PubMed Health⌕ Search

Biomedical subjects

Bernhard Zrenner

Publications and source records attributed to Bernhard Zrenner.

At least 19 recordsLinked to original sources
PubMed2006

Effects of circumferential or segmental pulmonary vein ablation for paroxysmal atrial fibrillation on cardiac autonomic function.

BACKGROUND: Circumferential and segmental pulmonary vein ablations are two established treatment strategies for ablation of atrial fibrillation. Both techniques require the application of radiofrequency current at anatomical sites that are close to autonomic ganglia. However, the effects of current pulmonary vein ablation techniques on cardiac autonomic function are unknown. OBJECTIVE: The purpose of this study was to analyze the short- and long-term effects of circumferential and segmental pulmonary vein ablation on cardiac autonomic function. METHODS: One hundred patients with highly symptomatic atrial fibrillation were randomly assigned to undergo either circumferential or segmental pulmonary vein ablation. Holter recordings were recorded at baseline and at regular intervals for up to 1 year after ablation. Autonomic function was assessed by deceleration capacity and acceleration capacity of heart rate as well as by standard measures of heart rate variability. RESULTS: In the circumferential pulmonary vein ablation group, deceleration capacity and acceleration capacity decreased highly significantly from 5.7 +/- 2.1 ms and -8.0 +/- 1.9 ms at baseline to 3.3 +/- 1.8 ms and -5.5 +/- 2.3 ms directly after ablation, respectively (P<.00001). Impairment of deceleration capacity and acceleration capacity was present up to 1 year after ablation. In the segmental pulmonary vein ablation group, deceleration capacity and acceleration capacity decreased from 5.8 +/- 2.0 ms and -7.8 +/- 1.6 ms at baseline to 3.4 +/- 1.2 ms and -6.0 +/- 2.4 ms directly after ablation (P<.00001), respectively. However, deceleration capacity and acceleration capacity returned to baseline values within 1 month. CONCLUSIONS: Circumferential and segmental pulmonary vein ablations induce an immediate decrease of autonomic function. However, while this decrease is only transient with segmental pulmonary vein ablation, it persists with circumferential pulmonary vein ablation for at least 1 year.

Aged↗
PubMed2006

Near-fatal incident on routine induction of ventricular fibrillation at the replacement of an implantable cardioverter defibrillator.

The case of a 54-year-old patient with severe coronary artery disease and storms of ventricular tachyarrhythmias is presented. On the replacement of an implantable cardioverter defibrillator due to battery depletion, he suffered life-threatening complications associated with arrhythmia induction. Performing a routine induction of ventricular arrhythmias on the occasion of pulse generator replacement may be reconsidered in selected patients.

Defibrillators, Implantable↗
PubMed2006

Electrical isolation of pulmonary veins in patients with atrial fibrillation: reduction of fluoroscopy exposure and procedure duration by the use of a non-fluoroscopic navigation system (NavX).

AIMS: The aim of the study was to investigate the feasibility of performing segmental pulmonary vein (PV) isolation guided by the NavX (Endocardial Solutions, St Jude Medical, Inc., St Paul, MN, USA) system without the three-dimensional (3D) geometric reconstruction option and whether the use of NavX system will reduce the radiation exposure and procedure duration. METHODS AND RESULTS: The study included 64 patients with symptomatic paroxysmal or permanent atrial fibrillation, in whom PV isolation was performed using fluoroscopic guidance (n=32) or the NavX system (n=32). Pulmonary vein mapping with a circular mapping catheter allowed the identification and localization of myocardial connections between the PV and the left atrium. PV isolation was performed by radiofrequency ablation of these connections at the atrial aspect of the PV ostium. Primary success rate for isolated PVs did not differ significantly in patients ablated under fluoroscopic guidance vs. those ablated under guidance of NavX system [100/107 PVs (93.5%) vs. 120/124 PV (96.8%; P=n.s.)]. Compared with fluoroscopy guided procedures, NavX-guided procedures showed a significant reduction in the fluoroscopy time (75.8+/-24.5 vs. 38.9+/-19.3 min, P<0.05), total X-ray exposure (93.2+/-51.6 vs. 56.6+/-37.9 Gy cm(2), P=0.03), and total procedural time (237.7+/-65.4 vs. 188.6+/-62.7 min, P=0.01). The mean follow-up was 9.5+/-3.0 months. One patient in each group was lost to follow-up. Seven-day Holter monitoring showed that 23 of 31 patients (74.2%) in the NavX-guided group and 21 of 31 patients (67.7%) in the fluoroscopy-guided group were in sinus rhythm (P=0.57). CONCLUSION: The 3D visualization of the catheters by NavX system allows a rapid and precise visualization of the mapping and ablation catheters at the PV ostia and markedly reduces fluoroscopy time, total X-ray exposure, and procedural duration during PV isolation compared with ablation performed under fluoroscopy guidance.

