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T Wichter

Publications and source records attributed to T Wichter.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Arrhythmogenic right ventricular cardiomyopathy. Etiology, diagnosis and therapy].

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by regional atrophy of right ventricular myocardium and subsequent replacement by fatty and fibrous tissue. The disease manifests in young adulthood with a predominance of males. Hallmarks of ARVC are ventricular tachyarrhythmias of left bundle branch block pattern which frequently occur during exercise. However, sudden death may also be the first manifestation of the disease. Characteristic findings are repolarization abnormalities and QRS prolongation in the right precordial leads of the surface ECG and regional abnormalities of right ventricular structure and wall motion. Left ventricular involvement may occur in later stages of the disease but rarely leads to progressive biventricular heart failure. Therapeutic efforts are mainly directed to the treatment of ventricular tachyarrhythmias and the prevention of sudden death. A tailored treatment strategy including antiarrhythmic drug therapy, catheter ablation and implantation of cardioverter-defibrillators may be used to improve the long-term prognosis of patients with ARVC.

Anti-Arrhythmia Agents↗
PubMed1998

Cardiac sympathetic innervation in patients with idiopathic right ventricular outflow tract tachycardia.

OBJECTIVES: This study investigated the neuronal reuptake of norepinephrine (uptake-1) and the beta-adrenoceptor density in patients with idiopathic right ventricular outflow tract tachycardia (RVO-VT). BACKGROUND: Clinical findings, such as the inducibility of ventricular tachycardia by stress or catecholamine infusion, and the therapeutic efficacy of antiarrhythmic drugs with antiadrenergic properties suggest abnormalities of cardiac sympathetic innervation in patients with idiopathic RVO-VT. METHODS: Eight patients with idiopathic RVO-VT and a total of 29 age-matched control subjects were investigated by positron emission tomography using [11C]hydroxyephedrine (HED) (volume of distribution of [11C]HED) to assess presynaptic norepinephrine reuptake; [11C]CGP 12177 (maximal binding capacity of [11C]CGP 12177) to measure postsynaptic beta-adrenoceptor density; and oxygen-15-labeled water for quantification of myocardial blood flow (MBF). RESULTS: Both myocardial catecholamine reuptake and beta-adrenoceptor density were significantly reduced in patients with idiopathic RVO-VT. The volume of distribution of [11C]HED in patients with RVO-VT was (mean +/- SD) 41.0 +/- 13.5 versus 71.0 +/- 18.8 ml/g in control subjects (p < 0.002). The maximal binding capacity of the beta-adrenoceptor antagonist [11C] CGP 12177 was 6.8 +/- 1.2 pmol/g in patients with RVO-VT versus 10.2 +/- 2.9 pmol/g in control subjects (p < 0.004). There were no significant differences in MBF at rest (0.98 +/- 0.14 vs. 0.97 +/- 0.24 ml/min per g, p = NS) between patients with RVO-VT and control subjects. CONCLUSIONS: The findings of the present study suggest that myocardial beta-adrenoceptor downregulation in patients with RVO-VT occurs subsequently to increased local synaptic catecholamine levels caused by impaired catecholamine reuptake.

Adult↗
PubMed1998

Left ventricular pseudoaneurysm in a patient with Dressler's syndrome after myocardial infarction.

Successful recanalisation of the left anterior descending coronary artery was performed in a 51 year old man who was admitted two weeks after acute anterior myocardial infarction. Fourteen days later, the patient developed Dressler's syndrome with cardiac tamponade, which was immediately punctured. Sternotomy was performed after two weeks because of progressive haemodynamic deterioration, and fibrinous masses were removed from the pericardium. The patient recovered but two weeks later echocardiography showed a perforation of the left ventricular free wall and formation of a pseudoaneurysm. Intensive monitoring showed significant enlargement of the pseudoaneurysm, which was subsequently resected. This case demonstrates that dangerous formation of a pseudoaneurysm can occur not only during the first days of acute myocardial infarction but also after weeks in patients suffering from non-infectious pericarditis caused by Dressler's syndrome. Although the incidence of Dressler's syndrome is declining, patients should be monitored carefully for several weeks, especially by echocardiography.

Aneurysm, False↗
PubMed1997

[Pregnancy in patients with transposition of great vessels corrected by the Mustard procedure. Report of a case and review of reported cases].

