In 1995, Wijffels and Alessie, using a curious goat model of atrial fibrillation, introduced the concept of atrial remodelling. The classical atrial substrate (anatomopathological-dilatation and hypokinesis-, and electrophysiological-short refractory periods and decreased conduction-), appeared not only to be one of the causes of atrial fibrillation but also the consequence of atrial fibrillation itself, the mechanism being a vicious circle. In addition to ventricular rhythmic cardiomyopathy, responsible for cardiac failure, the concept of atrial rhythmic cardiomyopathy with the same mechanical and electrophysiological consequences, has developed. These changes, characterised mainly by calcium overload associated with cellular hibernation and differentiation, have not been totally elucidated but have already renewed the physiopathology of atrial fibrillation.

The characteristics of neurocardiogenic syncope (NCS) in elderly patients remain unclear. We compared the hemodynamic profiles of young and older patients with consecutive and positive head-up tilt tests (HUT). Continuous, noninvasive, and reliable monitoring of arterial pressure (AP) and heart rate (HR) was done throughout 46 consecutive positive HUTs of symptomatic patients. The population (12-82 years old) was divided into two groups: younger patients, Y (n = 25, < or = 65 years), and older patients, O (n = 21). Changes in AP and HR after the first minute of tilting, during the stable orthostatic phase and during syncope were compared. Except for systolic pressure, baseline hemodynamic parameters were similar in Y and O. No difference appeared in the mean time elapsed before syncope (19+/-9 vs 22+/-2 min). Asymptomatic hypotension was observed, only in O, 1 minute after tilting, followed by a progressive fall in the mean AP before syncope (0+/-0.9 vs -1+/-0.7 mmHg/min) without HR increase (0.7+/-1 vs 0+/-0.6 beats/min). This pressure slope was strongly related to age (r = 0.54, P < 0.001). Hemodynamic recording during HUT identifies a dysautonomic pattern in elderly patients with NCS and the abnormal AP/HR responses to orthostasis may be a feature specific to this population. Although the central mechanism of NCS is common to all ages, the age-related characteristics of the trigger event may indicate the need for specific management at different ages.

Les aspects electrocardiographiques realises par les pathologies du faisceau de His sont particulierement polymorphes, et l'enregistrement endocavitaire est souvent necessaire pour confirmer un diagnostic qui peut etre evoque sur l'electrocardiogramme de surface grâce a un raisonnement rigoureux. Les blocs auriculoventriculaires tronculaires sont graves, car infranodaux, mais comportent un QRS supraventriculaire et donc souvent un banal QRS fin ; ils peuvent etre medians, avec une deflexion hisslenne dedoublee, mais aussi proximaux et distaux, de diagnostic plus difficile. Les extrasystoles hissiennes sont particulierement polymorphes, soit patentes. evoquant tout a tour extrasystoles auriculaires ou ventriculaires ; soit cachees, et realisant alors des aspects trompeurs de pseudo-blocs auriculoventriculaires du 1 er ou du 2 e degre. Rares, les tachycardies hissiennes compliquent les malformations cardiaques congenitales de l'enfant, notamment en phase postoperatoire.

The ECG appearances of His bundle pathology are very variable and endocavitory recordings are often required to confirm the diagnosis which may be suspected by close analysis of the surface ECG. Truncular AVB is a serious condition as the block is infranodal but with a supraventricular and therefore a narrow QRS complex: it may be median with a double His potential or proximal and distal, which are more difficult to diagnose. Hisian extrasystoles are particularly polymorphic, either overtly, suggesting successively atrial and ventricular extrasystoles, or masked with deceptive pseudo-1st or 2nd degree atrioventricular block. More rarely, hisian tachycardias complicating congenital heart disease in children are observed, particularly in the postoperative period.

Most cases of dizziness or syncope referred to the emergency department or to services of internal medicine are caused by vasovagal syndromes. They comprise relative bradycardia with vasoplegia, the cardiovascular response to a neurological stimulus. It is possible to distinguish vagal or vasovagal syncope which is very common, the very stereotype reflex syncopes, carotid sinus hypersensitivity sometimes associated with sinus node dysfunction and borderline forms such as orthostatic sinus tachycardia and cerebrovascular syncope. The differential diagnosis is vast, from simple hysteria to severe cardiac disease. Tilt testing should be indicated for diagnosis of most cases of syncope with apparently normal hearts. Therapeutic abstention is the rule, providing certain preventive measures are taken, but, should treatment be necessary, cardiac pacing remains an exceptional modality in vasovagal syncope. Strict clinical and physiopathological studies are still required to determine the long-term prognosis and the underlying mechanisms of these syndromes.

ECG criteria which for many years formed the basis of the classification of regular atrial tachycardias may now be completed by the results of endocavitary studies (stimulation and mapping). Flutter is a macroreentry phenomenon in the right atrium, anticlockwise in typical, common or classical forms, and more variable in atypical forms: sometimes antidromic and clockwise, sometimes functional more rapid without a gap of excitability, or in other cases, skirting around the sears of atriotomy, especially right-sided. Tachycardias are paroxysmal and often secondary to reentry; more rarely permanent, they are then often due to increased automaticity especially in young patients. The concordance with surface ECG changes is not perfect and the distinction between flutter and tachycardia often depends on the frequency of the tachycardia and the leads studied.

We describe in this report the development of chronic left main coronary artery (LMCA) occlusion in a young patient 2 years after an uncomplicated, successful ablation of idiophic left ventricular tachycardia. This complication appears to be a late consequence of trauma to the LMCA during the procedure rather than an acute or subacute embolic event.

New indications have recently appeared for cardiac pacing with haemodynamic and antiarrhythmic objectives without any symptomatic bradycardia. The best documented indication, though relatively rare, is stimulation of obstructive hypertrophic cardiomyopathy; initially reserved for cases with favorable results of an acute haemodynamic test, it is now used in other cases without this criterion; hypertrophic cardiomyopathy without permanent obstruction, atrial fibrillation or left bundle branch block. The improvement observed during follow-up is always greater as a real remodeling of the myocardium seems to occur with ventricular dilatation and/or septal thinning. However, the position of the atrial, and above all, of the ventricular pacing catheters is critical as is regulation of the pacemaker which should allow complete ventricular capture with an AV delay allowing good filling. The follow-up of these patients must therefore be regular and the effects on longevity are unknown. DDD pacing has also been proposed in dilated cardiomyopathy. The results are contradictory and only very selected cases with left bundle branch block and long PR interval seem justified with, again, optimisation of the pacing sites with high septal or biventricular stimulation. Recurrent atrial tachycardia, special algorithms preventing extrasystoles have been tried with variable results. In cases with inter-atrial block, atrial resynchronisation by bi-atrial stimulation has been assessed with promising results but many technical problems remain unsolved.