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H Kottkamp

Publications and source records attributed to H Kottkamp.

At least 55 records · Page 3Linked to original sources
PubMed1995

Radiofrequency catheter ablation of sustained ventricular tachycardia in idiopathic dilated cardiomyopathy.

BACKGROUND: The feasibility of radiofrequency (RF) catheter ablation for the treatment of sustained ventricular tachycardia (VT) in patients with coronary artery disease and remote myocardial infarction has recently been demonstrated. At present, therapeutic options for VT in patients with idiopathic dilated cardiomyopathy (DCM) include antiarrhythmic drugs and implantable cardioverter/defibrillators (ICD). The purpose of the present study was to investigate the feasibility of RF catheter ablation in patients with idiopathic DCM who could not be adequately treated by conventional treatment modalities because of incessant or frequent, recurrent VT. METHODS AND RESULTS: RF current application for ablation of 9 VTs (mean cycle length, 402 +/- 78 ms) was attempted in 8 patients with idiopathic DCM (4 men, 4 women; mean age, 54 +/- 6 years; mean left ventricular ejection fraction, 30 +/- 9%). Inclusion criteria for ablation were incessant VT (n = 4) or frequent, recurrent VT reproducibly inducible with programmed electrical stimulation (n = 5). Three patients had suffered aborted sudden cardiac death, and 2 had experienced syncope. Two patients were artificially ventilated and catecholamine dependent for hemodynamic reasons at the time of attempted ablation. Potential target sites for RF current application were identified by detailed endocardial mapping during sinus rhythm, activation and entrainment mapping during VT, and pace mapping. After 7 +/- 5 RF pulses (range, 2 to 18 pulses; median, 6 pulses) applied with 32 +/- 7 W for 39 +/- 9 seconds, 6 of the 9 target VTs (67%) were rendered noninducible (4 of 4 incessant VTs and 2 of 5 chronic recurrent VTs). In 6 patients, VTs with ECG morphologies other than the target VTs were inducible after RF catheter ablation. Seven patients were on antiarrhythmic drugs during the ablation procedure and during the follow-up period of 8 +/- 5 months (range, 2 to 17 months). One patient received an ICD before RF ablation, 4 patients after RF ablation, and 1 patient after ablation of an incessant VT and before attempted ablation of frequent, recurrent VTs. One patient underwent heart transplantation 5 months after ablation in end-stage heart failure. There were no acute complications during the mapping and ablation procedure. During the follow-up period, 1 patient had been resuscitated from ventricular fibrillation 6 weeks after ablation and finally died of congestive heart failure 2 weeks later. No further episodes of incessant VT occurred in the patients who had undergone RF current application for ablation of incessant VT. A complete prevention of VT could be achieved in 2 of 8 patients, whereas in 5 patients, VT episodes were stored in the ICD devices during follow-up. CONCLUSIONS: The results of the present study indicate that RF current application for ablation of VT in a select group of patients with idiopathic DCM is feasible. The efficacy of RF ablation may be high in patients presenting with incessant VT, whereas the success rate seems to be only moderate in patients with chronic recurrent VT. In all patients, additional treatment options, including antiarrhythmic drugs, ICDs, and/or heart transplantation, were applied after RF ablation, indicating that RF ablation for this indication may be an adjunctive and not a curative treatment option.

Anti-Arrhythmia Agents↗
PubMed1995

Localization and radiofrequency catheter ablation of left-sided accessory pathways during atrial fibrillation. Feasibility and electrogram criteria for identification of appropriate target sites.

