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Thomas Arentz

Publications and source records attributed to Thomas Arentz.

13 recordsLinked to original sources
PubMed2007

High-density mapping of spontaneous pulmonary vein activity initiating atrial fibrillation in humans.

INTRODUCTION: High-density three-dimensional (3D) mapping of the pulmonary vein (PV)-left atrial (LA) junction was performed to characterize spontaneous PV activity in humans. METHODS AND RESULTS: The activation patterns of ectopic beats and of the initial 2 seconds of atrial fibrillation (AF) from the PVs were analyzed using a 64-poles basket catheter. A focal mechanism was defined as a discrete site of early and centrifugal activation. Continuous activity was considered as an activation covering > or = 80% of the tachycardia beat-to-beat cycle length within the mapping field. In 35 patients, 123 spontaneous focal ectopic beats that did not induce AF and 95 that did induce AF were mapped. The mean coupling interval of ectopic discharges not inducing AF was 281 +/- 70 msec versus 236 +/- 90 msec for ectopies initiating AF (P < or = 0.01). The first ectopic activity of all 218 arrhythmogenic events showed exclusively a focal mechanism. During the 95 episodes of AF initiation, one or two ectopic beats from the PVs initiated AF in the LA in 39%, a stable focal tachycardia was recorded in 14%, continuous activity with important changes in cycle length (35 +/- 15 msec) suggestive of decremental or fibrillatory conduction was found in 18%, and in 29% the activation pattern could not be classified. No stable and sustained reentrant circuit could be identified by our mapping tool in the PV-LA junction. CONCLUSIONS: Arrhythmogenic activity from PVs in humans is predominantly due to discrete focal activity.

Atrial Fibrillation↗
PubMed2005

Pulmonary haemodynamics at rest and during exercise in patients with significant pulmonary vein stenosis after radiofrequency catheter ablation for drug resistant atrial fibrillation.

AIMS: Iatrogenic pulmonary vein (PV) stenosis after radiofrequency catheter ablation for atrial fibrillation (AF) is a new pathology in cardiology. The effects of PV stenosis on the pulmonary circulation are not yet known. We provide long-term follow-up data in patients with significant PV stenosis including magnetic resonance imaging (MRI) and Swan Ganz (SG) right heart catheterization. METHODS AND RESULTS: One hundred and seventeen patients had MRI 12-24 months after the AF ablation procedure. Eleven patients (58+/-7 years, nine males) with significant stenosis (n=9) or occlusion of the proximal PV (n=5) at this follow-up were re-examined using MRI and SG right heart catheterization at rest and during exercise (follow-up time since PV ablation 50+/-15 months). None of these underwent previous PV angioplasty. When compared with prior MRI studies, no significant changes were noted. At rest, no patient had pulmonary hypertension. At 100 W, seven patients had elevated pulmonary artery pressures, three of them probably caused, in part, by left ventricular dysfunction. CONCLUSION: Significant stenosis/occlusions of one or two PV do not create pulmonary hypertension at rest during long-term follow-up. However, seven of the 11 patients develop pulmonary hypertension during exercise. All three patients with stenosis/occlusions of two PV were affected.

Atrial Fibrillation↗
PubMed2005

Transesophageal echocardiography in comparison with magnetic resonance imaging in the diagnosis of pulmonary vein stenosis after radiofrequency ablation therapy.

OBJECTIVE: Doppler-derived flow velocity measured by transesophageal echocardiography (TEE) may overestimate pulmonary vein stenosis. We hypothesized that combining peak velocity with a stenotic flow pattern improves diagnosis compared with magnetic resonance imaging (MRI). METHODS: TEE and MRI were performed in 44 patients 19 +/- 11 months after radiofrequency catheter ablation. Pulmonary vein stenosis was defined by a peak velocity of 110 cm/s or more plus a stenotic flow pattern (turbulence and reduced flow variation) on TEE and a lumen reduction of more than 50% on MRI. RESULTS: In all, 175 pulmonary veins were studied. MRI showed 7 cases of pulmonary vein stenosis that were correctly identified by TEE. In addition, TEE criteria for pulmonary vein stenosis were met in 4 pulmonary veins that did not show obstruction on MRI. In all, 5 pulmonary veins with normal appearance on MRI had peak velocity of 110 cm/s or more with normal flow pattern. CONCLUSIONS: TEE Doppler measurements can be reliably used to detect or exclude significant pulmonary vein stenosis if the diagnosis is restricted to a combination of elevated peak velocity (> or = 110 cm/s) with turbulence and little flow variation.

