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Biomedical subjects

B Maisch

Publications and source records attributed to B Maisch.

At least 127 records · Page 7Linked to original sources
PubMed1998

Simplified implantation of single-lead pectoral cardioverter defibrillators using device-based testing.

Device-based testing of single-lead pectoral defibrillators (defibrillation efficacy testing without an external defibrillation system after complete implantation of the device) resulted in an adequate defibrillation threshold (< or = 20 J) in 45 of 50 study patients (90%). Mean surgical implantation time (skin to skin) was 62 +/- 29 minutes without perioperative mortality and without implantable cardioverter defibrillator infection during follow-up. Thus, device-based testing appears to be a simple and safe method to test defibrillation efficacy of single-lead pectoral defibrillators.

Adolescent↗
PubMed1998

[Artificial bradycardias due to tape-running problems of old long-term ECG records].

Artificial bradycardias due to tape-running alterations of old long-term ECG recorders were observed with increasing frequency in the last 2 years at our hospital. To document the extent of this problem, 115 consecutive 24-hour long-term ECG recordings of 10 still used tape recorders with an age of 12 +/- 4 years were examined. Analysis of the tapes with a new analysis system revealed artificial bradycardias with rates of 10 to 40/min in 22 of 115 long-term ECG recordings (19%). These artificial bradycardias were observed in 4 out of 10 examined tape recorders (40%). Three of 4 concerned recorders were 14 years old at the time of examination, and one recorder was only 5 years old. Artificial bradycardias were caused by extensive alterations of tape-running speed in all cases. Diagnostic proof of artificial bradycardias due to tape running alterations on long-term ECG are simultaneous with prolonged RR-intervals occurring increases in all ECG times including P-width. PQ-time, QRS-width and QT-duration with otherwise unchanged ECG morphology. To avoid prolonged hospital stays or therapeutic mistakes like unnecessary pacemaker implantation, especially older long-term ECG-tape recorders should be checked regularly and, if necessary, be replaced by new devices.

Artifacts↗
PubMed1998

[Angina pectoris in leiomyoma].

A 72-year-old patient presented himself with typical symptoms of coronary heart disease and was scheduled for invasive diagnostic procedures. Cardiac risk factors were smoking and arterial hypertension. The physical examination was inconspicious. In the laborchemistry a hemoglobin of 79 g/l with a mean corpuscular volume of 63 fl and a mean corpuscular hemoglobin of 20 pg was conspicuous. The serum iron was with 42 micrograms/dl in the lower norm. Transferrin, bili-rubin and lactate dehydrogenase were normal. Then in the gastrointestinal investigations he was diagnosed with a leiomyoma of the intestine that led to chronic anaemia and additionally to chest pain characteristic for angina pectoris. After the removal of the tumor and normalization of hemoglobin this patient was free from symptoms of the disease. The coronary angiography revealed a complex stenosis of the right coronary artery with collaterales and not significant stenosis both of the left coronary arteries. In patients with angina pectoris anaemia as the possible and only cause of angina ought to be verified. It is therefore necessary after normalization of hemoglobin and clarification of the cause for the anaemia to apply a test for coronary ischemia.

Aged↗
PubMed1998

[Coronary heart disease as inflammatory disease of the vascular bed? Etiology, sequela or misconception?].

In this editorial the traditional risk factors are contrasted with more recent modifications of the response to injury theory including the modified LDL-response to injury and the immunological response to injury theories. This issue of "Herz" is devoted to the missing points in the classic risk factor concepts and revisits them as well as the infectious theory with Chlamydia pneumoniae, cytomegalovirus and helicobacter pylori as well as the autoreactivity hypothesis.

Autoantibodies↗
PubMed1998

[Cytomegalovirus and herpes simplex virus in pathogenesis and progression of native arteriosclerosis and recurrent stenosis after intervention].

An increasing number of clinical and experimental studies point to a contribution of various infectious organisms like chlamydia pneumoniae or herpesviruses to atherosclerosis in man. Cytomegalovirus induces atherosclerotic lesions in animals. In vitro studies reveal functional changes of endothelial cells after infection with cytomegalovirus. Infection with this virus renders endothelial cells immunogenic for cellular and humoral immune reactions. In man a significant association of infections with herpesviruses and atherosclerosis could be established in several studies. Cytomegalovirus infection has been incriminated as an independent risk factor in restenosis after coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1998

[Lipid lowering therapy for primary prevention of coronary heart disease--pro lipid lowering therapy].

