European journal of cardiology最新文献

When given during acute myocardial infarction (AMI), vasodilators such as nitroglycerin (TNG) and nitroprusside (NP) improve some of the hemodynamic determinants of myocardial oxygen demand. TNG has been shown to reduce ischemic injury during AMI, but variable results have been noted with NP therapy. To compare the effects of these two agents, 8 closed chest sedated dogs with pre-existing multi-vessel coronary constrictions underwent repeated, random-order, acute 15-min balloon occlusions of the left anterior descending coronary artery during the following conditions: (1) saline infusion (control), (2) TNG infusion, and (3) NP infusion. The severity of myocardial ischemia was estimated by summating the ST-segment elevations (xi ST) measured from 7 intramyocardial electrodes; mean left atrial pressure (LAP), heart rate (HR), and mean systemic arterial pressure (SAP) were also measured. No dog had left ventricular failure either before or after occlusion. Since HR and SAP responses to TNG and NP are different, the dogs were randomized into two subgroups: TNG and NP were infused in 4 dogs to produce similar increases in HR (10--20% greater than control), and in the other 4 to produce similar decreases in SAP (15--20% less than control). In each subgroup, xi ST was significantly lower following TNG than following NP. Moreover, in the total group of 8 dogs, xi ST after 10 min of occlusion averaged 38 +/- 10 mV during TNG treatment compared to 46 +/- 10 mV during control occlusion (P less than 0.05). In contrast, xi ST after 10 min of occlusion averaged 57 +/- 11 mV during NP treatment (P less than 0.01 compared to control occlusion). Thus, (1) when given to achieve similar hemodynamic changes following acute coronary occlusion, TNG reduced while NP increased myocardial ischemia, (2) although both 'vasodilators', TNG and NP appear to have different actions on various vascular beds, and (3) the hemodynamic changes induced by vasodilators do not in themselves provide an accurate index of directional alterations in myocardial ischemia.

Short- and long-term prognosis were analysed in 59 patients admitted in the coronary care unit with an acute myocardial infarction, complicated with acute intraventricular (IV) conduction defects. In-hospital mortality of patients with IV conduction disturbances was more than twice (30%) the mortality of patients without IV conduction defects (13%; P less than 0.001). Mortality rate was very high among patients with all forms of incomplete trifascicular block or complete right bundle-branch block. Among survivors of the group with conduction defects, late death rate was significantly higher than in survivors of the group without IV blocks (25 vs 8%; P less than 0.01). Short-term prognosis of conduction defects in myocardial infarction depends on the extent of the necrosis. The conflicting results in long-term prognosis could be ascribed to variations in patient material and to different criteria used to define the acute nature of a block. Lastly the variable prognosis could correspond to differences in the site of the lesions within the conduction pathway.

The echocardiogram is able to diagnose on which valvular leaflet or cusp the bacterial vegetations are implanted; it is also able to recognize the type of lesion (destroying vegetations, prolapsing vegetations, etc.). In our experience the echocardiographi findings were fully confirmed at surgical intervention in 12 of the 13 patients studied.

From a symptom-limited bicycle exercise test 3 wk after acute myocardial infarction is 205 patients the prognostic significance for the 1-yr prognosis of the following variables was examined by a multivariate analysis (Cox's model): reasons for stopping, duration of work, maximal heart rate, maximal product heart rate x systolic blood pressure, maximal ST-deviation, time to maximal ST-deviation and ventricular ectopic beats (type and frequency). The reason for stopping was fatigue in 59% and angina pectoris in 15%. 48% exercised up to 6 min and 14% beyond 12 min with median duration of 7 min. The maximal heart rate was over 140/min in 30%. ST-deviations were found in 77%; in most patients below 3 mm. 44% had ventricular ectopic beats during the exercise. The only significant variable was the duration of of work with prognostic index for the 1-yr prognosis SE: SE = 1.21-0.16 x (duration of work). A probability of survival of over 0.95 after 1 yr required a duration of work over 13 min. The observed deaths were in good accordance with the expected with a little overestimation. 75% died from a definite cardial cause. There is a good predictive value for the 1-yr prognosis of the duration of work from an exercise test 3 wk after AMI.

Nineteen young men operated upon for coarctation of the aorta during childhood, between the ages of 6 and 14 yr, were studied. Twelve patients had a systolic hypertension in the right arm at rest, and generally during exercise, measured intra-arterially. All patients but 2 had systolic gradients between the right arm and leg at rest and even more so during exercise. There was no significant correlation between the degree of hypertension or gradient on the one hand and the width of the anastomosis, age at surgery or years since surgery on the other in this group of patients. No better correlation was found when the patients were studied during exercise. Thus, blood pressure measurements can not reveal whether a re- or rest-coarctation is at hand. It can be questioned whether an early operation could prevent postoperative hypertension in the long run.

