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Biomedical subjects

W Haverkamp

Publications and source records attributed to W Haverkamp.

At least 91 records · Page 5Linked to original sources
PubMed1995

Molecular analysis at the Harvey Ras-1 gene in patients with long QT syndrome.

Patients with long QT syndrome (LQTS; MIM 1921500) frequently suffer from syncope and are threatened by sudden cardiac death due to ventricular arrhythmias, typically of the torsade de pointes type. Initial progress in revealing the molecular basis of the disease was made by the observation of genetic linkage of the disease locus to the Harvey Ras-1 gene (HRAS 1) on chromosome 11p15.5. More recently loci on chromosomes 3, 4, and 7 have also been found to be linked to LQTS, thus demonstrating heterogeneity in the causes for this disease. The present study performed sequence analysis on the HRAS 1 gene in patients with congenital and acquired LQTS to determine the frequency of HRAS 1 mutations in patients with this disease. In neither group were no mutations identified in the coding regions or in the splice donor and acceptor sites. Alleles characterized by a T to C transition in exon 1 and an insertion/deletion polymorphism upstream of exon 1 showed no significant difference in their frequencies between LQTS patients and normal controls. No quantitative influence of the such characterized genotypes on the QT duration was observed. These results demonstrate that structural mutations in the HRAS 1 gene are not a frequent cause of LQTS. Also, since there was no association of different alleles at the HRAS 1 locus with changes in QT duration, it appears unlikely that this gene is a major contributor to this disease.

Alleles↗
PubMed1995

Electrophysiologic effects of potassium channel openers.

Potassium-channel openers or activators have been introduced as a new class of antihypertensive and antianginal agents that act by increasing membrane conductance to potassium, mainly through augmentation of the ATP-sensitive potassium current. Recent in vitro studies have shown that K(+)-channel openers exert concentration-dependent effects on cardiac electrophysiology. A shortening of the cardiac action potential by acceleration of repolarization has been reported in multicellular preparations as well as in isolated myocytes. However, drug concentrations that affect the action potential duration of myocardial cells are considerably higher (10- to 100-fold) than those needed for effects on vascular smooth muscle cells. Studies in which mostly high concentrations of K(+)-channel openers were used have demonstrated that these drugs may accelerate automaticity and may promote reentrant activity. Particular interest has focused on the question whether opening of potassium channels may be potentially arrhythmogenic in the setting of acute myocardial ischemia. On the other hand, recent studies have shown that K(+)-channel openers are effective in suppressing polymorphic ventricular tachyarrhythmias induced by early afterdepolarizations and triggered activity in vivo. The clinical relevance of these experimental studies to the clinical situation is still unclear. Some K(+)-channel openers have been shown to produce electrocardiographic T-wave changes in patients in whom their effectiveness as antihypertensives was tested. However, this effect was not associated with adverse effects and has not been demonstrated for all compounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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

Clinical implications of pleomorphic ventricular tachycardias on oral sotalol therapy.

In 90 consecutive patients with coronary artery disease and sustained monomorphic ventricular tachycardia, who were treated with oral sotalol and underwent programmed stimulation to determine drug effectiveness, the influence of sotalol on induced ventricular tachycardia morphology was retrospectively examined. In 54 patients (60%) sotalol rendered the tachycardia non-inducible. However, contrary to drug-testing with class I antiarrhythmic agents, induction of multiple morphologies at baseline study did not predict failure of subsequent drug-testing with sotalol. In the remaining 36 patients (40%), in whom sotalol did not modify inducibility, 21 patients (i.e. a total of 23%) manifested at least one new morphology during electropharmacological testing on sotalol. This effect was independent of the degree of left ventricular dysfunction, infarct location and numbers of morphologies at baseline, but corresponded with drug-induced changes in refractoriness. This observation may be related to a proarrhythmic effect of sotalol. Slowing of ventricular tachycardia rate and changes in morphology may have implications in patients receiving implantable cardioverter-defibrillators or those undergoing ablative procedures.

Administration, Oral↗
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↗
PubMed1995

[The idiopathic QT syndrome as the cause of epileptic and nonepileptic seizures].

The long QT syndrome (LQTS) is characterized by a pathological lengthening of the corrected QT interval on the surface ECG and the occurrence of syncopal attacks, sometimes presenting as a seizure disorder. They are caused by ventricular tachycardia of the torsade de pointes type, an arrhythmia that is also responsible for the high incidence of sudden death among these patients. Besides the acquired forms of LQTS which are transient (e.g. therapy with QT-prolonging drugs), congenital variants (Romano-Ward syndrome, Jervell/Lange-Nielsen syndrome, sporadic form) can occur as well. The latter mostly become manifest during childhood or adolescence. Because the syndrome is rare, it is often not included in the primary differential diagnosis of syncope. Thus, misinterpretation as epilepsy may occur. Especially if siblings are affected, a genetic epilepsy may be diagnosed. However, the correct diagnosis can be made by standard ECG methods. Early recognition of the syndrome is very importance because of prognostic and therapeutic consequences. In this article, two cases of idiopathic LQTS are presented. Problems regarding differential diagnosis and therapy are discussed.

