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C Stellbrink

Publications and source records attributed to C Stellbrink.

At least 19 recordsLinked to original sources
PubMed2006

Effect of transcoronary ablation of septal hypertrophy on clinical outcome in hypertrophic obstructive cardiomyopathy associated with atrial fibrillation.

BACKGROUND: Relatively few reports on the clinical impact of atrial fibrillation (AF) in hypertrophic obstructive cardiomyopathy (HOCM) are available. The aims of our study are to report the effect of transcoronary ablation of septal hypertrophy (TASH) on clinical outcome in HOCM associated with AF and to evaluate the influence of AF on symptoms and quality of life in HOCM. PATIENT AND METHODS: In 80 consecutive patients (38 f, mean age 56 +/- 17 years) with severely symptomatic HOCM referred for interventional treatment, we analyzed the prevalence of AF based on 240 Holter ECG recordings and patients' history, retrospectively. Symptoms, quality of life, number of hospital admissions and hemodynamic performance were obtained in all patients before and after TASH. Mortality was additionally investigated by letter and telephone contact. RESULTS: The overall prevalence of AF was 29%. Paroxysmal AF was detected in 17 pts (21.3%), persistent AF in 5 pts (6.3%). Only 1 pt (1.3%) suffered from permanent AF. Symptoms due to AF were present in 52.6% of the AF patients. Quality of life score was markedly improved after TASH (15.9 +/- 3.8 vs. 20.7 +/- 3.8, p < 0.001) with no difference between sinus rhythm and atrial fibrillation. However, hospital admissions were more frequent in the AF group (0.85 +/- 1.84 vs. 0.28 +/- 0.81, p = 0.03) in 32 +/- 13 months. AF patients suffered more often from syncope before TASH (30 +/- 70% vs. 10 +/- 30%, p = 0.008). Two patients with sinus rhythm at baseline died after 32 +/- 13 months from cardiovascular cause. CONCLUSIONS: Atrial fibrillation is the major cardiac arrhythmia in severe HOCM. The majority of AF patients demonstrate AF specific symptoms. The paroxysmal type of atrial fibrillation dominates by far. Both patients with and without atrial fibrillation showed similar quality of life with marked improvement after TASH.

Atrial Fibrillation↗
PubMed2006

Long and short QT syndrome.

In the past decade molecular genetic analysis has greatly expanded our knowledge about inherited arrhythmogenic syndromes. The congenital long QT syndrome (LQTS) and the recently described short QT syndrome (SQTS), with the defining characteristic of abnormal prolongation or shortening of the QTc interval on the surface electrocardiogram, are caused by cardiac ion channel dysfunctions. These "channelopathies" show a high degree of genetic heterogeneity of the molecular pathways in terms of the relationships between genetic defects and phenotypic expression. In this brief review we summarize the current understanding of the molecular basis of long and short QT syndrome with focus on the impact of molecular genetics on the clinical management of these diseases.

Channelopathies↗
PubMed2005

[Treatment of life-threatening cardiac arrhythmias].

Tachyarrhythmias represent a frequent problem in intensive care medicine. However, considerable uncertainty prevails among physicians regarding optimal pharmacotherapy, due also to numerous negative study results on chronic antiarrhythmic therapy. Moreover, in an emergency situation, the physician faces the dilemma of treating a potentially life-threatening arrhythmia as quickly as possible while simultaneously ensuring adequate diagnostic work-up, which will be decisive for long-term therapy once the patient has survived the crisis. The differential diagnosis between supraventricular and ventricular tachycardias is primarily facilitated by knowledge of a few salient points from the patient's history and 12-lead electrocardiography. This overview presents the most important principles for treating these arrhythmias. Interventional therapy principles (overstimulation, ablation) play an increasing role in these considerations. New insights on the pathogenesis of "malignant" arrhythmias and implementation of new concepts such as defibrillation by lay responders with the automatic external defibrillator will substantially influence emergency treatment of tachyarrhythmias in the coming years.

Anti-Arrhythmia Agents↗
PubMed2005

Home Monitoring in an ICD patient with incessant ventricular tachycardia.

Due to the increasing number of patients and complexity of modern tachycardia devices, efficient therapy surveillance as offered by Home Monitoring (HM) is of increasing importance. We report of an ICD patient with incessant ventricular tachycardia, in whom immediate arrhythmia transmission by HM permitted hospitalization and change of medication without time delay.

Aged↗
PubMed2005

Brain natriuretic peptide release in cardiac surgery patients.

