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Biomedical subjects

H O Hirzel

Publications and source records attributed to H O Hirzel.

At least 19 recordsLinked to original sources
PubMed1996

[Cardiology 1995].

Rapid progress in the field of cardiology calls for an almost continuous update on latest developments. In particular, this is the case with respect to indications for diagnostic and therapeutic interventions. The present contribution deals with some topics in this area. The first article elaborates on the theme of which diagnostic test is indicated, under what circumstances, and for which patient. Technical improvements in the surgical practice of coronary revascularization are discussed in the light of better therapeutic results. Unsolved questions of percutaneous dilatation (PTCA) are critically reviewed in a third article. Current problems in surgical treatment of valvular heart disease are dealt with in the fourth report. Finally, the enormous progress in pacemaker medicine that has accumulated since the world-wide first implant in 1959 by A. Senning is summarized in the last contribution.

Aged↗
PubMed1995

[Acquired heart diseases and pregnancy].

Understanding of the mechanisms of cardiovascular and hemodynamic adaptation during pregnancy helps to prevent or manage complications in cardiac patients during gestation. Manifestations of coronary heart disease are exceptional during pregnancy and delivery. The same is true of disorders of the pericardium. Peripartal cardiomyopathy is a myocardial disorder of undetermined cause occurring shortly before, during or after delivery, which may take a fatal course. Hypertrophic obstructive or non-obstructive cardiomyopathy is compatible with gestation and delivery without serious complications in most cases. Rheumatic mitral stenosis was the most common cardiac disorder until the 1950s. Nowadays it is rarely seen in this country. Surgical and other interventional therapies have greatly changed the outlook in pregnant women with valvular heart disease. A highly controversial issue is heart valve replacement in young women and management of anticoagulation during pregnancy. Like any other drug therapy, anticoagulation during gestation requires careful weighing of the benefit for the mother against toxic and teratogenic effects for the fetus. In women with heart disease the management of pregnancy should start, if possible, before conception. Thorough counseling and proper planning of pregnancy and of therapeutic measures is essential in order to avoid or manage complications.

Abnormalities, Drug-Induced↗
PubMed1993

[Work load in occupations].

Fewer subjects return to work after acute myocardial infarction or a cardiac surgical procedure than one would expect from the results of their medical examinations and cardiac tests. To decide whether a patient is able to return to work, one has to assess his individual prognosis and measure his maximal physical working capacity without cardiac dysfunction. Psychological and socioeconomic aspects have also to be considered. Recommendations are presented for practical procedure in assessing the ability of a patient to return to work.

Adaptation, Psychological↗
PubMed1992

Hemodynamic performance and myosin light chain-1 expression of the hypertrophied left ventricle in aortic valve disease before and after valve replacement.

Previously, we have reported on the selective accumulation of an atrial-like myosin light chain-1 (ALC1) in different forms of human ventricular hypertrophy. The present study involves the determination of ALC1 content in a control group and in patients with aortic stenosis or insufficiency before and 56 +/- 23 months after valve replacement and compares the hemodynamic and angiographic parameters. ALC1 was quantified densitometrically after two-dimensional electrophoretic resolution of biopsy specimens from the left ventricle and was expressed in percent of total ventricular light chain-1. The mean ALC1 content was 11.2 +/- 9.2% in preoperative aortic stenosis and 4.5 +/- 1.4% in aortic insufficiency, both being significantly (p less than 0.001) higher than the control value of 0.3 +/- 0.3%. After valve replacement, mean ALC1 content was lower than before, 4.2 +/- 3.3% (p less than 0.05) in stenosis and 3.4 +/- 3.1% (p = NS) in insufficiency. Left ventricular systolic pressure yields a significant (p less than 0.01) linear correlation (r = 0.45) with the ALC1 content in all preoperative and postoperative patients. Patient group averages of ALC1 content correlate directly with left ventricular systolic and end-diastolic pressure and wall thickness (r = 0.94-0.98) and, in an exponential fashion, with peak systolic circumferential wall stress (r = 0.98) but not with muscle mass or any other parameter. The ventricular ALC1 binds to myosin in proportion to its occurrence in the myocardium. The content of the endogenous ventricular light chain-1 did not change under pathological hemodynamics. The response in expression of the ALC1 to pressure and volume overload suggests an adaptational process.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Micrococcus luteus: a rare pathogen of valve prosthesis endocarditis].

