Cardiac resynchronisation therapy in chronic atrial fibrillation: impact on left atrial size and reversal to sinus rhythm.

OBJECTIVE: To evaluate the impact of long term cardiac resynchronisation therapy (CRT) on left atrial and left ventricular (LV) reverse remodelling and reversal to sinus rhythm (SR) in patients with heart failure with atrial fibrillation (AF). PATIENTS: 74 consecutive patients (age 68 (8) years; 67 men) with advanced heart failure and AF (20 persistent and 54 permanent) were implanted with a CRT device. MAIN OUTCOME MEASURES: Patients were evaluated clinically (New York Heart Association (NYHA) class, quality of life, six minute walk test) and echocardiographically (LV ejection fraction, LV diameters, and left atrial diameters) before and after six months of CRT. Additionally, restoration of SR was evaluated after six months of CRT. RESULTS: NYHA class, quality of life score, six minute walk test, and LV ejection fraction had improved significantly after six months of CRT. In addition, left atrial and LV end diastolic and end systolic diameters had decreased from 59 (9) to 55 (9) mm, from 72 (10) to 67 (10) mm, and from 61 (11) to 56 (11) mm, respectively (all p < 0.01). During implantation 18 of 20 (90%) patients with persistent AF were cardioverted to SR. At follow up 13 of 18 (72%) patients had returned to AF and none had spontaneously reverted to SR; thus, only 5 of 74 (7%) were in SR. CONCLUSION: Six months of CRT resulted in significant clinical benefit with significant left atrial and LV reverse remodelling. Despite these beneficial effects, 93% of patients had not reverted to SR.

[Impact of the aetiology of cardiac failure on the correlations between electrical and mechanical asynchrony of the ventricle]. / Influence de l'étiologie de l'insuffisance cardiaque sur la corrélation entre asynchronismes électrique et mécanique dans le ventricule.

Cardiac resynchronisation therapy (CRT) is indicated in refractory cardiac failure with electrical asynchrony defined by QRS complexes > or =120 ms duration. The search for mechanical asynchrony is proposed for better selection of patients for CRT. Ischaemic and non-ischaemic cardiomyopathy do not necessarily show the same form of asynchrony. The authors studied the differences in correlation between electrical and mechanical asynchrony in these two patient populations. Fifty patients (34 dilated non-ischaemic and 16 ischaemic cardiomyopathy) in NYHA Classes III and IV, LVEF < 35%, consecutively implanted for CRT in 2004, were included. The trans-thoracic echocardiography, the ECG and clinical parameters (NYHA, 6 minute walk test, VO2 max) were compared. A non-significant improvement of the correlation between the aortic pre-ejection time and QRS duration was observed in the non-ischaemic group (r = 0.78, p< 0.0001) compared with the ischaemic cardiomyopathy group ( r = 0.56, p = 0.019). Similarly, intraventricular asynchrony seemed to be correlated with the duration of QRS in the non-ischaemic group (r = 0.65, p < 0.0001) unlike the ischaemic cardiomyopathy group (ns). Sub-group analysis of patients with QRS durations < 150 ms and > or =150 ms showed an electromechanical correlation irrespective of the QRS duration in the non-ischaemic group but this was only observed with the aortic pre-ejection time with QRS > or =150 ms in the ischaemic group. The authors conclude that there is a significant correlation between electrical and mechanical asynchrony in patients with non-ischaemic cardiomyopathy. This correlation only applies to intraventricular asynchrony with QRS durations > or =150 ms in the ischaemic group. A decision for CRT requires echocardiographic evaluation in ischaemic cardiomyopathy.

[The role of cardiac pacing in the treatment of atrial arrhythmias]. / Place de la stimulation cardiaque dans la prévention et le traitement des arythmies atriales.

The role of cardiac pacing in the treatment of atrial arrhythmias can be analysed from the angle of prevention or treatment in a strategy of rhythm control or heart rate control. From the heart rate control viewpoint, "ablate and place" is a validated method, especially in terms of mortality based on the results of large registers, in cases of uncontrolled ventricular rhythms causing symptoms or left ventricular dysfunction. In a strategy of rhythm control, the theoretical bases of prevention of atrial fibrillation (AF) by atrial pacing are convincing but the clinical results of different prospective clinical trials, though encouraging, do not provide formal proof of the efficacy of preventive pacing. Permanent 100% atrial pacing remains the objective which has led to the development of many algorithms evaluated in the ADOPT, AF Therapy, PIPAF, ATTEST...trials, with contradictory results. The choice of atrial pacing site seems to be a determining factor for the success of the method with better results seemingly with the high or low septal positions. The results of the OASES trial support this hypothesis but they were not confirmed by the ASPECT trial. An interesting observation was made in the PIPAF and a new Danish trial on the deleterious effects of ventricular capture when not required which is the rule in patients paced for brady-tachycardia syndromes. As for the role of anti-tachycardia pacing, the technique remains to be validated. Perhaps, the association of different techniques evaluated--the site of pacing, the prevention algorithms, respect of the ventricular rhythms, reduction by anti-tachycardia stimulation--will provide multifunction devices capable of best managing atrial arrhythmias which do not require "curative" therapy, and in particular, endocavitary ablation. In practice, it is generally when faced with brady-tachycardia syndromes that the question of the preventive role of pacing is raised. The problem is to choose the site of stimulation and the most appropriate pacing device in the light of current knowledge.

[Role of cardiac resynchronisation in the treatment of cardiac failure]. / Place de la resynchronisation cardiaque dans le traitement de l'insuffisance cardiaque.

For 10 years cardiac resynchronisation has seen considerable development, as much on the technological side as at the level of its scientific validation. Several prospective studies have shown the functional benefits of cardiac resynchronisation in a selected population of refractory cardiac failure patients with improvement in symptoms, exercise tolerance and quality of life. Equally, cardiac resynchronisation allows a significant reduction in hospital episodes for cardiac failure and also has a beneficial effect on left ventricular inverse remodelling. Finally, the first results of morbidity/mortality trials are very encouraging with a significant reduction in overall mortality at one year in the COMPANION study with the biventricular defibrillator. However, numerous important, unresolved questions remain such as the problem of non-responders and thus patient selection, or such as the place of cardiac resynchronisation in patients with permanent atrial fibrillation. The choice of the type of implantable prosthesis (pacemaker or biventricular defibrillator) and the choice of the mode of pacing (biventricular or solely left ventricular) are still under discussion. New indications for cardiac resynchronisation could be seen next, for example such as the optimisation of stimulation mode in already paced patients or "systematic" biventricular pacing in patients with a conventional indication for pacing..... In 2004, cardiac resynchronisation must be considered as an effective adjuvant therapy in cardiac failure patients refractory to optimal medical treatment with left ventricular dysfunction and intraventricular conduction disorders.