary artery bypass grafting and myocardial infarction were post-PTCA gradient (p<.001) and a rising trend pattern (odds ratio = 2.91, p<.001), respectively. The dynamic behavior of the gradient trend provides additional useful information about the results of dilatation. This information is available before completion of dilatation and may assist in clinical decision making by identifying those patients who may be at risk for developing acute complications in the post-PTCA period.

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The value of serial electropharmacologic testing during long-term oral amiodarone therapy for prediction of long-term drug efficacy as well as characteristics of arrhythmia recurrence is controversial. One-hundred four consecutive patients with coronary artery disease and sustained ventricular tachyarrhythmias (VT) underwent initial electrophysiologic (EP) evaluation in the drug-free state and again after an amiodarone loading period of 25 ± 14 days (mean ± SD). Twenty-six patients (25%) had no inducible ventricular tachyarrhythmia during therapy with amiodarone (VT control group), whereas arrhythmia inducibility persisted in the remaining 78 patients (VT noncontrol group). During 17.4 ± 13.7 months of follow-up, two patients in the VT control group either had VT recurrence or died suddenly compared with 21 VT recurrences and eight sudden cardiac deaths in the VT noncontrol group (actuarial event rates at 36 months of 0. 11 and 0.56, respectively, p =.0065). The cycle lengths of recurrent VT in these 21 patients in the VT noncontrol group were compared with those observed at final EP testing. A significant linear correlation was demonstrated (r =.76, p =.0001). Subgroup analysis of patients in the VT noncontrol group showed no EP predictors of outcome, including cycle length of induced VT. However, patients dying suddenly during the follow-up period had a higher prevalence of new or worsening congestive heart failure (75%) compared with patients with VT recurrence (19%) or those with no arrhythmic event (29%) (p <.02). Patients with sudden death or VT recurrence had a less stable initial clinical course, with an increased prevalence of spontaneous VT episodes during the amiodarone loading period (50% and 43%), compared with those with no recurrent arrhythmia (20%, p <.05). These data indicate that serial EP testing during amiodarone therapy is useful for predicting arrhythmia recurrence as well as its rate in patients with persistently inducible arrhythmias in the absence of new or worsening congestive heart failure. However, EP data, other than inducibility, was not useful for predicting those patients at highest risk of sudden death.

ISSN:0009-7322    

出版商:OVID    

年代:1987

数据来源: OVID