The high rate of coronary artery disease (CAD) mortality needs preventive intervention. Several studies have documented the effectiveness of LDL-cholesterol lowering in CAD primary prevention. The West of Scotland Prevention Study resulted in risk reduction by about one third through LDL-cholesterol lowering. The data indicate that specifically patients at high risk benefit from lipid reduction. High risk patients have besides high LDL-cholesterol one or more additional risk factors such as family history of premature coronary artery disease, hypertension, smoking, low HDL-cholesterol or diabetes. Therapy primarily aims at life style changes, secession of smoking and weight reduction as well as dietary changes to achieve LDL-cholesterol levels of 115-175 mg/dl (3-4.5 mmol/L), depending on the individual risk constellation. This strategy allows to reduce the number of patients needed to treat in order to prevent one CAD event (56 in isolated hypercholesterolemia) to 14-24 in high risk persons, approaching the number (n = 13) known for effective lipid lowering in secondary prevention of coronary heart disease. Given the fact that only one third of patients suffering from a myocardial is likely to survive the first year after the event, its time for physicians to identify patients at high risk for coronary artery disease. This LDL-cholesterol lowering in primary prevention is an important and successful approach in preventive medicine. The high risk strategy for coronary primary prevention has shown to be cost effective more or at least similar to the treatment of hypertension.

Cholesterol, LDL↗
PubMed1998

Programmed ventricular stimulation for arrhythmia risk prediction in patients with idiopathic dilated cardiomyopathy and nonsustained ventricular tachycardia.

OBJECTIVES: This study investigated the role of programmed ventricular stimulation (PVS) for arrhythmia risk prediction in patients with idiopathic dilated cardiomyopathy (IDC) and spontaneous nonsustained ventricular tachycardia (VT). BACKGROUND: Nonsustained VT in patients with IDC has been associated with a high incidence of sudden cardiac death. METHODS: Over the course of 4 years, 34 patients with IDC, a left ventricular (LV) ejection fraction < or = 35%, and spontaneous nonsustained VT underwent PVS. All patients were prospectively followed for 24+/-13 months. RESULTS: Sustained ventricular arrhythmias were induced in 13 patients (38%). Sustained monomorphic VT was induced in three patients (9%), and polymorphic VT or ventricular fibrillation (VF) in another 10 patients (29%). No sustained ventricular arrhythmia could be induced in 21 study patients (62%). Prophylactic implantation of third-generation defibrillators (ICDs) with electrogram storage capability was performed in all 13 patients with inducible sustained VT or VF, and in nine of 21 patients (43%) without inducible sustained VT or VF. There were no significant differences between the additional use of amiodarone, d,I-sotalol, and beta-blocker therapy during follow-up in patients with and without inducible VT or VF. During 24+/-13 months of follow-up, arrhythmic events were observed in nine patients (26%) including sudden cardiac deaths in two patients and ICD shocks for rapid VT or VF in seven patients. Arrhythmic events during follow-up occurred in four of 13 patients with inducible ventricular arrhythmias compared with five of 21 patients without inducible ventricular arrhythmias at PVS (31% vs. 24%, p=NS). CONCLUSION: PVS does not appear to be helpful for arrhythmia risk stratification in patients with IDC, a left ventricular ejection fraction < or =35%, and spontaneous nonsustained VT. Due to the limited number of patients, however, the power of this study is too small to exclude moderately large differences in outcome between patients with IDC with and without inducible VT or VF.

Adolescent↗
PubMed1998

Failure of third-generation implantable cardioverter defibrillators to abort shock therapy for nonsustained ventricular tachycardia due to shortcomings of the VF confirmation algorithm.