Catheter Ablation↗
PubMed2005

Effects of circumferential ostial radiofrequency lesions on pulmonary vein activation recorded with a multipolar basket catheter.

AIMS: Two different ablation procedures are performed to cure patients of atrial fibrillation (AF): (1) the electrophysiological pulmonary vein (PV) isolation, and (2) the anatomical circumferential ablation of all four PV ostia. The aim of this study was to determine the effects of circumferential radiofrequency lesions around the ostia on PV activation. METHODS AND RESULTS: In 34 patients with drug refractory paroxysmal (N = 22) or persistent (N = 12) AF a 31-mm basket catheter (BC) was introduced transseptally in the PVs. After creating a circumferential ablation line around the PV ostia using a nonfluoroscopic 3D-navigation system, electrical isolation was achieved in 46% of the PVs, and prolongation of conduction time (+39 +/- 34 ms) was observed in 30%. PVs with persistent conduction (54%) were isolated by ablating the remaining conduction pathways using the BC. At 12 months follow-up, 62% of the patients were in stable sinus rhythm without antiarrhythmic drug therapy. Six patients had developed left atrial flutter. CONCLUSIONS: Anatomically guided, circumferential lesions around the PV ostia resulted in isolation in only 46% of the veins. At 12 months, 62% of the patients were free of AF without antiarrrhythmic drug treatment, however, 6 patients (18%) developed left atrial flutter.

Atrial Fibrillation↗
PubMed2004

"Dormant" pulmonary vein conduction revealed by adenosine after ostial radiofrequency catheter ablation.

INTRODUCTION: The endogenous nucleoside adenosine is an important intermediate in cellular metabolism, a regulator of function in many organ systems, and a pharmacologic agent with potent electrophysiologic effects. We studied the effects of adenosine on the activation of the pulmonary veins (PVs) after successful ostial isolation in patients with atrial fibrillation (AF). METHODS AND RESULTS: Twenty-nine patients (21 male; mean age 54 +/- 10 years) with refractory highly symptomatic persistent (n = 9) or paroxysmal (n = 20) AF were included in the study. PV isolation was performed using radiofrequency catheter ablation guided by a multipolar basket catheter (Constellation, Boston Scientific). After successful PV isolation, we studied the effects of intravenous adenosine (12-18 mg) on activation of the upper PVs. A total of 83 PVs were successfully isolated. After adenosine, PV activity was recorded in 10 (34%) of 29 left upper PVs studied and in 3 (13%) of 24 right upper PVs, coupled to atrial activity for 20 +/- 7 seconds (adenosine positive). In 8 (62%) of 13 cases, PV potentials were recorded in the distal electrodes of the basket catheter only. Dissociated PV rhythms (N = 8) present after PV isolation disappeared after adenosine for 18 +/- 7 seconds, even if reconduction was missing. In 14 patients (48%), a second EP study was performed for recurrence of AF. Adenosine-positive PVs had a nonsignificant higher rate of recovery of conduction than adenosine-negative veins (71% vs 35%, P = 0.095). CONCLUSION: Adenosine induces transient conduction in 25% of PVs following successful isolation. Further studies are necessary to determine the physiologic or pathophysiologic role of adenosine-induced reconduction in human hearts or other organ systems.

Adenosine↗
PubMed2003

Successful catheter ablation of electrical storm after myocardial infarction.

