European journal of cardiology最新文献

M-mode echocardiography was performed in 20 asymptomatic patients undergoing chronic hemodialysis, in order to assess pericardial involvement. Six of the patients had small to moderate amounts of pericardial effusion. One of these patients and 5 others showed an echocardiographic pattern of pericardial thickening. No correlation was found between pericardial involvement and age, sex, secondary hyperthyroidism, serum levels of urea, creatinine or uric acid. The traditional diagnostic techniques commonly used for the detection of pericardial disease such as physical examination, chest X-ray and electrocardiography were not helpful in our patients. Our study demonstrates the high incidence of pericardial involvement in asymptomatic chronically dialyzed patients. Periodic echocardiographic evaluation is recommended for assessment of the presence and significance of these findings.

Ninety-three patients with chest pain underwent both maximal 12-lead treadmill testing and coronary arteriography to ascertain whether exercise testing might predict multivessel coronary disease. Twenty-eight patients had normal coronary arteries, 20 single vessel disease (greater than 70% reduction in luminal diameter), 18 double and 22 triple vessel disease. Five patients had left main coronary disease. All 45 patients with double, triple or left main disease had positive 12-lead exercise tests whilst only 15/20 (75%) with single vessel disease had positive tests. Sensitivity of the 12-lead electrocardiogram during maximum stress testing was 92%, with 15% false negatives. The predictive value of a positive test was 100% (no false positives) and 85% for a negative test. Significant predictors of severe triple vessel and left main coronary disease were the sum of ST segment depression (xi ST), the number of ECG leads which developed ST segment depression, the stage at which ST depression developed and the ST segment recovery time. There was a significant correlation between the anatomical location of coronary artery stenoses and the area of ischaemia indicated by the exercise electrocardiogram.

The cardiovascular actions of prostacyclin (PGI2) were investigated in a double-blind, randomised, balanced study. Six healthy volunteers received intravenous infusions of PGI2 in a range of doses up to 4 ng/kg per min, which is the lowest dose which consistently inhibits platelet aggregation. Measurements of systolic time intervals, peak normalised first derivative of the apexcardiogram, high-speed surface electrocardiogram and arterial blood pressure were made during each infusion. PGI2 caused dose-related decreases in diastolic blood pressure, preejection period and QS2 index, and an increase in heart rate. Systolic blood pressure, left ventricular ejection time index, the peak normalised first derivative of the apexcardiogram, and PR interval, QRS duration, QT index and T-wave amplitude were unchanged. Facial flushing was seen in all subjects at PGI2 4 ng/kg per min. These results suggest that PGI2 has an important arteriolar vasodilator action, but do not exclude a minor direct effect on contractility.

A model of myocardial ischaemia is described and has been characterized in terms of functional, ultrastructural, electrophysiological and metabolic changes. The model fulfills a number of criteria considered to be of importance in any model of myocardial ischaemia namely (1) the myocardium is ischaemic as opposed to hypoxic, (2) the coronary flow is reduced but not totally abolished, (3) that flow reaching the ischaemic myocardium is fully oxygenated and contains a mixture of substrates. It is proposed that this model is of value for the investigation and assessment of pharmacological interventions during myocardial infarction.

Radionuclide measurement of left ventricular ejection fraction (LVEF) response to exercise has been proposed as a way to help identify patients with coronary artery disease (CAD). Previous studies were done using an exercise bicycle or a treadmill and showed that patients with CAD do not increase ejection fraction (EF) to the same extent as normal (control) subjects. The present studies were done using a coaxial Gamma Cor cardiac probe. Because radiocardiograms (RCG) obtained with the cardiac probe require 1/10 the dose required for a scintillation camera, serial measurements could be made before, during and following exercise. Although 3 of our 9 patients showed an unchanged and 3 showed a decreased EF at the time of maximal exercise, 3 others were able to increase their EF, and in 2 this increase occurred concomitantly with angina. Thus, not all the CAD patients could be identified by failure to increase EF in response to exercise. However, looking at the period just following exercise, one can see that most of our patients with CAD maintain or increase LVEF during the first 6 to 9 min after stopping exercise; normal (control) subjects rapidly return to the preexercise value. The normal pattern is an increase in EF during exercise followed by a prompt return toward normal after cessation of exercise. Changes of this normal pattern of EF increase and decrease occurred in all except 1 patient with CAD, and consequently provided a better indication of the presence of significant disease than the response during exercise alone.