OBJECTIVES: The purpose of the present study was to assess the feasibility of and electrophysiologic criteria for successful radiofrequency catheter ablation of left-sided accessory pathways during atrial fibrillation in patients with Wolff-Parkinson-White syndrome. BACKGROUND: The onset of recurrent or sustained atrial fibrillation can complicate or significantly prolong accessory pathway catheter ablation procedures. METHODS: We studied 19 consecutive patients (mean age [+/-SD] 44 +/- 16 years) with Wolff-Parkinson-White syndrome who had ongoing atrial fibrillation with rapid anterograde conduction over the accessory pathway (mean ventricular rate [+/-SD] 173 +/- 26 beats/min, range 130 to 220) at the beginning of the localization procedure during radiofrequency catheter ablation. Localization and ablation of the accessory pathway were performed with a 7F deflectable catheter (4-mm tip) that was placed underneath the mitral valve annulus. The electrophysiologic criteria from unipolar and bipolar local electrograms were compared for successful (n = 18) and unsuccessful (n = 39) sites. RESULTS: The accessory pathways were localized in the left posteroseptal (n = 6), posterior (n = 1), posterolateral (n = 7) and lateral (n = 5) regions and successfully ablated during atrial fibrillation in 18 (95%) of 19 patients with a mean of 3 +/- 2 radiofrequency pulses (range 1 to 8, median 2). Presence of an accessory pathway potential (94% vs. 44%), early activation time of the ventricular electrogram (-3.2 +/- 9.2 vs. -15.3 +/- 12.6 ms) and recording of atrial activation (88% vs. 61%) from the ablation catheter were helpful in identifying successful sites (p < 0.001, p < 0.001 and p < 0.05, respectively, compared with unsuccessful sites). In addition, the ventricular activation time in relation to the intrinsic deflection of the unipolar electrogram was significantly earlier at successful than unsuccessful sites (18.1 +/- 4.8 vs. 24.4 +/- 6.6 ms, p < 0.01). A QS complex on the unipolar electrogram was observed at 96% of successful sites and at 94% of unsuccessful sites (p = 0.74). Multivariate logistic regression analysis revealed that the presence of an accessory pathway potential (p < 0.002) and early ventricular activation time in relation to the onset of the QRS complex (p < 0.001) were independent predictors of ablation success. CONCLUSIONS: Localization and radiofrequency catheter ablation of left-sided accessory pathways is possible in patients with sustained atrial fibrillation and rapid anterograde conduction over the accessory pathway during the ablation procedure. The electrophysiologic criteria described here can be used to reliably identify successful sites for radiofrequency ablation.

Adult↗
PubMed1995

An anatomically and electrogram-guided stepwise approach for effective and safe catheter ablation of the fast pathway for elimination of atrioventricular node reentrant tachycardia.

OBJECTIVES: We describe a new stepwise anatomically and electrogram-guided strategy for radiofrequency catheter ablation of the fast pathway. BACKGROUND: Anatomically and electrogram-guided approaches have been developed for slow pathway ablation in patients with atrioventricular (AV) node reentrant tachycardia; however, no stepwise systematic approaches exist for fast pathway ablation. METHODS: Fifty-three patients (mean [+/- SD] age 43 +/- 11 years) with AV node reentrant tachycardia underwent attempted ablation of the fast pathway. The ablation catheter was initially positioned posterior and slightly superior to the site of the maximal His bundle recording region. At these sites, the amplitude of the local atrial potential was usually at least twice as high as the local ventricular potential, and a small proximal His bundle potential was recorded. When the first pulse was ineffective, the ablation catheter was repositioned stepwise slightly inferior to more midseptal sites. RESULTS: After a mean of 3.4 +/- 3.1 radiofrequency pulses (median 2, range 1 to 12), AV node reentrant tachycardia was noninducible in 51 patients (96%). No inadvertent complete AV block occurred. The AH interval was prolonged from 79 +/- 19 to 145 +/- 37 ms (p < 0.001). Thirty-eight patients (72%) developed complete ventriculoatrial block. Recording of a His bundle potential at the target site, stability of the local electrograms and occurrence of fast junctional rhythms during energy applications were more often observed at successful sites than transiently effective or noneffective sites. During a follow-up period of 12 +/- 7 months, 3 (6%) of 51 patients had a clinical recurrence of AV node reentrant tachycardia. CONCLUSIONS: Radiofrequency catheter ablation of the fast pathway using a combined anatomically and electrogram-guided stepwise approach is highly effective and safe. The safety of this approach seems to be due to the stable position of the ablation catheter at the interatrial septum, rather than across the tricuspid annulus, and the larger distance to the central body of the AV node and bundle of His.

Adult↗
PubMed1995

Induction of transient third degree atrioventricular block during radiofrequency catheter ablation in a patient with ventricular tachycardia and remote myocardial infarction.

