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Biomedical subjects

G Hindricks

Publications and source records attributed to G Hindricks.

At least 19 recordsLinked to original sources
PubMed2005

Radiofrequency ablation of accessory pathways. Contemporary success rates and complications in 323 patients.

INTRODUCTION: 17 years ago the first radiofrequency catheter ablation of an accessory pathway (AP) was performed. The aim of this study was to describe the contemporary success rates and procedure related complication rates of radiofrequency (RF) ablation of accessory pathways (APs). In addition, the present study describes the anatomical distribution of APs according to the new nomenclature introduced by NASPE and ESC in 1999. METHODS: The analysis included all patients, who underwent RF ablation of an AP in the Heart Center Leipzig between January 2000 and December 2003. RESULTS: Over a 4 year period 336 APs were ablated in 323 patients. 201 APs (60%) presented with antegrade and retrograde conduction and showed preexcitation on ECG. For the remaining 135 APs (40%), only retrograde conduction over the AP was documented. According to the new nomenclature APs were classified as left-sided, right sided, septal and paraseptal APs. 188 APs (56%) were located on the left, 41 (12%) on the right, 64 (19%) in the paraseptal space and 31 APs (9%) presented with a septal or parahisian localization, respectively. Because of atypical course and/or characteristics 12 APs (4%) could not be classified. Ablation of all pathways were successful in 315 patients (98%). In 289 patients (89%) success was achieved within a single ablation session. The left-sided pathways had a re-intervention rate of 5%, which was significantly lower compared to the remaining localizations. The highest re-intervention rate was observed in the septal APs (23%). Complications were observed in less than 2% of all treated patients. CONCLUSIONS: 17 years after the first RF catheter ablation of an AP this therapy is established as a highly effective procedure. The success rate has improved to 98% and the complication rate has been minimized to less than 2%. The most frequent localization of APs is left posterior. Left sided APs also presented with the lowest re-intervention rate. The introduction of the new nomenclature in 1999 by NASPE and ESC has simplified the description of the exact anatomical localization of an AP.

Adolescent↗
PubMed2005

Expression of connexins 40 and 43 in human left atrium in atrial fibrillation of different aetiologies.

OBJECTIVE: To test the hypothesis that atrial fibrillation (AF) is associated with changes in the expression of connexins 40 and 43 in the left atrium with more pronounced changes in mitral valve disease than in lone AF. METHODS: Protein concentrations of connexin 40 and connexin 43 were analysed in left atrial tissue of patients undergoing cardiac surgery. One group of patients had lone AF (n = 41), one group had AF and mitral valve repair (n = 36), and one group in sinus rhythm served as controls (n = 15). RESULTS: Western blot analysis of connexin 40 and connexin 43 expression showed an increase of both gap junctional proteins (connexin 43 > connexin 40) in patients with AF of all forms compared with patients in sinus rhythm (p = 0.01 and p = 0.011, respectively). Subgroup analysis showed increased concentrations of connexin 40 in lone AF and AF with mitral valve disease compared with sinus rhythm (p = 0.06 and p = 0.029, respectively), whereas the same analysis for connexin 43 reached significance only in the mitral valve disease group (p = 0.031). No differences in connexin 40 and connexin 43 expression were detectable between lone AF and AF with mitral valve disease. Within the groups connexin 40 and connexin 43 expression did not differ between patients with paroxysmal AF and patients with chronic AF. CONCLUSION: The present study shows for the first time that AF can induce changes in the left atrium with increased connexin expression. Furthermore, no systematic differences between patients with paroxysmal and chronic AF were detected.

Atrial Fibrillation↗
PubMed2004

[Electrophysiological study: procedure and indications].

The purpose of an electrophysiological study is to verify the mechanism of arrhythmias and to decide the means of therapy for the clinical arrhythmia (pharmacological, radiofrequency catheter ablation, pacemaker-, ICD-implantation). The electrode catheters are introduced percutaneously into the right atrium, to the His-bundle, into the coronary sinus and/or into the right ventricle. By this electrode catheters the intracardiac electrograms are registered and programmed stimulation of the heart is performed. The electrical conduction properties are analysed. With stimulation manoeuvres most of the clinical tachycardias can be induced. In the first part of this overview we describe the procedure of an electrophysiological study, in the second part the indications are discussed.

