ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

ABSTRACTWe compared secular trends in ischemic heart disease (IHD) mortality in four southeastern states (North Carolina, Georgia, South Carolina, and Virginia) with those in three selected other states (California, New York, and Utah). Mortality data were obtained from U.S. vital statistics and population information from the U.S. Census Bureau. Age‐adjusted IHD mortality increased until 1968 in the southeastern states and then declined and declines were greatest in the nonwhite female population. In contrast, IHD mortality in all groups in California and in the female population in New York and Utah began to decline in the early 1950s, with accelerated declines since 1968. In all states the decline in rates in nonwhite populations have been greatest in the younger age groups. This has not been true in the white populations. Declining IHD mortality correlated moderately well with the decline in death from all cardiovascular disease and from all causes, but not with the declining cerebrovascular disease mortality. Respiratory cancer mortality increased in similar proportions in California and South Carolina, two states with dissimilar IHD trends. These findings suggest that improved control of hypertension and changing patterns of cigarette smoking may not be responsible for the recent decline in IHD mortality.Circulation 68, No. 1, 3‐8, 1983.

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

ABSTRACTThe feasibility of the use of a Cox model for risk assessment of individualized hospital discharge after myocardial infarction was evaluated. First, a previously developed prognostic index computed at the fifth day after admission was tested on a new population of 1140 patients. It was confirmed that after 5 days half of the patients (52%) could be discharged with low risk. Second, a new competing risk variant of the Cox model that updates prognosis according to the occurrence of complications was developed that describes the risk of death, cardiac arrest, and cardiogenic shock within 44 days after hospital admission. With a risk of one of these events being below 2% during a 14 day period after proposed discharge, 453 patients of 966 survivors (47%) could be discharged after only 5 days. A longer stay (of up to 30 days) was proposed for 338 patients (35%) to achieve the same level of risk. The savings in hospitalization days would be 15%. These results were confirmed in a new sample of 197 patients from the same institution who were discharged according to the proposed system. Of the 169 day 5 survivors, 67% were discharged on days 6 through 15 and this resulted in only two unexpected deaths and a 20% savings in hospitalization days. We conclude that individually determined discharge time is feasible without increased risk of death of severe complications after early discharge.Circulation 68, No. 1, 9‐16, 1983.

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

ABSTRACTVarious parameters of erythrocyte membrane sodium transport were measured in patients with untreated essential hypertension, in the normotensive offspring of parents with hypertension, and in patients whose hypertension had been controlled by medication. Net sodium efflux, measured by an isotopic tracer technique, was 2.12 ± 0.17 mM Na+/1 of red blood cells (RBCs)/hr in patients with untreated essential hypertension, compared with 1.55 ± 0.12 mM Na/1 of RBCs/hr in a group of normotensive controls (p < .025). Partitioning sodium efflux into ouabain‐sensitive and ouabain‐insensitive components revealed a significant elevation of both components of membrane sodium transport in the patients with untreated essential hypertension. Ouabain‐sensitive sodium efflux was 1.38 ± 0.09 mM Na/1 RBCs/hr in the patients, compared with 1.04 ± 0.07 mM Na/1 RBCs/hr in the controls. Ouabain‐insensitive sodium efflux was also increased from 0.51 ± 0.05 mM Na/1 RBCs/hr in the controls to 0.74 ± 0.09 mM Na/l RBCs/hr in those with untreated hypertension. Despite these changes in sodium efflux, Na,K‐ATPase activity in the erythrocyte membrane, measured at maximum velocity (Vmay), was normal, suggesting that the observed abnormalities in membrane sodium transport in patients with untreated essential hypertension resulted from a change in pump control mechanisms rather than a change in enzyme activity. With the techniques used in this study we were unable to identify changes in erythrocyte membrane transport in the normotensive offspring of hypertensive parents. Membrane sodium transport was also examined in hypertensive patients whose blood pressure had been controlled by medication. In this group it was found that erythrocyte sodium transport did not differ from that in our control group, which suggests that treatment of hypertension can modify fundamental pathophysiologic changes at the level of the cell membrane.Circulation 68, No. 1, 17‐22, 1983.

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

ABSTRACTPatients with DDD pacemakers who have intact retrograde conduction are known to be at risk of developing ventricular and “endless loop” tachycardia. To address this problem, a pacing protocol was designed in which V2A2conduction was assessed in 16 patients during ventricular pacing alone (standard method) and during paced atrioventricular (AV) sequential drive (AV sequential method); the results were then compared. In eight of 16 patients who had intact retrograde conduction with both methods (group 1), the V2A2intervals were significantly shorter (by 60 to 340 msec) with the AV sequential method. In the remaining eight patients, who demonstrated V2A2block with the standard method, no V2A2block occurred with the AV sequential method. In this study, two sets of AV intervals were programmed to produce collision of the two impulses (atrial and ventricular), either in the AV node or the His‐Purkinje system (HPS). The site of V2A2facilitation was related to the site of impulse collision. These results can be explained by earlier excitation by the atrial impulse (of AV node and/or HPS) during AV sequential pacing. However, in some cases it was evident that antegrade propagation of the atrial impulse was responsible for subsequent facilitation. The data suggest that assessment of retrograde conduction in candidates for DDD pacemakers can be made most accurately by the AV sequential method.Circulation 68, No. 1, 23‐32, 1983.

