[Catheter ablation of atrial fibrillation]. / Katheterablation bei Vorhofflimmern. Läsionen errichten elektrische Blockaden.

In patients with drug-refractory atrial fibrillation, left-atrial catheter ablation represents a new curative therapeutic option. Segmental ostial or circumferential pulmonary vein isolation can achieve stable sinus rhythm in some 70% of patients with paroxysmal atrial fibrillation but no severe structural heart disease. In patients with chronic atrial fibrillation, complex left-atrial linear, or substrate-oriented ablation strategies may additionally be applied. In patients with cardiac insufficiency or more severe systolic left-ventricular dysfunction, restoration of a stable sinus rhythm through the use of left-atrial catheter ablation can improve the left-ventricular ejection fraction and reduce the severity of cardiac failure. Potential complications of ablation include, in particular, pulmonary veins stenosis, iatrogenic left-atrial tachycardia, thromboembolic events and fatal atrio-esophageal fistulas.

Bundle branch reentrant tachycardia in a patient with a calcified bicuspid aortic valve and normal ventricular function.

We report the case of a bundle branch reentrant tachycardia (BBRT) in a 40-yearold patient with a calcified bicuspid aortic valve and normal left ventricular function. The ventricular tachycardia was eliminated by successful radiofrequency ablation of the right bundle branch. As the aortic valve annulus is in close proximity to the specialized conduction system, premature degeneration of a bicuspid aortic valve may involve the bundle of His and the proximal bundle branches by invading calcifications. We speculate that calcifications invading the proximal bundle branches from the bicuspid aortic valve may have created the substrate for the BBRT in this patient.

Risk factors for recurrence of atrial fibrillation in patients undergoing hybrid therapy for antiarrhythmic drug-induced atrial flutter.

AIMS: Catheter ablation of the inferior vena cava-tricuspid annulus isthmus and continuation of antiarrhythmic drug therapy have been shown to be an effective hybrid therapy for atrial flutter which results from antiarrhythmic drug treatment of atrial fibrillation. The aim of this study was to determine the risk factors for recurrence of atrial fibrillation in patients undergoing hybrid therapy for antiarrhythmic drug-induced atrial flutter. METHODS AND RESULTS: 90 patients with paroxysmal (n=46) or persistent atrial fibrillation (n=44) developed atrial flutter due to the administration of amiodarone (n=48), flecainide (n=22), propafenone (n=14) or sotalol (n=6). Recurrence of atrial fibrillation after ablation was assessed during follow-up on continued antiarrhythmic drug therapy and during long-term follow-up, irrespective of the initial antiarrhythmic medication. During the follow-up on continued antiarrhythmic drug therapy (16+/-13 months), recurrence of atrial fibrillation was documented in 24 of 90 patients (27%). The presence of accompanying pre-ablation episodes of atrial fibrillation on antiarrhythmic treatment (Odds ratio 7.1, 95% confidence interval 2.3 to 25, p=0.001) and decreased left ventricular ejection fraction (Odds ratio 3.7, 95% confidence interval 1.01 to 12.5, p=0.048) were significant and independent predictors of post-ablation atrial fibrillation. Antiarrhythmic medication was discontinued during long-term follow-up due to adverse drug effects (amiodarone, n=12; flecainide, n=1) in 13 patients (14%). During the long-term follow-up, irrespective of the initial antiarrhythmic medication (21+/-15 months), stable sinus rhythm was maintained in 60 of 90 patients (67%). CONCLUSION Hybrid therapy can be considered as the first line therapy for patients with antiarrhythmic drug-induced atrial flutter but patients should be carefully evaluated for accompanying pre-ablation episodes of atrial fibrillation and possible adverse drug effects before initiation of hybrid therapy.

Early reinitiation of atrial fibrillation following external electrical cardioversion in amiodarone-treated patients.

UNLABELLED: Early reinitiation of atrial fibrillation (ERAF) following external or internal electrical cardioversion is one of the factors determining unsuccessful electrical cardioversion. Prevention of ERAF has not been studied systematically in patients on amiodarone therapy. METHODS AND RESULTS: 22 patients had ERAF within 1 min after external electrical cardioversion of atrial fibrillation. 11 patients were on amiodarone therapy and 11 patients had no antiarrhythmic medication. The effect of atropine, post-shock atrial pacing and intravenous ajmaline on ERAF was consecutively tested in these patients. Administration of atropine before repeated defibrillation or post-shock atrial pacing prevented ERAF in 9 of the 11 patients (82%) on amiodarone therapy but in only 3 of 11 patients (27%) without amiodarone (p<0.05). In the remaining patients, intravenous ajmaline was effective in the suppression of ERAF in 5 patients without amiodarone and in 1 patient with amiodarone. The PP interval preceding the atrial premature beat reinitiating atrial fibrillation was nonsignificantly longer in amiodarone-treated patients (1127+/-419 ms) in comparison to patients without amiodarone (896+/-271ms). 27% of patients without amiodarone at the time of electrical cardioversion and 55% of patients with amiodarone remained in sinus rhythm during the follow-up of 29+/-14 and 30+/-14 months, respectively. CONCLUSIONS: ERAF in patients on amiodarone can be treated by atropine or atrial pacing to prevent bradycardia-dependent ERAF. ERAF in amiodarone-treated patients does not apparently predict late recurrence of atrial fibrillation on continued amiodarone therapy.

