[Bradycardic arrhythmias--part 1: pathophysiology and symptoms].

Bradycardic arrhythmias are classified into disorders of impulse formation and conduction. Impulse formation disorders are diseases of the sinus node. Conduction disturbances are the sinoatrial (SA), atrioventricular (AV) block and bundle branch block. The conduction disturbances are also subdivided in different grades (grade I to III). Clinical manifestations of bradycardic arrhythmias are usually syncope, Morgagni-Adam-Stokes seizures, dizziness, palpitations, or heart failure. The investigation of syncope as the most visible clinical manifestation of bradycardic arrhythmias, is performed in three steps with the goal of risk stratification for sudden cardiac death or major adverse cardiac events. If symptomatic bradycardia is present, there is usually an indication for pacemaker implantation. Prior to a definitive pacemaker implantation reversible or preventable causes must be investigated and treated.