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Biomedical subjects

S Effert

Publications and source records attributed to S Effert.

At least 37 records · Page 2Linked to original sources
PubMed1987

Localization of significant coronary arterial narrowings using body surface potential mapping during exercise stress testing.

The ability of body surface potential mapping to localize coronary arterial narrowings during exercise stress testing was investigated. An array of 48 chest wall electrodes, simultaneously recorded, was used. Digital filtering and signal processing, data reduction techniques and discriminant analysis were applied to process the information. Forty patients whose coronary angiograms showed a single significant narrowing of either the left anterior descending or right coronary artery were selected for further study. On the basis of body surface potential mapping, the site of coronary arterial narrowing was correctly classified in 88% of the patients.

Coronary Disease↗
PubMed1987

Residual coronary stenosis after thrombolysis with rt-PA or streptokinase: acute results and 3 weeks follow-up.

Ninety-one patients with acute myocardial infarction were assigned to intravenous treatment with streptokinase or rt-PA as part of the randomized trial carried out by the European Study Group for Recombinant Tissue-Type Plasminogen Activator (rt-PA). A patent coronary artery was found in 37 of 45 (82%) patients treated with rt-PA and in 27 of 46 (59%) patients treated with streptokinase 75-90 minutes after start of infusion. Patients were subsequently anticoagulated with heparin or dicoumarol up to a repeat angiography 3 weeks after the infarction. Of the 64 patients with successful reperfusion, 3 died and 3 suffered reocclusion of the vessel. Quantitative analysis of the coronary stenosis both immediately after thrombolysis and at 3 weeks follow-up was possible in 33 cases. Residual stenosis (percentage narrowing of diameter) decreased from 74 +/- 14% to 56 +/- 17% (P less than 0.05). No difference was observed between the groups of patients treated with streptokinase (74 +/- 9% to 57 +/- 12%, N = 17) and with rt-PA (74 +/- 17% to 56 +/- 21%, N = 16). Despite the significant regression, a coronary stenosis of more than 50% of the diameter persisted in 82% of the patients three weeks after the infarction.

Cineangiography↗
PubMed1986

[Heart valve replacement in patients over 60].

UNLABELLED: Between 1976 and 1984, 182 patients over 60 years with valvular defects were examined invasively and valve replacement was performed. 34 patients (19%) were older than 70 years. Hospital mortality was 2% in aortic valve replacement, 4% in mitral valve and 8% in double valve replacement. Overall early mortality in patients between 60 and 70 years of age was 3.4% and 6% in patients over 70 years for all operations. Simultaneous aortocoronary bypass surgery did not enhance the operation risk. During the follow-up period of 23 +/- 22 months a total of 21 patients died (12%). Only 4% of the survivals showed clinical deterioration by at least one NYHA class. Clinical tendency to improvement was as clearly evident among the patients of over 70 years of age as among the entire group. Preoperative invasive and noninvasive data do not display any significant correlation with the result of surgery. Significantly higher (P less than 0.05) mortality rates or inferior functional operation results were seen only with higher age, a preceding valve operation, and preoperative NYHA class IV. CONCLUSION: In elderly patients indication for valve replacement should not be more restrictive than in younger ones. Postponement of valve replacement in these age groups until the patient experiences symptoms when at rest (NYHA class IV) will adversely affect the chances of success and increase the mortality risk.

Aged↗
PubMed1986

Right ventricular volume determination in isolated human hearts.

For right ventricular volume determination a new method was developed that took into account right ventricular imaging by apical two-dimensional echocardiography in the four- and two-chamber views. Right ventricular volume was calculated by subtraction of the partial volume of the left ventricle and interventricular septum from the total heart volume of the right and left ventricles including the interventricular septum. Accuracy of the subtraction method was evaluated in isolated human hearts by two-dimensional echocardiography and radiography. Regression analysis indicated that for both the echocardiographic and radiologic procedures, the subtraction method gave the best correlation with the right ventricular filling volume. The correlation coefficients obtained using the echocardiographic procedure were 0.964, 0.848, and 0.851 for the subtraction method, pyramid method, and Simpson's rule method, respectively. For the radiographic procedure, these values were 0.946, 0.860, and 0.872. Percentage difference calculations indicated that the subtraction method systematically underestimated (-7.4%) the filling volume in the echocardiographic procedure, but this was not seen with the radiologic procedures. The random error associated with the subtraction method was only half (10.5%, 13.9%) of that seen with the other two methods in both the echocardiographic and radiological procedures. These results indicate that right ventricular volume determination by the subtraction method seems to be suitable for apical two-dimensional echocardiography and is more accurate than the pyramid method and Simpson's rule method.