BACKGROUND: In patients after atrial switch operation (Mustard or Senning procedure) for transposition of the great arteries (TGA), the anatomic right (anterior) ventricle works as the systemic ventricle. Although this is associated with an increased rate of congestive heart failure, the prognosis for long-term survival is good. Therefore a large proportion of these patients has reached their reproductive years and consult cardiologists and obstetricians because they plan a pregnancy or are already pregnant. Because of the substantial hemodynamic changes and the increase in cardiac output during pregnancy, potential risk factors and complications have to be considered. PATIENTS: Initiated by the presentation of a pregnant patient with TGA after surgery in our hospital, we analyzed the information referenced in MEDLINE. Including our patient, there were reports on 27 patients after the Mustard procedure with a total of 39 pregnancies. FETAL OUTCOME: Three abortions occurred during the first trimenon, another one was electively induced because of maternal cardiac deterioration. One late abortion occurred in the 23rd week of pregnancy. 35 babies (one twinpair) were born healthy without cardiovascular anomalies. MATERIAL OUTCOME: No maternal deaths occurred. Eight women developed clinical signs of systemic (= right) heart failure including all three patients with former complex TGA. Four of these patients recovered after delivery, four showed persistent reduction of physical abilities or signs of heart failure. Further complications were supraventricular tachycardias (five patients) and a high incidence of hypertension and pre-eclampsia (22% of patients). CONCLUSION: Overall, the outcome for mothers after Mustard procedure for TGA and their children is good, but there is need for intensive and specialized follow-up.

Adult↗
PubMed1997

Efficacy and safety of d,l-sotalol in patients with ventricular tachycardia and in survivors of cardiac arrest.

OBJECTIVE: The aim of this study was to assess the antiarrhythmic efficacy and safety of d,l-sotalol in patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) and in survivors of cardiac arrest and to identify the factors that are associated with arrhythmia suppression and therefore might be helpful in predicting drug efficacy. BACKGROUND: Despite increasing use of the class III antiarrhythmic agent d,l-sotalol, data on its short- and long-term efficacy in a large patient cohort are lacking. Information on its long-term tolerability and safety is limited. METHODS: A total of 396 patients with inducible sustained VT or VF (VT/VF) underwent programmed stimulation before and after receiving oral d,l-sotalol (240 to 640 mg/day). Patients in whom VT/VF was rendered either noninducible or more difficult to induce (more extrastimuli or faster drive cycle length needed for VT/VF induction) were discharged on a regimen of oral d,l-sotalol. RESULTS: d,l-Sotalol suppressed VT/VF in 151 patients (38.1%) and rendered the arrhythmia more difficult to induce in 76 patients (19.2%). The extent of drug-induced prolongation of right ventricular refractoriness and a shorter VT cycle length at baseline were independent predictors of immediate drug efficacy. Torsade de pointes developed in seven patients (1.8%). Two hundred ten patients (53%) continued to receive d,l-sotalol and were followed up for 34 +/- 18 months (mean +/- SD). The actuarial rates for the absence of arrhythmic recurrence (either VT/VF or sudden death) at 1 and 3 years were 89% and 77%, respectively. Actuarial rates for overall survival at 1 and 3 years were 94% and 86%, respectively. VT/VF suppression by d,l-sotalol was an independent discriminant variable that separated patients with and without arrhythmia recurrence. However, noninducibility of VT/VF did not predict freedom from sudden death. CONCLUSION: Oral d,l-sotalol is effective and safe in patients with VT/VF. However, sudden cardiac death develops in a significant proportion of patients, and programmed stimulation seems to be of limited value for its prediction.

Administration, Oral↗
PubMed1996

Temperature-controlled slow pathway ablation for treatment of atrioventricular nodal reentrant tachycardia using a combined anatomical and electrogram guided strategy.

AIMS: Anatomical and electrogram-guided techniques have been used separately for slow pathway ablation in atrioventricular nodal reentrant tachycardia. The aims of the present study were to analyse electrogram characteristics of target sites and biophysical parameters using a combined anatomical and electrogram-guided technique for temperature-controlled radiofrequency catheter ablation of the slow pathway. METHODS AND RESULTS: Using a temperature-controlled (pre-selected 60 degrees C) catheter system, 53 patients with atrioventricular nodal reentrant tachycardia underwent slow pathway radiofrequency ablation. Mapping was started posteroseptally near the coronary sinus ostium and continued towards the midseptal area if needed. The longest and latest atrial electrograms with an atrioventricular ratio of < or = 0.5 were targeted. After a median of two pulses (mean 2.36 +/- 1.33), atrioventricular nodal reentrant tachycardia was rendered non-inducible in all patients without complications. Successful sites had longer atrial electrograms (78.8 +/- 9.8 vs 67.6 +/- 13.3 ms, P < 0.003) and larger ventricular electrogram amplitudes (92.4 +/- 51.2 vs 63.1 +/- 28.8 mV, P < 0.05) than the failed sites, but had a similar atrioventricular ratio, P-A interval and atrial electrogram amplitude. Overall, an atrial electrogram duration of > or = 70 ms was associated with effective radiofrequency delivery, with 86% sensitivity and 62% specificity. The achieved temperature maximum was 62.3 +/- 9.8 degrees C at successful and 58.8 +/- 9.0 degrees C at unsuccessful sites (ns). There was no significant difference between successful and unsuccessful applications with respect to power output, impedance and total delivery energy. During a pre-discharge study, three patients with inducible atrioventricular nodal reentrant tachycardia underwent a repeat ablation. During 12.3 +/- 2.5 (6-15) months of follow-up, three others had a clinical recurrence of atrioventricular nodal reentrant tachycardia. CONCLUSIONS: The combined approach for slow pathway ablation is highly effective, requiring a low number of radiofrequency pulses. Long atrial activation time seems to be the most powerful predictor of success. Similar catheter tip temperature levels during successful and unsuccessful radiofrequency applications indicate that suboptimal selection of target sites rather than ineffective heating due to poor catheter tissue coupling is responsible for unsuccessful energy delivery.