BACKGROUND: We report on 4 patients (aged 57 to 77 years; 3 men) who developed drug-refractory, repetitive ventricular tachyarrhythmias after acute myocardial infarction (MI). All episodes of ventricular arrhythmias were triggered by monomorphic ventricular premature beats (VPBs) with a right bundle-branch block morphology (RBBB). METHODS AND RESULTS: Left ventricular (LV) mapping was performed to attempt radiofrequency (RF) ablation of the triggering VPBs. Activation mapping of the clinical VPBs demonstrated the earliest activation in the anteromedial LV in 1 patient and in the inferomedial LV in 2 patients. Short, high-frequency, low-amplitude potentials were recorded that preceded the onset of each extrasystole by a maximum of 126 to 160 ms. At the same site, a Purkinje potential was documented that preceded the onset of the QRS complex by 23 to 26 ms during sinus rhythm. In 1 patient, only pace mapping was attempted to identify areas of interest in the LV. Six to 30 RF applications abolished all local Purkinje potentials at the site of earliest activation and/or perfect pace mapping and suppressed VPBs in all patients. No episode of ventricular tachycardia or fibrillation has recurred for 33, 14, 6, and 5 months in patients 1, 2, 3, and 4, respectively. CONCLUSIONS: Incessant ventricular tachyarrhythmias after MI may be triggered by VPBs. RF ablation of the triggering VPBs is feasible and can prevent drug-resistant electrical storm, even after acute MI. Catheter ablation of the triggering VPBs may be used as a bailout therapy in these patients.

Aged↗
PubMed2003

Feasibility and safety of pulmonary vein isolation using a new mapping and navigation system in patients with refractory atrial fibrillation.

BACKGROUND: Ostial pulmonary vein (PV) isolation by radiofrequency (RF) catheter ablation can cure patients with atrial fibrillation (AF); however, this procedure carries the risk of PV stenosis. The aim of this study was to assess the feasibility of a new mapping and navigation technique using a multipolar basket catheter (BC) for PV isolation in patients with refractory AF and to analyze its safety with regard to PV stenosis at long-term follow-up. METHODS AND RESULTS: We studied 55 patients (mean age, 53+/-11 years; 40 male) with drug-refractory AF (paroxysmal, n=37; persistent, n=18). A 64-pole BC was placed transseptally into each of the accessible PVs. By use of a nonfluoroscopic navigation system, the ablation catheter was guided to the BC electrodes at the PV ostium, with earliest activation during sinus rhythm. RF was delivered by use of maximum settings of temperature at 50 degrees C and power at 30 W. The end point of the procedure was the complete elimination of all distal and fragmented ostial PV potentials. Of 165 targeted veins, 163 were successfully isolated with a mean RF duration of 720+/-301 seconds per vein. At 1-year follow-up, 62% of the patients were in sinus rhythm without antiarrhythmic drugs. Contrast-enhanced magnetic resonance angiography revealed 2 PV stenoses of >25% out of 165 treated vessels. CONCLUSIONS: The use of a multipolar BC allowed effective and safe PV isolation by combining 3D mapping and navigation. At 1-year follow-up, 62% of the patients were in sinus rhythm without antiarrhythmic drugs, and the incidence of relevant diameter reduction of the treated PVs was 1.2%.

Atrial Fibrillation↗
PubMed2003

[3-d mapping of pulmonary veins using a multipolar basket catheter. Implications for catheter ablation of atrial fibrillation].

