Bradycardia: Difference between revisions

===Device Therapy===

Implantable pacemakers activate cardiac myocardium with electrical stimulation, leading to muscle contraction. Due to the nature of a pacemaker, the activation is different from the physiological conduction system, there are electrical and mechanical consequences. It is therefore important to adjust pacemaker setting to the individual patient. The type of pacemakers and their settings are extensively covered in the device chapter of cardiac arrhythmias. The indications for pacemaker implantation in patients with bradyarrhythmias are mentioned below.

Pacemaker implantation should be considered in patients with sinus node disease which manifests as symptomatic bradycardia in which the symptom-rhythm correlation must have been 1) spontaneously occurring or 2) drug-induced where alternative drug therapy is lacking. Furthermore other eligible candidates for permanent pacing are patients with syncope with sinus node disease, either spontaneously occurring or induced at electrophysiological study and sinus node disease manifests as symptomatic chronotropic incompetence which is 1) spontaneously occurring or 2) drug-induced where alternative drug therapy.

Patients with sinus node disease without symptoms including use of bradycardia-provoking drugs, ECG findings of sinus node dysfunction with symptoms not due directly or indirectly to bradycardia or symptomatic sinus node dysfunction where symptoms can reliably be attributed to non-essential medication do not have an indication for permanent pacemaker therapy.

The following patients with AV conduction block have an indication for pacemaker therapy; 1) chronic symptomatic third or second degree (Mobitz I or II) atrioventricular block 2) neuromuscular diseases (e.g. myotonic muscular dystrophy, Kearns–Sayre syndrome,

etc.) with third-degree or second-degree atrioventricular Block or 3) third or second degree (Mobitz I or II) atrioventricular block after catheter ablation of the atrioventricular junction or after valve surgery when the block is not expected to resolve. Patients with asymptomatic first degree atrioventricular block, asymptomatic second degree Mobitz I with supra-Hisian conduction block or atrioventricular block expected to resolve do not require a pacemaker implantation.

Patient which show a intermittent third-degree atrioventricular block, second-degree Mobitz II atrioventricular block. alternating bundle branch block or findings on electrophysiological study of markedly prolonged His-Ventrical interval (≥100ms) or pacing-induced infra-His block in patients with symptoms have an indication for pacemaker therapy. Patients with a bundle branch block without atrioventricular block or symptoms and bundle branch block with first-degree atrioventricular block without symptoms should not have a pacemaker implanted.