Adolescent↗
PubMed1996

Variants of preexcitation--specialized atriofascicular pathways, nodofascicular pathways, and fasciculoventricular pathways: electrophysiologic findings and target sites for radiofrequency catheter ablation.

INTRODUCTION: In the present report, the electrophysiologic findings in patients with different types of variants of preexcitation, i.e., atriofascicular, nodofascicular, and fasciculoventricular fibers, and the results of radiofrequency catheter ablation using different target sites are described. METHODS AND RESULTS: Twelve patients (mean age 36 +/- 17 years) with variants of the preexcitation syndromes underwent electrophysiologic study and radiofrequency catheter ablation. The atrial origin of atriofascicular pathways remote from the normal AV node was assessed by application of late atrial extrastimuli that advanced ("reset") the timing of the next QRS complex without anterograde penetration into the AV node. In patients with atriofascicular pathways, ablation of the accessory pathway or the retrograde fast AV node pathway was attempted. Ablation of the atriofascicular pathways was guided by a stimulus-delta wave interval mapping in the first five patients and by recording of atriofascicular pathway activation potentials in the next five patients. A nodofascicular pathway was suggested if VA dissociation occurred during tachycardia and if atrial extrastimuli failed to reset the tachycardia without anterograde penetration into the AV node. A fasciculoventricular connection was suggested if the proximal insertion of the accessory pathway was found to arise from the His bundle or bundle branches. The PR interval was expected within normal limits during sinus rhythm and the QRS complex to be slightly prolonged with a discrete slurring of the R wave, suggesting a small delta wave. Ten of the 12 patients had evidence for atriofascicular pathways and one patient each for a nodofascicular and fasciculoventricular pathway. In six patients, the atriofascicular pathways were successfully ablated, and in two patients, the retrograde fast AV node pathway. In one patient, a concealed right posteroseptal accessory AV pathway served as the retrograde limb and was successfully ablated. The nodofascicular pathway was shown to be a bystander during AV node reentrant tachycardia. After successful fast AV node pathway ablation resulting in marked PR prolongation, no preexcitation was present during sinus rhythm because of the proximal insertion of the nodofascicular pathway distal to the delay producing parts of the AV node. The proximal insertion of the fasciculoventricular pathway was suggested to arise distal to the AV node at the site of the penetrating AV bundle. The earliest ventricular activation at the His-bundle recording site indicated the ventricular insertion of this accessory connection into the ventricular summit. The fasciculoventricular connection gave rise to a fixed ventricular preexcitation and served as a bystander during orthodromic AV reentrant tachycardia incorporating a left-sided accessory AV pathway. CONCLUSION: The majority of patients with variants of the preexcitation syndrome present with specialized atriofascicular pathways that seem to originate from remnants of the specialized AV ring tissue. Nodofascicular and fasciculoventricular pathways exist and may give rise to preexcitation, although their functional role in participation of clinical arrhythmias still needs to be elucidated. In the present study, both a fasciculoventricular pathway and a nodofascicular pathway acted as a bystander.

Adolescent↗
PubMed1996

[Methods of catheter ablation in ventricular tachycardic arrhythmias].

Catheter ablation has evolved as the therapy of choice in patients with atrioventricular nodal reentrant tachycardia or atrioventricular tachycardia involving accessory pathways. Radiofrequency current catheter ablation is now generally accepted and most frequently used. In patients with ventricular tachycardia and no organic heart disease (idiopathic ventricular tachycardia) the success rates range between 80-90%. In addition, in patients with bundle branch reentrant tachycardia up to 100% success rates are described. The usefulness of radiofrequency ablation in patients with structural heart disease is still controversial. Although in patients with incessant ventricular tachycardia high acute success rates are observed, the results in post-myocardial infarction tachycardia or dilative cardiomyopathy range only between 40 and 75%. Further refinement of localization techniques as well as improvement of ablation technology is mandatory until the routine use of this technique as a curative procedure for ventricular tachycardia is defined.