Aged↗
PubMed2006

Implantable cardioverter defibrillator (ICD) in children.

BACKGROUND: Implantable cardioverter defibrillators (ICD) proved to be effective in the prevention of sudden cardiac death in adults. In children, the experience of ICD therapy is limited. This retrospective study was undertaken to review our experience with ICD implantation in children with special consideration of psychosocial impact of this therapy. METHODS AND RESULTS: Sixteen children (f:5, m:11, median age 12.2 years, range 4-15.9 years) received an ICD. Eleven patients had survived sudden cardiac death with documented ventricular fibrillation (VF) and five patients had sustained ventricular tachycardia (VT) with hemodynamic significance. The underlying heart disease was congenital in 5, hypertrophic cardiomyopathy in 2, myocarditis in 2 and primary electrical in 7 patients. All leads were implanted transvenously. Mean follow up was 43.1 months (range 1-105 months). All patients are alive. In 7 patients, a total of 387 sustained VT episodes were detected by the ICD. At follow-up, 10 inappropriate shocks were delivered in four patients. One early and six late lead revisions were done in seven patients. 12/16 (75%) patients had concomitant antiarrhythmic drug therapy. About half of the adolescents showed signs of depression and/or anxiety. CONCLUSION: ICD therapy via transvenous access for prevention of sudden cardiac death is feasible and effective even in small children. However, the occurrence of lead complications is significant. Since about half of the adolescents showed signs of depression and/or anxiety, professional psychological surveillance should be considered in these patients.

Adolescent↗
PubMed2006

Mapping and ablation of atypical flutter in congenital heart disease with a novel three-dimensional mapping system (Carto Merge).

Mapping and successful ablation of an intra-atrial re-entry tachycardia in a patient after Fontan operation were performed within the anatomy, superimposed from the computed tomography study. In this case, the new system enabled us to display the complex anatomy of the right atrium in detail, whereas the conventional electro-anatomic three-dimensional geometry showed significant inconsistencies.

Adult↗
PubMed2006

Left atrial tachycardia after circumferential pulmonary vein ablation for atrial fibrillation: incidence, electrophysiological characteristics, and results of radiofrequency ablation.

AIMS: To investigate the incidence, electrophysiological properties, and ablation results for left atrial (LA) tachycardia as a sequel to the circumferential pulmonary vein ablation (CPVA) for atrial fibrillation (AF). METHODS AND RESULTS: Sixty-seven patients with AF underwent CPVA. Sustained LA tachycardia developed in 21/67 (31%) patients and in 16/21 symptomatic patients 55 LA tachycardias (3.4+/-2.4 per patient) were mapped: 18 (33%) tachycardias were related to macro-re-entry around the mitral valve (7) or pulmonary vein(s) (11). In 20 tachycardias (36%), a 'small-loop' LA re-entrant tachycardia (LART) was identified; gaps in prior ablation lines (7 LART) or an area of extremely slow conduction adjacent to the CPVA lesions (13 LART) were crucial for these re-entries. Seventeen tachycardias (31%) were too unstable for complete mapping. Ablation was a primary success in 34 of 38 (89%) mapped LART, but in eight of 21 procedures, cardioversion was necessary to achieve sinus rhythm. CONCLUSION: LART develops in a high percentage of patients after CPVA. Small-loop re-entry, which is difficult to map, may arise and patients suffer from several and/or unstable variants of LART. Thus, mapping and ablation of these LART is challenging and the overall success is yet not satisfactory.