A rare case of prosthetic valve endocarditis caused by Micrococcus luteus is described and compared with the few cases reported in the literature, as well as the clinical features, microbiological profile, therapy, and prognosis of common prosthetic valve endocarditis. Micrococcus luteus is a constituent of the normal human buccal bacterial flora which forms yellowish colonies and appears as a gram-positive coccus typically arranged in tetrades. Although of low virulence, the germ may become pathogenic in patients with impaired resistance, colonizing the surface of heart valves. In contrast to staphylococci (for which it may easily be mistaken) it is usually penicillin-sensitive. However, the most promising antibiotic regimen proposed for treatment of Micrococcus luteus seems to be a combination of vancomycin, amikacin, and rifampicin. If the infection leads to severe hemodynamic alterations, however, valve replacement may become necessary similar to the situation in prosthetic valve endocarditis caused by more aggressive and highly resistant bacteria.

Aged↗
PubMed1991

[Emergency surgery for PTCA complications: tactics and results].

Incidence, risk and results of emergency coronary bypass surgery after failed percutaneous transluminal coronary angioplasty (PTCA) have been analyzed in a retrospective study. Failed PTCA has been defined as visible pathology (dissection, occlusion) of the dilated vessel associated with acute chest pain and ECG changes. From 3-1-1987 to 11-30-1990, 23 patients of 433 (5%) underwent emergency surgery for failed PTCA (19 male, 4 female, mean age 55 +/- 8 years). PTCA was performed in 16 cases of one-vessel-disease, 3 cases of two-vessel-disease and 4 cases of three-vessel-disease. All had an ejection fraction beyond 40%. 19 patients remained in stable hemodynamic condition. In average 2.1 vessels have been bypassed; in 13 cases the internal mammary artery (IMA) has been used, in 10 cases the saphenous vein (VSM) only. No early nor late death occurred. The perioperative infarction rate is 30%. Comparing the group with IMA and the group with VSM only, no difference could be found regarding the number of unstable hemodynamics, the use of catecholamines nor the perioperative infarction rate. After a mean follow-up period of 14.3 months, 21 patients are in NYHA class I, 2 in NYHA class II. Emergency coronary bypass surgery can be performed with low risk and favorable results, if the operation is timed without delay after the onset of acute chest pain and ECG changes in failed PTCA. The infarction rate is remarkably higher than in elective coronary surgery. The use of the IMA seems to be no additional risk factor.

Angioplasty, Balloon, Coronary↗
PubMed1990

[Heart center surgery in the private hospital: heart surgery in the hospital with covering physicians].

Based upon the experiences at the "Herzzentrum Hirslanden" Zurich it is demonstrated that heart surgery and invasive cardiology, including cardiac catheterization and PTCA, can readily be performed by surgeons and cardiologists in private practice at a private hospital not receiving any government funds. The needs for additional heart surgical beds in the greater area of Zurich is confirmed. Manpower needed and necessary apparative infrastructure are discussed and present activities at the "Herzzentrum Hirslanden" illustrated. Finally problems with medical insurance companies covering the cost are dealt with.

Cardiac Surgical Procedures↗
PubMed1989

Effects of ischemia, bypass surgery and past infarction on myocardial contraction, relaxation and compliance during exercise.

Abnormalities of left ventricular function during ischemia have been described in animal models and in humans. Exercise, while a physiologic means of inducing ischemia, has a complex effect on left ventricular function by itself. In addition, patients with coronary artery disease have a diversity of chronic changes in myocardial structure and function. Therefore, with use of micromanometer left ventricular pressure measurements and ventricular volumes, calculated from biplane cineangiograms, left ventricular function at rest and during exercise was studied in 57 patients. Exercise-induced ischemia produced a decrease in ejection fraction, an increase in end-systolic volume, dramatic increases in diastolic pressures and an upward shift in the diastolic pressure-volume relation. Central to these changes was abnormal myocardial contraction and relaxation, with reduced regional shortening and impaired left ventricular pressure decay. However, nonischemic areas were capable of augmented shortening, and global pressure decay did accelerate slightly. These findings demonstrate that exercise-induced adjustments in contraction and relaxation are intertwined with ischemia-related abnormalities. Exercise studies in patients after bypass surgery and in patients with scars from distant myocardial infarction were useful in clarifying confounding factors. For example, asynchrony of contraction and relaxation, and chronic changes in passive chamber properties, also compromise systolic and diastolic function during exercise. In patients with coronary artery disease without ischemia during exercise, left ventricular end-diastolic pressure, but not early diastolic pressure, increased during exercise. The increase in pressure was appropriate for a slight increase in end-diastolic volume in a ventricle with a steep pressure-volume relation. Furthermore, end-systolic volume, while maintained during exercise, was not reduced, as occurs normally.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1989

[Late potentials and ventricular arrhythmia in patients with chronic coronary heart disease].

