Definition and Management of Sinus Node Dysfunction

In this article, we will discuss the Definition and Management of Sinus Node Dysfunction. So, let’s get started.

Sinus Node Dysfunction

The sinus node is a natural dominant pacemaker. Its intrinsic rate of discharge is highest (60–100 bpm) than other potential cardiac pacemakers (e.g. atrium, AV node, ventricle), hence, it suppresses the activity of all other pacemakers, hence called king of his own empire. It is influenced by autonomic nervous system; alterations in autonomic nervous system is responsible for the normal acceleration of heart during exercise and the slowing during rest and sleep. Sympathetic stimulation increases its discharge rate; while parasympathetic stimulation slows the discharge rate. In case the SA node defaults, the lower subsidiary pacemaker, i.e. AV node or ventricle may take up the control of cardiac rhythm. The SA node lies in the right atrium and has dual blood supply.

Management

• Treat the underlying cause.
• Administer atropine (if necessary).
• Insertion of permanent pacemaker is the mainstay of treatment for symptomatic patients. Patients with intermittent paroxysms of bradycardia or sinus arrest are usually adequately treated by demand ventricular pacemaker. Patients with symptomatic chronic sinus bradycardia or frequent prolonged episodes of sinus node dysfunction do better with dual chamber pacemakers that preserve the normal AV activation sequence (AV synchrony).

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