INTRODUCTION: Radiofrequency catheter ablation has been demonstrated to be an effective and safe therapy in patients with so-called idiopathic ventricular tachycardia, whereas the benefit/risk profile for ablation of ventricular tachycardia in patients with chronic myocardial infarction and severely compromised left ventricular function still needs to be determined. The present report describes the unintended induction of transient third-degree atrioventricular block in a patient with remote myocardial infarction who underwent radiofrequency catheter ablation of ventricular tachycardia. METHODS AND RESULTS: Endocardial catheter mapping and radiofrequency ablation were performed in a 57-year-old patient with chronic recurrent ventricular tachycardia, who had previously suffered from anterior and posterior wall myocardial infarction. Additionally, the patient presented with complete right bundle branch block during sinus rhythm. Radiofrequency energy applied to a critical site of the reentrant tachycardia at the left ventricular basal septum during sinus rhythm induced third-degree atrioventricular block after 20 s of current delivery, which lasted for 24 h. At this site, a presumable left bundle branch potential was recorded during sinus rhythm. CONCLUSIONS: Radiofrequency current application for ablation of ventricular tachycardia may induce third-degree atrioventricular block in patients with remote myocardial infarction. When current is delivered to target sites at the left ventricular basal septum, radiofrequency energy should be applied during sinus rhythm to allow continuous monitoring of atrioventricular conduction. Special caution should be given to patients with right bundle branch block during sinus rhythm.

Catheter Ablation↗
PubMed1995

Successful radiofrequency catheter ablation of right sided accessory pathways during sustained atrial fibrillation.

Up to now there have been no descriptions in the literature of endocardial catheter mapping and successful radiofrequency catheter ablation of the right sided accessory pathway during sustained atrial fibrillation. We attempted ablation of a right posterolateral and a right lateral accessory pathway during sustained atrial fibrillation with rapid anterograde conduction over the accessory pathway in two patients with Wolff-Parkinson-White syndrome. In both patients (aged 47 and 52 years), sustained atrial fibrillation occurred during the electrophysiological study to assess accessory pathway conduction properties. The mean ventricular rate during atrial fibrillation was 180 and 170 beats.min-1, respectively. Both patients were successfully ablated with a single radiofrequency impulse. At the successful ablation sites, a potential of the accessory pathway was consistently recorded preceding the onset of preexcitation in the surface electrogram, by 25 ms in patient 1 and 30 ms in patient 2. The unipolar electrogram recorded from the ablation catheter showed a QS morphology and the accessory pathway potential preceded the intrinsic deflection by 10 ms in both patients. Onset of the ventricular electrogram (patient 1: -20 ms; patient 2: -15 ms) and its activation time (patient 1: -15 ms; patient 2: +5 ms) in relation to the onset of preexcitation in the surface electrocardiogram also indicated the close proximity of the ablation catheter to the accessory pathway. Preexcitation disappeared within 2 s after energy application in both patients. Thus, radiofrequency catheter ablation of right sided accessory pathways during sustained atrial fibrillation is feasible and may obviate the need for medical or electrical cardioversion.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMed1995

Idiopathic left ventricular tachycardia: new insights into electrophysiological characteristics and radiofrequency catheter ablation.