Anti-Arrhythmia Agents↗
PubMed2004

[Catheter ablation of atrial flutter and atrial fibrillation].

Within the past 20 years, refinements in electrophysiologic mapping techniques have provided a better understanding of the pathophysiology of atrial flutter and atrial fibrillation (AF), which resulted in the development of catheter ablation techniques for this arrhythmias. Nowadays, catheter ablation has become the first line treatment of recurrent symptomatic or hemodynamically significant atrial flutter. In contrast, catheter ablation of AF is still an investigational procedure and should be restricted to patients with symptomatic AF who have been refractory to multiple antiarrhythmic drugs. In symptomatic patients with AF and an uncontrolled ventricular rate who have failed treatment with several antiarrhythmic drugs and who do not fit for primary catheter ablation of AF atrioventricular junction ablation with prior pacemaker implantation is recommended.

Anti-Arrhythmia Agents↗
PubMed2004

Fibrosis in left atrial tissue of patients with atrial fibrillation with and without underlying mitral valve disease.

OBJECTIVE: To examine the hypothesis that major extracellular matrix (ECM) proteins are expressed differently in the left atrial tissue of patients in sinus rhythm (SR), lone atrial fibrillation (AF), and AF with underlying mitral valve disease (MVD). DESIGN: Case-control study. PATIENTS: 118 patients with lone AF, MVD+AF, and SR. MAIN OUTCOME MEASURES: Collagen I, collagen III, and fibronectin protein expression measured by quantitative western blotting techniques and immunohistochemical methods. RESULTS: Protein concentrations increased in patients with AF (all forms) compared with those in SR (all forms): collagen I (1.15 (0.11) v 0.45 (0.28), respectively; p = 0.002), collagen III (0.74 (0.05) v 0.46 (0.11); p = 0.002, and fibronectin (0.88 (0.06) v 0.62 (0.13); p = 0.08). Especially, collagen I was similarly enhanced in both lone AF (1.49 (0.15) and MVD+AF (1.53 (0.16) compared with SR (0.56 (0.28); both p = 0.01). Collagen III was not significantly increased in lone AF but was significantly increased in AF combined with MVD (0.84 (0.07) both compared with SR (0.46 (0.11); p = 0.01). The concentration of fibronectin was not significantly increased in lone AF and MVD+AF (both compared with SR). Furthermore, there was a similar degree of enhanced collagen expression in paroxysmal AF and chronic AF. CONCLUSIONS: AF is associated with fibrosis. Forms of AF differ from each other in collagen III expression. However, there was no systematic difference in ECM expression between paroxysmal AF and chronic AF. Enhanced concentrations of ECM proteins may have a role in structural remodelling and the pathogenesis of AF as a result of separation of the cells by fibrotic depositions.

Atrial Fibrillation↗
PubMed2003

[Surgical treatment of therapy resistant atrial fibrillation].

Atrial fibrillation in patients with isolated, therapy resistant, chronic or paroxysmal atrial fibrillation (AF) or AF in combination with additional valvular and non-valvular cardiac pathology can be surgically treated by different techniques. Unipolar high frequency, cryotherapy and microwave energy is a curative approach for the treatment of the left atrium for AF. The postoperative mortality and morbidity rate is comparable to other cardiac surgery procedures. It is a technically less challenging procedure as compared to the MAZE procedure and can be applied using a minimally invasive approach. Alternative techniques such as new cryotechnologies, laser application and bipolar high frequency energy need to be evaluated for effectiveness and safety.

Atrial Fibrillation↗
PubMed2002

A stepwise mapping approach for localization and ablation of ectopic right, left, and septal atrial foci using electroanatomic mapping.