Aged↗
PubMed2006

Atresia of the coronary sinus in patients with supraventricular tachycardia.

BACKGROUND: Atresia of the coronary sinus (CS) ostium with retrograde drainage of the cardiac veins via the persistent left superior vena cava (PLSVC) is a rare abnormality and only a few case reports in association with electrophysiological studies have been reported. METHODS: During standard electrophysiological study in three patients with a focal left atrial tachycardia, atrial fibrillation and common type right atrial flutter, the CS could not be cannulated despite several attempts. Assuming an occluded CS ostium we advanced a multipurpose catheter via the right atrium and the right superior vena cava in a PLSVC and performed CS angiography. RESULTS: CS angiography showed that the CS was occluded in all 3 patients and the PLSVC was used as a drainage route to the superior vena cava. After retrograde placement of a 2.5 Fr nonsteerable diagnostic catheter via the PLSVC in the CS, the intracardiac CS electrogram was recorded. Successful ablation could be performed in all three cases. CONCLUSIONS: The cases highlight the possibility that failure to access the CS during electrophysiological studies may be related to this anomaly and that retrograde cannulation via PLSVC enables the CS access and acquisition of its electrograms.

Aged↗
PubMed2006

Long-term follow-up of patients supplied with single-chamber or dual-chamber cardioverter defibrillators.

INTRODUCTION: In patients who have an indication for an implantable cardioverter defibrillator (ICD) a dual-chamber device is indicated in the case of concomitant significant sinus node disease or atrioventricular block. It is a matter of debate whether dual-chamber ICD may be beneficial for patients with preserved sinus and atrioventricular nodal function as data from prospective randomized trials are limited. Mid- or long-term follow-up data are unavailable. METHODS AND RESULTS: One hundred patients (age 60+/-12 years, 11 women) with the indication for the implantation of an ICD and without antibradycardia pacing indication were randomly assigned to either receive a dual-chamber ICD (n=52) or a single-chamber ICD (n=48). Patients were followed-up for a mean of 52+/-14 months. Mortality and arrhythmogenic morbidity were assessed. All-cause mortality was 21% for single-chamber and 31% for dual-chamber ICD recipients, respectively (P=0.26). Cardiovascular mortality was 13% for single-chamber ICD recipients versus 21% in the dual-chamber group (P=0.25). Subgroup analysis using 35% of ventricular paced beats as cutoff value in the dual-chamber ICD group revealed a 42% mortality rate for the patients with frequent ventricular pacing compared to 10% of patients with a low rate of ventricular pacing (P=0.05, relative risk 4.21, 95% confidence interval: 0.9-19.8). As for arrhythmogenic morbidity, the difference in the ventricular tachyarrhythmia load was not different in both groups (single chamber: 23+/-74 VT episodes, dual chamber: 54+/-134 VT episodes, P=0.17). CONCLUSION: In ICD recipients without conventional indication for dual-chamber pacing, dual chamber compared to single-chamber ICD has no advantage concerning mortality and arrhythmogenic morbidity in a long-term follow-up. In these patients the implantation of a single-chamber device is sufficient.

Arrhythmias, Cardiac↗
PubMed2006

Cardiac pacing in a patient with diaphragm pacing for congenital central hypoventilation syndrome (Ondine's curse).

Mechanical ventilation support and diaphragm pacing has improved the prognosis of patients with idiopathic congenital central hypoventilation syndrome (CCHS; Ondine's curse). However, severe bradyarrhythmias may occur. This report is about a patient who was supplied with a bilateral diaphragm pacing system at early childhood. At the age of 17 years, he experienced multiple syncopes due to sinus nodal arrest, which was successfully treated by the implantation of a dual chamber pacemaker.

