Biomedical subjects

L Gencel

Publications and source records attributed to L Gencel.

23 records · Page 2Linked to original sources

PubMed1994

Electrocardiographic characteristics and catheter ablation of parahissian accessory pathways.

BACKGROUND: Accessory pathways may be located in close proximity to the His bundle, resulting in a high risk of heart block during attempted surgical or electrical interruption of these pathways. This study reports the prevalence, ECG characteristics, and results of catheter ablation of parahissian accessory pathways. They were defined on the basis of both the presence of a high amplitude (> 0.1 mV) of His bundle potential at the ablation site and an exclusion of anteroseptal or midseptal location of the accessory pathway. METHODS AND RESULTS: Eight patients with a parahissian accessory pathway were identified among 582 consecutive patients who underwent radiofrequency ablation of an accessory pathway. They were six males and two females with a mean age of 21 +/- 9 years. During maximal preexcitation, the ECG showed a positive delta wave in leads I, II, and a VF in all patients: six had a negative delta wave in leads V1 and V2 instead of the positivity usually observed in anteroseptal accessory pathways. This pattern had a sensitivity of 75%, a specificity of 96%, a positive predictive value of 86%, and a negative predictive value of 93% for a parahissian location in comparison with a group of 28 patients with anteroseptal accessory pathways. At the successful ablation site, the mean amplitude of the His bundle potential was 0.2 +/- 0.1 (0.12 to 0.4 mV). All accessory pathways were successfully ablated without causing heart block using 5 to 20 W of radiofrequency energy. CONCLUSIONS: Parahissian accessory pathways have a preexcitation pattern that is distinctive from that of anteroseptal accessory pathways. Catheter ablation of these pathways is feasible using low energy with preservation of normal atrioventricular conduction.

Adolescent↗

PubMed1994

[Ablation of the accessory pathways by radiofrequency currents].

The introduction of ablative methods has revolutionised therapeutic strategy in cardiac arrhythmias. Accessory pathways are the most commonly targeted arrhythmogenic substrate. Several parameter may be used to determine the optimal site of ablation: accessory pathway potential, atrioventricular interval, atrial or ventricular pole of the pathway, morphology of the unipolar wave. The localisation of the accessory pathway sometimes requires specific techniques. The success rate reported in the literature is generally over 90%. However, the number of applications of radiofrequency current varies according to the authors from an average of three to eight. A combination of "timing related" criteria and direction of activation and the use of infraliminal stimuli minimise the number of radiofrequency applications. The incidence of complications in multicenter registers is 5% and the relapse rate is 8%. The long-term effects of catheter ablation are unknown, especially when used in childhood. A certain reserve should be maintained in the indications of ablation. Only high-risk, life-threatening arrhythmias, or those resistant to pharmacological intervention, are formal indications. Other (so-called "convenience") indications depend on the express wish of patients clearly informed of the advantages and risks of this method.

Arrhythmias, Cardiac↗

PubMed1994

[Choice of the mode of stimulation after ablation of the bundle of His. Experience based on a retrospective survey of 192 patients].

A retrospective study of 192 patients centered on the outcome of supraventricular arrhythmias after catheter ablation of the atrioventricular junction provided some useful information concerning the choice of pacing mode in these patients. With the exception of atrioventricular bloc after ablation of the rapid nodal pathway where simple DDD pacing is adequate, rate adaptive pacing would seem to be essential. The VVIR mode should be the mode of choice in atrial flutter, permanent atrial fibrillation, poorly controlled atrial fibrillation and paroxysmal atrial fibrillation of elderly subjects (over 70 years) and/or of male sex, and/or complicating advanced cardiac disease (valvular, ischaemic or primary). The DDDR mode (with an algorithm to prevent endless loop tachycardia) is the mode of choice in sinus node dysfunction and/or in young patients (under 60), and/or females and/or in idiopathic arrhythmias and/or when retrograde VA conduction persists. When the pacemaker is replaced, the indication should be reviewed with respect to the outcome of the arrhythmia, which underlines the value of accurate implanted Holter systems.

Aged↗

PubMed1994

[Atrial fibrillation, restoration of sinus rhythm].

Conversion to sinus rhythm (cardioversion) is recommended to prevent the haemodynamic and thromboembolic complications of atrial fibrillation. Prior anticoagulation is compulsory except in emergencies. The duration of anticoagulant therapy depends on the terrain and chronicity of the arrhythmia. Cardioversion may be proposed for the majority of patients in whom it is thought that sinus rhythm can be maintained by appropriate therapy. It may be carried out pharmacologically by oral or intravenous antiarrhythmic therapy. Amiodarone is the drug of choice. Cardioversion may also be carried out by external or internal direct current shock. The success rate of external electrical defibrillation depends on the energy administered, the site of the electrodes and a number of factors related to thoracic impedence. Internal electrical defibrillation may be performed with an endocavitary catheter or by the oesophageal approach, with few complications. The main problem resides in maintaining sinus rhythm in the long term. When this is not possible, cardioversion is useless, and therapy to slow the cardiac rhythm should be instituted.

Amiodarone↗

PubMedDate not supplied

Radiofrequency catheter ablation for AV nodal reentrant tachycardias (AVNRT).

Radiofrequency (RF) catheter ablation is the curative treatment of choice for atrioventricular (AV) nodal reentrant tachycardia (AVNRT). Analogous to the development of surgical techniques, catheter ablation has evolved from AV nodal ablation to selective "fast" and "slow" pathway ablation. "Slow" ablation is now the method of choice because of the lower incidence of associated AV block. Though slow pathway ablation can be achieved with equal success using either the anatomic or the electrogram-guided approach, fewer applications of RF energy are required for the potential-guided technique.

Catheter Ablation↗