AIMS: We describe a new strategic stepwise mapping approach for fast and accurate identification and ablation of ectopic atrial foci using an electroanatomic mapping system. METHODS AND RESULTS: Mapping procedures started with the acquisition of four points at the superior/septal part of the tricuspid annulus. According to this activation sequence, maps were continued towards the right atrial free wall if relatively early activation was shown at the superior part of the initial map or towards the triangle of Koch and, if necessary, to the left atrium, in cases of relatively early activation at the septum. High density mapping and detailed electrogram analysis only of the target area allowed identification and ablation of 34 foci in 30 of the 32 studied consecutive patients. A small number of mapping points were sufficient within a procedure time of 90 +/- 41 min for right 148 +/- 68 min and for left sided foci and a total fluoroscopy time of 9.6 +/- 7.2 min and 24.8 +/- 16.4 min respectively. Sixteen foci were located at the right free wall, eight at the left free wall, and 10 at the right or left side of the septum. CONCLUSION: Strategic electroanatomic mapping with fast identification of the area of tachycardia origin and high density mapping only of this target area allowed fast and successful localization and ablation of right and left free wall and septal ectopic atrial foci.

Adolescent↗
PubMed2001

Simultaneous noncontact mapping of left atrium in patients with paroxysmal atrial fibrillation.

BACKGROUND: Catheter ablation of pulmonary vein ectopic foci is a potentially curative treatment strategy for patients with atrial fibrillation. However, identification of arrhythmogenic pulmonary veins with conventional mapping is difficult, especially in patients with rare focal activity, multiple active foci, or extrapulmonary foci. The present study was designed to investigate use of simultaneous noncontact mapping in this setting. METHODS AND RESULTS: In 17 consecutive patients with paroxysmal atrial fibrillation, a catheter-mounted noncontact multielectrode array positioned in the left atrium was used to reconstruct 3300 electrograms simultaneously from a single beat. Isopotential maps were generated during sinus rhythm and focal activity. After ectopic foci were identified, radiofrequency catheter ablation was performed in patients with 1 or 2 foci. However, in patients who had multiple foci, intraoperative ablation of atrial fibrillation was advised. A total of 28 ectopic foci (25 pulmonary vein foci and 3 extrapulmonary vein foci) were identified by use of isopotential maps generated from a single beat of focal activity. Radiofrequency catheter ablation guided by noncontact mapping was attempted in 12 patients with 1 or 2 ectopic foci. Successful ablation of atrial fibrillation was achieved in 9 of 12 patients (75%). CONCLUSIONS: Noncontact mapping allows rapid and precise identification of arrhythmogenic pulmonary veins in addition to extrapulmonary vein foci. Thus, the present study shows that the technology may be used not only to guide radiofrequency catheter ablation, but also as a diagnostic tool to develop individual treatment strategies.

Atrial Fibrillation↗
PubMed2001

Effectiveness of two radiofrequency ablation systems in atrial tissue.

OBJECTIVE: The efficacy of the left atrial radiofrequency ablation procedure, for the curative treatment of atrial fibrillation, is dependent upon obtaining a confluent transmural line of hyperthermic cellular death. We compare the in vitro effectiveness of obtaining transmural hyperthermic cellular death (>55 degrees C) of both the Osypka single electrode and Boston Scientific Thermaline multi-electrode radiofrequency systems. METHODS: Isolated cadaver porcine hearts were used to measure epicardial temperatures either 'central' or at the 'edge' in relation to an endocardial applied radiofrequency electrode. Reference set point was 70 degrees C, and 4-6-mm thick atrial tissue was used for all applications. 'Edge' temperatures with the Boston Scientific unit were measured whilst activating both adjacent electrodes. RESULTS: Boston Scientific: Probe temperature closely approximated the set point. 'Central' epicardial temperature was lower than probe temperature until after 40 s application (P<0.05), 55 degrees C was reached at 50 s, maximal mean temperature 63.0+/-8.9 degrees C was reached at 100 s. Epicardial 'edge' temperature remained lower than probe temperature for the entire 120 s (P<0.05). Osypka: Probe temperature tended to overshoot the set point. 'Central' epicardial temperature paralleled and occasionally exceeded probe temperature reaching 55 degrees C within 10 s, maximal mean temperature 76.3+/-12.7 degrees C was reached at 10 s and exceeded the set point thereafter. 'Edge' temperature was no different to probe temperature or 'central' epicardial temperature. The mean epicardial temperatures produced with a 65 degrees C set point was no different to that with the 70 degrees C set point, except for a lower final temperature at 60 s. CONCLUSIONS: The Boston Scientific system (70 degrees C set point) requires a minimum in vitro application of 40 s to transmurally increase 4-6 mm atrial tissue temperature above 55 degrees C, and 120-s duration per application would appear to be a reasonable clinical recommendation. The Osypka system transfers thermal energy more effectively, requiring less than 10 s in vitro to achieve a similar transmural temperature, and a 30-s application can be recommended. However, a tendency to overshoot both probe and set point temperature, suggests that a lower set point of 65 degrees C might be safer and as effective.

