Sick Sinus Syndrome

Sick Sinus Syndrome (SSS) or sinus node dysfunction refers to a group of irregular heart rhythms that are caused mostly due to abnormal functioning of the sinus node. Sinus node, also called sinoatrial node is the heart's primary pacemaker tissue located in right atrium of the heart. It generates an impulse for regulation of heartbeat. Irregular heartbeats include slow heart rate - usually 40-50 beats per minute (bradycardia), fast heartbeat - 100 beats per minute (tachycardia) and an alternation of both (bradycardia-tachycardia) with a long pause in between. SSS is more common among elderly persons and about 3 in 10,000 people suffer from this syndrome.

SSS Causes

Sick sinus syndrome is caused due to many reasons and many a time, it is idiopathic. Any disorders that cause inflammation, scarring or damage in sinus node and heart tissue can lead to SSS. Some of the important causes include cardiac amyloidosis, a condition in which amyloid protein gets deposited in heart tissue that can affect sinus node and cardiac myopathies, characterized by abnormal functioning of muscles of the heart.

Sometimes, small inflammatory bumps known as sarcoidosis that generally affects the lymph nodes appear in surrounding tissues of the heart and cause sick sinus syndrome. Other causes of SSS are arteritis (inflammation in the walls of arteries), Chagas disease (parasitic disease caused by protozoa), collagen vascular disease and due to effects of certain drugs.

SSS Symptoms and Diagnosis

Major symptoms of sick sinus syndrome are sinus arrest and sinoatrial block. In sinus arrest there is cessation of sinus node activity and in case of sinoatrial block, the electrical signal or impulse travels slowly resulting in abnormally slow heart rate. Other common symptoms include chest pain, fainting, dizziness, fatigue, muscle pain, palpitation, confusion and shortness of breath.

It is hard to diagnose sick sinus syndrome as symptoms are vague and very often get confused with other diseases. Diagnosis is done based on heart rate, symptoms, medical history, and certain other tests. Electrocardiogram (ECG) is one of the most important procedures done for testing SSS. Instead of the standard ECG, which records the electrical activity of the heart for a brief period, the doctor may conduct holter monitor ECG and event recorder ECG for confirmation. In holter monitor, the heart rate is recorded for a 24-hour period with the help of a portable device carried along with the person. In case of event recorder ECG, recording of heart rate is done only during symptoms of SSS by pushing a button.

SSS Treatment

Treatment of sick sinus syndrome is usually done by implantation of an artificial pacemaker. This technique requires a minor surgery wherein a small battery-operated electronic device is implanted under the skin near the collarbone for normal regulation of the heart rate.

In case of a person under medication of some other diseases, the doctor may seek information about the current medications, perhaps making some changes. It is observed that medications for heart disease and high blood pressure often cause SSS. For such patients, altering the medications can treat the symptoms of sick sinus syndrome.

In addition, the doctor may prescribe arrhythmia medications for regulation of normal heartbeat. Sick sinus syndrome should be treated as soon as possible as severe cases can lead to complications such as heart failure and stroke. It is always advisable to consult your physician in case of any change in the heart rate so that proper diagnosis and treatment can be done at the right time. Even after treatment, if the symptoms of SSS persist, then he/she should report to the concerned physician for immediate medical attention.