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About Your Diagnosis

Sick sinus syndrome refers to an abnormality of the sinus node that can result in any one or all of the following: a persistent slow heart rate, alternating slow and rapid heart rates, sinus arrest (long pauses when there is no heartbeat), or high-degree heart blocks. In order for the heart muscle to contract, it must be stimulated by a small electrical impulse. This impulse originates from an area of the heart called the sinus node. The heart is divided into four chambers: two atria and two ventricles. There is a right and left atrium as well as a right and left ventricle, and the sinus node is located in the right atrium. This sinus node serves as the electrical pacemaker of the heart. Sick sinus syndrome means that there is a problem with the impulse formation in the sinus node.

Sick sinus syndrome is typically observed in the middle-aged and the elderly and accounts for half of the pacemakers inserted in the United States. Sick sinus syndrome can be associated with any condition that affects the heart (e.g., hypertension, coronary artery disease, rheumatic heart disease, mitral valve prolapse), any disease process that can invade the heart muscle (e.g., amyloidosis, hemochromatosis, scleroderma, hypothyroidism), and any connective tissue disease. Many drugs can cause sick sinus syndrome, including digitalis, beta-blockers, calcium blockers, amiodarone, and lithium.

When detected, sick sinus syndrome can be effectively treated. It is not contagious, meaning it is not spread from one person to another.

The most effective way to detect sick sinus syndrome is with a 24-hour monitor called a Holter monitor. A routine electrocardiogram (ECG) may also be helpful in detecting sick sinus syndrome.

Living With Your Diagnosis

The most common symptom of sick sinus syndrome is passing out, syncope, and the sensation that you are going to pass out, near syncope. Other symptoms include palpitations, heart racing, skipping, or missing a beat, fatigue, and dizziness. Physical signs include a slow pulse, usually less than 50 beats per minute, or intermittent bouts of fast heart rates (140 to 150 beats per minute) alternating with slow heart rates.

Ideally, the best way to make the diagnosis is to note the rhythm disturbance at the same time the patient is having symptoms.


The main treatment of patients with sick sinus syndrome is implantation of a permanent pacemaker. This can be done by a cardiologist experienced in pacemaker insertions (electrophysiologist) or by a cardiothoracic surgeon.

In the form of sick sinus syndrome called tachycardia-bradycardia syndrome, the use of medications to slow down the fast heart rates; also helps prevent the slow heart rates, however this decision should be made between you and your cardiologist (physician specializing in diseases of the heart).

There are many different types of pacemakers available. Type of pacemaker, the mode of sensing and firing of the pacemaker, and the placement require consultation with your cardiologist.

The DOs
  • Seek cardiology advice on pacemaker insertion. Decisions regarding whether the pacemaker wires should be placed only in the atrium or only in the ventricle or in both chambers depends on the type of sinus node dysfunction that exists. Other decisions regarding the use of certain pacemaker sensors (e.g., pacemakers sensing respiratory rate or oxygen level) need to be made.
The DON'Ts
  • Don't forget that the pacemaker serves to prevent the heart from going too slow; it has nothing to do with preventing the heart from going too fast. You may have to be on other medicines to prevent the heart from going too fast. In addition, many patients with sick sinus syndrome go into a rhythm called atrial fibrillation. A patient with atrial fibrillation carries a five times greater chance of stroke when compared with a patient who is not in atrial fibrillation. This is due to small blood clots that can form in the atria of patients in atrial fibrillation. To prevent this, your physician may recommend long-term use of a blood thinner called warfarin.
When to Call Your Doctor
  • If you are experiencing palpitations, dizziness, or fainting spells.
  • If you are taking warfarin and you are noticing blood in the stools or urine. Warfarin is a blood thinner and can lead to easy bleeding.
  • If you need a referral to a electrophysiologist (EPS);(a physician specializing in the electrical activity of the heart).
For More Information
American Heart Association National Center
7272 Greenville Ave.
Dallas, Texas 75231


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