A new method was used for the quantitative analysis of left ventricular angiography in 22 patients with an anterior aneurysm. The line of demarcation between the aneurysm (A) and the remaining myocardium (RM) was determined accurately by looking at a sudden change in the percentage of shortening of two contiguous half-axes, the left ventricular cavity being divided by 19 parallel and equidistant axes. The total volume of the left ventricle, the volume of the A and that of the RM were calculated using a method derived from Chapman's method. Total ejection fraction, ejection fraction and VCF of the RM were also calculated. A comparison was made between patients with heart failure (Group I) and those without (Group II). In Group I, the A was much larger (P less than 0.01) but volume, ejection fraction and VCF of the RM, were not significantly different, indicating that the surgical resection should give a favorable result. The validity of this method of quantitative analysis was confirmed by a comparison of the calculated preoperative remaining left ventricular volume with the volume of the postoperative cavity in 8 patients. These measurements lead to a better evaluation of patients with ventricular aneurysm in view of selection for surgery.

Shortened return cycles after premature atrial stimulation (PAS) are commonly referred to as sinoatrial entrance block and exit delay at the sinoatrial junction or sinus-node reentries. In the 2 reported cases PAS at critical coupling intervals was followed by shortened return cycles characterized by a changed high right electrogram (and surface P waves in 1 case) and a normal sequence of atrial activation with unaltered intraatrial conduction. These changes lasted for some beats and a concomitant shorter or longer atrial cycle length was observed. Electrophysiological events furnish indirect evidence of sinoatrial pacemaker shift as a cause of incomplete interpolation in man.

In order to describe exercise-induced changes of left ventricular function in patients with atypical chest pain and to determine the diagnosis accuracy of radionuclide angiography in the differential diagnosis of various chest pain syndromes, we studied a consecutive series of 26 patients and 20 healthy volunteers. Only patients with ejection fractions > 0.50 at rest, without antianginal therapy and without a prior myocardial infarction who eventually underwent diagnostic left heart catheterization were included in the study. In all healthy volunteers ejection fraction increased during exercise by at least 10% over the resting level (from 0.61 +/- 0.05 to 0.76 +/- 0.07; P < 0.001). A similar ejection fraction response was found in 14 of the 26 patients (group A): ejection fraction increased from 0.60 +/- 0.06 to 0.72 +/- 0.07 (P < 0.001), whereas in the remaining 12 patients (group B) ejection fraction decreased from 0.62 +/- 0.06 to 0.57 +/- 0.07 (P < 0.01). Left heart catheterization revealed normal coronary arteries in 13/14 group-A patients while 10/12 group-B patients had significant coronary artery lesions (> 50%). The other two group-B patients were found to have idiopathic cardiomyopathies. We conclude that normal subjects with atypical chest pain during exercise have a normal ejection fraction response to exercise despite their symptoms and that therefore radionuclide angiography during exercise is a valuable noninvasive method in the differential diagnosis of exercise-induced chest pain syndromes.

The protective effect of hydroxymercurifluorescein (Mercurascan, MSC) on the ischemic myocardium was evaluated in dogs. MSC was given 17 min after ligation of the descending branch of the left coronary artery in closed-chest animals. The favorable effect of this drug was confirmed (1) by an immediate decrease of ST-segment elevation in electrograms from epicardial electrodes, (2) by a reduced number of Q waves 24 h after the ligation, and (3) by the preservation of CPK activity in the sites with moderate early ST-segment elevations. Microscopic examination also confirmed this. We conclude that MSC given shortly after coronary artery occlusion in dogs protects some cells in the border zone of ischemic focus from the development of necrosis. The membrane stabilizing effect or neutralization of proteolytic enzymes are the suggested explanations for the mechanism of MSC action.

The effects of changes in posture on left ventricular (LV) diameter and function were studied by echocardiography in 14 healthy children. On changing from the supine to the standing position, enddiastolic LV diameter decreased by 13 +/- 5% (P < 0.001), heart rate increased (P < 0.05) and calculated stroke index (-37 +/- 11%, P < 0.001) and cardiac index (-32 +/- 14%, P < 0.001) fell. There was not a significant change in the echocardiographic measurement. % delta s, mean Vcf and max Vpwm (ns) but mean Vcf increased in relation to mean blood pressure in 3 patients, suggesting an increase in LV contractility. Squatting was accompanied by an increase in LV cavity dimension (P < 0.001), while heart rate fell slightly and calculated stroke index (%35 +/- 28%, P < 0.001) and cardiac index (+33 +/- 27%, P < 0.001) increased. Mean blood pressure increased by 19 +/- 18% (P < 0.01). There was again no significant change in % delta s, mean Vcf and max Vpwm. Most patients fell on the control (supine) blood pressure--mean Fcf curve; in 2 patients there was a residual increase in sympathetic tone and LV contractility.