Brain natriuretic peptide (BNP) release is a marker of increased myocardial wall tension, which is elevated in patients with disturbed left ventricular function. As it is increasingly being used as a reliable marker for diagnosis, optimization of pharmacological treatment, and risk stratification, BNP measurement might be also relevant for patients undergoing cardiac surgery. Measured BNP levels can be used to predict postoperative complications and the risk of further cardiac events. Preoperative BNP levels support the decision for the timing of aortic valve replacement in asymptomatic severe aortic stenosis. An increase in BNP levels early predicts allograft rejection after cardiac transplantation or ineffective cardiac resynchronization therapy. Moreover, BNP levels can be used to differentiate between cardiac and non-cardiac reasons for acute dyspnea in the management of surgical patients. Finally, the application of recombinant human BNP seems to improve recovery after cardiac surgical procedures. Thus, BNP can be a helpful tool for monitoring and treating patients before, during, and after cardiac surgery to predict and improve the effectiveness of therapy and reduce hospitalization and costs.

Cardiac Surgical Procedures↗
PubMed2002

Low molecular weight heparin for prevention of thromboembolic complications in cardioversion--rationale and design of the ACE study (Anticoagulation in Cardioversion using Enoxaparin).

The modality and duration of anticoagulation before, during, and after cardioversion of atrial fibrillation--either with or without guidance by transesophageal echocardiography (TEE)--is still an unresolved issue. Intravenous infusion of unfractionated heparin until effective anticoagulation with phenprocoumon or warfarin is used as the standard therapy. However, this approach may be associated with several days of hospitalization because of the necessity for intravenous heparin administration. Moreover, there may be an increased risk of bleeding complications or, conversely, episodes of undercoagulation. Low-molecular weight heparin is an attractive alternative as it not only provide a safe and predictable level of anticoagulation with fewer side effects but can also be administered safely on an outpatient basis. In addition, no anticoagulation monitoring is needed. The ACE study (Anticoagulation in Cardioversion using Enoxaparin) is a randomized, prospective, open-label multicenter trial comparing the safety and efficacy of subcutaneous enoxaparin with intravenous heparin/oral phenprocoumon before and after cardioversion (stratified to TEE guidance or no TEE guidance). This article presents the rationale, design and status of the ACE study.

Administration, Oral↗
PubMed2002

Steroid-eluting and fractally coated electrodes in children with high pacing thresholds.

High pacing thresholds in epicardially implanted leads are a frequent issue in children after cardiac surgery. In 2 infants, repeated revisions of non-steroid-eluting leads were necessary. To avoid further frequent replacements, two epicardial ventricular leads, one steroid-eluting and an additional fractally coated electrode as a pacing "backup" were connected to the atrial and ventricular outlet of a DDD pacemaker, allowing a comparison between two both electrodes. Showing no differences in long-term measurements, both electrodes seem to provide a comparably high level of safety.

Cardiac Pacing, Artificial↗
PubMed2002

The value of permanent follow-up of implantable pacemakers--first results of an European trial.

A clinical study investigates the use of Home Monitoring (HM) in pacemaker therapy. For 3 months patients are supervised by daily automatic HM messages. Endpoints are the technical feasibility and the clinical benefit of HM. Ninety three patients have currently been included and followed for 72 +/- 30 days. Three patients were excluded due to insufficient mobile net coverage at their living sites. For the other patients, 5311 of 5911 messages were successfully registered. Interrupts in the sequence of messages occurred 331 times. Two hundred ten of these (63%) lasted just 1 day, 14 interrupts (4%) lasted 5 or more days. Two patients did not show any interrupts, 34 patients (38%) had interrupts of 3 and more days. The clinical benefit of Home Monitoring was found in the remote detection of arrhythmia and lead dislocation.

Adult↗
PubMed2001

Effect of resynchronization therapy stimulation site on the systolic function of heart failure patients.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves systolic function in heart failure patients with ventricular conduction delay by stimulating the left ventricle (LV) or both ventricles (biventricular, BV). Optimal LV site selection is of major clinical interest for CRT device implantation; however, the dependence of hemodynamics on LV stimulation site has not been established. Thus, the objective of this study was to compare the hemodynamic response to CRT for 2 LV coronary vein sites: the free wall and anterior wall. Methods and Results- A total of 30 patients (mean NYHA class, 2.7; mean QRS interval, 152 ms; mean PR interval, 194 ms) enrolled in the PATH-CHF-II trial were studied. CRT was administered with LV and BV stimulation in VDD mode at 4 AV delays. LV stimulation was at the lateral free wall or anterior wall, whereas right ventricular stimulation was fixed near the apex. LV+dP/dt(max) and aortic pulse pressure changes from baseline during CRT were compared for LV sites. Free wall sites with LV and BV stimulation yielded significantly larger LV+dP/dt(max) (14% versus 6%, P<0.001 for LV; 12% versus 5%, P<0.001 for BV) and pulse pressure (8% versus 4%, P<0.001 for LV; 9% versus 5%, P<0.001 for BV) compared with anterior sites. In one third of patients, CRT at free wall sites increased LV+dP/dt(max), whereas it decreased at anterior sites over most AV delays. CONCLUSION: CRT with LV free wall stimulation produced significantly better LV systolic performance compared with anterior stimulation. Further studies are warranted to prove the clinical superiority of the LV free wall as a site for long-term CRT.