Unnecessary shocks by ICDs for rhythms other than sustained VT or VF have been described as the most frequent adverse event in ICD patients. To avoid unnecessary shocks for self-terminating arrhythmias, the third-generation Jewel PCD defibrillators 7202, 7219, and 7220 Plus use a specially designed VF confirmation algorithm after charge end. The purpose of this study was to determine the ability of this VF confirmation algorithm to recognize nonsustained VT, and to analyze the reasons for failure of the PCD device to abort shock therapy for nonsustained VT despite use of this VF confirmation algorithm. Analysis of stored electrograms of electrical events triggering high voltage capacitor charging in the programmed VF zone of the device showed 36 spontaneous episodes of nonsustained VT (227 +/- 21 beats/min) during 18 +/- 7 months follow-up in 15 patients who had a Jewel PCD implanted at our hospital. Intracardiac electrogram recordings and simultaneously retrieved marker channels demonstrated that the ICD shock was appropriately aborted according to the VF confirmation algorithm in 24 (67%) of 36 episodes of nonsustained VT. Twelve episodes (33%) of nonsustained VT, however, were followed by spontaneous ICD shock in 6 (40%) of the 15 study patients. The only reason for all 12 shocks for sustained VT was the inability of the device to recognize the absence of VT after charge end due to shortcomings of the VF confirmation algorithm: 11 of the 12 shocks for nonsustained VT were triggered by the occurrence of paced beats during the VF confirmation period and 1 shock for nonsustained VT was triggered by the occurrence of 2 premature beats after charge end. Thus, better VF confirmation algorithms need to be incorporated in future PCD devices to avoid unnecessary shocks for nonsustained VT.

Defibrillators, Implantable↗
PubMed1998

Interactions between pacemakers and security systems.

Electromagnetic fields arising from a variety of different sources have been shown to interfere with normal pacemaker function. This study evaluated the possible interactions between two modern security systems and different pacemaker types. Fifty-three patients (27 single chamber pacemakers, 25 dual chamber pacemakers) have been tested routinely for their pacemaker function. Thirty-eight patients presented with unipolar sensing and 15 with bipolar sensing. The patients were asked to walk through an installed security system, an antitheft device, and electromagnetic access device with different field strengths while a six-channel ECG monitored the patients. The pacemaker systems were first measured in their basic programmed modes, then the intervention frequency was changed to 100/min and, thereafter, the maximum sensitivity without T wave oversensing was added. In the security system with the highest field strength (2,700 mA/m), a pacemaker malfunction could be observed in 13% of the monitored patients. In one case, a pacemaker (VVIR) switched to ventricular safety pacing (VOO mode). In the security system with the lower field strength (1,600 mA/m) we found a pacemaker malfunction in 4% of the tested patients. In the antitheft device (50 mA/m), in the electromagnetic access device (300 mA/m), and in pacemaker systems with bipolar sensing, none of these dysfunctions were observed. Phantom programming as described previously did not occur in any of the systems. Persons who are often in the vicinity of security systems should be equipped with a bipolar pacemaker system. Our findings indicate that patients with pacemakers should avoid contact with security systems.

Adult↗
PubMed1998

Heart rate variability during head-up tilt testing in patients with suspected neurally mediated syncope.

The relation between heart rate variability (HRV) and outcome of head-up tilt testing (HUT) in patients with neurally mediated syncope (NMS) was studied in 30 patients with presumed NMS (33 +/- 13 years) and in 11 age-matched controls. After 15 minutes of baseline supine observation, patients were tilted to 60 degrees for 45 minutes or until syncope occurred. HRV parameters included RR intervals, standard deviation of normal-to-normal RR intervals (SDNN), and root mean square successive differences (RMSSD). HRV analysis was performed during 5-minute intervals in the supine position immediately after onset of HUT and before syncope or after 30-35 minutes of tilt in patients without syncope. Syncope occurred after a mean tilt duration of 32 minutes in 14 (47%) of 30 patients with presumed NMS, whereas all controls had an uneventful HUT. In the supine position, RR intervals and RMSSD were comparable among HUT-positive patients, HUT-negative patients, and controls (RR intervals: 799 +/- 92, 854 +/- 137, and 818 +/- 128 ms, P = NS; RMSSD: 43 +/- 40, 36 +/- 34, and 53 +/- 42 ms, P = NS). Baseline SDNN was also comparable in HUT-positive patients versus HUT-negative patients with presumed NMS (50 +/- 26 vs 52 +/- 20 ms, P = NS). Within 5 minutes preceding syncope or after 30-35 minutes of tilt, RR intervals and RMSSD were shorter in HUT-positive patients compared to HUT-negative patients, or to controls (RR intervals: 606 +/- 86 vs 710 +/- 117 and 739 +/- 123 ms, P < 0.05; RMSSD: 12 +/- 5 vs 23 +/- 19 and 40 +/- 32 ms, P < 0.05). Thus, HRV analysis in the baseline supine position was not a predictor of HUT outcome in patients with suspected NMS. Syncope during HUT seemed to be preceded by increased sympathetic activity manifested by an increase in heart rate and by a decreased parasympathetic tone manifested by a decrease in RMSSD measured for 5 minutes before the event, in comparison with HUT-negative patients and with controls.