To assess the value of late potential recordings in predicting complex ventricular arrhythmias in chronic coronary heart disease, signal-averaged ECG and 24-h Holter were performed in 101 consecutive patients following coronary arteriography. In 69 of 101 patients, non-sustained ventricular tachycardia (VT) (22 patients) or monotopic or polytopic ventricular premature beats (VPB) (47 patients) were detected. When the different patient groups (VT, VPB, no arrhythmias) were compared, the parameters defining the late potentials demonstrated broad variability. Patients with non-sustained ventricular tachycardia showed a tendency to increased late potentials, though this tendency was not significant. In patients with pathologic late potentials the predictability of non-sustained ventricular tachycardia was only 38%. - It is therefore concluded that late potentials in patients with chronic coronary heart disease are not directly linked to the extent and severity of arrhythmias recorded in the ambulatory 24-h Holter.

Action Potentials↗
PubMed1989

Determination of the ratio of pulmonary blood flow to systemic blood flow by derivation of amplitude weighted mean velocity from continuous wave Doppler spectra.

Conventional Doppler echocardiographic techniques for the estimation of blood flow ratios depend on the precise measurement of the diameters of the aorta and the pulmonary artery and the mean blood flow velocities in these vessels. A simpler and quicker method is described, based on the calculation of the systolic time integrals of the amplitude weighted mean velocities from continuous wave Doppler spectra within the great arteries. In 30 controls the mean (2 SD) ratio of pulmonary to systemic blood flow averaged 0.952 (0.085). The results of the new technique showed a good agreement with those of quantitative dye dilution and oximetry in 16 patients with intracardiac left to right shunts.

Adolescent↗
PubMed1988

[Pregnancy and delivery in a mother with Ebstein's anomaly].

Ebstein's anomaly is characterized by abnormalities both in the basal and in the free attachments of the leaflets of the tricuspid valve. Fairly frequently the developmental defect is associated with a WPW syndrome (Type B). The main obstetric problems arise from tachyarrhythmias. Since tachycardias in these patients are due to physical stress, correct planning of delivery calls for lightening of the hemodynamic burden of labor, careful analysis of the cardiac status, meticulous preparation for optimum antiarrhythmic therapy and correct timing for induction of labor. The case of a young primipara with Ebstein's anomaly is presented to typify the need for cooperation of subspecialities.

Adult↗
PubMed1987

Atrial and ventricular isomyosin composition in patients with different forms of cardiac hypertrophy.

In man, various forms of compensatory and idiopathic hypertrophic states can be differentiated by haemodynamic and angiographic parameters. They are morphologically indistinguishable with regard to muscle fibre diameter and non-muscle tissue content. They are, however, accompanied by contractile dysfunction of various degrees or even by hypercontractility. In hearts subjected to chronic increase in workload the peptide pattern of the slow ventricular myosin heavy chain (HC) type VM-3 does not change, while that of the fast atrial type HC does. In atria also the ventricular type of myosin light chain-2 (VLC-2) is occurring. In certain forms of hypertrophy we found the atrial type ALC-1 occurring in the ventricular tissue, in individual cases amounting to 30% of total LC-1, on average, 12% in dilated cardiomyopathy, 6% in pressure and 3% in volume overload and 2% in cases with reduced myocardial mass due to infarction. No such increase of ALC-1 was found in hypertrophic cardiomyopathy or in coronary heart disease without infarction. The isoform expression of myosin HC and LC is thus governed independently of one another in response to altered physiological or pathological conditions. A significant correlation of the ALC-1 content in ventricles could be established with the peak circumferential wall stress. This may imply the involvement of the LC-1 in the contractile properties of the myofibrils.

Adenosine Triphosphatases↗
PubMed1987

Early results after mitral valvuloplasty for pure mitral regurgitation.