Electroanatomical mapping for visualization of atrial activation in patients with incisional atrial tachycardias.

AIMS: Incisional atrial tachycardias in patients following surgery for congenital heart disease are based on complex structural abnormalities in these hearts. The aim of this study was to evaluate the use of the electroanatomical mapping system, CARTO, in consecutive patients with different forms of incisional atrial tachycardia. METHODS AND RESULTS: The electroanatomical mapping system combines electrophysiological and spatial information and allows visualization of atrial activation in a three-dimensional anatomical reconstruction of the atria. Electroanatomical mapping of right atrial activation was performed in 10 patients after surgery for congenital heart disease, surgery for Wolff-Parkinson-White syndrome, or heart transplantation presenting with 13 incisional atrial tachycardias. The three-dimensional mapping allowed a rapid distinction between focal (n=3) and reentrant mechanisms (n=10) and visualization of the activation wavefronts along anatomical and surgically created barriers. Electroanatomical activation maps (mean right atrial activation time 213+/-107 ms) were constructed with 89+/-60 catheter positions during an average mapping time of 48+/-33 min. Reentrant tachycardias propagating through the tricuspid annulus-vena cava inferior isthmus (n=6) or along periatriotomy loops (n=4) were identified in eight patients. Ectopic atrial foci near surgical scars could be localized in three patients. Catheter ablation by creation of a lesion in a critical isthmus of conduction or by targeting the arrhythmogenic focus eliminated 11 of 13 incisional atrial tachycardias. CONCLUSION: Visualization of atrial activation in a three-dimensional reconstruction of the right atrium using the electroanatomical mapping system CARTO facilitates understanding of the mechanism and defines the reentrant circuits of incisional atrial tachycardias. This new method may improve the success rate of electrophysiologically guided and anatomically guided catheter ablation of incisional atrial tachycardias.

Catheter ablation of atrial flutter due to amiodarone therapy for paroxysmal atrial fibrillation.

AIMS: Antiarrhythmic drug treatment for atrial fibrillation can cause atrial flutter-like arrhythmias. The aim of this study was to clarify the effect of catheter ablation of the tricuspid annulus-vena cava inferior isthmus on amiodarone-induced atrial flutter and to determine the incidence of atrial fibrillation after catheter ablation of amiodarone-induced atrial flutter in comparison to regular typical flutter. METHODS AND RESULTS: Among 92 consecutive patients with typical atrial flutter who underwent isthmus ablation 28 patients had atrial flutter without a history of previous atrial fibrillation (group I), 10 patients had atrial flutter following the initiation of amiodarone therapy for paroxysmal atrial fibrillation (group II) and 54 patients had atrial flutter and atrial fibrillation (group III). Atrial cycle length during atrial flutter in amiodarone-treated patients (group II) (277+/-24 ms) was significantly longer as compared to the cycle length of atrial flutter in group I (247+/-33 ms) and group III patients (235+/-28 ms). The rate of successful transient entrainment and overdrive stimulation to sinus rhythm was not different between patients with (60%) or without amiodarone therapy (group I: 71%, group III: 53%). Successful isthmus ablation with bidirectional conduction block eliminating right atrial flutter was achieved in 90% of amiodarone-treated patients and 93% of patients without amiodarone therapy. In the amiodarone-treated patient group atrial conduction times during pacing in sinus rhythm were significantly prolonged by 20-30% before and after ablation in all regions of the reentrant circuit. During a mean follow-up of 8+/-3 months post-ablation, atrial fibrillation recurred in two of 10 patients on continued amiodarone therapy after successful isthmus ablation. Thus, successful catheter ablation of atrial flutter due to amiodarone therapy was associated with a markedly lower recurrence rate of paroxysmal atrial fibrillation (20%) as compared to patients with atrial flutter plus preexisting paroxysmal atrial fibrillation (76%) and was similar to the outcome of patients with successful atrial flutter ablation without preexisting atrial fibrillation (25%). CONCLUSION: These data suggest that isthmus ablation with bidirectional block and continuation of amiodarone therapy is an effective therapy for the treatment of atrial flutter due to amiodarone therapy for paroxysmal atrial fibrillation.

New mapping technology for atrial tachycardias.

