Holter implantable: reveal [The implantable loop recorder]

The implantable loop recorder developed by Medtronic (Reveal plus) is a small device inserted subcutaneously under local anesthesia in patients with syncope of unexplained origin. This device enables a single lead-ECG recording and has autonomy of two years. Memories are activated during episodes of bradycardia or tachycardia, either automatically or manually. Several studies have shown a high diagnostic rate reaching 50% and demonstrated its cost-effectiveness. There is also a significant reduction in syncopal episodes and a higher quality of life score in patients with syncope of unexplained origin

Long term biventricular resynchronisation therapy in advanced heart failure: effect on neurohormones

Objective: To assess prospectively the effect of cardiac resynchronisation therapy (CRT) on New York Heart Association (NYHA) functional class, cardiac function, cardiopulmonary exercise performance, and neurohormonal activation during 24 months’ follow up. Design: Controlled study. Patients and Results: 124 patients with severe congestive heart failure (ejection fraction < 35%, NYHA III–IV) and left bundle branch block (QRS duration > 150 ms) were enrolled (control group, n  =  59; CRT group, n  =  65) and followed up at 1, 3, 12, and 24 months. Compared with the control group, CRT led to significant short and long term improvements in functional NYHA functional class (mean (SEM) 2.1 (0.4) v 2.8 (0.4) at 24 months, p < 0.05), mean ejection fraction (25.7 (4)% v 21.1 (5)% at 24 months, p < 0.05), peak Vo(2) (16.8 (3.9) v 12.6 (3.5) ml/kg × min at 24 months, p < 0.01), and Vo(2) at anaerobic threshold (14.4 (3.7) v 10.8 (3.2) ml/kg × min at 24 months, p < 0.05). In addition, CRT for one and 12 months significantly decreased the plasma concentrations of noradrenaline (norepinephrine) and N-terminal fragment of pro-brain natriuretic peptide, whereas no changes were observed for other neurohormones such as antidiuretic hormone, aldosterone, and endothelin. Conclusion: Long term CRT (⩽ 24 months) results in significant improvement of NYHA class and cardiopulmonary exercise capacity and a short term decrease in neurohormonal activation

Propagation velocity kinetics and repolarization alternans in a free-behaving sheep model of pacing-induced atrial fibrillation.

AIMS: Experimental models have reported conflicting results regarding the role of dispersion of repolarization in promoting atrial fibrillation (AF). Repolarization alternans, a beat-to-beat alternation in action potential duration, enhances dispersion of repolarization when propagation velocity is involved. METHODS AND RESULTS: In this work, original electrophysiological parameters were analysed to study AF susceptibility in a chronic sheep model of pacing-induced AF. Two pacemakers were implanted, each with a single right atrial lead. Right atrial depolarization and repolarization waves were documented at 2-week intervals. A significant and gradual decrease in the propagation velocity at all pacing rates and in the right atrial effective refractory period (ERP) was observed during the weeks of burst pacing before sustained AF developed when compared with baseline conditions. Right atrial repolarization alternans was observed, but because of the development of 2/1 atrioventricular block with far-field ventricular interference, its threshold could not be precisely measured. Non-sustained AF was not observed at baseline, but appeared during the electrical remodelling in association with a decrease in both ERP and propagation velocity. CONCLUSION: We report here on the feasibility of measuring ERP, atrial repolarization alternans, and propagation velocity kinetics and their potential in predicting susceptibility to AF in a free-behaving model of pacing-induced AF using the standard pacemaker technology

Passe, present et futur des technologies d'ablation percutanee des arythmies cardiaques. [Past, present and future of percutaneous catheter ablation technologies for cardiac arrhythmias]

Drug therapy treatment of cardiac arrhythmias has been disappointing, while percutaneous catheter ablation, efficient and at low risk, has become the first line therapy of the majority of rhythm disturbances, in only two decades. The ultimate challenge, which is atrial fibrillation ablation, is on the way to be successfully solved. This is mainly due to: innovative ablational energy sources; 3D virtual electro-anatomical reconstructions of heart cavities, to map and understand complex arrhythmias' circuits; revolutionary magnetic navigation systems that permit the target positioning of the catheters in the most inaccessible places, even though the operator works at a command board placed away from the patient

Apport de l'analyse de l'alternance de l'onde T dans la stratification du risque de mort subite postinfarctus

Malgré de considérables progrès dans la prise en charge de la maladie coronarienne, une proportion substantielle de patients souffre d'arythmles ventriculaires fatales dans les suites d'un infarctus du myocarde. L'étude MADIT 2 a démontré récemment la supériorité des défibrillateurs automatiques Implantables comparés à une approche médicamenteuse chez les patients souffrant d'une dysfonctlon ventriculaire postinfarctus, mais au prix de l'implantation Inutile d'un nombre conséquent de défibrillateurs. L'alternance de l'onde T de l'ECG, qui reflète l'alternance de la repolarisation des cellules cardiaques favorise la survenue de fibrillation et tachycardie ventriculalres. De récentes études cliniques, cumulant près de 3000 patients, ont démontré le potentiel de cette technique dans la stratification du risque de mort subite postinfarctus. En tenant compte des données les plus récentes, Il est estimé qu'environ un tiers des patients postinfarctus souffrant d'une dysfonction ventriculaire gauche importante (fraction d'éjection du venta cule gauche, FEVG, &lt; 30%) ne devrait pas développer d'alternance de l'onde T lors d'un test d'effort. La valeur prédictive négative de cette technique étant supérieure à 90%, l'analyse de l'alternance de l'onde T pourrait ainsi améliorer l'identification des patients bénéficiant le plus de l'Implantation d'un défibrillateur automatique