Atrioventricular Node↗
PubMed1995

Are there gender differences in patients with coronary artery disease presenting with spontaneous sustained ventricular tachycardia and ventricular fibrillation?

The incidence of coronary artery disease (CAD) is greater in men than in women. The aim of the study was to analyze whether any gender-related differences in patients with CAD and documented spontaneous sustained ventricular tachyarrhythmias exist, and which parameters influence the induction of sustained ventricular tachyarrhythmias. The data of 250 patients [43 women (17.2%) and 207 men (82.8%)] with spontaneous sustained ventricular tachycardia [n = 190 (76%)] and fibrillation [n = 60 (24%)] who underwent coronary and left ventricular angiography, electrophysiological study, and signal-averaging electrocardiogram (ECG) form the basis of this analysis. No gender-related differences could be observed in age, number of diseased coronary arteries, history, location and number of myocardial infarctions, presence of left ventricular aneurysm, ejection fraction, type of spontaneous or induced arrhythmias, right ventricular effective refractory period, and signal-averaged ECG parameters. Age, presence of previous myocardial infarction, and ejection fraction were significant predictors (p < 0.001) of inducibility of sustained ventricular tachyarrhythmias. Once CAD has begun, female and male patients present similar clinical and electrophysiologic characteristics. Thus, both genders should benefit similarly from diagnostic and therapeutic approaches if they are referred to the hospital or to invasive interventions at similar intervals in the course of their illness.

Age Factors↗
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

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

Response to sotalol predicts the response to amiodarone during serial drug testing in patients with sustained ventricular tachycardia and coronary artery disease.

UNLABELLED: It was analyzed whether the response to sotalol can predict the response to amiodarone as evaluated by programmed ventricular stimulation in 30 patients with coronary artery disease and documented recurrent sustained ventricular tachycardia (VT). Programmed ventricular stimulation was performed using 1 or 2 extrastimuli during sinus rhythm and 4 drive cycle lengths at 2 right ventricular sites. If no ventricular tachyarrhythmia was induced, a third extrastimulus was introduced during a paced cycle length of 500 ms. During the control study, VT (mean cycle length 305 +/- 63 ms) was induced in all patients, and the right ventricular effective refractory period (during S1-S1 = 500 ms) was 223 +/- 12 ms. After sotalol, sustained and nonsustained VT were inducible in 22 (73%) and 7 (23%) patients, respectively. One patient did not undergo stimulation on sotalol, because of side effects. After amiodarone, sustained and nonsustained VT were inducible in 23 (77%) and 7 (23%) patients, respectively. The mean cycle length of the induced VT was prolonged after both drugs by 17% (p < 0.001). The effective refractory period was prolonged by 15% (p < 0.001) after sotalol and by 13% (p < 0.001 compared with baseline study; p = NS between both drugs) after amiodarone. Thus, concordant results (effective or ineffective drug) between sotalol and amiodarone were found in 26 patients (87%). IN CONCLUSION: (1) The effects of sotalol and amiodarone on the cycle length of induced VT and on right ventricular effective refractory period were similar; and (2) inability to suppress VT by amiodarone can be predicted from the response to sotalol.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiodarone↗
PubMed1994

Implantable cardioverter defibrillator therapy in patients with arrhythmogenic right ventricular cardiomyopathy, long QT syndrome, or no structural heart disease.

Recent technical developments in implantable cardioverter defibrillator (ICD) systems and reduced operative mortality and morbidity rates associated with ICD implantation have expanded the indications for ICD treatment of ventricular tachyarrhythmias. This review summarizes data regarding ICD therapy in patients with arrhythmogenic right ventricular cardiomyopathy, long QT syndrome, and idiopathic ventricular fibrillation and presents preliminary concepts for identification of patients who will benefit more from ICD therapy than from pharmacologic and other nonpharmacologic approaches. Recent studies suggest that ICD therapy may improve long-term prognosis by reliably terminating recurrences of life-threatening arrhythmias. Appropriate ICD therapies during mean follow-up periods of 12 to 36 months occurred in 30% of patients with idiopathic ventricular fibrillation to 50% of patients with arrhythmogenic right ventricular cardiomyopathy and long QT syndrome. At present no strict recommendations can be given for ICD implantation in these patients. However, at least in cardiac arrest survivors in whom the clinical arrhythmia is not reproducibly inducible during electrophysiologic study, ICD therapy appears to be superior to other treatment options with regard to long-term survival and thus should be considered as a first-line treatment. We are hopeful that continued study of long-term follow-up with and without ICD treatment and improved risk stratification will lead to better criteria for selection of treatment options.

Adult↗