The effect of slow-release nitroglycerin and nitroglycerin ointment in reducing anterior myocardial infarction size was assessed in 18 patients by means of epicardial mapping. The sum of all ST elevations (sigma ST), the number of leads with ST elevations greater than 1 mm (NST), the sum of the ST segment elevations of those leads with ST elevations greater than 1 mm (sigma STmm) and the average ST segment elevations (ST) were evaluated. No statistically significant difference between the two forms of nitroglycerin and placebo was found over a 72-h period. These data suggest that no benefit in terms of reduction in myocardial infarction size, assessed by epicardial mapping, is obtained from therapy with oral slow release nitroglycerin and nitroglycerin ointment.

Development of a computer-aided system for routine quantitation of spontaneously occurring ventricular arrhythmias in isolated perfused hearts is described. The technique essentially involves statistical treatment of electrocardiographic data to determine beat interval standard deviations. To minimize standard deviations arising from changes in heart rate, mean R-R intervals and standard deviations of 1-min sets of data are grouped and subjected to one-tailed analysis of variance. Residual standard deviation (derived from the difference between total variation and between set variation) expressed as a percentage of group mean is utilized as the Rhythm Disturbance Unit. It is proposed that this system can be used to facilitate investigations into mechanisms underlying arrhythmogenesis and in addition may have potential application in the screening of anti-arrhythmic interventions.

The red blood cell aggregation value (AW) in a group of 39 patients with coronary artery disease (CAD) was measured and compared with that of an age- and sex-equivalent group of normals and a group of 12 patients with suspected CAD, whose coronary arteries were found to be normal by coronary arteriography. The AW was significantly higher in CAD patients than in both normal groups (2P < 0.01 and 2P < 0.02 respectively). The AW in a group of 12 CAD-patients treated with the aggregation lowering drug clofibrate was significantly lower than in the untreated CAD-group. The predictive value of AW was calculated by means of mathematical methods. Measurement of AW could be a useful aid in the study of detection of CAD.

Simultaneous measurement of brachial artery pressures, systolic time intervals, initial pulse upstroke gradient and pulse rate was made in 7 adult hypertensive outpatients during rest supine and during bicycle ergometry at 2 different work rates. Measurements were repeated after 1, 6 and 13 wk on oral propranolol 80 mg thrice daily. Rise of pulse upstroke period (reversed after 1 wk) and of inflection time--analogous with preejection period--and fall of inflection, or diastolic, pressure (most marked at 1 wk) can be explained by early reduction of myocardial contractility and pulse rate. The fall of upstroke period, of peak, or systolic, pressure and of pulse rate (more marked after 1 wk) is related to a later 'adaptive' decrease in peripheral resistance. Much useful information can be obtained by such simple examination of the characteristics of the pulse wave in the brachial artery without complex, albeit noninvasive, cardiac investigations.

Echocardiography was used to study the quantitative and qualitative alterations of pulmonary valve echograms. 228 infants and children with congenital heart disease and with known pulmonary artery pressure were studied to evaluate which echocardiographic parameters would be most useful in predicting pulmonary artery hypertension. Right ventricular systolic time intervals (RVSTI) were studied and when patients with complete right bundle branch block (CRBBB) or transposition of the great arteries (TGA) had been excluded the strongest correlation was found between right ventricular preejection period/right ventricular ejection time (RPEP/RVET) and pulmonary artery diastolic pressure (PADP) (r = 0.73). In patients with TGA the correlation coefficient for LPEP/LVET and PADP was r = 0.88. We did not find a significant correlation between right ventricular isovolumetric contraction time (RICT) or RICT/RVET and PADP in patients with CRBBB. The correlation between the amplitude of the a-wave and PADP was fair (r = 0.48). BC slope, EF slope and the maximum amplitude of opening of the pulmonary valve were all related to PADP but the correlation coefficients were low. A-wave of 2 mm or less, systolic fluttering or systolic notching of the pulmonary valve echo were seen significantly more often in patients with PADP above 20 mm Hg but were less valuable in predicting pulmonary artery hypertension. RVSTI seem to be more useful than the other echocardiographic parameters for evaluation of pulmonary artery hypertension and RPEP/RVET appears to be the most reliable of them.