ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTTo determine the relative influence of preload, afterload, and inotropic state on postextrasystolic potentiation (PESP) of ventricular performance in man, we computed angiographic left ventricular volume and wall stress frame by frame for a control and potentiated beat in each of 31 patients. In 10 normal subjects, PESP increased ejection fraction by 14%, while left ventricular enddiastolic volume increased by 8% (p < .001) and end-systolic stress fell by 21% (p < .005). Enhanced diastolic filling (+ 6%, p < .005) with a small decline in end-systolic stress (-8%, p = NS) likewise contributed to potentiation of ejection fraction (+ 14%, p < .001) in seven patients with aortic stenosis. Diastolic filling was not significantly augmented during the compensatory pause in six patients with isolated mitral regurgitation, nor in eight patients with aortic regurgitation (+ 2%, p = NS for both). Although afterload tended to fall for potentiated beats in patients with aortic (- 11% p = NS) and mitral regurgitation (- 23%, p = NS), analysis of ejection fraction-end-systolic stress relationships demonstrated an independent effect of inotropic state on potentiated ejection performance. Thus, utilization of preload reserve contributed to PESP in normal subjects and patients with aortic stenosis, but not in those with volume overload imposed by chronic valvular regurgitation. Enhanced inotropic state independent of small changes in afterload was demonstrated in all subgroups.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTThis study describes six generations of a family with autosomal dominant cardiac conduction system and myocardial disease with recognizable clinical stages. A 20 year follow-up of nine family members, a medical questionnaire of 196, electrocardiographic screening of 91, noninvasive testing of 20, and catheterization with endomyocardial biopsy of six are the basis of this report. The clinical stages are as follows: Stage I occurs in the second and third decades of life and is characterized by an absence of symptoms, normal heart size, sinus bradycardia, and premature atrial contractions. Stage II is marked by first-degree atrioventricular block in the third and fourth decades. Stage III occurs in the fourth and fifth decades and is accompanied by chest pain, fatigue, lightheadedness, and advanced atrioventricular block followed by the development of atrial fibrillation or flutter. Stage IV, in the fifth and sixth decades of life, is characterized by congestive heart failure and recurrent ventricular arrhythmias. Light microscopy of right ventricular endomyocardial biopsy specimens from patients in stage II revealed very mild fibrosis; electron microscopy of the specimens demonstrated mild dilatation of tubules, mitochondrial swelling, and minimal myofibrillar loss. Biopsy specimens from patients with stage III disease were similar to those from patients with stage IL disease except for an increase of myofibrillar loss. The stage IV specimens had diffuse fibrosis and more severe tubular dilatation, mitochondrial cristolysis, and myofibrillar loss. At autopsy in the proband, the atrial changes were more severe than the ventricular and were especially marked in the sinoatrial and atrial myocardium. Early recognition of the disease and use of pacemakers and antiarrhythmic agents have proved beneficial for affected family members. Thorough family studies of patients with conduction system disease and/or dilated cardiomyopathy are necessary to better understand the hereditary basis and natural course of this category of disease.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTThis study offers a unifying mechanism of left ventricular filling dynamics to link the unexplained mid-diastolic motion of the mitral valve with an associated increase in transmitral flow, with the phasic character of pulmonary vein flow, and with changes in the atrioventricular pressure difference. M mode echograms of mitral valve motion and Doppler echocardiograms of mitral and pulmonary vein flow velocities were recorded in 12 healthy volunteers (heart rate = 60 + 9 beats/ min). All echocardiograms showed an undulation in the mitral valve (L motion) at a relatively constant delay from the peak of the diastolic phase of pulmonary vein flow (K phase). In six subjects, the L motion was also associated with a distinct wave of mitral flow (L wave). Measured from the onset of the QRS complex, Q-K was 577 ± 39 msec; Q-L was 703 + 42 msec, and K-L was 125 + 16 msec. Multiple measurements within each subject during respiratory variations in RR interval indicated exceptionally small differences in the temporal relationships (mean coefficient of variation 2%). Early rapid flow deceleration is caused by a reversal of the atrioventricular pressure gradient, and the L wave arises from the subsequent reestablishment of a positive gradient due to left atrial filling via the pulmonary veins. The mitral valve moves passively in response to the flowing blood and the associated pressure difference. This interpretation is confirmed by (1) a computational model, and (2) a retrospective analysis of data from patients with mitral stenosis and from conscious dogs instrumented to measure transmitral pressure-flow relationships.