Showing papers by "Etienne Aliot published in 1996"

DDD pacing in hypertrophic cardiomyopathy: a multicentre clinical experience.

Abstract: BACKGROUND--DDD pacing has been advocated as an effective treatment for drug refractory obstructive hypertrophic cardiomyopathy. This study reports the outcome of pacing in 56 patients with refractory symptoms referred to four tertiary centres. METHODS--Core data on symptoms, drug burden, and left ventricular outflow tract gradient were recorded. Patients underwent a temporary pacing study with optimisation of the atrioventricular (AV) delay for greatest gradient reduction without haemodynamic compromise. Patients were assessed after implantation in terms of changes in symptoms, drug load, and outflow tract gradient. RESULTS--56 patients underwent pacing assessment. The mean (SD) left ventricular outflow tract gradient before pacing was 78 (31) mm Hg. At temporary study the mean (SD) left ventricular outflow tract gradient was 38 (24) mm Hg with a median (range) optimised sensed AV delay of 65 (25-125) ms. Fifty three patients were implanted and followed up for a mean (SD) of 11 (11) months. The median (range) programmed sensed AV delay was 60 (31-200) ms. Left ventricular outflow tract gradient at follow up was 36 (25) mm Hg. Forty four patients had improved functional class. Although a correlation (r = 0.69) was shown between acute and chronic left ventricular outflow tract gradient reduction, there was no correlation between magnitude of gradient reduction and functional improvement, and no appreciable change in pharmacological burden. CONCLUSION--This series confirms symptomatic improvement after DDD pacing in hypertrophic cardiomyopathy. There remains, however, a discrepancy between perceived symptomatic benefit and modest objective improvement. Furthermore, the optimal outcome has been achieved only with continued pharmacological treatment. Current methods of temporary evaluation do not predict functional outcome which seems to be independent of the magnitude of gradient reduction.

Atrioventricular Node Ablation for Optimization of Pacemaker Treatment in Hypertrophic Obstructive Cardiomyopathy

Abstract: Dual chamber pacing is a new indication for the treatment of drug resistant hypertrophic obstructive cardiontyopathy (HOCM) in patients with normal atrioventricular (AV) conduction. In sinus rhythm, the efficacy of the treatment is mainly related to the ability to bypass the normal AV conduction system in order to obtain a complete and permanent right ventricular (RV) capture. This is achieved by programming short AV delays. On the other hand, patients with HOCM frequently have co-existing left ventricular diastolic dysfunction, and the atrial contribution to left ventricular filling is critical. The lack of improvement, rarely encountered, is probably due to incomplete RV capture andlor to the deleterious effect of short AV delay. Instrumental AV node prolongation may he indicated in this situation. This procedure should be undertaken when previous drug-induced AV prolongation has failed. In theory, AV node modulation (i.e., creating a I ± AV block) seems ideal. However, this technique remains difficult, with disappointing chronic results. Most authors hence perform “conventional” AV node ablation. Particular attention is taken in order to perform a proximal node ablation, resulting in a complete AV block with narrow QRS escape rhythm. The reported incidence of AV node prolongation ranges from 7.5%-37.5%. The efficacy of the procedure on symptoms is explained by improved left ventricular filling and/or a further reduction in the systolic gradient evoked by complete RV capture. Another indication for AV node ablation in HOCM is the occurrence of atrial fibrillation, in order to restore adequate and permanent RV capture.

History of Pacing in Hypertrophic Cardiomyopathy

Abstract: The history of pacing in hypertrophic obstructive cardiomyopathy (HOCM) begins in 1964 and ends in the early 1990s when several well-documented articles confirmed that pacing the apex of the right ventricle could be considered as an effective primary therapy of severe, drug resistant HOCM. The first pacemaker implantation was reported in a patient with HOCM who developed a complete AV block. The efficacy of right ventricular (RV) pacing on the gradient was enhanced, but the concept of pacing in the absence of conduction abnormalities was not suggested. In 1967, Hassenstein was the first to demonstrate that right apex ventricular pacing in HOCM with intact AV conduction induced gradient reduction. He subsequently performed the first hemodynamic implantation several years later. The largest series confirming the undoubted efficacy of pacing in HOCM were reported by Jeanrenaud in Switzerland and Fananapazir in the USA in the early 1990s.

Value of unipolar and bipolar recordings in radiofrequency ablation of accessory atrioventricular pathways

Abstract: The aim of the study was to compare the value of different modes of endocavitary recordings: unipolar alone, bipolar alone and the association of unipolar and bipolar recordings in radiofrequency ablation of accessory atrioventricular pathways. A retrospective analysis by three independent observers of 135 endocavitary recordings obtained immediately before radiofrequency application in 82 subjects who underwent radiofrequency ablation for symptomatic accessory atrioventricular pathways. In each case, the authors selected the "successful" record which corresponded to the final radiofrequency application and 0.1 or 2 records of "failures". Each initial recording being of 3 types (unipolar, bipolar and association of uni- and bipolar), a total of 390 anonymous and randomised recordings were analysed by the observers who determined whether the appearances indicated successful ablation. Univariate analysis of variants showed a correlation between success with the mode of recording (p = 0.03) and a left lateral position of the accessory pathways. In multivariate analysis, three variables remained correlated with successful ablation: the observer variable (p = 0.001), and two interactions observer - mode (p = 0.005) and observer-stability (p = 0.02). The benefits of the association of unipolar and bipolar recordings with respect to bipolar recording alone, seemed to be important in predicting failure. The results of tests of concordance in the group of failures were confirmatory: concordance between observers was only found between the unipolar mode alone and the association of unipolar and bipolar recordings. The results of this study suggest that the association of unipolar and bipolar endocavitary recordings may reduce the number of unnecessary application of radiofrequency energy by improved identification of recording showing failure.