Adult↗
PubMed1998

Baroreflex sensitivity and heart rate variability in coronary disease compared to dilated cardiomyopathy.

This study was designed to compare baroreceptor sensitivity and heart rate variability as measures of cardiac autonomic tone in patients with coronary disease (CAD, n = 49) and idiopathic dilated cardiomyopathy (IDC, n = 130). Time domain heart rate variability, including SDNN, SDANN, and pNN50, was determined during 24-hour Holter ECG. Baroreflex sensitivity was analyzed nonivasively using the phenylephrine method. Baroreflex sensitivity and heart rate variability were comparable between patients with CAD versus IDC (baroreflex sensitivity: 6.1 +/- 3 vs 6.9 +/- 5 ms/mmHg; SDNN: 97 +/- 40 vs 114 +/- 41 ms; SDANN: 83 +/- 33 vs 99 +/- 41 ms; pNN50: 3.9 +/- 4 vs 9.6 +/- 13 ms, P = NS for all comparisons). Likewise, a subgroup analysis of patients with a left ventricular ejection fraction (LVEF) < or = 30% showed no significant difference in baroreceptor sensitivity and heart rate variability between IDC and CAD patients. Patients with CAD and an LVEF > 30% had a decreased heart rate variability but not a decreased baroreflex sensitivity compared to patients with IDC and LVEF > 30% (baroreflex sensitivity: 6.4 +/- 4 vs 8.3 +/- 6 ms/mmHg, P = NS; SDNN: 98 +/- 19 vs 128 +/- 42 ms, P < 0.05; SDANN: 86 +/- 21 vs 112 +/- 43 ms, P < 0.05; pNN50: 4.2 +/- 3 vs 12.3 +/- 8 ms, P < 0.05). Patients with a markedly depressed LVEF show comparable alterations in cardiac autonomic tone whether they have CAD or IDC. Patients with CAD and preserved LV function, however, have a decreased heart rate variability compared to patients with IDC and preserved LV function. The prognostic significance of these findings will be determined prospectively in a large patient cohort at our institution.

Baroreflex↗
PubMed1998

Noninvasive arrhythmia risk stratification in idiopathic dilated cardiomyopathy: design and first results of the Marburg Cardiomyopathy Study.

The Marburg Cardiomyopathy Study (MACAS) is a prospective, observational study designed to determine the value of the following potential noninvasive arrhythmia risk predictors in at least 200 patients with idiopathic dilated cardiomyopathy (IDC) over a 5-year follow-up period: NYHA-class, left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter, left bundle branch block and atrial fibrillation on ECG, QT/JT dispersion on 12-lead ECG, signal-averaged ECG, ventricular arrhythmias and heart rate variability (HRV) on 24-hour Holter ECG, baroreflex sensitivity, and microvolt T wave alternans during exercise. This article describes the findings among the first 159 patients with IDCs enrolled in MACAS until May 1998 (40 women, 119 men; age: 49 +/- 12 years; LVEF: 32 +/- 10%). Twenty-nine patients (18%) had atrial fibrillation and 130 patients (82%) were in sinus rhythm. Patients with sinus rhythm were further stratified according to LVEF < 30% (n = 54) versus LVEF > or = 30% (n = 76). Compared to patients with LVEF > or = 30%, patients with LVEF < 30% more often had left bundle branch block (43% vs 25%, P < 0.05), nonsustained VT (44% vs 22%, P < 0.05), decreased HRV (SDNN: 95 +/- 39 vs 128 +/- 42 ms, P < 0.01), decreased baroreflex sensitivity (5.6 +/- 4 vs 8.3 +/- 6 ms/mmHg, P < 0.01), and T wave alternans (59% vs 37%, P < 0.05). The prognostic significance of these findings will be determined by multivariate Cox analysis at the end of a 5-year follow-up. Primary endpoints in MACAS are overall mortality and arrhythmic events (i.e., sustained VT or VF, or sudden cardiac death).