BACKGROUND: Focal discharges from pulmonary veins are the major sources of paroxysmal atrial fibrillation. The aim of this study was to analyze the activation pattern of pulmonary veins during sinus rhythm and ectopy with the help of a multipolar basket catheter and to disconnect them from the left atrium by localized radiofrequency catheter ablation. PATIENTS AND METHODS: We studied 65 patients (43 male, 22 female, mean age 54 +/- 12 years) with drug-refractory atrial fibrillation (paroxysmal n = 42, persistent n = 23). A 64-pole basket catheter (Figure 1) with a diameter of 31 or 38 mm (Constellation, Boston Scientific) was placed transseptally into the pulmonary veins to record its activation during ectopic beats and during sinus rhythm or coronary sinus pacing (Figure 2). The ablation catheter was placed as ostial as possible next to the electrodes showing the earliest pulmonary vein activation during sinus rhythm or coronary sinus pacing (Figures 3 and 4a). The radiofrequency energy was delivered with a maximum temperature of 50 degrees C and a maximum power of 30 W. In 32 patients, an irrigated-tip catheter (Thermocool, Biosense-Webster) was used. Endpoint of the procedure was the complete elimination of all distal pulmonary vein potentials during sinus rhythm (Figure 4b). RESULTS: The mean number of procedures per patients was 1.25, mean procedure time 236 +/- 79 min, and mean fluoroscopy time 40 +/- 17 min, respectively. In 16 veins, repetitive discharges (more than three) could be recorded under stable conditions (Figures 2 and 5). In twelve of these 16 pulmonary veins (75%), the activation pattern during ectopic beats was identical in the same vein, but different from one vein to another (Figure 2). In four veins, changing activation patterns were observed in the same vein. Focal atrial fibrillation was recorded in four pulmonary veins (Figures 6 and 7). A total of 187 out of 190 mapped veins were successfully isolated at the ostium by ablating 2.3 +/- 1.1 separated conduction pathways. In 16 patients, a second EP study was performed for recurrence of atrial fibrillation. Recovery of conduction of a previously isolated pulmonary vein was identified as the primary reason for recurrence of atrial fibrillation. The second reason were ostial foci, localized proximal to the ablation line (Figure 8). COMPLICATIONS AND FOLLOW-UP: One pericardial tamponade occurred. Carbonization on the splines of the basket catheter-observed in twelve cases with use of a nonirrigated-tip catheter-was prevented by use of irrigated-tip catheters. At 12 months, 36 out of 65 patients (55%) are in sinus rhythm without antiarrhythmic drug use, 28 of 42 patients (67%) with paroxysmal atrial fibrillation. Only one pulmonary vein stenosis > 50% was detected by angiomagnetic resonance imaging 1 year after the procedure. CONCLUSION: 75% of the arrhythmogenic pulmonary veins showed a stable and specific pattern during repetitive ectopic activity. Ostial ablation of 2.3 +/- 1.1 separated conduction pathways from the left atrium into the pulmonary veins resulted in complete conduction block in 187 of 190 veins.

Adult↗
PubMed2003

Incidence of pulmonary vein stenosis 2 years after radiofrequency catheter ablation of refractory atrial fibrillation.

AIMS: Pulmonary vein ablation offers the potential to cure patients with atrial fibrillation. In this study, we investigated the incidence of pulmonary vein stenosis after radiofrequency catheter ablation of refractory atrial fibrillation by systematic long-term follow-up. METHODS AND RESULTS: Forty-seven patients with refractory and highly symptomatic atrial fibrillation underwent radiofrequency catheter ablation of arrhythmogenic triggers inside the pulmonary veins and/or ostial pulmonary vein isolation with conventional mapping and ablation technology. These patients had follow-up examinations at 2 years with transoesophageal doppler-echo and/or angio magnetic resonance imaging for the evaluation of the pulmonary veins. Seventy-seven percent of the patients were free from atrial fibrillation, 51% were without antiarrhythmic drugs, and 26% were on previously ineffective antiarrhythmic drug therapy. However, 13 of the 47 patients showed significant pulmonary vein stenosis or occlusion. Only three of these 13 patients complained of dyspnoea. Distal ablations inside the pulmonary vein were associated with a 5.6-fold higher risk of stenosis than ostial ablations. CONCLUSIONS: At 2-year follow-up, the risk of significant pulmonary vein stenosis/occlusion after radiofrequency catheter ablation of refractory atrial fibrillation with conventional mapping and ablation technology was 28%. Distal ablations inside smaller pulmonary veins should be avoided because of the higher risk of stenosis than ablation at the ostium.