Animals↗
PubMed2001

Atypical left atrial flutter after intraoperative radiofrequency ablation of chronic atrial fibrillation: successful ablation using three-dimensional electroanatomic mapping.

Curative treatment of chronic atrial fibrillation (AF) remains a challenging task for electrophysiologists. Eliminating the initiating triggers by focal radiofrequency ablation in a subset of patients with paroxysmal AF and modifying the maintaining substrate by performing linear lesions within the left atrium in patients with prolonged episodes of AF are among the alternative approaches for management of these patients. Recently, a new intraoperative treatment procedure aimed at eliminating left atrial anatomic "anchor" reentrant circuits by induction of contiguous lesions using radiofrequency energy under direct vision was introduced. However, atypical left atrial flutter may occur during follow-up after intraoperative ablation of AF. These arrhythmias most likely are due to discontinuities in linear lesions; therefore, they can be successfully mapped and ablated in a subsequent percutaneous catheter ablation procedure. We report and discuss the case of a patient who underwent successful intraoperative ablation of chronic AF, but who developed atypical left atrial flutter postoperatively. Three-dimensional nonfluoroscopic electroanatomic mapping revealed a gap in the linear lesion line connecting the left upper and right upper pulmonary vein orifices. Ablation at the exit site of the breakthrough was successful.

Aged↗
PubMed2001

Impact of radiofrequency catheter ablation of accessory pathways on the frequency of atrial fibrillation during long-term follow-up; high recurrence rate of atrial fibrillation in patients older than 50 years of age.

AIMS: Atrial fibrillation represents a frequent and potentially life-threatening arrhythmia in patients with accessory atrioventricular pathways. Radiofrequency ablation has become the curative treatment of first choice for these patients. Investigations after successful surgical pathway dissection reported an almost complete elimination of paroxysmal atrial fibrillation. However, there are only a few reports which include a small number of patients undergoing radiofrequency ablation. The purpose of this study was to examine whether successful radiofrequency ablation of accessory pathways prevents the occurrence of paroxysmal atrial fibrillation, and to identify possible predictors of atrial fibrillation recurrence. METHODS AND RESULTS: A total of 116 consecutive patients (mean age 42+/-15 years) with manifest or concealed accessory pathways and documented paroxysmal atrial fibrillation underwent radiofrequency catheter ablation. The patients were reexamined at 6 and 12 months. Long-term follow-up information was obtained by questionnaire and/or by consulting the referring physician. Pathway conduction was abolished in 101 cases (87%). Late follow-up information was obtained from 91 of these 101 patients (90%) with successful ablation with a mean follow-up duration of 23.9+/-12.3 months. During follow-up, 25 of 91 patients (27%) experienced arrhythmias. Recurrent episodes of atrial fibrillation were observed in 18 of these 25 cases (i.e. 20% of the 91 patients). Differences between patients with and without recurrences of atrial fibrillation were examined for age, sex, associated cardiac disease, presence of multiple pathways, pathway location, atrial fibrillation inducibility during the procedure and cycle length of the atrioventricular reentrant tachycardia. Only older age was a significant independent predictor of atrial fibrillation recurrence (P=0.02). Eleven of 31 patients (35%) older than 50 years of age had atrial fibrillation recurrences during follow-up compared to seven of 60 patients (12%) under age 50. The recurrence rate of atrial fibrillation was even higher in patients older than 60 years (6 of 11 patients, i.e. 55%). In comparison, the occurrence rate of atrial fibrillation during follow-up in a control group of 100 consecutive patients with successful accessory pathway ablation, who did not have evidence of paroxysmal atrial fibrillation prior to ablation, was 4% and, thus, significantly lower than in the study group of the 91 patients (P=0.001). CONCLUSIONS: The recurrence rate of paroxysmal atrial fibrillation after successful radiofrequency ablation of accessory pathways shows an age-related increase, being low in patients younger than 50 years of age (12%) and high in the older patients: 35% in patients older than 50 years and 55% in patients older than 60. These results have significant therapeutic implications concerning the decisions on pharmacological therapy after successful ablation in patients older than 50 years. Furthermore, these data will help physicians advise older patients properly about their risk of recurrence of atrial fibrillation after ablation.