Arrhythmias, Cardiac↗
PubMed1997

Identification of mitochondrial antigens recognized by antibodies in sera of patients with idiopathic dilated cardiomyopathy by two-dimensional gel electrophoresis and protein sequencing.

Antimitochondrial antibodies in sera of patients with idiopathic dilated cardiomyopathy (IDC) have been described previously, but the corresponding antigens have not been analyzed systematically. We therefore used both 1-dimensional and high-resolution 2-dimensional gel electrophoresis followed by immunoblotting and N-terminal amino acid sequencing to identify the relevant mitochondrial antigens, which are recognized by serum antibodies. Sera were obtained from patients with IDC (n = 75) and healthy controls (n = 182). For detection of antimitochondrial antibodies the mitochondrial antigen fraction, consisting of submitochondrial particles isolated from a bovine heart, was separated on SDS-PAGE and all sera were examined by immunoblot analysis. For further characterization of the mitochondrial epitopes the antigen fraction was separated in the first dimension according to isoelectric points using isoelectric focusing followed by gel electrophoresis. Proteins recognized by serum antibodies in 2-dimensional immunoblots were analyzed by N-terminal amino acid sequencing. In 1-dimensional immunoblot analysis, 51% of patients with IDC and 34% of controls contained serum antibodies reacting with mitochondrial protein bands with molecular weights of about 30, 43, 60, and preferentially 50 to 55 and 70 to 75 kD (p <0.01). We identified a 75-kD subunit of nicotinamide-adenine dinucleotide dehydrogenase (17% in IDC patients vs 5% in controls, p <0.05) and 2 core proteins of ubiquinol-cytochrome-c reductase (core P1: 39% in IDC patients vs 15% in controls, p <0.05; core P2: 20% in IDC patients vs 10% in controls, p <0.1), both enzymes of the respiratory chain, as are most relevant mitochondrial antigens. Furthermore, serum antibodies of patients with IDC were directed against lipoamide-dehydrogenase (15% vs 10% in controls) and a subunit of pyruvate-dehydrogenase (9% vs 3% in controls). Because these antigens play an important role in energy metabolism, the respective antibodies can be more than merely diagnostic markers of cell damage. To attribute them also to pathogenetic relevance appears to be a most attractive but still speculative hypothesis.

Adult↗
PubMed1997

Prognostic value of bisoprolol-induced hemodynamic effects in heart failure during the Cardiac Insufficiency BIsoprolol Study (CIBIS).

BACKGROUND: To further evaluate the mechanism of beta-blocker-induced benefits in heart failure, the relationships between bisoprolol-induced hemodynamic effects and survival were studied during the Cardiac Insufficiency BIsoprolol Study (CIBIS). METHODS AND RESULTS: In 557 patients studied, bisoprolol significantly reduced heart rate (-16.3+/-15.3 versus -1.6+/-13.4 bpm, respectively; P<.001) compared with placebo at 2 months after inclusion in the study. Heart rate change over time had the highest predictive value for survival (P<.01). Left ventricular fractional shortening (LVFS) significantly increased in the bisoprolol group compared with the placebo group 5 months after inclusion (+0.04+/-0.06 versus -0.001+/-0.05, respectively; P<.001; n=160). LVFS change over time was also significantly correlated with further survival (P<.02 by Cox analysis). Using a nonparametric approach, we demonstrated a significant interaction between study treatment group and LVFS over time. Patients who demonstrated improvement of LVFS over time (82% and 51% of patients in the bisoprolol and the placebo groups, respectively; P<.02) were at lower risk, but the hazard did not further decrease with a further increase of fractional shortening, and there was no significant difference between study treatment groups. Finally, it could be demonstrated that each of the three factors (heart rate change over time, LVFS change over time, and bisoprolol treatment) made a specific contribution to mortality rate. CONCLUSIONS: Preservation of left ventricular function appears to play a key role in the bisoprolol-induced beneficial effects on prognosis in heart failure. Short-term beta-blocker-induced cardiac effects could provide a means to identify those patients who will experience improved survival over the long term.

