Biomedical subjects
Publications and source records attributed to C Schmitt.
A different approach to transvenous implantation in a patient after tricuspid valve replacement with a mechanical prosthesis is described. To our knowledge, this is the first report in this setting, using a CPI system with a single shock electrode only.
BACKGROUND: Coronary stent placement may be an effective primary intervention in acute myocardial infarction. Recently published or reported data indicate that primary stenting may be superior to primary plain balloon angioplasty in this setting. The aim of this study was to analyze the long-term clinical and angiographic follow-up of patients treated with primary intracoronary stenting and to identify the predictive factors of an adverse outcome. METHODS: The study population was composed of 519 consecutive patients with acute myocardial infarction (43 in cardiogenic shock) and attempted primary stent implantation. Adverse clinical events such as death, recurrent infarction, and target vessel revascularization were recorded. Six-month follow-up angiography was performed in 78.2% of the eligible patients, and coronary dimensions were assessed with an automated quantitative system. RESULTS: Procedural success was achieved in 500 patients (96.3%). The incidence of reocclusion was 3.2%. Thirty-day mortality rate was 5. 4% (2.5% in patients without shock); adverse clinical events were encountered in 10.4% of the patients. Independent risk factors for an adverse outcome were longer time to treatment, Killip class, reduced left ventricular function, overlapping stents, and residual dissection. The incidence of angiographic restenosis was 30.6%. One-year survival rate was 89.0%; 86.5% of the patients did not have a myocardial infarction and 71.7% did not have any major adverse event. CONCLUSIONS: Primary intracoronary stenting in patients with acute myocardial infarction is associated with a favorable early and long-term outcome. This is the result of low reocclusion and restenosis rates achieved by stenting.
The present study was designed to evaluate the feasibility of the recording of monophasic action potentials (MAP) with fractal-coated iridium electrodes in a clinical setting. In 18 patients who underwent an electrophysiological study for various arrhythmias, we performed MAP recordings with both 1.3-mm2 and 6-mm2 tip surface area fractal-coated iridium and standard silver--silver chloride (Ag/AgCl) electrodes in the high right atrium and two ventricular positions. Amplitude and MAP duration at 90%, 50%, and 25% of repolarization were calculated during steady-state pacing at 600, 500, and 400 ms cycle lengths with extrastimuli application. Morphology comparisons of MAP signals recorded with both types of electrodes were performed by regression analysis using 5% of the repolarization segments of the MAP trajectory. Differences between MAP duration at 90%, 50%, and 25% of repolarization recorded with fractal-coated and Ag/AgCl electrodes were statistically insignificant. Amplitude values recorded with 6-mm2 tip electrodes were significantly smaller than those recorded with Ag/AgCl electrodes for all comparisons. During steady-state pacing, the correlation coefficients between Ag/AgCl and fractal-coated 1.3-mm2 and 6-mm2 tip electrodes were within the range of 0.93-0.999 and 0.87-0.999, respectively. The correlation of MAP amplitude and duration at 90%, 50%, and 25% of repolarization following the extrastimulus S2, recorded with both types of electrodes, was significantly weaker for right atrial recordings (r value range 0.78-0.92) as compared to ventricular recordings (r value range 0.92-0.99). The MAP sensing features of fractal-coated iridium and Ag/AgCl electrodes are comparable. The best results for recording of MAPs with fractal-coated electrodes can be achieved with small surface area tip electrodes.
Whether the conduction disturbances of the interatrial connections play a role in the genesis of ECG variants of atrial flutter is almost completely unknown. We present a patient with typical counterclockwise atrial flutter in whom the ablation of the coronary sinus (CS) area during ongoing atrial flutter produced significant ECG changes without alterations in the activation sequence within the right atrium (RA). This case highlights the possible role of alterations of the interatrial connections in the genesis of atypical ECG manifestations of common type atrial flutter.
