Abnormal Heart Rhythm

Sinus Node Dysfunction

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

The sinus node, the natural pacemaker of the heart, is located in the heart's upper chamber, called the atrium. It is responsible for initiating the electrical impulse that travels through the heart, causing it to beat in a regular rhythm and heart rate. If the sinus node is not functioning normally -- due to damage from surgery, drugs, congenital heart defects or other causes -- the heartbeat may become very slow with a decrease in blood pressure.

This normal transmission is called normal sinus rhythm, with a regular heartbeat of 60 to 100 times per minute.

Sinus node dysfunction (SND) may lead to an abnormally slow heart rhythm called bradycardia.

SND may cause the following symptoms:

• Palpitations, which can be skipping, fluttering or pounding in the chest
• Fatigue
• Chest pressure or pain
• Shortness of breath
• Fainting, also known as syncope, or near-syncope
• Lightheadedness or dizziness

It is important to note that children with SND may not know how to describe what they are feeling. They may have trouble keeping up with other children or realize they are having "spells" and want to sit down and rest. Some children do not experience any symptoms at all.

Reviewed by health care specialists at UCSF Children's Hospital.
Last updated May 8, 2007