UNLABELLED: Prerequisite for succesful radiofrequency catheter ablation of tachycardias is the exact mapping during the electrophysiological study. The new mapping system CARTO allows a three-dimensional color-coded electroanatomic map of impulse propagation using electromagnetic technology. The aim of this study was to determine the feasibility and safety of the new electromagnetic mapping technology CARTO for atrial tachycardias. RESULTS: Electrophysiologic study and CARTO mapping was performed in 38 atrial tachycardias. The mapping procedure took 26 +/- 23 min. We created 33 maps within the right atrium and 5 maps within the left atrium with a mean of 74 +/- 38 different catheter positions. The mechanism was determined as reentrant in 9, junctional in 1 and focal in 28 tachycardias. In focal tachycardias the tachycardia cycle length (CL) and the total atrial activation time (AT) were clearly different (352 +/- 98 ms vs 99 +/- 25 ms). Reentrant tachycardias had a comparable CL and AT (236 +/- 44 ms vs 240 +/- 56 ms). In 83% of the focal tachycardias and in 67% of the reentrant tachycardias, ablation was performed successfully. No complications occured. CONCLUSION: The electroanatomic mapping system allows high resolution visualization of electrical activity and may therefore improve precision and simplify the determination of the arrhythmogenic substrate during tachycardias for successful catheter ablation.

Slow pathway ablation in a patient with common AV nodal reentrant tachycardia and complete situs inversus.

A 72-year-old woman with complete situs inversus underwent successful slow pathway ablation of typical AV nodal reentrant tachycardia. Catheter ablation of AV nodal reentrant tachycardia in dextrocardia required a lengthy procedure but was safe and without complications.

Effects of Class I drugs on atrial fibrillation.

This article reviews our knowledge about the efficacy of Class I antiarrhythmic agents, especially quinidine, propafenone, and flecainide, for pharmacologic conversion of atrial fibrillation to sinus rhythm. When given intravenously or orally for the long term, conversion rates between 50% and 90% are reported for restoration of sinus rhythm as well as for maintenance of sinus rhythm after DC cardioversion. Based on transtelephonic monitoring of arrhythmia recurrences as well as tolerance, Class IC agents appear to be especially effective for suppressing clinical symptoms in patients with paroxysmal atrial fibrillation. For patients who develop atrial fibrillation following coronary artery surgery, Class I agents are the second choice of treatment only. The concept of single oral loading with Class IC agents for conversion of atrial fibrillation appears attractive, but more data are needed before we conclude that it is efficacious as well as safe when given to ambulatory patients. Because all Class I antiarrhythmic agents have the potential for lethal proarrhythmia, the greatest and as yet unsettled issue is safety. Until the advent of large-scale and long-term trials demonstrating the efficacy and safety of Class I agents for the treatment of patients with atrial fibrillation, this strategy, although very popular to suppress frequent and unpleasant symptoms due to atrial fibrillation, cannot be regarded as firmly established.

[Repetitive monomorphic ventricular tachycardia (Gallavardin type): clinical and electrophysiological characteristics in 20 patients]. / Repetitive monomorphe ventrikuläre Tachykardie (Typ Gallavardin): Klinische und elektrophysiologische Charakteristika von 20 Patienten.

Repetitive monomorphic ventricular tachycardia (RMVT) is defined by the presence of numerous monomorphic isolated, premature ventricular complexes, couplets, and runs of unsustained ventricular tachycardia having the same morphology in patients without structural heart disease. Patients with RMVT mostly demonstrate the typical left bundle branch block morphology with normal or rightward axis during tachycardia. At our institution, 20 patients with RMVT have been systematically studied: a syncope had occurred in 35% of our patients, in three cases a syncope was the first manifestation of the RMVT. Of our RMVT patients, 25% developed sustained episodes (> 3 min) of ventricular tachycardia as documented by Holter ECG. The salvos of ventricular tachycardia are generally short in RMVT. This behavior and the typical exercise dependence differentiates RMVT from paroxysmal sustained idiopathic ventricular tachycardia. Exercise testing is mandatory for correct diagnosis of RMVT. In our institution, 85-90% of RMVT patients demonstrated runs of ventricular tachycardia or sustained ventricular tachycardia while on a treadmill (exercise test) or during isoproterenol infusion. RMVT was inducible by programmed electrical right ventricular stimulation in only 13% of our patients. Therefore, in patients with suspected RMVT programmed electrophysiological stimulation is only useful to differentiate a ventricular tachycardia from a supraventricular tachycardia with bundle brunch block or in patients with unexplained syncope. The prognosis is considered generally good; in our patients no life threatening ventricular tachyarrhythmias were observed during a follow-up of up to 4 years. Verapamil and beta-adrenoceptor antagonists generally offer symptomatic improvement. In some cases treatment with a class III antiarrhythmic agent is necessary. While drug-refractory paroxysmal sustained idiopathic ventricular tachycardia can be abladed with both immediate and long-term success, catheter ablation of RMVT is only rarely indicated.