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTOver a 5.5 year period, 1264 consecutive patients with acute myocardial infarction as confirmed by enzyme levels were prospectively identified. Of these, 25 (2%) suffered ventricular septal rupture (pulmonary/systemic flow range 1.5 to 6) 7 + 7 days after onset of myocardial infarction. Death occurred in 14 patients (56%) and was more common after inferior than anterior myocardial infarction (11 of 15 [73%] vs three of 10 [30%], p < .05). Among 133 variables analyzed, survivors and nonsurvivors were similar with respect to all premorbid clinical characteristics, infarct size as assessed by peak creatine kinase values, shunt size, two-dimensional echocardiographic and hemodynamic indexes of left ventricular function, and extent of coronary disease. Compared with survivors, the nonsurvivors had greater impairment of right ventricular function as determined by a higher two-dimensional echocardiographically derived right ventricular wall motion index (RVWMI) (0.55 + 0.87 vs 1.70 + 0.45, p < .001), greater elevation of right ventricular end-diastolic pressure (11 + 6 vs 17 ± 6, p < .02), and greater mean right atrial pressure (10 ± 6 vs 16 3, p < .01). Of interest, two of the three patients who presented with anterior myocardial infarction and who died had inferiorly extended infarcts and all had abnormal RVWMIs (2 1.0). As expected, cardiogenic shock shortly after onset of ventricular septal rupture was associated with a 91% mortality, but was more common after inferior than anterior myocardial infarction (60% vs 20%, p < .05). The mean effective cardiac index was also higher in survivors than nonsurvivors (2.1 ± 0.5 vs 1.2 ± 0.5, p < .001). Finally, multivariate analysis indicated that all nonsurvivors could be identified based on: (1) an effective cardiac index of 1.75 liters/min/m2 or less, (2) the presence of extensive right ventricular and septal dysfunction on the two-dimensional echocardiogram, (3) a mean right atrial pressure of 12 mm Hg or more, and (4) early onset of ventricular septal rupture. Thus, our data demonstrate that: (1) mortality is higher when ventricular septal rupture complicates inferior than when it complicates anterior myocardial infarction, (2) survivors can be distinguished from nonsurvivors and the prediction of outcome is highly accurate, and (3) combined right ventricular and septal dysfunction has a substantial impact on prognosis.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTForty-three consecutive patients with acute inferior transmural myocardial infarction but no history or electrocardiographic evidence of prior myocardial infarction were evaluated prospectively to assess the clinical and prognostic importance of persistent precordial (V1-V4) ST segment depression. Patients were evaluated within 24 hr of admission by history, physical examination, cardiac enzyme levels, right heart catheterization, and radionuclide angiography; all were followed for 1 year. Ten of the 43 patients (group I) had persistent anterior precordial ST segment depression, defined as 1 mm or greater in one or more precordial leads (V1-V4) 24 hr after admission to the coronary care unit, and 33 patients (group II) did not. Clinical variables that differed between groups and LI, respectively, included mean age (67 + 9 [+ 1 SD] vs 59 8 years; p < .01), incidence of Killip class II to IV (100% vs 33%; p < .001), and average peak creatine kinase concentration (2878 + 1139 vs 1511 + 1034 IU/liter; p < .001). Hemodynamic differences between groups I and II included a higher pulmonary arterial wedge pressure (19 + 4 vs 11 + 5 mm Hg; p < .001) and a lower cardiac index (2.0 + 0.5 vs 2.6 + 0.7 liters/min/m2; p < .05). An evaluation of left ventricular ejection fraction and wall motion index by radionuclide angiography showed that group I had a lower ejection fraction (44 + 1l % vs 53 + lOo%; p < .05) and higher wall motion index (1.7 + 0.4 vs 1.4 ± 0.3; p < .05) compared with group II. Prognostically, group I had a higher incidence of recurrent myocardial infarction (30% vs 0%; p < .01) and a higher 1 year mortality (60% vs 0%; p < .001). Univariate analysis revealed that several clinical, electrocardiographic, hemodynamic, and radionuclide angiographic variables were predictive of 1 year mortality, with persistent precordial ST segment depression being the most powerful (r = .73). Multivariate analysis was used to determine which variables had independent value for predicting death within 1 year. The most important variables were persistent precordial ST depression followed by elevated heart rate. No other variables added to this combination improved their predictive value (r 82). We conclude that patients with their first acute inferior transmural myocardial infarction who have persistent precordial (V,-V4) ST segment depression have clinical, hemodynamic, and noninvasive evidence of decreased left ventricular performance and a high 1 year mortality.