OBJECTIVES: This study was performed to investigate the electrophysiological characteristics of idiopathic left ventricular tachycardia and to determine the feasibility of radiofrequency catheter ablation for nonpharmacological cure. BACKGROUND: The underlying electrophysiological mechanism of idiopathic left ventricular tachycardia with right bundle branch block morphology and left-axis deviation is presently not known. Additionally, only limited data describing the results of radiofrequency catheter ablation for treatment of idiopathic left ventricular tachycardia so far exist. METHODS: Electrophysiological studies and radiofrequency catheter ablation were performed in 5 patients (3 male and 2 female, mean age 31 +/- 10 years) with idiopathic left ventricular tachycardia (cycle length 376 +/- 72 msec). The patients had a history of recurrent palpitations of 4 +/- 1 years and had been treated unsuccessfully with 2 +/- 1 antiarrhythmic drugs. Sustained ventricular tachycardia with right bundle branch block morphology and left- or right-axis deviation was documented in all patients. RESULTS: Inducibility with critically timed ventricular extrastimuli, inverse relationships of the coupling interval of the initiating extrastimulus and the interval to the first beat of the tachycardia, continuous diastolic or mid-diastolic electrical activity during ventricular tachycardia, and fragmented late potentials during sinus rhythm suggested reentrant activation as the underlying mechanism in three patients. On the other hand, induction dependent on isoproterenol infusion and rapid ventricular pacing and exercise inducibility indicated different electrophysiological characteristics in the remaining two patients. During electrophysiological study, intravenous verapamil terminated ventricular tachycardia in all patients, whereas ventricular tachycardia did not respond to intravenous adenosine, autonomic maneuvers, or intravenous beta-blocking agent esmolol. Catheter mapping revealed earliest endocardial activation during ventricular tachycardia in different areas of the left ventricular septum being distributed from the base to the mid-apical portion of the septum in all patients. In 4 of 5 patients, radiofrequency catheter ablation (median number of pulses 4, range 1-9) resulted in complete abolition of idiopathic left ventricular tachycardia during a follow-up of 4-43 months (median 10) without antiarrhythmic drugs. Successful target sites for catheter ablation included continuous diastolic or mid-diastolic electrical activity during ventricular tachycardia and late potentials during sinus rhythm (2 patients), polyphasic fragmented presystolic potentials during ventricular tachycardia (1 patient), and pace mapping with identical QRS morphology compared to the ventricular tachycardia and "earliest" detectable activity during tachycardia (1 patient). No procedure related complications occurred. CONCLUSIONS: Two different patterns of electrophysiological properties of idiopathic left ventricular tachycardia were observed, indicating that this arrhythmia entity does not represent a homogeneous group. The "origin" of the tachycardias as identified by successful radiofrequency catheter ablation was located in different areas of the left ventricular septum and was distributed from the base to the mid-apical region. Radiofrequency catheter ablation was an effective and safe treatment modality in most of these patients. Distinct target site characteristics for successful catheter ablation including polyphasic diastolic activity during tachycardia and fragmented late potentials during sinus rhythm could be identified.

Adult↗
PubMed1995

[High frequency current catheter ablation in treatment of supraventricular and atrioventricular tachycardia].

Radiofrequency catheter ablation has been established as a first line therapy for the curative treatment of patients with atrioventricular nodal reentrant tachycardia and atrioventricular tachycardia encompassing accessory pathways as well as for ablation of the "normal" AV-junction. For these indications, the success rates exceed 90%. Acute complications during ablation of accessory pathway and ablation of the "normal" AV-junction occur in approximately 2-5% of patients treated. The incidence of complications during modification of the atrioventricular node to cure AV-nodal reentrant tachycardias clearly depends on the ablation technique used. The anterior approach with ablation of the so-called "fast pathway" carries a significantly higher risk of complete AV-block when compared to the inferior approach (so-called "slow pathway ablation") (approximately 4-8% vs. 2%). Arrhythmia recurrence after successful ablation of the "normal" AV-junction occurs only rarely, while the recurrence rate after modification of the AV-node or ablation of accessory pathway is approximately 10% during long-term follow-up. Recently, it has been shown that other, rare types of supraventricular tachycardia (sinus-atrial reentrant tachycardia, ectopic atrial tachycardia, human type I atrial flutter) can also be successfully ablated using radiofrequency current. In addition, first clinical results indicate that modification of anterograde AV-nodal conduction properties in patients with atrial fibrillation and fast ventricular rate by radiofrequency application to postero- and midseptal sites might be a useful therapeutic tool to slow ventricular rate. Because of the high success-rate and the relative low incidence of severe procedure related complications, the indications of radiofrequency ablation procedures for the treatment of supraventricular tachycardias will be extended in the future. In addition, it might be reasonable to expect that during the next years, all types of supraventricular tachycardia, except atrial fibrillation, can be targeted and cured by radiofrequency ablation in the majority of cases.

Atrioventricular Node↗
PubMed1995

[Electrophysiologic findings and high frequency catheter ablation in atriofascicular and nodoventricular pathways ("Mahaim bundles")].