Adult↗
PubMed2000

Electromagnetic versus fluoroscopic mapping of the inferior isthmus for ablation of typical atrial flutter: A prospective randomized study.

BACKGROUND: Radiofrequency catheter ablation within the tricuspid annulus-inferior caval vein isthmus can cure typical atrial flutter. The target for ablation, nonetheless, is relatively wide, and standard ablation procedures may require significant exposure to radiation. METHODS AND RESULTS: A total of 50 patients (mean age, 58+/-11 years) with typical atrial flutter were prospectively randomized to receive isthmus ablation using conventional fluoroscopy for catheter navigation (group I, n=24) or electromagnetic mapping (group II, n=26). Complete bidirectional isthmus block was verified with double potential mapping. If complete isthmus block could not be achieved after 20 radiofrequency pulses or 25 minutes of fluoroscopy, the patients were switched to the other group. Eight patients from group I (33%) but only 1 patient from group II (4%) were switched. Overall, complete isthmus block was achieved in 47 of 50 patients (94%). The overall fluoroscopy time, including the placement of the diagnostic catheters, was 22.0+/-6.3 minutes in group I and 3.9+/-1.5 minutes in group II (P:<0.0001). The fluoroscopy time needed for isthmus mapping was 17.7+/-6.5 minutes in group I and 0.2+/-0.3 minutes in group II (P:<0.0001). CONCLUSIONS: Electromagnetic mapping during the induction of linear lesions for the ablation of atrial flutter permitted a highly significant reduction in exposure to fluoroscopy while maintaining high efficacy, and it allowed the time required for fluoroscopy to be reduced to levels anticipated for diagnostic electrophysiological studies.

Atrial Flutter↗
PubMed2000

[Idiopathic right ventricular tachycardia or arrhythmogenic right ventricular tachycardia?].

HISTORY: While cycling a 38-year-old man suddenly experienced palpitations associated with marked weakness. 90 min later his general practitioner, having diagnosed a ventricular tachycardia (VT) with a rate of 218/min, terminated it by a drug injection. INVESTIGATIONS: Electrocardiography (ECG), echocardiography and biventricular cardiac catheterization with right ventricular contrast injection failed to provide any evidence of structural abnormality. However, ergometry and EPS with programmed ventricular stimulation induced VT of identical morphology (left bundle branch bloc [LBBB] with right axis deviation [RAD]). TREATMENT AND COURSE: Idiopathic right-ventricular outflow tract tachycardia (IRVT) having been diagnosed, the patient was put on a maintenance dose of 50 mg/d atenolol. After 6 months without symptoms he again experienced several attacks of tachycardia. Resting ECG merely revealed an epsilon potential and negative T waves in V1-V3. Right ventricular contrast injection revealed inferolateral dyskinesia. EPS demonstrated both the known VT and a second, morphologically different one (LBBB with LAD). These findings indicated arrhythmogenic right-ventricular cardiomyopathy (ARCV). A cardioverter/defibrillator was implanted (ICD) and over the subsequent 8 months he had six episodes of VT which were quickly terminated by the ICD. CONCLUSION: At first presentation of right-ventricular outflow tract tachycardia it is often not possible to differentiate between IRVT and arrhythmogenic RV cardiomyopathy. The two being significantly different in prognosis and treatment, follow-up monitoring is essential to establish the definitive diagnosis.