Fast pathway ablation in patients with common atrioventricular nodal reentrant tachycardia and prolonged PR interval during sinus rhythm.

AIMS: This study aimed to clarify the safety and efficacy of selective fast pathway ablation in patients with atrioventricular nodal reentrant tachycardia and a prolonged PR interval during sinus rhythm. Such patients have been reported to have an increased incidence of complete atrioventricular block. METHODS AND RESULTS: In this study, the earliest retrograde atrial activation during atrioventricular nodal reentrant tachycardia and right ventricular stimulation was localized. Fast pathway ablation was then performed in five patients with the common form of atrioventricular nodal reentrant tachycardia and a prolonged PR interval. Three of the five patients had almost incessant atrioventricular nodal reentrant tachycardia. Radiofrequency catheter ablation induced a complete ventriculo-atrial block during right ventricular stimulation in four patients and a marked prolongation of ventriculo-atrial conduction during right ventricular stimulation in one. Non-inducibility of common atrioventricular nodal reentrant tachycardia with and without isoproterenol was achieved in all five patients. The PR interval increased from 254 +/- 53 ms to 276 +/- 48 ms and the atrio-His interval from 172 +/- 46 ms to 192 +/- 45 ms. Second- or third-degree atrioventricular block did not occur during the ablation procedure. During the followup of 19 +/- 20 months none of the patients developed symptoms suggestive of atrioventricular nodal reentrant tachycardia or evidence of second- or third-degree atrioventricular block. CONCLUSION: These data suggest that atrioventricular node (retrograde) fast pathway ablation can apparently be safely performed in patients with common atrioventricular nodal reentrant tachycardia and a prolonged PR interval during sinus rhythm.

[Electro-anatomic mapping of the sinoatrial activation: initial experiences with the new CARTO mapping system]. / Elektroanatomisches Mapping der sinuatrialen Aktivierung: Erste Erfahrungen mit dem neuen Mappingsystem CARTO.

Prerequisite for successful radiofrequency catheter ablation on tachycardias is the exact mapping during the electrophysiologic study. The new mapping system CARTO allows a three-dimensional color-coded electroanatomic map of impulse propagation using electromagnetic technology. Mapping of sinuatrial activation in the right atrium of 11 patients represents the first clinical experience with this new system. The physiological activation sequence could be determined in all patients three-dimensionally, and the sinus node could be localized as a physiological activation focus with interindividual variability only in the sagital plane without complications. The nonfluoroscopic mapping system allows high resolution visualization of electrical activity and may therefore improve precision and simplify the determination of the arrhythmogenic substrate during tachycardias for successful catheter ablation.

[Radiofrequency catheter ablation of an accessory atrioventricular conduction pathway with persistent left superior vena cava and hypertrophic cardiomyopathy]. / Radiofrequenzkatheterablation einer akzessorischen atrioventrikulären Leitungsbahn bei persistierender oberer linker Hohlvene und hypertropher Kardiomyopathie.

A 43-year-old man with a 30-year history of WPW-syndrome and a hypertrophic cardiomyopathy developed acute heart failure after onset of atrial fibrillation with fast antegrade conduction, which could be converted to sinus rhythm with antiarrhythmic medication. Catheterization of the coronary sinus during EP testing demonstrated a persistent left superior vena cava. The accessory pathway could be localized at the orifice of an atypical epicardial vein. It was successfully abolished after subvalvular placement of the electrode catheter in the left ventricle. This constellation indicates a combined defect during the regression of the sinus venosus to the sinus coronarius with persistence of conducting muscle fibers. Successful RF ablation procedure provides an obvious risk reduction as a result of a lower frequency of atrial fibrillation and the eliminated risk of ventricular fibrillation due to rapid conduction via an accessory pathway. Beyond that, harmless therapeutic treatment of hypertrophic cardiomyopathy with a calcium-channel-blocker (verapamil type) can follow RF ablation.

[Left ventricular catheter ablation of the AV conduction system with radiofrequency electric current]. / Linksventrikuläre Katheterablation des AV-Uberleitungssystems mit Radiofrequenzstrom.

We report on a 32-year-old female patient with a history of recurrent atrial fibrillation and rapid ventricular response (up to 240 beats/min) resistant to multiple drug therapy. In this patient, we successfully performed a radiofrequency catheter ablation of the atrioventricular (AV) junction from the left ventricle, after radiofrequency energy application in His-position above the tricuspid valve was unsuccessful. This technique offers an-alternative treatment in patients in whom the conventional right-sided catheter ablation of the AV junction proves ineffective.