Aged↗
PubMed2001

Catheter stimulation of cardiac parasympathetic nerves in humans: a novel approach to the cardiac autonomic nervous system.

BACKGROUND: Cardiac parasympathetic nerves run alongside the superior vena cava (SVC) and accumulate particularly epicardially adjacent to the orifice of the coronary sinus (CS). In animals, these nerves can be electrically stimulated inside the SVC or CS, which results in negative chronotropic/dromotropic effects and negative inotropic effects in the atria but not the ventricles. Parasympathetic nerve stimulation (PS) with 20 Hz in the CS, however, also excites the atria, thereby inducing atrial fibrillation. The present study overcomes this limitation by applying high-frequency nerve stimuli within the atrial refractory period. Using this technique, we investigated for the first time whether neurophysiological effects similar to those in animals can be obtained in humans. METHODS AND RESULTS: In 25 patients, parasympathetic nerves were stimulated via a multipolar electrode catheter placed in the SVC (stimulation with 20 Hz; n=14) or CS (pulsed 200-Hz stimuli; n=11). A significant sinus rate decrease and prolongation of the antegrade Wenckebach period was achieved during PS in the SVC. During PS in the CS, a graded-response prolongation of the antegrade Wenckebach interval was observed with increasing PS voltage until third-degree AV block occurred in 8 of 11 patients. The negative chronotropic/dromotropic effects started and terminated immediately after the onset and termination of PS, respectively. Atropine abolished these effects (n=11). CONCLUSIONS: Human parasympathetic efferent nerve stimulation induces reversible negative chronotropic and dromotropic effects. PS may serve as an adjunctive tool for the diagnosis/treatment of supraventricular tachycardias and may be beneficial for ventricular rate slowing during tachycardic atrial fibrillation in patients with congestive heart failure.

Arrhythmias, Cardiac↗
PubMed2001

Cellular mechanisms of depressed atrial contractility in patients with chronic atrial fibrillation.

BACKGROUND: After cardioversion of atrial fibrillation (AF), the contractile function of the atria is temporarily impaired. Although this has significant clinical implications, the underlying cellular mechanisms are poorly understood. METHODS AND RESULTS: Forty-nine consecutive patients submitted for mitral valve surgery were investigated. Twenty-three were in persistent AF (>/=3 months); the others were in sinus rhythm. Before extracorporal circulation, the right atrial appendage was excised. ss-Adrenoceptors were quantified by radioligand binding, and G proteins were quantified by Western blot analysis. The isometric contractile response to Ca(2+), isoproterenol, Bay K8644, and the postrest potentiation of contractile force were investigated in thin atrial trabeculae, which were also examined histologically. The contractile force of the atrial preparations obtained from AF patients was 75% less than that in preparations from patients in sinus rhythm. Also, the positive inotropic effect of isoproterenol was impaired, and Bay K8644 failed to increase atrial contractile force. In contrast, the response to extracellular Ca(2+) was maintained, and the postrest potentiation was preserved. Beta-adrenoceptor density and G-protein expression were unchanged. Histological examination revealed 14% more myolysis in the atria of AF patients. CONCLUSIONS: After prolonged AF, atrial contractility was reduced by 75%. The impairment of beta-adrenergic modulation of contractile force cannot be explained by downregulation of ss-adrenoceptors or changes in G proteins. Dysfunction of the sarcoplasmic reticulum does not occur after prolonged AF. Failure of Bay K8644 to restore contractility suggests that the L-type Ca(2+) channel is responsible for the contractile dysfunction. The restoration of contractile force by high extracellular Ca(2+) shows that the contractile apparatus itself is nearly completely preserved after prolonged AF.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2001

Electromechanical assessment of left ventricular function following successful percutaneous coronary revascularization.

Percutaneous electromechanical mapping was applied to evaluate the impact of coronary revascularization on electrical and mechanical parameters in patients with prior myocardial infarction. In 15 patients with prior (> or = 4 weeks) myocardial Q-wave infarction and regional wall motion abnormalities, left ventricular endocardial mapping was performed immediately prior to percutaneous coronary revascularization. Patients underwent repetitive mapping during 6-month follow-up angiography with good revascularization results in all patients. Mean regional unipolar electrogram (UP) amplitude of all regions remained unchanged (10.4 +/- 4.2 mV prerevascularization vs. 10.2 +/- 4.4 mV postrevascularization), whereas mean local shortening (LS) of all regions increased from 6.0% +/- 5.8% to 9.7% +/- 5.3% (P < 0.001). The percentage of electromechanical match regions (LS < 6% and UP < 9 mV) remained unchanged after revascularization (15% vs. 10%; NS), whereas the percentage of mismatch regions (LS < 6% and UP > 9 mV) declined from 38% to 10% (P < 0.0001). We conclude that electromechanical mapping allows the sensitive detection of improved mechanical function after successful revascularization. Electrical activity remains unchanged 6 months after revascularization and the number of regions with an electromechanical mismatch decrease.