Echocardiography↗
PubMed1986

Intracoronary thrombolysis and early bypass surgery for acute myocardial infarct: five years' experience.

During the five-year period between March 1980 and February 1985 selective intracoronary thrombolysis with streptokinase was performed in 469 patients with clinical and ECG signs of acute transmural myocardial infarct. Coronary arteriography prior to thrombolysis showed the infarct related vessel still or again patent in 21% of the patients. Among 372 patients with complete occlusion streptokinase infusion was successful in 87%, but failed in 13%. Due to the high risk of reocclusion, early bypass surgery was performed in 69 patients (18.5%) of the successfully reperfused group. Indication was based primarily on an ischemic time interval of less than 4 hours between the acute onset of clinical symptoms and reperfusion. Early mortality was 1.5% in this surgically treated group and actuarial survival was 92% at 5 years with all but 3 patients in functional class I or II. Marked but non-fatal early congestive heart failure was more significant when patients underwent operation within the first 2 days after thrombolysis than thereafter. Late recatheterization studies in 29 patients showed a slight but statistically insignificantly higher occlusion rate for vein grafts to the infarct vessel (14%) than to concomitantly grafted arteries (6%). No correlation was found between the initial ischemic time interval and graft patency. Late left ventricular function was excellent or minimally impaired in 52% of these patients while 48% had significantly reduced LV function. Again, no correlation was found between the ischemic time interval and late LV function. LV aneurysm, however, occurred only in patients with an ischemia of more than 3 hours. Thrombolysis combined with early bypass surgery represents the optimal therapy for acute myocardial infarct.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Electrocardiogram in acute anterior wall infarct after restoration of the blood supply].

Changes in QRS complexes and ST-T segments were measured in 70 patients after acute anterior-wall myocardial infarction. Intracoronary streptokinase infusion was undertaken in the acute phase in 58 patients, 12 other patients treated conventionally without infusion serving as controls. Precordial ECG mapping employed 48 unipolar precordial leads. If recanalization of an occluded coronary artery was achieved, there was a significant rise in R amplitude (sum of R-wave amplitudes in the 48 leads) from 12.4 +/- 10.9 to 16.2 +/- 11.2 mV, within a period of up to four months after the acute stage. If thrombolysis failed or only conventional treatment had been practised, there was no rise in R-wave amplitude. Renewed occlusion of a vessel previously re-opened by streptokinase infusion produced a reduction in R-wave amplitude from 14.0 +/- 13.0 to 9.8 +/- 11.0 mV. The S-T segment elevation regressed immediately after recanalization of the coronary artery. The S-T segments were iso-electric after four months. Re-occlusion caused renewed S-T segment elevation up to monophasic form. Precordial ECG mapping is thus well suited for serial controls after various re-perfusion measures.

Electrocardiography↗
PubMed1985

[Intracoronary streptokinase in acute myocardial infarct. Experience with 461 patients].

Between March 1980 and July 1984, coronary angiography was performed on 461 consecutive patients (no age limit) with acute myocardial infarction, and the partially or completely obstructing thrombus lysed by selective intracoronary infusion of streptokinase. At the time of first coronary angiography 96 patients (21%) had a high degree of stenosis but no total occlusion of the infarct vessel (group A). In 365 patients (79%) there was complete occlusion which in 315 patients (86%) was removed successfully after an occlusion period of 213 +/- 87 minutes (group B). In 50 patients (14%) (group C) attempts at reperfusion failed. In 129 of 163 patients (79.1%) with one-vessel disease, PTCA (percutaneous transluminal coronary angioplasty) was successful. Patients with multiple-vessel disease and an occlusion time of less than four hours, on the other hand, were treated surgically within the first ten days (78 patients). In the remaining 254 patients conservative treatment was practised. Within the first 30 days there were seven deaths (14%) in group C, while among group A and B patients, under conservative treatment, 16 died (7.8%). After successful PTCA four patients (3.1%) died. The lowest mortality was among patients with a short occlusion time and early bypass operation (2.6%). The most frequent cause of death was cardiogenic shock (20 of 29 patients), more rarely ventricular fibrillation (3) or other causes (4). Ventricular rupture occurred in three patients, one of whom was saved by pericardial tap. One year later the mortality among the conservative group was 21.2%, after successful PTCA or bypass operation 9.3% and 6.4%, respectively.