Adolescent↗
PubMed1994

The role of implantable cardioverter defibrillators in dilated cardiomyopathy.

Depending on the severity of the disease, patients with dilative cardiomyopathy (DCM) have a poor prognosis. No definite data are available to show that complex ventricular ectopy, the presence of ventricular late potentials, or programmed electrical stimulation in patients without symptoms with DCM identify patients at risk of sudden cardiac death. Although poor left ventricular function seems to be the most potent predictor of total cardiac death, the prediction of sudden death in patients without symptoms with DCM is poor. Studies with either class I antiarrhythmic drugs or amiodarone have not yet demonstrated a reduction in total mortality rates or sudden death. The usefulness of an implantable cardioverter defibrillator (ICD) in patients without symptoms with DCM is currently under investigation. The usefulness of serial electropharmacologic testing for patients with documented sustained ventricular tachycardia or ventricular fibrillation and DCM is still controversial. Because most patients with DCM and VT or out-of-hospital cardiac arrest have either no inducible ventricular tachyarrhythmia at baseline or the reproducibility of ventricular tachycardia/ventricular fibrillation induction is poor, implantation of an ICD should be considered in most of these patients. The indication for implantation of an ICD should be made on clinical judgment of the patient's functional status and other prognosis-limiting factors, such as rapid progression of heart failure, end-stage heart failure, and age.

Anti-Arrhythmia Agents↗
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↗
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

Role of programmed ventricular stimulation in patients with idiopathic dilated cardiomyopathy and documented sustained ventricular tachyarrhythmias: inducibility and prognostic value in 102 patients.

The role of programmed ventricular stimulation (PVS) in patients at high risk of sudden death related to idiopathic dilated cardiomyopathy (DCM) is still controversial. The possible reason is that most study series have been too small or that only a few patients had documented sustained ventricular tachyarrhythmias. This study therefore, looked at PVS performed in 102 patients with DCM and documented sustained ventricular tachycardia (VT; n = 63) or ventricular fibrillation (VF; n = 39). Sustained VT was induced in 27 of 63 patients (43%) with documented sustained VT and in 14 of 39 patients (36%) with documented VF (ns). VF was induced in nine patients (14%) with a history of sustained VT and in seven (18%) with a history of VF (ns). At a mean follow-up of 32 +/- 15 months, sudden death occurred in 14 (14%) patients, a rate similar in both patients with documented VT and VF (ns). Incidence of sudden death at 36 months was 6% in patients with inducible sustained VT/VF compared to 29% in patients without inducible VT/VF (P < 0.05). A favourable drug regimen (response to drug and no intolerable side effects) was obtained by serial drug testing in 25 of all 102 patients (25%). A cardioverter defibrillator (ICD) was implanted in 32 patients, in 63% of whom discharges were observed during 18 +/- 11 months of follow-up; only one patient (3%) died suddenly. Thus, in patients with DCM, there was no relationship between documented and inducible ventricular tachyarrhythmias, and initiation of sustained VT or VF had little prognostic value for the prediction of subsequent sudden death. Wherever antiarrhythmic drug therapy was of limited value, implantation of an ICD may improve the prognosis of these high risk patients.

Anti-Arrhythmia Agents↗
PubMed1994

Efficacy of ajmaline and propafenone in patients with accessory pathways: a prospective randomized study.

In a prospective randomized study, we assessed the electrophysiologic effects and the efficacy of ajmaline versus propafenone in patients with accessory pathways (APs). During initiated atrioventricular (AV) reentrant tachycardia or atrial fibrillation (AF), ajmaline (1 mg/kg as bolus followed by infusion of 15 micrograms/kg/min) or propafenone (2 mg/kg, followed by infusion of 30 micrograms/kg/min.) were randomly administered intravenously (i.v.) in 40 patients with APs. AV reentrant tachycardia terminated in 15 of 16 patients (94%) on ajmaline and in 12 of 15 patients (80%, NS) on propafenone. AF ceased in 4 of 4 patients receiving ajmaline and in 3 of 5 patients receiving propafenone (n.s.). During continuous infusion of drugs, AV reentrant tachycardia became noninducible in 10 (50%) patients receiving ajmaline, as compared with 6 (32%) receiving propafenone (NS). Both drugs significantly prolonged the anterograde and retrograde effective refractory periods (ERPs) of the AP. There were no significant differences in changes in electrophysiologic parameters between the two drugs. Ajmaline and propafenone are highly effective and safe in terminating and preventing reinitiation of AV reentrant tachycardia or AF in patients with APs. Both drugs significantly prolonged the anterograde and retrograde ERPs of the APs.

Accessory Nerve↗