Aged↗
PubMed2001

[Onset, stability and electrogram width criteria: efficacy and safety in the detection of supraventricular tachycardia in implantable cardioverter-defibrillators].

Inadequate therapies for supraventricular tachycardia (SVT) by implanted cardioverter defibrillators (ICD) are potentially arrhythmogenic and impair the patient's quality of life. Inadequate detection (ID) of SVT can be reduced by using detection enhancements like the onset- and stability criteria (O + S) or the electrogram width criterion (EGW). 103 patients (85 male, 18 female, mean age 65 +/- 9 years, mean ejection fraction 40 +/- 16%) were initially randomized to O + S active (Onset 12/89%, Stability 30 ms) or O + S inactive in the lowest detection zone. Cross-over between O + S active and O + S inactive occurred every 3 months. In 40 patients (39%) with ICD capable of EGW, this feature was programmed to passive. The number of ID was referred to 1 year of follow-up. During the follow-up period (485 +/- 226 d), 31 patients (32%) developed SVT in the lowest detection zone, 11 patients (11%) ventricular tachycardia (VT) and 14 patients (14%) both. In total, 387 SVT and 127 VT were observed. The mean number of ID was 10.7 +/- 4.8 ID/year with inactive O + S, and was significantly reduced to 1.1 +/- 0.3 ID/year when O + S were active (p < 0.0001). During the whole study period no delayed or inhibited adequate therapy for VT due to O + S was observed. During follow-up using EGW (n = 40), when O + S were inactivated, resulted in a significant reduction from 19.8 +/- 11.6 to 0.5 +/- 0.2 ID/year (p = 0.007). Even while O + S were active EGW would further reduce ID from 1.2 +/- 0.5 to 0.2 +/- 0.1 ID/year (p = 0.028). However, 2 adequate therapies of VT in 2 patients would have been suppressed if EGW had been activated. This results in a sensitivity of 98% and a specificity of 93% when O + S were inactive and respectively 95 and 79% when O + S were active. The empirical programming of O + S is therefore a safe method for the reduction of ID in patients with ICD. Using EGW leads to further reduction of ID but may lead to underdetection in individual cases.

Aged↗
PubMed2001

Myocardial viability assessment by endocardial electroanatomic mapping: comparison with metabolic imaging and functional recovery after coronary revascularization.

OBJECTIVES: The objective of this study was to compare electroanatomic mapping for the assessment of myocardial viability with nuclear metabolic imaging using positron emission computed tomography (PET) and with data on functional recovery after successful myocardial revascularization. BACKGROUND: Animal experiments and first clinical studies suggested that electroanatomic endocardial mapping identifies the presence and absence of myocardial viability. METHODS: Forty-six patients with prior (> or =2 weeks) myocardial infarction underwent fluorine-18 fluorodeoxyglucose (FDG) PET and Tc-99m sestamibi single-photon emission computed tomography (SPECT) before mapping and percutaneous coronary revascularization. The left ventricular endocardium was mapped and divided into 12 regions, which were assigned to corresponding nuclear regions. Functional recovery using the centerline method was assessed in 25 patients with a follow-up angiography. RESULTS: Regional unipolar electrogram amplitude was 11.0 mV +/- 3.6 mV in regions with normal perfusion, 9.0 mV +/- 2.8 mV in regions with reduced perfusion and preserved FDG-uptake and 6.5 mV +/- 2.6 mV in scar regions (p < 0.001 for all comparisons). At a threshold amplitude of 7.5 mV, the sensitivity and specificity for detecting viable (by PET/SPECT) myocardium were 77% and 75%, respectively. In infarct areas with electrogram amplitudes >7.5 mV, improvement of regional wall motion (RWM) from -2.4 SD/chord +/- 1.0 SD/chord to -1.5 SD/chord +/- 1.1 SD/chord (p < 0.01) was observed, whereas, in infarct areas with amplitudes <7.5 mV, RWM remained unchanged at follow-up (-2.3 SD/chord +/- 0.7 SD/chord to -2.4 SD/chord +/- 0.7 SD/chord). CONCLUSIONS: These data suggest that the regional unipolar electrogram amplitude is a marker for myocardial viability and that electroanatomic mapping can be used for viability assessment in the catheterization laboratory.

Aged↗