Atrial Fibrillation↗
PubMed2003

Dissociated pulmonary vein arrhythmia: incidence and characteristics.

INTRODUCTION: The incidence and characteristics of dissociated arrhythmia confined to the pulmonary vein (PV) following disconnection have not been described in a large number of patients with paroxysmal atrial fibrillation. METHODS AND RESULTS: This was a prospective study of 152 patients (29 female, mean age 51 +/- 11 years) referred for catheter ablation of drug-refractory paroxysmal atrial fibrillation. Following ostial ablation, the rate and regularity of any dissociated venous activity was analyzed with and without isoproterenol infusion (to achieve a heart rate of 120-140 beats/min). Patients then were classified according to their venous dissociated activity. Group 1 consisted of patients in whom the dissociated PV spike had a slow rhythm >1,200 ms. Group 2 consisted of patients with spontaneous repetitive dissociated discharges confined in the vein with a cycle length <400 ms. A total of 384 PVs were ablated in 152 patients. Disappearance of all venous potentials was observed in 88% of the treated veins; at least one dissociated venous potential was observed in the remaining 12%. Group 1 activity was seen more often than group 2 (23 patients, mean cycle length 2,300 +/- 1,100 ms vs 13 patients, mean cycle length 179 +/- 77 ms). Dissociated PV arrhythmia was seen most often in the right superior PV (19%). CONCLUSION: Dissociation as the endpoint of PV disconnection was observed in 12% of PVs. Due to the capricious nature of this activity, the actual incidence is almost certainly higher. The dissociated venous rhythm usually is slow and, less commonly, is rapid and repetitive.

Adult↗
PubMed2002

Mapping and ablation of idiopathic ventricular fibrillation.

BACKGROUND: Ventricular fibrillation is the main mechanism of sudden cardiac death. The feasibility of eliminating recurrent episodes by catheter ablation has not been reported. METHODS AND RESULTS: Twenty-seven patients without known heart disease (13 men, 14 women, 41+/-14 years of age) were studied after being resuscitated from recurrent (10+/-12) episodes of primary idiopathic ventricular fibrillation; 23 had received a defibrillator. The first initiating beat of ventricular fibrillation had an identical electrocardiographic morphology and coupling interval (297+/-41 ms) to preceding isolated premature beats typically noted in the aftermath of resuscitation. These triggers were localized by mapping the earliest electrical activity and ablated by local radiofrequency delivery. Outcome was assessed by Holter and defibrillator memory interrogation. Premature beats were elicited from the Purkinje conducting system in 23 patients: from the left ventricular septum in 10, from the anterior right ventricle in 9, and from both in 4. The interval from the Purkinje potential to the following myocardial activation varied from 10 to 150 ms during premature beat but was 11+/-5 ms during sinus rhythm, indicating location at peripheral Purkinje arborization. The premature beats originated from the right ventricular outflow tract muscle in 4 patients. The accuracy of mapping was confirmed by acute elimination of premature beats during local radiofrequency delivery. During a follow-up of 24+/-28 months, 24 patients (89%) had no recurrence of ventricular fibrillation without drug. CONCLUSIONS: Primary idiopathic ventricular fibrillation is a syndrome characterized by dominant triggers from the distal Purkinje system. These sources can be eliminated by focal energy delivery.

Adult↗
PubMed2002

Role of Purkinje conducting system in triggering of idiopathic ventricular fibrillation.

Ventricular fibrillation is the main mechanism of sudden cardiac death, but the source of its spontaneous initiation has not been mapped. 16 patients were investigated by electrography and radiofrequency ablation after resuscitation from recurrent idiopathic ventricular fibrillation. Triggers of ventricular fibrillation originated from various locations within the Purkinje system in 12 patients and from the ordinary myocardial muscle in four. The accuracy of mapping was confirmed by acute elimination of triggers by radiofrequency delivery, and there was no recurrence of ventricular fibrillation in 14 patients. Long-term follow-up is necessary to establish that ablation is curative and avoids use of a defibrillator.

Adolescent↗