Aged↗
PubMed1985

Sensitivity of cross-sectional echocardiography in detection of impaired global and regional left ventricular function: prospective study.

In order to establish the sensitivity and specificity of cross-sectional echocardiography for detection of global and regional left ventricular function a prospective study was performed in 80 patients suspected of having coronary artery disease. Twenty four hours before heart catheterization, cross-sectional echocardiograms were recorded in the apical RAO-equivalent view and high quality echocardiograms were obtained in 71/80 patients (89%). M-mode echocardiograms of the left ventricle could be performed in 56/71 patients (79%). Based on normal values sensitivity and specificity of cross-sectional echocardiography were calculated in comparison to cineventriculography. For fractional shortening (normal value greater than 25%) sensitivity measured 46% and specificity 93%, and when the E-point septal separation was measured (normal value less than 7 mm), sensitivity increased to 73% and specificity was 84%. For detection of increased end-diastolic volume (less than 155 ml) sensitivity reached 84% and specificity 98% and for increased end-systolic (less than 70 ml) volume it was 86 and 97%, respectively. A depressed left ventricular ejection fraction (greater than 49%) was found with a sensitivity of 93% and specificity of 100%. Regional left ventricular wall motion, analyzed by an area method, revealed for anterior wall motion a sensitivity of 68% and a specificity of 94%, whereas for posterior wall motion sensitivity reached 80% and specificity 96%. Regression equation between the number of pathological segments and left ventricular ejection fraction for cineventriculography was given by Y = -4.06 X + 73.4, r = 0.93 and for cross-sectional echocardiography by Y = -3.69 X + 62.6, r = 0.85. We conclude that cross-sectional echocardiography can be used as a screening method to detect impaired left ventricular function. It is superior to M-mode echocardiography. Reduced regional function of the posterior wall can be found with high sensitivity, but depressed motion of the anterior wall may be overlooked.

Adult↗
PubMed1985

Myocardial infarction and thrombolysis. Electrocardiographic short term and long term results using precordial mapping.

In a consecutive series of 56 patients with acute myocardial infarction, ST segment depression and elevation in the electrocardiographic limb leads I, II, and III were summated for each patient before and immediately after intracoronary streptokinase infusion and the results compared with the angiographic findings. Forty three patients had angiographically confirmed reperfusion of an initially occluded vessel and showed a significant decrease in summated ST shift. The ST segment changes in the limb leads virtually returned to normal in all 43 patients, and in most, inverted T waves developed. Thrombolysis was unsuccessful in 10 patients, and the infarct related coronary artery was already patent in three. When these two groups are combined, all 13 patients without reperfusion showed no significant change in summated ST segment shift. During percutaneous transluminal angioplasty inflation of the balloon in the vessel that was previously occluded simulated reocclusion and was followed by new ST elevation if the artery supplied viable myocardium. In a further consecutive study of 54 patients with anterior myocardial infarction, the precordial R waves and Q waves were studied over the four to six months following infarction using a standardised 48 electrode mapping system. All patients underwent a repeat angiogram after four to six months. In 36 patients the infarct related vessel was patent. They showed a significant mean increase in summated precordial R wave amplitude and a reduction in the mean number of precordial leads without R waves. In 18 patients with unsuccessful thrombolysis or reocclusion there was a further reduction in mean summated R wave amplitude and an increased number of precordial leads not showing R waves. Precordial R wave mapping seems to be a valuable non-invasive method of assessing the salvage of myocardium after reperfusion and the damage caused by reocclusion. Loss of R waves in the acute phase of myocardial infarction does not necessarily mean an irreversibly damaged myocardium.

Adult↗
PubMed1985

[Residual stenosis following successful selective lysis of complete thrombotic coronary artery occlusion in acute myocardial infarct].