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

ABSTRACTA transvenous electrode catheter technique was used for direct recording of bipolar sinus node electrograms during postpacing atrial pauses. Multiple repetitive local sinus node electrograms during atrial quiescence validate sinus node electrograms. Such atrial pauses with sinus node electrograms are due to sinoatrial block; atrial pauses without sinus node electrograms are due to overdrive suppression or improper recording. Eight consecutive patients were prospectively selected on the basis of a corrected sinus node recovery time greater than 1500 msec during diagnostic electrophysiologic evaluation. Six patients had atrial pauses with sinus node electrograms; three patterns of sinus node electrograms during atrial pauses were observed. We conclude that (1) sinus node electrogram recording is of value in understanding the mechanism underlying postpacing atrial pauses; (2) atrial pauses are usually (6/8) caused by sinoatrial block; (3) three patterns of sinus node electrograms are observed, thus making indirect interpretation unreliable.Circulation 68, No. 1, 33‐41, 1983.

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

ABSTRACTA high‐resolution method of spectral analysis, of the class generally called “maximum entropy method,” was used in a study of aortic porcine valve closing sounds in 37 patients (ages 19 to 76). Spectra from 27 normal xenografts, implanted from 2 weeks to 61 months previously, were characterized by a dominant frequency peak, F1, at 89 ± 15 Hz (mean ± SD), with a lower amplitude peak, F2, at 154 ± 25 Hz. Eight of nine patients with aortic porcine valve dysfunction were proved surgically to have leaflet degeneration or infection and had either F1(139 ± 54 Hz) and/or F2(195 ± 74 Hz) significantly higher than normal (p < .001). In two patients with paravalvar leak but no leaflet abnormality, F1and F2were in the normal range. Estimation of F1and F2was highly reproducible and was unaffected by duration of implant up to 5 years. Spectral analysis of aortic porcine valve closing sounds by the maximum entropy method may be useful for detection of intrinsic xenograft dysfunction.Circulation 68, No. 1, 42‐49, 1983.

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

ABSTRACTPulse wave velocity (PWV) was measured by means of transcutaneous Doppler techniques in the aorta, right arm, and right leg of 480 normal subjects of both sexes in urban Beijing, China (age range 3 to 89 years, mean age 41 ± 20.8 SD); supine blood pressure was recorded in the brachial artery of each subject with standard sphygmomanometric procedures. Serum cholesterol was determined in a subgroup of 79 subjects (age 17 to 85 years, mean 47 ± 26 SD). PWV (y in cm/sec) was found to vary with age (x, years) at each of the three locations according to the following regression equations: aorta, y = 9.2x + 615, r = .673 (p < .001); right arm, y = 4.8x + 998, r = .453 (p < .001); right leg, y = 5.6x + 791, r = .630 (p < .001). Systolic, diastolic, mean, and pulse pressures were found to increase with age. PWV also increased with mean supine blood pressure but was not related to serum cholesterol (average 4.49 ± 0.11 [SEM], mmol/l). Compared with that of Western populations, serum cholesterol tended to be lower at all age groups, systolic pressure higher at ages over 35 years, and PWV higher at all ages. Because change in PWV is directly related to change in arterial compliance, these results indicate that aging and not concomitant atherosclerosis (known to be rare in Asian populations) is the dominant factor associated with reduced arterial compliance and increased left ventricular load in these subjects.Circulation 68, No. 1, 50‐58, 1983.

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

ABSTRACTLeft ventricular filling dynamics were examined at rest and during supine bicycle exercise in 33 patients at cardiac catheterization; 23 had coronary artery disease (ischemia group), five with prior infarction had an akinetic area at rest (scar group), and five had minimal cardiovascular disease (control). Peak filling rate and mean filling rate during the first half and second half of diastole were assessed by biplane angiography. Simultaneous micromanometer pressures were used to compute the time constant of isovolumic pressure decay (T). Peak filling rate and mean filling rate during the first half of diastole increased with exercise in all groups (from 615 to 1050 and 358 to 681 ml/sec in controls and comparably in the scar group and from 697 to 1035 and 347 to 768 ml/sec in the ischemia group). However, T was greater (reduced rate of pressure decay) with exercise in the ischemia group (38 vs 26 msec in controls; p < .05). Changes in the atrial driving pressure for filling appeared to counterbalance the difference in T. Mean filling rate during the second half of diastole increased with exercise in controls and in the scar group but only modestly in the ischemia group (from 202 to 349 ml/sec). The reduction in late diastolic filling during exercise‐induced ischemia was associated with increased filling in early diastole, with a middiastolic volume increase from 160 to 186 ml and an upward shift in the diastolic pressure‐volume relation. Thus left ventricular filling is not impaired at rest in patients with coronary artery disease who have normal ejection fractions. Furthermore, the augmentation of early filling induced by exercise is not blunted but is maintained during ischemia, apparently at the expense of elevated left atrial pressure. However, late filling is restricted with ischemia by an increase in impedance.Circulation 68, No. 1, 59‐67, 1983.

ISSN:0009-7322    

出版商:OVID    

年代:1983

数据来源: OVID