Construction of three-dimensional activation maps and evaluation of ablation-created bidirectional block in the tricuspid valve-inferior vena caval (TV-IVC) isthmus in patients with atrial flutter (AF) are difficult with conventional mapping technique. In 36 patients with type I AF (25 men, 11 women; mean age 62 +/- 10.5 years) a multielectrode basket catheter (BC) was deployed in the right atrium (RA). Out of 64 BC electrodes, 56 bipolar electrograms were derived. Three-dimensional activation patterns were constructed with a software program. Stable electrograms of satisfactory quality were obtained in 49 +/- 2 electrode pairs. Capture was possible in 36 +/- 3 of bipoles. In counterclockwise AF (CCW-AF) and clockwise AF (CW-AF) episodes, cycle lengths and TV-IVC isthmus conduction times were 248 +/- 26 ms and 251 +/- 23 ms, (P = 0.74) and 105 +/- 28 ms and 106 +/- 33 ms (P = 0.92), respectively. Conduction velocity in the TV-IVC isthmus was lower than in the anterior or septal limbs of the circuit, in counterclockwise or clockwise episodes. Double potentials were recorded in 94% of patients. Three-dimensional activation patterns were delineated and displayed as isochronal maps. The reentry circuit involved the TV-IVC isthmus, septal, and anterior walls and a part of the RA roof anterior to superior vena cava. Postablation isthmus conduction was evaluated through the sequence criteria, local electrogram-based criteria, and the analysis of three-dimensional activation patterns of the paced rhythms. The complete isthmus block was associated with a significant increase of the low anterior low septal conduction interval (152 +/- 29 vs 104 +/- 32 ms, P = 0.001) and the low septal-low anterior conduction interval (150 +/- 31 vs 107 +/- 33 ms, P = 0.001). Radiofrequency ablation was successful in 32 (90%) of 36 patients. In conclusion, the current mapping system enables construction of three-dimensional activation patterns and facilitates evaluation of the postablation TV-IVC isthmus block in patients with AF.
We report two patients who had isolated atrial fibrillation in the left atrium and regular activation of the entire right atrium. Mapping of the arrhythmia was performed using a 64-electrode basket catheter that was inserted intravenously and deployed in the right and left atria. Both patients manifested a single, stable interatrial electrical connection conducting in a left-to-right direction, consistent with Bachmann's bundle location. The right and left sides of the interatrial septum were activated discordantly, each reflecting activation characteristics of the respective atria. A filtering effect at the level of interatrial septum was demonstrated by calculating the fibrillation intervals on both sides of the operative interatrial connection. It was concluded that differences in activation of the left and right surfaces of the interatrial septum and preferential use and the filtering effect of the interatrial connections play a significant role in explaining the differences in activation patterns of the left and right atria in patients with atrial fibrillation.
INTRODUCTION: Electrophysiologic remodeling is involved in the self-perpetuation of atrial fibrillation. To define whether differences in atrial electrophysiology already are present in patients with increased susceptibility for atrial fibrillation, we compared patients in sinus rhythm with and without heart failure. METHODS AND RESULTS: Atrial specimens were obtained from patients with reduced left ventricular ejection fraction (LVEF; n = 10) and normal LVEF (n = 16) who were undergoing aortocoronary bypass surgery and from donor hearts (n = 4). Enzymatically isolated atrial myocytes were investigated by whole cell, patch clamp techniques. Total outward current was significantly larger in myocytes of hearts with low LVEF than normal LVEF (19.4 +/- 1.3 vs 15.1 +/- 1.2 pA/pF at pulses to +60 mV, respectively). Analysis of inactivation time courses of different outward current components revealed that the observed current difference is due to the transient calcium-independent outward current I(to1) which is twice as large in the low LVEF group than in the normal LVEF group (9.4 +/- 0.9 vs 4.7 +/- 0.4 pA/pF at pulses to +60 mV, respectively). I(to1) recovery from inactivation was significantly more rapid in myocytes of hearts with low LVEF, and action potential plateau in these cells was significantly shorter. The results of I(to1) and action potential measurements in atrial myocytes of donor hearts were very similar to the results of patients with preserved heart function. CONCLUSION: I(to1) in human atrial myocytes of patients with reduced LVEF has an increased density and altered kinetics in sinus rhythm. These differences in outward current may explain the reduced plateau phase of action potentials.