So-called "Mahaim-pathways" represent a distinct subset of accessory pathways and the preexcitation syndromes with unique electrophysiologic properties. During sinus rhythm, preexcitation is minimal or absent whereas incremental atrial stimulation reveals preexcitation with a left bundle branch block like morphology. "Mahaim-fibers" exhibit long conduction times, decremental conduction properties by atrial extrastimuli or incremental atrial pacing, and conduction only in the anterograde direction. The typical atrioventricular reentrant tachycardia incorporating a "Mahaim-pathway" is a preexcited antidromic tachycardia with anterograde conduction over the accessory pathway and retrograde conduction over the AV node. "Mahaim-fibers" may be associated with dual AV node physiology or common atrioventricular accessory pathways. The original concept of "Mahaim-fibers" consisted of accessory pathways originating in the AV node and inserting into the distal right bundle branch ("nodofascicular" pathways) or the right ventricle ("nodoventricular" pathways). This understanding has been challenged by surgical interventions identifying the atrial insertion of "Mahaim-pathways" at the parietal tricuspid annulus. Later, electrophysiologic and surgical studies have confirmed the antero-to posterolateral atrial origin of these accessory pathways remote from the atrioventricular node. Therefore, the concept of nodoventricular pathways has been replaced by the concept of atriofascicular pathways. Recently, endocardial catheter mapping and radiofrequency catheter ablation have substantially contributed to the characterization of this unusual form of the preexcitation syndrome. Distinct, high-frequency activation potentials of atriofascicular accessory pathways can be recorded at the atrial insertion at the antero- to posterolateral tricuspid annulus and along the entire ventricular course up to the ventricular insertion in the right ventricular apical region near or at the distal right bundle branch. The long conduction times and the decremental conduction properties result from a delay in the interval from the local atrial activation at the atrial insertion to the activation potential of the accessory pathway whereas the conduction time between the activation potential of the accessory pathway and the local activation at the ventricular insertion is relatively constant. Overall, the current knowledge about atriofascicular pathways is indicative of a proximal AV-node-like component and a distal bundle-branch-like component and, therefore, suggestive of an accessory AV conduction system. Radiofrequency current application for ablation of atriofascicular pathways can be accomplished at their atrial insertion and along their entire ventricular course. Highfrequency activation potentials of the atriofascicular pathways identify target sites for ablation. Transient mechanical conduction block by catheter manipulation at the subannular level of the atrial insertion has also been introduced as a marker for successful ablation of these unusual accessory pathways.

Adult↗
PubMed1995

[High frequency current catheter ablation in ventricular tachycardia].

Since its introduction into clinical practice in 1982, catheter ablation has evolved as a first-line mode of non-pharmacological therapy in patients with atrioventricular nodal reentrant tachycardia and in patients with atrioventricular tachycardia involving an accessory pathway. The initial experience was based on the use of direct current for ablative purposes. However, since severe complications have been observed using this energy source, radiofrequency (RF) current catheter ablation is now the most frequently used technique. Efficacy rates are high (> 80%) in patients with idiopathic ventricular tachycardia and bundle-branch reentrant tachycardia. In addition, the technique also has a relatively high acute success-rate in patients with incessant ventricular tachycardia. However, RF current catheter ablation is less effective in patients with drug-resistant, chronic, sustained ventricular tachycardia after myocardial infarction or in the presence of dilated cardiomyopathy. Further improvements which include new criteria for the localization of the origin of ventricular tachycardia as well as technical improvements are particularly needed in this subgroup of patients. Thus, RF current catheter ablation in patients with ventricular tachycardia can be considered a promising new mode of non-pharmacological therapy. The efficacy rate of the procedure is highly dependent on the presence and type of organic heart disease as well as the mechanisms underlying ventricular tachycardia. Due to the limited experience, especially with respect to the long-term results, RF current catheter ablation is still an experimental mode of antiarrhythmic treatment.

Cardiomyopathy, Dilated↗
PubMed1994

Clinical significance and management of ventricular arrhythmias in heart failure.

Ventricular arrhythmias are a frequent finding in patients with heart failure, and heart failure is a major underlying condition which is correlated to sudden death. Therefore, both sudden death and death from progression of heart failure strongly overlap. Besides long-term ECG recording, newer diagnostic techniques have been developed. The prognostic significance of the signal-averaged ECG in patients with advanced left ventricular dysfunction in the presence of coronary artery disease has been demonstrated; however, in patients with dilated cardiomyopathy, signal-averaging for detection of late potentials has not yet been clearly established as a useful diagnostic tool. Furthermore, heart period variability has been shown to correlate to overall mortality but not to a specific mechanism. Finally, programmed ventricular stimulation, though useful in patients with left ventricular dysfunction and/or heart failure in the setting of coronary artery disease, is of questionable significance in patients with dilated cardiomyopathy. With increasing degrees of left ventricular dysfunction, the efficacy of antiarrhythmic drugs decreases. On the other hand, with increasing degrees of heart failure, antiarrhythmic drugs demonstrate a greater negative inotropic effect, more frequent proarrhythmic effects, and more frequent bradyarrhythmias. Currently, several ongoing amiodarone trials are assessing different approaches of antiarrhythmic treatment in patients with heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Radiofrequency catheter ablation of idiopathic left ventricular tachycardia: further evidence for microeentry as the underlying mechanism.