In this study we present the results of 105 consecutive patients with pure mitral regurgitation who underwent surgical treatment. In all patients mitral regurgitation was associated with mitral valve prolapse: 54 patients underwent mitral valvuloplasty and 51 patients mitral valve replacement. Clinical assessment and echocardiography were used as follow-up criteria at one year after surgery. After mitral valvuloplasty, NYHA decreased from 2.7 +/- 0.8 to 1.1 +/- 0.7 (P less than 0.01) and workload capacity increased from 65 +/- 28% to 96 +/- 25% (P less than 0.001); left endsystolic atrial dimension and enddiastolic dimension decreased from 6.2 +/- 0.8 to 4.8 +/- 1.2 cm (P less than 0.001) and from 7.2 +/- 1.3 to 5.9 +/- 0.8 cm (P less than 0.01); ventricular contraction fraction did not change significantly. After mitral valve replacement, clinical and echocardiographic improvement was significant but less remarkable than after valvuloplasty; ventricular contraction fraction fell from 39 +/- 7% to 29 +/- 8% in contrast to patients undergoing mitral valvuloplasty in whom no significant change occurred. Complications were rare in both groups though only a minority of patients undergoing mitral valvuloplasty received anticoagulants. We conclude that mitral valvuloplasty in patients with pure mitral regurgitation when compared with the patients after mitral valve replacement.

Echocardiography↗
PubMed1985

[Percutaneous transluminal coronary angioplasty: results after a 5-year follow-up period].

In the first series of 50 patients in whom percutaneous transluminal coronary angioplasty (PTCA) was attempted, the procedure was successful in 32. 23/32 patients were followed up clinically over 62.2 +/- 5.6 (SD) months. Repeated non-invasive laboratory tests were carried out in 15/23 patients. Moreover, 11/15 patients were restudied by arteriography at the end of the follow-up period. Early recurrence of the stenosis occurred in 5/32 patients (16%) and was again successfully treated by a second PTCA in 2. 3 patients underwent surgery as requested. 22/23 (95%) remained symptom-free during the follow-up period. The results of the non-invasive laboratory tests were in close agreement with the clinical findings. Coronary arteriography performed at the end of the follow-up period revealed an excellent lasting effect of PTCA in 8/11 patients. 2 showed a slight progression of the three stenoses treated by PTCA, and in 1 patient late recurrence of the stenosis was suspected since he had been symptom-free up to 2 weeks prior to restudy. Thus, in patients who are suitable for PTCA, this treatment is of long-lasting effect and represents an excellent alternative to coronary artery bypass surgery.

Adult↗
PubMed1985

Silent myocardial ischemia: hemodynamic changes during dynamic exercise in patients with proven coronary artery disease despite absence of angina pectoris.

The hemodynamic changes during exercise occurring in 36 patients with proven coronary artery disease (10 without and 26 with previous myocardial infarction) who tolerated the stress test without angina were analyzed and compared with changes observed in a control group of 36 carefully matched patients whose exercise was limited by angina. All patients were exercised to the same extent, reaching a similar rate-pressure product at the end of the stress test (19,508 +/- 4,828 [SD] versus 19,247 +/- 4,117 beats/min X mm Hg [NS] in the study and control groups without prior infarction, and 19,665 +/- 3,950 versus 17,701 +/- 4,600 beats/min X mm Hg [NS] in the respective groups with infarction). In all groups left ventricular end-diastolic pressure increased from rest to exercise (from 18 +/- 4 to 36 +/- 11 and from 13 +/- 5 to 29 +/- 9 mm Hg, respectively, in the study and control groups without prior infarction and from 17 +/- 7 to 32 +/- 13 and from 19 +/- 7 to 36 +/- 9 mm Hg in the respective groups with prior infarction). Left ventricular ejection fraction decreased (from 59 +/- 7 to 50 +/- 15 and from 60 +/- 4 to 52 +/- 9% in the study and control groups without prior infarction and from 54 +/- 9 to 47 +/- 10 and 55 +/- 9 to 50 +/- 4% in the respective groups with prior infarction). Whereas the changes from rest to exercise were highly significant within each group, no significant differences were noted between the corresponding groups. Regional de novo hypokinesia appeared in all patients without prior infarction and in 25 and 22 patients, respectively, of the groups with prior infarction. Thus, under similar physical stress conditions, comparable hemodynamic changes indicative of ischemia are observed in patients with significant coronary artery lesions with or without previous myocardial infarction irrespective of the occurrence of angina. Therefore, angina pectoris cannot be considered a prerequisite for hemodynamically significant ischemia during exertion.