We report the use of a novel noncontact mapping system used to perform left atrial mapping and to guide radiofrequency ablation in two patients, each with atrial fibrillation (AF) triggered by left atrial ectopy. A noncontact multielectrode probe and ablation catheter were advanced into the left atrium through a transseptal puncture or a patent foramen ovale. Isopotential mapping delineated the focal origin at the ostium of the right lower pulmonary vein in one patient and close to the ostium of the left upper pulmonary vein in the other patient. The ablation catheter was guided to the target sites using a locator signal. The foci were ablated successfully in both patients. No recurrences of AF were observed during follow-up at 4 and 6 months, respectively.
The case of a 25-year-old woman presenting with chest pain, ECG changes, and laboratory findings suggestive of myocardial infarction is reported. Cardiac catheterization showed impaired left ventricular performance but otherwise normal coronary arteries. Laboratory analyses revealed primary hypoparathyroidism, and supplementation with calcium and vitamin D(3) was initiated. There was subsequent improvement in laboratory findings as well as echocardiographically determined left ventricular performance. Thereafter, the patient remained asymptomatic. Apart from some persisting ECG repolarization disturbances, there was complete normalization of the initial changes. This case demonstrates a combination of clinical, blood biochemical, and ECG findings mimicking acute myocardial infarction.
Seven patients co-infected with hepatitis B virus (HBsAg and HBeAg carriers, quantifiable HBV DNA with the bDNA technic) and human immunodeficiency virus received a triple antiretroviral combination therapy, including lamivudine (150 mg twice a day). Hepatitis B viral load rapidly became undetectable in 6/7 patients. It remained below the level of detection in 2 subjects, after 20 and 22 months of treatment, with one of them achieving HBeAg/anti-HBe seroconversion. However, in the other 4 individuals, hepatitis B viremia increased again after 8 to 16 months of lamivudine-containing regimen. The last patient was a non-responder. The 4 relapsers developed a double mutation Leu(528) for Met(528) and Met(552) for Val(552), on hepatitis B virus polymerase, either concomitant (M8 and M16) with a hepatitis B virus DNA increase, or 2 months earlier (M10 and M12). The high frequency of hepatitis B virus resistance to lamivudine emphasizes the necessity of identifying more effective strategies, such as double combination therapies.
We report a case of endogenous aspergillus endophthalmitis. This infection occurred in a young immunocompromised boy of 6 years old. The localisation of the chorioretinitis was unusual because out of the posterior area. The evolution was favorable with recovering of the visual acuity under general treatment and intravitreous injections.
The non-contact mapping device (Ensite, Endocardial Solution) enables a simultaneous, spatial detection of the myocardial depolarization. An isopotential map is visualized in the 3D reconstruction of the cardiac chamber. The analysis of focal premature beats, of unstable arrhythmias and of macro reentry mechanisms is possible. The current article demonstrates the use of the non-contact mapping device for analysis and ablation of atrial flutter, premature beat associated atrial fibrillation and of ventricular tachycardias.
Fifty-three heroin addicts, nineteen of them methadone treated, were asked about their use of flunitrazepam. Drug abuse began after a medical prescription in 50% of cases; flunitrazepam was taken per os, but also i.v. in 19% of cases. The mean daily dose was about 20 mg/day, often associated with other psychotropic drugs, alcohol, opiates or cocaine. Attention is focused on the amnesia and increased feeling of power (11% of cases), often resulting in serious violent offenses.
Recent multicenter studies have shown that the implantable cardioverter defibrillator (ICD) is superior compared to antiarrhythmic agents after sudden cardiac death (SCD) in patients with congestive heart failure. Further ICD studies have to be performed for primary prevention of SCD in patients with heart failure. Primary prevention studies of SCD with Amiodarone or new class III agents (e.g., Dofetilide) were not able to lower cardiac mortality in these patients. How much the new method of biventricular pacing in patients with heart failure and left bundle branch block will reduce cardiac mortality has to be proven in future prospective trials.