INTRODUCTION: Idiopathic left ventricular tachycardia with a QRS pattern of right bundle branch block and left-axis deviation constitutes a rare but electrophysiologically distinct arrhythmia entity. The underlying mechanism of this tachycardia, however, is still a matter of controversy. This report describes findings in a 42-year-old man who underwent successful radiofrequency catheter ablation of idiopathic left ventricular tachycardia. METHODS AND RESULTS: On electrophysiologic study, the tachycardia was reproducibly induced and terminated with double ventricular extrastimuli. Intravenous verapamil terminated the tachycardia whereas adenosine did not. Detailed left ventricular catheter mapping during sinus rhythm revealed a fragmented delayed potential at the mid-apical region of the inferior site near the posterior fascicle of the left bundle branch. At the same site, continuous electrical activity throughout the entire cardiac cycle was recorded during ventricular tachycardia. Repeated spontaneous termination of this continuous electrical activity in late diastole was followed immediately by termination of the tachycardia. Single application of radiofrequency current for 20 seconds at this site completely abolished inducibility of the tachycardia. After catheter ablation, at the identical site of preablation recording of the fractionated potential during sinus rhythm, no fragmented delayed activity could be recorded. There was no complication from the ablation procedure. CONCLUSION: The preablation recordings of fragmented delayed potentials during sinus rhythm and continuous diastolic electrical activity during tachycardia, together with ablation characteristics and previously reported electrophysiologic properties of this arrhythmia, may further support microreentry as the underlying mechanism in idiopathic left ventricular tachycardia.

Adult↗
PubMed1994

Recurrence and late block of accessory pathway conduction following radiofrequency catheter ablation.

INTRODUCTION: Many issues regarding the recurrence of accessory pathway conduction and the long-term outcome of late block of accessory pathway conduction are still unknown or controversial. METHODS AND RESULTS: Data from 217 patients who underwent an initially successful radiofrequency ablation of accessory pathways and 7 patients with late block of accessory pathway conduction following an initially unsuccessful ablation were analyzed. During a mean follow-up of 19 +/- 11 months, accessory pathway conduction resumed in 21 (10%) of 217 patients following an initially successful ablation and in 6 (86%) of 7 patients with late block of accessory pathway conduction (P < 0.01). After initially successful ablations, the recurrence rates of accessory pathway conduction at 1, 3, and 6 months were 5.9%, 7.4%, and 11.3%, respectively. A late electrophysiologic study at 6 months uncovered recurrence in only 1 of 124 asymptomatic patients, but failed to detect the late recurrence in 2 patients in whom the accessory pathway conduction resumed after more than 6 months. Multivariate analysis revealed that independent predictors for recurrence of accessory pathway conduction were concealed accessory pathway, presence of transient effect of radiofrequency pulse, and more than 5 pulses required for initial cure. Accessory pathway location, length of the tip electrode of the ablation catheter, and repeat radiofrequency pulses ("safety pulses") after effective pulses did not predict resumption of accessory pathway conduction. CONCLUSIONS: After initially successful ablation, the recurrence rates of accessory pathway conduction at 1, 3, and 6 months were 5.9%, 7.4%, and 11.3%, respectively. Late electrophysiologic testing had little prognostic value in asymptomatic patients following successful ablation. Application of "safety pulses" did not prevent recurrence. Late block of accessory pathway conduction did not predict long-term efficacy.

Adolescent↗
PubMed1994

[High frequency catheter ablation of left-sided manifest accessory conduction pathways during sinus rhythm and in continuous atrial fibrillation].