Adrenergic beta-Antagonists↗
PubMed1997

Effect of amiodarone on QT dispersion in the 12-lead standard electrocardiogram and its significance for subsequent arrhythmic events.

BACKGROUND AND HYPOTHESIS: QT dispersion, measured as interlead variability of QT intervals in the surface electrocardiogram, has been demonstrated to provide an indirect measurement of the inhomogeneity of myocardial repolarization. The purpose of the present study was twofold: (1) to analyze the effect of amiodarone on QT dispersion measured in the 12-lead standard ECG, and (2) to examine the association between QT dispersion on amiodarone and subsequent arrhythmic events. METHODS: To determine the effect of amiodarone on QT dispersion and its clinical significance for subsequent arrhythmic events, QT dispersion was measured in the 12-lead standard electrocardiogram (ECG) in 52 patients before and after administration of empiric amiodarone for ventricular tachyarrhythmias. RESULTS: QT intervals increased from 401 +/- 44 ms before amiodarone to 442 +/- 53 ms after amiodarone therapy, and rate corrected QT intervals (QTc) increased from 452 +/- 43 ms to 477 +/- 37 ms, respectively (p < 0.01). QT dispersion, QTc dispersion, and adjusted QTc dispersion, which take account of the number of leads measured, were not significantly different before and after initiation of amiodarone therapy (58 +/- 24 ms vs. 61 +/- 26 ms, 68 +/- 29 vs. 66 +/- 26 ms, and 22 +/- 8 vs. 22 +/- 8 ms, respectively, p = NS). During 31 +/- 25 months follow-up after initiation of amiodarone therapy, arrhythmic events defined as sustained ventricular tachycardia, ventricular fibrillation, or sudden death occurred in 11 of 52 study patients (21%). QT dispersion, QTc dispersion, and adjusted QTc dispersion on amiodarone were not different between patients with and without arrhythmic events during follow-up (65 +/- 14 vs. 59 +/- 29 ms, 73 +/- 15 vs. 64 +/- 28 ms, and 25 +/- 6 vs. 21 +/- 8 ms, respectively, p = NS). CONCLUSIONS: We conclude that (1) amiodarone increases QT intervals and QTc intervals during sinus rhythm but does not significantly change measures of QT dispersion; and (2) QT dispersion measured in the 12-lead standard ECG after initiation of amiodarone therapy does not appear to be a useful marker for subsequent arrhythmic events.

Amiodarone↗
PubMed1997

Autoantibodies in sera of patients with myocarditis: characterization of the corresponding proteins by isoelectric focusing and N-terminal sequence analysis.

In myocarditis an antigen-specific immune response to cardiac epitopes has been demonstrated by several investigators. In 54 patients with histologically proven myocarditis, autoantibodies to cardiac tissue were observed in 73% of patients utilizing the indirect immunofluorescence test with human myocardium and adult heterologous cardiocytes. By immunoblot, 44% of sera from patients reacted with cardiac tissue. These antibodies were directed preferentially against proteins with the molecular weight of 43 up to 67 kDa. Three particular proteins were identified by the use of two-dimensional immunoblot and further characterized by amino acid sequence analysis. To characterize the epitopes recognized by the autoantibodies isoelectric focusing followed by SDS-PAGE was used to separate the complex mixture of proteins from human heart. Immunoblot analysis of antigens revealed proteins ranging from a size of 30-67 kDa at isoelectric points of 6.5-8.5 to be of particular interest. Five of these proteins have now been analyzed by N-terminal amino acid sequencing (Edman degradation). One was found to be creatine kinase and one was identified as a yet unknown protein. Three proteins were N-terminally blocked and were investigated further by enzymatical digestion, followed by separation of the usually complex peptide mixtures on HPLC. One of the peptides was found to be dihydrolipoamide dehydrogenase, a membrane enzyme, and one was identified as a sarcomere specific creatine kinase. Because these proteins are intracullularly located enzymes, their pathogenetic role as antigens for the autoantibodies remains to be elucidated further.

Adult↗