Adult↗
PubMed1985

Left ventricular systolic and diastolic function in coronary artery disease: effects of revascularization on exercise-induced ischemia.

Left ventricular systolic and diastolic function were studied before and after surgical revascularization in a group of 24 patients with stable angina who all had an excellent clinical response to surgery. With use of micromanometer left ventricular pressure measurements and ventricular volumes, calculated from biplane cineangiograms, left ventricular function at rest and during exercise before and after surgery was compared. Before surgery all patients had exercise-induced ischemia with new asynergy, a fall in ejection fraction from 57% to 49% (p less than .001), and a rise in left ventricular end-diastolic pressure from 23 to 37 mm Hg (p less than .001). Postoperative exercise resulted in no new asynergy and ejection fraction rose from 59% to 61% (p less than .05). Left ventricular end-diastolic pressure still rose from 17 to 25 mm Hg (p less than .01). Left ventricular pressure decay during exercise was greatly improved after revascularization and allowed maintenance of reduced early diastolic pressures. The early diastolic pressure nadir before surgery rose from 9 to 21 mm Hg (p less than .001); the postoperative nadir was 5 mm Hg at rest and 6 mm Hg during exercise. All patients had an upward shift in the diastolic pressure-volume relationship during preoperative exercise. After revascularization there was no upward shift in some patients and a much smaller shift in others. The postoperative increase in left ventricular end-diastolic pressure was due to increased end-diastolic volume, not altered compliance. There was an increase in mean right atrial pressure during exercise either before (6 to 11 mm Hg) or after surgery (4 to 10 mm Hg). These increases were quite variable, suggesting no consistent role of pericardial restraint during exercise. Early diastolic peak filling rate during exercise was greater after surgery (1260 vs 950 ml/sec, p less than .001). In fact, during postoperative exercise early diastolic filling rates were greater than normal, reflecting the persistence of abnormally high atrial pressures for filling. As at preoperative study, late diastolic filling during exercise was restricted after revascularization when compared with that in a control group. Postoperatively patients undergoing bypass procedures with a good clinical result showed significantly improved left ventricular diastolic and systolic function. Persistent elevation of end-diastolic and atrial pressures and other abnormalities of diastolic function may reflect chronic structural changes and need to be taken into account when evaluating patients after bypass surgery.

Adult↗
PubMed1985

Relationship between myosin isoenzyme composition, hemodynamics, and myocardial structure in various forms of human cardiac hypertrophy.

Hemodynamic and angiographic parameters, muscle fiber diameter, nonmuscle tissue content, and myosin light chain isoform composition were determined in the left ventricle of nine patients with primary (four with hypertrophic, five with dilated cardiomyopathy) and 27 patients with secondary hypertrophy (11 with aortic regurgitation, 16 with aortic stenosis), nine patients with coronary heart disease, and seven controls. In various forms of hypertrophy, a new atrial-like light chain 1 occurred in two-dimensional electrophoresis of total tissue homogenates amounting up to 29% of total light chain 1. Total light chain 1 content remained constant in all groups when related to tropomyosin. The mean content of this atrial light chain 1 was highest in dilated cardiomyopathy (12.1%), less in cases with pressure (6.4%) and volume overload (2.9%), but as low in hypertrophic cardiomyopathy (0.3%) as in controls (0.4%). In cases with coronary heart disease without prior infarction, it was lower (0.6%) than with infarction (1.9%). Its occurrence was not affected by digoxin administration. In ventricular myocardium, an atrial-like light chain 2 was never observed. Peptide patterns after limited proteolytic digestion of isolated myosin heavy chains from cases with pressure overload and hypertrophic cardiomyopathy were identical to those from controls. The content of the atrial-like light chain 1 was not correlated to either muscle fiber diameter or nonmuscle tissue content, both of which were increased in all hypertrophy groups. In individual cases, no firm correlation could be established between atrial-like light chain 1 content and various parameters of ventricular load and function. However, a significant correlation resulted when the mean values of atrial-like light chain 1 content of each disease group were related to the respective mean values of peak circumferential wall stress (r = 0.96). Thus, the shift of myosin light chain 1 isoforms in ventricle seems to characterize biochemically the hypertrophy process induced by mechanical stress.

Adult↗