Adult↗
PubMed2000

Combined stentless mitral valve implantation and radiofrequency ablation.

BACKGROUND: The aim of this study was to evaluate the results of combined stentless mitral valve (SMV) replacement and intraoperative radiofrequency ablation for chronic atrial fibrillation (IRAAF) to restore physiologic hemodynamic function. METHODS: Since July 1998 12 patients (72+/-4 years, 10 women, mitral stenosis/mitral incompetence 8/4, NYHA 3.3+/-0.4, CI 1.8+/-0.5) had SMV implantation and received additional IRAAF by inducing continuous left atrial lesion lines from the MV annulus to all four pulmonary veins and to the atriotomy. RESULTS: The flexible SMV was implanted at the papillary muscles and at the annulus using a conventional (n = 6) or a minimally invasive approach (n = 6). Sinus rhythm was successfully restored in 10 of 12 patients with 6- and 12-months' follow-up; 2 required DDD-pacemaker implantation. However, in the early postoperative period several interventions including medical treatment (sotalol or amiodarone) in 9 and electrical cardioversion in 7 patients was required. Two patients required reinterventions: 1 cardioversion and 1 amiodarone medication after 3 and 6 months, respectively. At echocardiography the SMV demonstrated good hemodynamic function and atrial contraction. CONCLUSIONS: Restoration of physiologic cardiac function by SMV implantation and IRAAF is advantageous and no further anticoagulation is required.

Aged↗
PubMed2000

[High frequency catheter ablation of accessory atrioventricular pathways].

Radiofrequency catheter ablation has established as the first line therapy for the curative treatment of patients with accessory pathways. For left-sided accessory pathways, the retrograde approach over the aortic valve is commonly used for ablation of the ventricular insertion. For right-sided and septal accessory pathways, the atrial insertion is usually approached from the right atrium. Atrioventricular accessory pathways irrespective of the exact localization can be successfully ablated in more than 90-95% of all cases. Severe complications associated with the ablation procedure are rare and occur in approximately 2-3% of patients treated. The recurrence rate after successful ablation is approximately 5-10%. Recurrences of accessory pathway conduction occur almost exclusively within the first 3 months following successful ablation whereas late recurrences are rare. Because of the favorable efficacy--risk profile, radiofrequency catheter ablation can be recommended as the first line therapy to all symptomatic patients with accessory atrioventricular pathways.

Catheter Ablation↗
PubMed2000

[Complications and risk of high frequency catheter ablation of tachycardiac arrhythmias].

Radiofrequency catheter ablation has established itself as a first line therapy for the curative treatment of many patients with supraventricular or atrioventricular tachycardias and also for selected types of ventricular tachycardia. The success rates of catheter ablation of various types of cardiac arrhythmias are impressively high. Procedure related complications can be attributed to the invasive nature of the technique (e.g., bleeding or other vascular complications, radiation exposure) but may also occur as a specific complication related to the type of intervention performed (e.g., complete AV-block following attempted modification of the AV-node). In patients undergoing radiofrequency ablation procedures, radiation exposure carries a small but measurable risk of malignancy and hereditary disorders. The risk of fatal malignancy has been calculated to be approximately 1/1000 per hour of fluoroscopy and the risk of significant hereditary disorders approximately 10 per 1 million live births per hour fluoroscopy time. However, it is important to realize that these risks are age and sex dependent being higher in young and/or female patients. For the physician performing catheter ablation procedures no significant risks related to fluoroscopy exposure may be expected as long as all established tools for protection are used. Based on the results of large single center studies and multicenter investigations, complications during or after radiofrequency catheter ablation of supraventricular or atrioventricular arrhythmias may occur in 4-5% of cases. Severe complications (life threatening or permanently disabling complications) may occur in approximately 1-2% of patients treated. In patients undergoing ablation of ventricular tachycardia, a higher incidence of total procedure related complications between 5-7% and severe complications (3-4%) may be expected. The higher incidence of complications in patients with ventricular tachycardia when compared to catheter ablation of supraventricular or atrioventricular tachycardia may be explained by the fact that many patients with ventricular tachycardia suffer from severe cardiovascular disease.

Adult↗