We have previously shown that thymic CD34+ cells have a very limited myeloid differentiation capacity and differentiate in vitro mostly into CD1a+-derived but not CD14+-derived dendritic cells (DC). Herein we characterized the human neonatal thymic DC extracted from the organ in relationship with the DC generated from CD34+ cells in situ. We show that in vivo thymic DC express E cadherin, CLA, CD4, CD38, CD40, CD44, and granulocyte-macrophage colony-stimulating factor-R (GM-CSF-R; CD116) but no CD1a. According to their morphology, functions, and surface staining they could be separated into two distinct subpopulations: mature HLA-DRhi, mostly interleukin-3-R (CD123)-negative cells, associated with thymocytes, some apoptotic, and expressed myeloid and activation markers but no lymphoid markers. In contrast, immature HLA-DR+ CD123hi CD36+ cells with monocytoid morphology lacked activation and myeloid antigens but expressed lymphoid antigens. The latter express pTalpha mRNA, which is also found in CD34+ thymocytes and in blood CD123hi DC further linking this subset to lymphoid DC. However, the DC generated from CD34+ thymic progenitors under standard conditions were pTalpha-negative. Thymic lymphoid DC showed similar phenotype and cytokine production profile as blood/tonsillar lymphoid DC but responded to GM-CSF, and at variance with them produced no or little type I interferon upon infection with viruses and did not induce a strict polarization of naive T cells into TH2 cells. Their function in the thymus remains therefore to be elucidated.
Forty hospitalized patients with sudden hearing loss and tinnitus were compared to a control group (N = 28) of inpatients of an ear-nose-throat ward. They were similar in various background variables except for the kind of disorder itself. The main objective of our study was to test the hypothesis of stress as a predisposing risk factor in the development of sudden hearing loss and tinnitus. Thus, differences in life events and daily "hassles" were expected between groups, as were differences in coping styles, habitual worrying, and social support. The hypothesis of more frequent and more stressful life events and daily hassles was supported empirically. The dominant role of daily hassles, especially their stressfulness as a risk factor, was shown clearly. Those in the experimental group also reported more coping endeavors and more worrying. Social support had no discriminating function. The prospective part of the study aimed at the prediction of chronicity of sudden hearing loss and tinnitus (3 months after onset) by sociodemographic, psychological, and disease-associated variables. The strongest predictor of chronicity was the degree of well-being at the time of first assessment (soon after disease onset). Coping and a fatalistic locus of control also had some predictive power. Methodological limitations of the study are discussed.
This report concerns a 74-year-old patient who had undergone aortic valve replacement 11 years earlier. On admission, the patient complained of shortness of breath when climbing two flights of stairs; there was no history of dizziness, fainting or sensations of arrhythmias. An ECG at rest showed first-degree atrioventricular (A-V) block together with left bundle branch block (LBBB). On bicycle ergometry, there was a fall in blood pressure and in heart rate due to a second-degree (2:1) A-V block along with the LBBB. After termination of exercise, the PR interval increased further from 0.24 s to >0.3 s, together with right bundle branch block (RBBB) and 1:1 A-V conduction instead of LBBB. Finally, at a constant atrial rate of 98/min, the RBBB disappeared, LBBB recurred, again with 2:1 A-V conduction. The diagnosis was bilateral BBB together with first degree A-V block at rest and higher-degree A-V block on effort. The patient underwent pacemaker implantation and was discharged shortly thereafter free of symptoms.
RNA2 of grapevine fanleaf virus is replicated in trans by the RNA1-encoded replication machinery. Full processing of the RNA2-encoded polyprotein P2 yields protein 2A of unknown function, the movement protein 2B(MP), and the coat protein 2C(CP). Analysis of a set of deletion mutants in the P2-coding sequence revealed that protein 2A is necessary but not sufficient for RNA2 replication. In addition to the 5' and 3' noncoding sequences and the 2A-coding sequence, an additional sequence coding for 2B(MP) and/or 2C(CP) or the green fluorescent protein (GFP) is necessary for RNA2 replication. When 2A fused to GFP (2AGFP) was transiently expressed in uninfected T-BY2 protoplasts, 2AGFP appeared as punctate structures evenly distributed in the cytoplasm. However, in cells cotransfected with grapevine fanleaf virus RNAs and the 2AGFP construct, 2AGFP was predominantly found in a juxtanuclear location along with 1D(pro) and 1C(VPg), two RNA1-encoded proteins involved in RNA replication. Viral RNA replication as traced by 5-bromouridine 5' triphosphate (BrUTP) incorporation into newly synthesized RNA occurred at the same location. This colocalization is consistent with the hypothesis that 2A enables RNA2 replication through its association with the replication complex assembled from RNA1-encoded proteins.