Adolescent↗
PubMed2006

Management of far-field R wave sensing for the avoidance of inappropriate mode switch in dual chamber pacemakers: results of the FFS-test study.

BACKGROUND AND OBJECTIVE: Far-field R wave sensing (FFS) in the atrial channel of dual chamber pacemakers is a relevant source for inappropriate mode switch from the DDD mode to the DDI or VDI mode. Inappropriate loss of atrioventricular synchrony due to false positive mode switch is hemodynamically disadvantageous, may induce atrial tachyarrhythmias, can lead to pacemaker syndrome, and impairs the reliability of pacemaker Holter data. The aim of the study was to determine whether individual adjustment of the postventricular atrial blanking period (PVAB) based on an additional test is effective in avoiding inappropriate mode switch due to FFS when compared with standard programming of the PVAB. METHODS: A total of 207 patients were supplied with a St. Jude Medical Identity DR or Identity ADx DR dual chamber pacemaker for sinus nodal disease (n = 84), atrioventricular block (n = 79), binodal disease (n = 35), or other indications (n = 9). At hospital discharge, they were randomized to an individually optimized PVAB (n = 100) or to a control group with the PVAB left at the nominal of 100 msec (n = 107). Primary endpoint was the occurrence of inappropriate mode switch due to FFS within 3 months after pacemaker implantation assessed by stored electrograms of the pacemaker. RESULTS: At the 3-month follow-up, 28/107 (26%) patients with the standard programming of the PVAB showed at least one episode of inappropriate mode switch due to FFS versus 10/100 (10%) patients with optimized PVAB (P < 0.01). The optimized PVAB was shorter than the nominal PVAB in about one-third of patients and longer in about two-third of patients. Different atrial lead localizations were not associated with the occurrence of inappropriate mode switch. CONCLUSIONS: Individual adjustment of the PVAB significantly reduces the incidence of inappropriate mode switch due to FFS.

Aged↗
PubMed2005

Freedom from atrial tachyarrhythmias after catheter ablation of atrial fibrillation: a randomized comparison between 2 current ablation strategies.

BACKGROUND: Data on the comparative value of the circumferential pulmonary vein and the segmental pulmonary vein ablation for interventional treatment of atrial fibrillation are limited. We hypothesized that the circumferential pulmonary vein ablation approach was superior to the segmental pulmonary vein ablation approach. METHODS AND RESULTS: One hundred patients with highly symptomatic atrial fibrillation were randomly assigned to undergo either circumferential (n=50) or segmental pulmonary vein ablation (n=50). Freedom from atrial tachyarrhythmias in a 7-day Holter monitoring at 6 months was the primary end point. Secondary end points were freedom of arrhythmia-related symptoms and a composite of pericardial tamponade, thromboembolic complications, and pulmonary vein stenosis (safety end point). On the basis of the results of the 7-day Holter monitoring at 6 months, 21 patients (42%) after circumferential pulmonary vein ablation and 33 patients (66%) after segmental pulmonary vein ablation (P=0.02) were free of atrial tachyarrhythmia episodes. During the 6-month follow-up period, 27 patients (54%) after circumferential pulmonary vein ablation and 41 patients (82%) after segmental pulmonary vein ablation remained free of arrhythmia-related symptoms (P<0.01). No significant difference was found in the safety end point (6 versus 7 events; P=0.77) in the circumferential versus segmental pulmonary vein ablation group, respectively. CONCLUSIONS: This study demonstrates no superiority of the circumferential pulmonary vein ablation over segmental pulmonary vein ablation for treatment of atrial fibrillation in terms of efficacy and safety.

Aged↗
PubMed2005

Atypical access to typical atrial flutter.

Typical atrial flutter with reentry around the tricuspid valve can easily be cured by ablating the cavotricuspid isthmus. In the reported case, transvenous access to the tricuspid valve was not possible because of a total cavopulmonal connection in congenital mitral atresia. Successful angioplasty of a small fenestration between the total cavopulmonal connection and the genuine right atrium (RA) allowed anterograde transvenous access to the RA. Electroanatomic RA mapping confirmed peritricuspid reentry, and successful ablation was performed.