Atrial fibrillation is frequently initiated during radiofrequency catheter ablation of accessory pathways. It has been generally believed that initiation of atrial fibrillation may complicate the localization of accessory pathway. Therefore, most centers currently perform cardioversion in order to continue the ablation session. The purpose of the present study was to assess the feasibility and the electrophysiologic criteria for successful radiofrequency catheter ablation of left sided accessory pathways during atrial fibrillation in patients with WPW-syndrome. Radiofrequency ablation was performed in 87 patients with left-sided manifest accessory pathways during atrial fibrillation (n = 16) or during sinus rhythm (n = 71). The criteria for localization of accessory pathways were recording of stable accessory pathway potentials, local ventricular activation preceding the onset of the intrinsic flection of the unipolar electrogram and a QS pattern of the unipolar electrogram. Overall, the accessory pathways were successfully interrupted in 85/87 patients (98%). During the first ablation procedure, abolishing of accessory pathways was achieved in 15 of 16 patients (94%) during atrial fibrillation compared to 64 of 71 patients (90%) during sinus rhythm (n.s.). The total procedure time and fluoro time was significantly shorter during atrial fibrillation than during sinus rhythm (161 +/- 91 min vs. 216 +/- 128 min, p < 0.05, and 31 +/- 24 vs. 41 +/- 26 min. p < 0.05, respectively). Thus, it is feasible and very effective to perform radiofrequency ablation of left-sided manifest accessory pathways during atrial fibrillation. Precise localization of accessory pathway during atrial fibrillation seems even easier than during sinus rhythm as indicated by shorter procedure and fluoro times in the atrial fibrillation group.

Adolescent↗
PubMed1994

[Problems with anti-arrhythmia therapy in atrial fibrillation].

The prevalence of atrial fibrillation increases with age, with rates of 2-5% among people over the age of 60 years. Patients may be highly symptomatic or may suffer from hemodynamic compromise or thromboembolic complications. However, antiarrhythmic drug treatment implies problems like the choice of the suitable drug, the individual benefit/risk profile, and alternative treatment strategies. Experimental and clinical data support the concept that atrial fibrillation in the clinical setting in most cases is due to multiple reentrant wavelets. A critical number of three to six simultaneously circulating reentrant wavelets seems to be necessary for the maintenance of atrial fibrillation. Consequently, antiarrhythmic drugs may terminate or prevent atrial fibrillation by prolonging the refractory period or slowing conduction velocity, thereby leading to conduction block. In clinical practice, antiarrhythmic therapy may act by slowing of the ventricular rate due to depression of atrioventricular nodal conduction or by termination and/or prevention of atrial fibrillation. Digitalis is commonly used for the control of the ventricular rate. Betablocking drugs and verapamil are effective in this respect during exercise performance. For antiarrhythmic conversion and prophylaxis of recurrences of atrial fibrillation, class Ia (e.g., quinidine), Ic (e.g., flecainide and propafenone), and class III (e.g., amiodarone and sotalol) drugs of the Vaughan Williams classification are useful. Presently, no general concept exists whether medical or electrical cardioversion should be used as a first line approach for termination of atrial fibrillation. In the individual patient with atrial fibrillation, the potential benefit of restoring sinus rhythm must be weighed against the morbidity and mortality of the arrhythmia and the morbidity and mortality of the antiarrhythmic agents used.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Arrhythmia Agents↗
PubMed1994

[The pro-arrhythmic effects of anti-arrhythmia agents].

Proarrhythmia is defined as the provocation of new cardiac arrhythmias or the aggravation of preexisting arrhythmias by antiarrhythmic drugs. The possible types of manifestation of proarrhythmia are manifold. With respect to prognosis, drug-induced ventricular tachyarrhythmias seem to be of particular importance. Monomorphic ventricular tachycardia and ventricular tachycardias of the torsade de pointes type have to be distinguished. The former seem to be mainly based on reentrant mechanisms, while the later is supposed to result from triggered activity. Drug-induced monomorphic tachycardia is most often observed during therapy with drugs which slow conduction (class I agents, proarrhythmic potency: IC > IA > IB). Patients with depressed left ventricular function and previously documented life-threatening tachyarrhythmias are the most susceptible candidates. Torsade de pointes can be preferentially observed during therapy with antiarrhythmic drugs which prolong myocardial repolarization (i.e. class IA and class III agents). Electrolyte abnormalities and/or bradycardia are factors which often predispose to the development of this particular type of proarrhythmia. The physician who prescribes antiarrhythmic drugs must be aware of the different types and clinical manifestations of proarrhythmia. This is necessary to assess the degree of proarrhythmic risk and to determine the benefit/risk ratio before the start of drug therapy.

