[Sinus node disease - diagnosis and treatment]

The concept of sinus node disease is defined by a group of clinical and electrocardiographic features related to sinus node dysfunction whatever its mechanism; the organicity of the disease can be proven if total or subtotal histological alterations of the sinus node are demonstrated. The most typical symptoms are neurological (syncopes and dizziness). Sinoatrial block, sinus arrest, sinus bradycardia or bradyarrhythmia, and the bradycardia-tachycardia syndrome are the most usual electrocardiographic aspects. The diagnosis is often rendered difficult by the usually intermittent and frequently nonspecific character of the symptoms and of the ECG signs. Holter monitoring is often essential to resolve these difficulties. If the diagnosis remains dubious, the use of electrophysiological methods is necessary: direct recording of the sinus nodal intracardiac potential can now be added to the classical rapid and premature atrial stimulation, possibly complemented by pharmacological tests. Finally, therapeutic indications can be considered after a correct clinical, electrocardiographical and electrophysiological evaluation of the patient. Medical treatment alone is usually ineffective in controlling the attacks of arrhythmia and the neurological episodes. If the sinus nodal dysfunction is obvious and symptomatic, permanent pacing is the treatment of choice. Its short and medium term results are generally excellent, while the long term results, especially with regard to survival of the patients, could be improved by the most recent pacing techniques.