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTIn this paper we examine the relationship between risk factors and angiographically determined coronary artery disease for blacks and whites enrolled in the Coronary Artery Surgery Study (CASS). Analysis of data from the CASS registry indicated that blacks had a higher incidence of hypertension and current cigarette smoking than did whites in CASS and that chest pain was the major reason that both blacks and whites underwent coronary angiography for suspected or proven coronary disease. The CASS data also showed that, despite high levels of risk factors and chest pain, blacks had minimal or absent coronary disease. The results of this study raise several questions. First, to what extent are blacks in CASS representative of (1) blacks in the general population and (2) blacks undergoing coronary angiography? Additionally, are risk factors for coronary artery disease different for blacks than for whites? And finally, how does the physician effectively treat the black patient with high levels of risk factors and minimal coronary disease?

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTTo better understand the relationship between the transient myocardial ischemia seen during an exercise test and ischemic activity out of hospital, 39 patients with well-documented coronary artery disease underwent standard treadmill exercise testing (Bruce protocol) and 24 to 48 hr of continuous ambulatory electrocardiographic monitoring during normal daily activities. A total of 245 episodes of transient ischemia were recorded in 21 of 32 patients with positive exercise electrocardiograms (group I), whereas seven patients with negative test results (group II) had no episodes of transient ischemia, during monitoring out of hospital (p < .01). Certain measures in the exercise test were related to the severity of ischemia out of hospital: there were more episodes and a greater total duration of transient ischemia per 24 hr of ambulatory monitoring in patients who developed ischemic electrocardiographic changes before 6 min of exercise (p ' .021) or at a heart rate of less than 150 beats/min (p = .005) and in those in whom these ST segment changes persisted for more than 5 min after exercise (p ' .016). In contrast, there was no relationship between transient ischemia out of hospital and the commonly quoted exercise variables: chest pain, total exercise duration, and the maximum levels of heart rate, systolic blood pressure, and double product. Thus, patients with coronary artery disease and negative exercise electrocardiograms are most unlikely to experience active ischemia during normal daily life. However, certain features of the positive exercise test, namely the exercise duration at onset of significant ST depression, the heart rate at this threshold point, and the persistence after exercise of these ischemic changes, are all related to the level of this disease activity during daily life. This may help to assess risk and explain why the early positive exercise test is an adverse sign for coronary events.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTRegional myocardial perfusion and exogenous glucose uptake were assessed with rubidium-82 (82Rb) and 18F-2-fluoro-2-deoxyglucose (FDG) in 10 normal volunteers and 12 patients with coronary artery disease and stable angina pectoris by means of positron emission tomography. In patients at rest, the myocardial uptake of 82Rb and FDG did not differ significantly from that measured in normal subjects. The exercise test performed within the positron camera in eight patients produced typical chest pain and ischemic electrocardiographic changes in all. In each of the eight patients a region of reduced cation uptake was demonstrated in the 82Rb scan recorded at peak exercise, after which uptake of 82Rb returned to the control value 5 to 14 min after the end of the exercise. In these patients, FDG was injected in the recovery phase when all the variables that were altered during exercise, including regional myocardial 82Rb uptake, had returned to control values. In all but one patient, FDG accumulation in the regions of reduced 82Rb uptake during exercise was significantly higher than that in the nonischemic regions, i.e., the ones with a normal increment of 82Rb uptake on exercise. In the nonischemic areas, FDG uptake was not significantly different from that found in normal subjects after exercise. In conclusion, myocardial glucose transport and phosphorylation seem to be enhanced in the postischemic myocardium of patients with exercise-induced ischemia.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID