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Biomedical subjects

M Aschermann

Publications and source records attributed to M Aschermann.

At least 19 recordsLinked to original sources

Evaluation of body surface potential mapping changes after successful percutaneous transluminal coronary angioplasty.

OBJECTIVE: To assess the progress of chronic myocardial ischemia after successful percutaneous transluminal coronary angioplasty (PTCA) using body surface potential mapping (BSPM). DESIGN: For BSPM analysis the following kinds of maps were used: isopotential repolarization maps corresponding to 70% of ST-T interval's duration and isointegral maps corresponding to 0% to 20% of ST-T duration. BSPM measurements were taken before the PTCA and usually one to six days after this intervention. In 17 patients BSPM was carried out within two days after PTCA. Eleven to 14 BSPM examinations were usually carried out during six months of follow-up. Control coronary angiography was performed after six months in all but three patients. RESULTS: Substantial focal decrease of positive potential in repolarization caused by myocardial ischemia recovered gradually after successful PTCA. This appeared to be caused by the regression of "hibernating myocardium'. An increase of positive potential was statistically significant (P < 0.01) after the fifth week of PTCA intervention. There was a positive correlation between BSPM findings and chest discomfort of patients after PTCA. Chronic myocardial ischemia could be observed on isopotential and/or isointegral maps examined before the PTCA in 21 of 25 cases (sensitivity 84%).

Adult

Assessment of coronary artery disease by radionuclide cineangiography. History, current applications, and new directions.

In recent years, the utility of radionuclide cineangiography in prognostication has made it a mainstay of management decision making. With evolution of therapeutic modalities and concomitant alteration in management strategies, however, the technique and its application are undergoing parallel evolution to optimize response to current needs. Thus, in addition to standard planar rest and exercise assessment of left ventricular function, newer approaches are involving combined perfusion and function assessment, application of pharmacological stress to permit technically advantageous variations in imaging protocols, and application of SPECT technology in collecting blood pool data for tomographic display and analysis.

Acute Disease

Repolarization pattern of body surface potential maps (BSPM) in coronary artery disease.

The aim of our study was to assess if repolarization BSPM were able to evaluate the site, size and severity of chronic ischaemic damages and if BSPM were in any way related to the regional attenuation of myocardial contractility or to the site of coronary artery occlusion. The BSPM were obtained from 69 patients suffering from coronary artery disease confirmed by coronarography, with at least 75% occlusion of at least one coronary artery. According to the site of single occlusion, or a combination of the sites of multiple occlusions, the patients were divided into 6 subgroups. According to the region of attenuated kinetics the same group of 69 patients was also divided into other 6 subgroups. As in the polarity distribution there was only a limited accordance in BSPM with coronarographic and echocardiographic findings, in the localization of extreme values there were very important specific changes in patients with normal kinetics as determined by both contrast ventriculography and two-dimensional echocardiography. The repolarization maps can distinguish patients with coronary artery disease and normal echocardiography from healthy persons with a sensitivity of 85% and a specificity of 65% in the case of the isoareal map from the ST segment (RIAM) and 90% and 85%, respectively, in the case of the isointegral map from the whole ST-T segments (RIIM).

Adult

[Indications for cornary angiography].

This is a summary of relative indications for the selection of patients for coronary angiography. Coronary angiography is an important part of clinical evaluation of patients with ischemic heart disease, valve heart disease, cardiomyopathies. Main groups of patients with ischemic heart disease are: angina pectoris after low levels of effort despite a good medical treatment, unstable angina, variant angina, angina with high risk of acute coronary syndromes from noninvasive exercise testing. In addition coronary angiography is indicated in patients with unexplained congestive heart failure, in patients with acute myocardial infarction with mechanical complication requiring cardiac surgery such as hemodynamically important mitral insufficiency, large ventricular septal defect or a large aneurysm leading to heart failure. Also in patients with sudden death syndrome unrelated to acute myocardial infarction. Patients with silent ischemia with known coronary artery disease and with known risk factors should undergo coronary angiography. Indication for coronary angiography is also in patients with hemodynamically important valvular, subvalvular or supravalvular heart disease in whom corrective surgery is contemplated.

Coronary Angiography

[Comparison of the effects and safety of atenolol and nifedipine in the treatment of angina pectoris].

The effects of atenolol (100 mg/day) and nifedipine (60 mg/day) on angina symptoms and exercise tolerance were compared in an open, randomized study. Twelve-week treatment period was compared with two weeks of placebo treatment in 51 patients with chronic stable angina pectoris. Mean frequency of angina attacks decreased significantly from 8.3 to 1.6 attacks per week after atenolol treatment (p < or = 0.05). Both drugs increased exercise tolerance to development of signs of ischemia on electrocardiogram (p < or = 0.05) and increased maximal exercise tolerance as well (p < or = 0.05). Mean ST segment depressions at peak exercise were significantly decreased after treatment with atenolol and nifedipine (p < or = 0.05). Both drugs also increased total exercise capacity in comparison with placebo period, stated as 100%:192% after atenolol and to 191% after nifedipine. No significant changes of heart rate and blood pressure were noted during treatment period. Twelve patients did not finished study, two of them suffered myocardial infarction with death in one of them (atenolol group, other one nifedipine group). Thus, atenolol in one daily dose is as effective as nifedipine in chronic stable angina patients when administered as single therapy.

Adult

[Uncommon indications for coronary angioplasty].

During the period between March 16, 1989 and October 7, 1992 at the Second Medical Clinic of the First Medical Faculty, Charles University Prague a total of 173 coronary angioplasties were performed. With expanding experience and greater availability of controllable super thin conductors and balloon catheters with a small profile, gradually the indication criteria of coronary angioplasty were extended. In 93.1% of patients simple balloon dilatation of a significant stenosis of the coronary arteries was performed and in 6.9% before dilatation in addition an attempt of recanalization of a chronic occlusion of the coronary artery was made. In 74% of the patients one coronary stenosis was dilated, in 16.7% several stenoses, in 1.2% of the patients a covered stenosis of the trunk of the left coronary was dilated and in the same number an aortocoronary bypass was performed. Even in the group of patients where only one coronary stenosis was dilated the type B coronary affection according to the classification ACC/AHA predominated and the same applied to the entire group of patients.

Angioplasty, Balloon, Coronary

[Visual and quantitative evaluation of coronarography findings in patients with percutaneous transluminal coronary angiography].

To compare the accuracy of visual and quantitative estimation of coronary angiograms we studied 114 coronary artery stenosis in 62 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) before and after dilatation. Before PTCA the visual estimate of the mean percentage of stenosis severity was 77.2% (SD + 10.1%) which was significantly higher than the value, obtained with quantitative angiography -71.8% (SD 8.8%) (p < 0.01). Immediately after PTCA the visual estimate of the mean residual stenosis was 18.3% (SD + 10.4%), which was significantly lower, than value from quantitative angiography -23.3% (SD + 10.6%) (p < 0.01). The visual estimation of coronary artery stenosis provides quick and inexpensive data which are not accurate in comparison with data from quantitative angiography. Comparison of the visual and quantitative estimates of coronary angiography before PTCA showed visual overestimation of the severity of stenosis. Immediately after PTCA most visual estimates showed an underestimation of the lesion. Thus, the only visual interpretation of the severity of the coronary artery stenosis before and after PTCA leads to optimistic assessment of primary success of the procedure. Quantitative angiography provides more accurate data, but has some limitations, discussed in the paper.

Angioplasty, Balloon, Coronary

[Stress echocardiography in the selection of patients for coronarography].

Exercise echocardiography has in recent years become the best non-invasive method for detection of IHD. The authors made an investigation with the objective to test the feasibility of exercise echocardiography, under our technically imperfect but generally available conditions, for the selection of patients for coronarography. In 44 consecutive patients (30 men, 14 women, mean age 50 years) the authors used before planned coronarography exercise echocardiography and 24-hour monitoring of ECG according to Holter with evaluation of ST segments. The results of all three non-invasive methods were compared with the coronarographic findings. The criterium of positivity of coronarographies was 75% stenosis. Such a stenosis is an unequivocal indication for cardiosurgery or percutaneous angioplasty. On comparison of results of non-invasive examination methods with coronarographic findings the best indicators as regards reliability were obtained with exercise echocardiography. Its sensitivity was 71%, specificity 69%, positive predictive value 77% and negative predictive value 61%. The sensitivity of exercise echocardiography increased, depending on the number of affected arteries (50, 71 and 100%). On isolated evaluation of findings in individual main coronary arteries the sensitivity was highest in the area supplied from the ramus interventricularis anterior (67%), the specificity was 77%. For the ramus circumflexus the sensitivity was 50% and the specificity 96%. For the right coronary artery the sensitivity was 25% and the specificity 96%. The sensitivity of exercise ECG (44%) was even lower than Holter sensitivity (57%). The specificity, on the other hand, was lower in Holter (47%) than in exercise ECG (61%). Electrocardiographic methods were not, contrary to echocardiography, usable for evaluation fo the extent of damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

[Occurrence and prognosis of silent ischemia].

The authors assessed in a group of 486 asymptomatic middle-aged men (50-60 years) the prevalence of silent myocardial ischaemia. For screening they used the exercise test on a bicycle ergometer and in men with a positive test the presence of silent ischaemia was confirmed by perfusion scintigraphy with thallium-201 or by. The prevalence of silent ischaemia was compared with the incidence of angina angiography, myocardial infarction and sudden deaths in a similar group of 1419 men followed up for 10 years in the same department. In patients with a confirmed diagnosis of silent ischaemia the prognosis was monitored, as well as possible clinical manifestations of IHD, in the course of 4-7 years of the investigation. The presence of silent ischaemia was confirmed in 32 men, i.e. 6.6%. As compared with other forms of IHD, silent ischaemia was detected almost equally frequently as myocardial infarction and as compared with angina pectoris it was observed twice as frequently. In the course of the investigation period two patients were subjected to a revascularization (CABC or PTCA). In the remaining group of 30 patients who underwent conservative treatment two patients died (sudden deaths), seven developed angina and five myocardial infarctions (incl. one clinically silent).

Adult

[Early results and complications of percutaneous transluminal coronary angioplasty].

The authors summarize the early results of coronary angioplasty in 234 patients, with special emphasis on complications. The follow-up group included 182 men (77.8%) and 52 women (22.2%) with a mean age of 52 (34-74) years. Single-artery involvement prevailed (216 patients, 92.3%); multiple artery involvement was diagnosed in 18 patients (7.7%). Overall, dilatation was performed in 273 stenoses; of this number, 213 procedures were successful (78.0%). The primary success rate in the whole group was 76.9% (180/234). The highest success rates were attained in concentric stenoses (88.8%), the lowest ones in complete occlusions (53.8%). Complications were present in 36 patients (15.3%), of this number 14 patients (5.9%) developed acute arterial occlusion; the complications were less severe in 22 patients (9.4%). Of the 14 patients with acute occlusion, eight (3.5%) developed severe complications. One female patient (0.43%) died, one (0.43%) had emergency surgery, and six (2.6%) developed uncomplicated acute myocardial infarction. Perfusion was restored by multiple dilatation in four patients; arterial occlusion, with good collateral circulation, did not result in myocardial infarction in two. Other complications were less severe and had no sequelae including, most often, arterial spasm (3.4%), large dissection demonstrated by angiography (2.6%), protracted hypotension (0.8%), and ventricular fibrillation in one case (0.43%). The article also considers the factors raising the risk of severe complications of coronary angioplasty, and the potential for their prevention and treatment. Coronary angioplasty, employed in an increasing number of patients with symptomatic stenosing atherosclerosis of the coronary arteries, is an effective method successful in 85-95% of patients. The complication rate, while low, is not absolutely negligible.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

[Present possibilities of use of intravascular ultrasound examinations].

Catheter intravascular imaging is currently used as an adjunct to contrast angiography and angioscopy in peripheral and coronary arteries. At present the smallest catheters are 3.0 F (1.0 mm). Frequencies used are from 10 to 40 Mz, which allow high resolution imaging of structures close to the transducer. Mechanical and phased array systems are used, introduced either on the wire or through fine plastic catheter. More recent is the monorail system improving the flexibility and tracking of the mechanical systems. The review presents current status of catheters and diagnostic possibilities. Normal arteries have typical three layered appearance (intima, media, adventitia). Ultrasound can be reliably used to distinguish abnormal vascular segments. Atherosclerotic plaques can be subclassified on the basis of plaque composition. Thrombus is characterized by granular appearance with varying sonographic gray levels. Dissection and intimal flaps are also visualized by intravascular ultrasound. Potential utility of intravascular ultrasound in the assessment of endovascular interventions and its limitations are discussed.

Blood Vessels

[Noninvasive diagnosis of coronary spasm].

The objective of this work was to compare the sensitivity of non-invasive tests used for the diagnosis of variant angina pectoris (VAP). In a group of 38 patients with VAP the authors compare the sensitivity of the cold test (CT), hyperventilation test (HT), handgrip (HG), bicycle ergometry (BE) and a newly suggested combination of hyperventilation with HG and BE resp. The authors evaluated first the sensitivity of ST elevations which are an entirely specific sign and in particular denivelization of ST (by depression or elevation) which is a less specific sign. The sensitivity of different tests was as follows: CT 5% and 5% resp., HT 18% and 39% resp., HG 13% and 29% resp., BE 26% and 66% resp., HV+HG 37% and 63% resp., HV+BE 50% and 87% resp. Then the authors assessed the sensitivity of repeated examinations HV+HG 47% and evaluation during denivelization of ST 63%, HV+BE 66% and 89% resp. The authors evaluated moreover the sensitivity of ST elevations in patients according to the activity of the disease. Patients with at least five stenocardias per week had a higher sensitivity, as compared with patients with less frequent attacks: HV+HG 42% and 25% resp., HV+BE 60% and 33% resp. The highest sensitivity was found in a combination of HV+BE. Repetition of the test in case of a negative result increased markedly the sensitivity, a higher sensitivity was found also in patients with more frequent stenocardias.

Adult

[Significance of coronarography for therapeutic strategy in patients with ischemic heart disease].

In 100 consecutive patients where planned coronary arteriography was performed, in the majority on account of IHD, the authors analyzed retrospectively information on risk factors of IHD, medicamentous treatment and the reasons for coronarography, findings on the coronary arteries, the size and function of the left ventricle and the final choice of subsequent treatment. A significant finding on the coronary arteries (stenosis of more than 50%) was recorded in 65% of the patients, in 22% of the patients the coronarographic finding was normal, in another 7% only insignificant changes were found (stenosis of less than 50%) and in 6% of the patients on coronarography a spasm of the coronary artery was recorded. A bypass operation was performed in 15% of the patients subjected to coronarography, in another 6% successful PTCA was performed, i.e. a total of 21% patients were revascularized. These results are compared with those of other departments in Czechoslovakia and abroad and the causes of revealed differences are discussed. Finally the authors emphasize the necessity of stratification of IHD patients according to risk and the selection of suitable candidates of coronarography and subsequent possible revascularization of the heart muscle according to accepted criteria for indication.

Adult

[Changes in the extent of residual stenosis in coronary arteries after thrombolytic therapy in acute myocardial infarct].

The extent of residual coronary artery stenosis has been studied immediately after thrombolysis using streptokinase and after 3.-4. weeks follow-up in 28 patients with acute myocardial infarction. Thrombolysis was successful in 19 patients (67.9%). In these patients the extent of residual coronary artery stenosis (percentage narrowing of diameter) decreased from 73.4% to 66.1% (p less than 0.05). The residual stenosis did not change in 5 patients (26.3%), increased in 1 patient (5.2%), 3 patients suffered reocclusion of the vessel (15.8%). Marked improvement was found in 10 patients (52.6%). It means despite significant regression a coronary artery stenosis of more than 50% of diameter persisted in 47.4% of patients with successful thrombolysis 3.-4. weeks after the infarction. The factors which could be involved in regression of residual stenosis of vessel related to myocardial infarction are discussed.

Coronary Angiography

[Relation of angina pectoris before myocardial infarct to coronarographic findings after thrombolytic therapy].

Patients with significant residual stenosis after thrombolytic therapy during acute myocardial infarction have higher risk of reinfarction, periinfarction ischemia and sudden death. Early revascularisation can prevent such complications. To find out patients who are at increased risk and are candidates for early angiography 74 patients undergoing angiography after thrombolytic therapy were reviewed. Significant residual stenosis (greater than or equal to 50% diameter reduction) of infarct related artery was present in 85%, high grade stenosis (greater than or equal to 75%) in 58% of patients respectively. The group of patients with preinfarction angina (Canadian class I to IV. 24 hours before infarction) had higher mean residual stenosis than patients without angina (76.5% vs 64%). There was significant difference in presence of preinfarction angina in patients with high grade stenosis and without high grade stenosis (79% and 21% respectively). Thus preinfarction angina can be used to identify patients with higher risk of reocclusion after thrombolytic therapy during acute myocardial infarction. Early coronary angiography and revascularisation can prevent serious complications in these patients.

Angina Pectoris

Randomized double-blind comparison of isosorbide dinitrate and nifedipine in variant angina pectoris.

The antianginal and anti-ischemic effect of isosorbide dinitrate (ISDN), 120 mg once daily, and nifedipine, 20 mg twice daily, both in slow-release formulations, were compared in 17 patients with variant angina pectoris in a randomized, double-blind trial. The design included a placebo run-in period and two 6-week crossover periods of active treatment. Mean frequency of angina decreased significantly from 43 attacks per week during the placebo period to 4 per week with ISDN and 8 with nifedipine (p less than 0.001). Sublingual nitroglycerin consumption decreased significantly from 37 tablets per week with placebo to 3 tablets per week with ISDN and 7 with nifedipine (p less than 0.001). Both drugs reduced the silent and symptomatic ST-segment deviations on ambulatory electrocardiographic recording and increased maximal exercise tolerance. Episodes of coronary spasm could be provoked, by hyperventilation, in all patients during the placebo phase but in no patient during therapy with either active drug. Thus, both ISDN and nifedipine, in their slow-release formulations, are effective in the treatment of variant angina pectoris.

Adult

[Restenosis after percutaneous transluminal coronary angioplasty].

Restenosis after percutaneous transluminal coronary angioplasty is a critical factor limiting the usefulness of this procedure. It has been reported to occur in 25% to 50% of patients averaging 33%. In the majority of patients it appears within 6 months after procedure. Some clinical, angiographic and procedural factors can predict higher incidence of restenosis--they are discussed in the article. Main mechanisms which result in restenosis are intimal hyperplasia and smooth muscle cellular proliferation. Exercise thallium-201 scintigraphy and coronary angiography are the best methods in diagnosis of restenosis. The prevention and the therapy of restenosis appear as a difficult problems. Successful pharmacological approach doesn't exist until now. In about 50% of patients with restenosis coronary angioplasty is repeated with the same success and restenosis rate as in the first angioplasty.

Angioplasty, Balloon, Coronary