Adolescent↗
PubMed2005

Rescue ablation of electrical storm in patients with ischemic cardiomyopathy: a potential-guided ablation approach by modifying substrate of intractable, unmappable ventricular tachycardias.

OBJECTIVES: The purpose of this study was to evaluate a substrate-modifying, primarily potential-guided catheter ablation approach as a bailout therapy in patients with complex myocardial infarction and electrical storms due to ventricular tachycardias (VTs). BACKGROUND: Management of electrical storm is a domain of medical treatment. A definite trigger or delineated scar has been characterized as a requirement for substrate-orientated ablation of intractable unmappable ventricular tachyarrhythmias but can be absent, as shown in the presented cases. METHODS: Five patients who presented with ischemic cardiomyopathy and severe reduced left ventricular ejection fraction also suffered from multiple types of unstable VTs that deteriorated into drug-refractory electrical storm. Patients had 96 to 580 VT episodes requiring therapy with an implantable cardioverter-defibrillator (ICD) and received 3 to 310 shock deliveries prior to ablation. Treatment with beta-blockers, amiodarone, class IB antiarrhythmic drugs, deep sedation, and overdrive pacing and/or cardioversion of incessant VTs failed to stabilize the electrical storm but enabled left ventricular electroanatomic voltage mapping. A simplified substrate modification was performed by ablation of delayed fractionated potentials in areas identified by pace mapping, matching three to eight documented types of VTs per patient in complex scar areas. RESULTS: All patients could be stabilized after ablation. During 12 to 30 months of follow-up, three patients remained free of any VT episode requiring ICD treatment, and two patients had <1 VT episode per month. CONCLUSIONS: The cases presented demonstrate that rescue VT ablation of drug-refractory electrical storm is possible by a substrate-orientated ablation approach even in patients with complex chronic infarction and various VTs.

Aged↗
PubMed2005

Catheter ablation of left atrial focal tachycardia guided by electroanatomic mapping and new insights into interatrial electrical conduction.

BACKGROUND: Experience in catheter ablation of left atrial (LA) focal tachycardia and information about interatrial electrical connections during LA focal tachycardia are limited. OBJECTIVES: The purpose of this study was to describe our experience in electroanatomic mapping-guided catheter ablation of LA focal tachycardia and to investigate interatrial electrical connections during LA focal tachycardias. METHODS: Thirty-three patients undergoing catheter ablation for LA focal tachycardia guided by electroanatomic mapping were reported. Interatrial electrical connections were analyzed in LA focal tachycardias with biatrial electroanatomic maps. RESULTS: Of the 35 LA focal tachycardias (cycle length 309 +/- 100 ms) mapped, 19 (54%) originated from the pulmonary veins (PVs), 6 (17%) from the mitral annulus, 3 (8.6%) from LA roof, 3 (8.6%) from LA posterior wall, 2 (5.7%) from LA appendage, and 2 (5.7%) from LA septum. Fourteen of the 19 PV tachycardias (74%) were located in proximity to PV ostia. In 14 (7 PV, 7 non-PV) LA focal tachycardias with biatrial electroanatomic maps, posterior right atrium breakthrough sites at the intercaval area were identified in 7 PV tachycardias and 1 non-PV tachycardia. Five of the 7 PV tachycardias used only the posterior breakthrough for interatrial propagation. Procedural success was achieved in 33 of 35 LA focal tachycardias (94%) in 31 patients. During 23 +/- 19 months of follow-up, 2 patients (6%) had recurrence of ablated tachycardia, and 3 (10%) developed new LA focal tachycardias. CONCLUSIONS: The PVs and the mitral annulus were the main sources of LA focal tachycardias. The majority of PV tachycardias originated from PV ostia. A posterior interatrial connection appeared to play a major role in interatrial electrical propagation during PV tachycardias. Electroanatomic mapping facilitated precise localization of LA focal tachycardias and achievement of a high rate of ablation success.

