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Sick sinus syndromeDefinition Sick sinus syndrome is a collection of heart rhythm disorders that include:
Causes, incidence, and risk factors Overall, sick sinus syndrome is relatively uncommon. Among the various forms of sick sinus syndrome, sinus bradycardia occurs more often than the other types. Tachycardias that arise from the upper chambers of the heart (atrial fibrillation, atrial flutter/tachycardia, and supraventricular tachycardia) are also common forms. Typically, a period of elevated heart rates is followed by very slow heart rates when the tachycardia ends. Abnormal heart rhythms are often worsened by medications such as digitalis, calcium channel blockers, beta-blockers, and anti-arrhythmics. Disorders that cause scarring, degeneration, or damage to the conduction system of the heart can cause sick sinus syndrome. Sick sinus syndrome usually occurs in people older than 50, where the cause is often a non-specific, scar-like degeneration of the heart's conduction system. In children, a common cause of sick sinus syndrome is heart surgery, especially to the atria (upper chambers). Coronary artery disease, high blood pressure, and aortic and mitral valve diseases may be associated with sick sinus syndrome, although those diseases may have nothing to do with the syndrome. Symptoms
Signs and tests The symptoms are non-specific and may mimic other disorders. The patient's heart rate may be very slow at any time or after termination of an episode of tachycardia. Blood pressure may be normal or low. Sick sinus syndrome may cause symptoms of heart failure to occur or worsen. The diagnosis of sick sinus syndrome includes a history of symptoms that occur only during episodes of arrhythmia. However, this correlation often is difficult to prove. An ECG may show various arrhythmias characteristic of sick sinus syndrome. Exercise testing has not proven particularly effective as a screening tool. Holter monitoring is a sensitive tool to diagnose sick sinus syndrome because of the episodic nature of the disorder. Extreme slowing of the heart rate and prolonged pauses may be seen during Holter monitoring along with episodes of non-sustained atrial tachycardias. An EPS (intracardiac electrophysiology study) is a very specific test for this disorder, although it is often unable to confirm the diagnosis. Treatment If the disorder is not causing symptoms, treatment may not be necessary. Your doctor may evaluate any medications you are taking to make sure they are not worsening your condition. Do not stop taking any medication unless instructed by your doctor. A permanent implanted pacemaker may be necessary when it has been established that the symptoms are related to bradycardia (slow heart rate). Any associated tachycardia (a fast heart rate) may be treated with medications after the person is protected from symptomatic bradycardia by a permanent implanted pacemaker. Sometimes an invasive, cauterization-like catheter procedure, called radiofrequency ablation may be used to eliminate tachycardias. Expectations (prognosis) This syndrome is slowly progressive. As long as the person remains without symptoms, no treatment is necessary. If a permanent pacemaker is implanted, the long-term outlook is excellent. Complications
Calling your health care provider Call for an appointment with your health care provider if you experience light-headed spells, episodes of passing out, palpitations, or other symptoms. Prevention It may help to treat related disorders. You may need to avoid some medications, based on the guidance of your physician. Many times, the condition is not preventable. Page Content: Bradycardia-tachycardia syndrome; Sinus node dysfunction ; sinus node dysfunction; tachycardia bradycardia syndrome |
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