After successful lysis of a thrombotic coronary obstruction in acute myocardial infarction, both PTCA and bypass surgery can be useful in preventing reocclusion and providing long-term success in selected patients. One condition to perform such measures is a high degree of residual narrowing at the previous site of occlusion. Other investigations concerning the extent and further development of these lesions are methodically inhomogenous and different in their results. Following successful intracoronary lysis of a complete thrombotic occlusion, the remaining stenosis was measured in 106 patients using at least 2 angiographic projections both immediately after reperfusion, and 3 days later. The degree and development of the residual lesion were analysed with special regard to its anatomy and to the occlusion time. During the observation period, no mechanical intervention (PTCA) or bypass surgery took place. The 1st angiogram after thrombolysis revealed an average cross section stenosis of 90.5 +/- 6.2%, which decreased up to the control angiogram to 86.3 +/- 10.6% (p less than 0.05). In only 16 cases there was an improvement of 10% or more, in fact it was not relevant (less than 10%) in 66 patients, and in 24 a slight increase in residual narrowing could even be found. The decrease of eccentric (-5.5 +/- 9.2%) and concentric (-3.3 +/- 5.7%) lesions was not statistically different. Stenoses up to 5 mm of length (-5.7 +/- 7.2%), between 5 and 10 mm (-3.4 +/- 6.7%), and over 10 mm (-4.4 +/- 8.2%) again did not differ significantly. There was no linear correlation between degree of stenosis and total time of occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗
PubMed1985

[Stress tolerance of various catheters in the electrical interruption of AV conduction].

To date, only commercially available cardioverters and standard electrode catheters have been used for closed-chest ablation of the atrioventricular conduction system; the latter are primarily designed for temporary pacing and electrophysiological examinations, both procedures requiring rather low voltages and currents. Therefore, the purpose of this experimental study was to assess the electrical charge when using high energies, for instance of 400 joules. A total of 7 different catheters with 2-4 electrodes produced by various manufacturers were tested. After discharging the capacitor (400 joules; commercially available cardioversion unit) the voltage and current were measured using an oscilloscope and the electrical flash was photographed. For temporary pacing previously used and newly sterilized catheters of varying sizes and numbers of electrodes tolerated only one single charge of 400 joules, a completely new catheter only a maximum of 3 discharges. Any additional test resulted in a non directional discharge, caused by an insulation defect. A Josephson catheter (USCI) and a newly developed catheter with modified insulation and electrode material (Cordis) had a higher stability. Both tolerated at least 5 charges per electrode, and in addition the Cordis probe tolerated another 20 charges of the 2nd lead without any non directional discharges. Thus, commercially available electrode catheters are of limited electrical stability when used for closed-chest ablation of the atrioventricular conduction system. For the protection of the patient and to prevent therapeutic failure, a maximum of 3 electrical discharges are possible when using a completely new catheter. As modified catheters demonstrate (currently only available in prototype), the electrical quality could be improved.(ABSTRACT TRUNCATED AT 250 WORDS)

Bundle of His↗
PubMed1984

[Resection of the septum im hypertrophic obstructive cardiomyopathy. Long-term results in 33 patients].

Interventricular septal resection (after Morrow) was performed in 33 patients (24 males, 9 females; average age 48 [13-72] years) with hypertrophic obstructive cardiomyopathy (HOCM). Indications for operation were high resting pressure gradient, severe symptoms despite chronic and high-dosage drug treatment. One patient died on the ninth postoperative day, all others survived. Repeat cardiac catheterization was performed on 20 patients, 1-16 months postoperatively. There was a significant decrease in resting pressure gradient (mean 67 +/- 29 to 7 +/- 10 mm Hg, P less than 0.05). After an average of 30 (range 1-76) months, 25 patients were re-examined: 18 had definite improvement in their symptoms, five partial improvement and only two reported no change. At an operation risk of 3% the procedure is the treatment of choice in patients with symptoms.

Adolescent↗
PubMed1984

[Coronary vessel dilatation using guided balloon catheters. Experiences with the first 100 dilatations in stable and unstable angina pectoris].

Between April and December 1983 100 transluminal coronary dilatations in 98 patients were performed using new steerable balloon catheter systems. The primary success rate (diameter enlargement greater than 20%) overall was 87%, in stenoses of the anterior interventricular branch 88.1% (59 out of 67 interventions), in stenoses of the right coronary artery 88.9% (16 out of 18), and in circumflex branch stenoses 84.6% (11 out of 13). Within the first 50 interventions the success rate was 80%. Among the second 50 cases it was improved to 94%, mainly due to the increasing experience of the investigators. Emergency bypass operations had to be performed in two patients in whom coronary vascular occlusion had occurred. No patient died and in only one a small infarction occurred, probably due to occlusion of a side branch with an increase of creatine kinase to a maximum of 120 U/l. These figures show that steerable balloon systems clearly improve the primary success rate despite broadening of indications and diminish serious complications.

Adult↗