Adult↗
PubMed2005

Congenital and surgically acquired Wolff-Parkinson-White syndrome in patients with tricuspid atresia.

OBJECTIVES: There are reports associating an increased incidence of Wolff-Parkinson-White syndrome with tricuspid atresia. Here we report on electrophysiologic studies in patients with tricuspid atresia and Wolff-Parkinson-White syndrome after the Fontan operation. In these patients the atrial arrhythmia often seen in patients undergoing the Fontan operation triggered atrioventricular re-entrant tachycardia or caused life-threatening arrhythmias. METHODS: Five patients with tricuspid atresia after palliation with a modified Fontan operation (atrioinfundibular connections) and Wolff-Parkinson-White syndrome are presented. RESULTS: Four of these patients had symptomatic paroxysmal orthodromic atrioventricular re-entrant tachycardia and a history of syncope; one of them additionally had atrial flutter with 2:1 conduction to the ventricle. A fifth patient presented with a life-threatening broad-complex tachycardia. In electrophysiologic studies an accessory pathway was localized in the right septal area in 3 patients. In 2 patients the accessory atrioventricular pathways were created by means of surgical intervention, connecting the right atrial appendage to the right ventricular outflow tract. All patients could be managed successfully by means of catheter ablation. CONCLUSIONS: In patients with tricuspid atresia, there are congenital and surgically acquired accessory pathways responsible for the increased rate of Wolff-Parkinson-White syndrome. Both types of accessory pathways can and should be treated by means of catheter ablation because atrial arrhythmia often seen in patients undergoing the Fontan operation can trigger atrioventricular re-entrant tachycardia or cause life-threatening tachycardia. Congenital accessory pathways should be excluded carefully before surgical intervention for total cavopulmonary anastomosis in patients with tricuspid atresia.

Adolescent↗
PubMed2005

Successful pacemaker lead implantation via the subclavian vein despite of high degree stenosis of the vein.

This case reports on an 81-year-old man with implanted dual-chamber pacemaker for binodal disease who required ventricular lead revision due to loss of ventricular capture. Successful placement of a new lead via the subclavian vein despite of high degree stenosis of the medial part of the vein is described using a very thin bipolar ventricular pacing lead. Currently available pacing electrodes for this purpose are reviewed.

Aged↗
PubMed2005

Acute and long-term results of slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia--an analysis of the predictive factors for arrhythmia recurrence.

BACKGROUND: Predictors of atrioventricular nodal reentrant tachycardia (AVNRT) recurrence after radiofrequency ablation including the importance of residual slow pathway conduction are not known. The aim of this study was to report the acute and long-term results of slow pathway ablation in a large series of consecutive patients with AVNRT and to analyze the potential predictors of arrhythmia recurrence with a particular emphasis on the residual slow pathway conduction after ablation. METHODS: The study included 506 consecutive patients with AVNRT (mean age 52.6 +/- 16 years, 315 women) who underwent slow pathway ablation using a combined electrophysiological and anatomical approach. The end point of ablation procedure was noninducibility of the arrhythmia. The primary end point of the study was the recurrence of AVNRT. RESULTS: Acute success was achieved in 500 patients (98.8%). After ablation, 471 patients (93%) were followed up for a mean of 903 +/- 692 days. Of the 465 patients with successful ablation, 24 patients (5.2%) developed AVNRT recurrences during the follow-up. No significant differences in the cumulative rates of AVNRT recurrence were observed in groups with or without electrophysiological evidence of residual slow pathway conduction (P = 0.25, log-rank test). Multivariate analysis identified only age as an independent predictor of AVNRT recurrence (hazard ratio 0.96, 95% confidence interval 0.94-0.99, P = 0.004) with younger patients being at an increased risk for arrhythmia recurrence. CONCLUSIONS: Our study demonstrated that only younger age, but not other clinical or electrophysiological parameters including residual slow pathway conduction predicted an increased risk for AVNRT recurrence after slow pathway radiofrequency ablation.

Adolescent↗