Anti-Arrhythmia Agents↗
PubMed1994

[Drug prevention of recurrence in paroxysmal and chronic atrial fibrillation].

In many patients with paroxysmal or chronic atrial fibrillation, long-term antiarrhythmic drug therapy is performed to prevent recurrences of atrial fibrillation or to reduce the incidence of paroxysmal attacks of atrial fibrillation. The results of several studies on the efficacy of antiarrhythmic drugs in patients with paroxysmal atrial fibrillation have revealed that the incidence of recurrent attacks of atrial fibrillation can be reduced and the duration of arrhythmia free intervals can be prolonged by antiarrhythmic drug therapy. However, complete prevention of atrial fibrillation can be achieved only in a minority of patients. At present, there is no evidence that antiarrhythmic drug treatment of patients with paroxysmal atrial fibrillation might worsen the prognosis by an increase in cardiac mortality induced by antiarrhythmic drugs. In patients with chronic atrial fibrillation, the recurrence rate of the arrhythmia can be significantly reduced by antiarrhythmic drug therapy within the first year of treatment. However, there is evidence that antiarrhythmic drugs might worsen the prognosis when compared to patients with atrial fibrillation not treated with antiarrhythmic drugs. Accordingly, the indication for antiarrhythmic drug therapy to prevent recurrences in patients with chronic atrial fibrillation has to be made restrictively and should be largely based on the symptomatic status of the patients. Antiarrhythmic drug therapy seems to be indicated only in patients who are significantly symptomatic or compromised by the arrhythmia. In patients without or with only mild symptoms, medical therapy with the aim to slow the ventricular response with digitalis, calcium antagonists or betablocking agents seems to be more adequate. Currently, with respect to efficacy and safety, there is no antiarrhythmic drug that has been proved to be superior to others and that can thus be recommended as the drug of first choice for patients with paroxysmal or chronic atrial fibrillation to prevent recurrences. The choice of the optimal antiarrhythmic drug should be made by taking individual factors (e.g., etiology of the arrhythmia, patient compliance, liver and renal function of the patient, additional medical therapy) into account. Major problems during long-term antiarrhythmic drug therapy may arise in patients with pre-existing sinus node dysfunction or conduction disturbances of the atrioventricular node. In addition, the conversion of atrial fibrillation with relatively slow ventricular rates to the atrial flutter with fast ventricular rates that is occasionally observed during treatment with class I-antiarrhythmic drugs may complicate long-term therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Anti-Arrhythmia Agents↗
PubMed1994

[Significance of temperature-controlled energy generation in high-frequency catheter ablation of accessory conduction pathways].

Radiofrequency catheter ablation has become an established treatment modality for definite cure of patients with WPW-syndrome or concealed accessory pathways. On-line monitoring of the induced tissue effects plays an important role concerning the efficacy and safety of this procedure. In a 50 year-old man with recurrent atrioventricular tachycardia, endocardial catheter mapping revealed a left anterolateral concealed accessory pathway. A temperature-guided radiofrequency pulse with a preselected temperature of 70 degrees C was applied during tachycardia when stability of the local electrogram, continuous ventriculoatrial activity during orthodromic tachycardia, and registration of a Kent-potential indicated electrogram criteria for a successful ablation. However, orthodromic tachycardia did not terminate, and catheter tip temperature only reached a plateau of 45 degrees C with maximal power output of 50 watts indicating an insufficient catheter tip-tissue-contact. Therefore, the bending of the catheter curve was slightly straightened during energy application without pushing the catheter forward in order to achieve a better tip electrode contact with the tissue. Simultaneously, a sudden increase in catheter tip temperature was observed accompanied by termination of the tachycardia indicative of the successful ablation of the accessory pathway. At present, a control of radiofrequency catheter induced tissue effects can be best achieved by temperature-guided energy application whereas monitoring of current, voltage, and impedance are insufficient in this respect. In the present case, correction of the catheter placement during energy application could be achieved because of the on-line monitoring of the catheter tip temperature thereby allowing successful ablation of the accessory pathway with a single radiofrequency pulse.

Bundle of His↗