Sick sinus syndrome
Sick sinus syndrome is another term for sinus node disease (alternately, sinus node dysfunction). It is a condition that arises in the heart. Sick sinus syndrome is a collection of symptoms, all of which stem from a malfunctioning sinus node (sinoatrial node).
Definition & Facts
The sinus node is a collection of special cell tissue located in the heart. Often referred to as the heart's pacemaker, the node is responsible for emitting electrical impulses to control the heartbeat. In a healthy heart, these impulses happen at regular intervals, producing a normal heartbeat. In a heart affected with sinus node disease, the impulses are irregularly timed, which can result in irregular heartbeat (cardiac arrhythmia).
Symptoms & Complaints
- Bradycardia (pulse is slower than normal).
- Heart palpitations (rapid, pounding, fluttering heartbeat).
- Trouble breathing.
- Light-headedness or dizziness.
- Fainting episodes.
- Angina (pains in the chest).
Many people who are eventually diagnosed with sick sinus syndrome have only mild (if any) symptoms in the early stages. Eventually, the symptoms increase, and this is positively correlated with age.
To date, researchers still are not clear on the exact causes of sick sinus syndrome. What they do know is that sick sinus syndrome can be traced to other health issues. Some health issues that are now known to contribute to the possibility of developing sick sinus syndrome include the following:
- Prior heart attack and/or prior heart surgery.
- Prior history of taking drugs to treat high blood pressure or medications to treat heart disease.
- Diagnosis of sleep apnea or ongoing sleep difficulties.
- Diagnosis of heart disease.
- Diagnosis of hyperkalemia (excess of potassium in blood).
- Diagnosis of hemochromatosis (excess of iron in blood).
- Prior exposure to diphtheria.
- Diagnosis of muscular dystrophy.
- Diagnosis of amyloidosis.
In addition, any incident that has caused scarring or damage to the heart mechanism or cardiac muscles will increase the risk of developing sick sinus syndrome. While sick sinus syndrome can occur even in infants, the natural aging process increases the risk of developing sick sinus syndrome.
Diagnosis & Tests
The testing process usually begins with a test called an electrocardiogram or ECG. There are several different ECG tests that may be used to produce a definitive diagnosis.
- Standard ECG. The standard ECG test is done in the doctor's office. Non-invasive electrodes are placed on the body at certain key points to record a log of the heart's electrical activity.
- Holter monitor. With this longer ECG test, an electrode-based monitoring system is worn for 24 to 48 hours to record a longer log of heart activity.
- Cardiac event recorder test. This ECG test can last up to 30 days to record a comprehensive log of heart activity.
- Implantable loop recorder. With this test, a tiny recording device is implanted beneath the skin to monitor heart activity continuously. It is designed to capture erratic or atypical heart activity that occurs less frequently but is still considered to be a health risk.
Treatment & Therapy
Typically, the treating physician will first screen the person to see if any medications may be causing the heart irregularities. If this is the case, ceasing or lessening the dose can ease the symptoms. If no medication interactions are discovered, doctors may recommend prescription medications or the implantation of a artificial cardiac pacemaker. Sometimes both of these options are used concurrently on an ongoing basis to ensure the heartbeat stays normal. The most commonly prescribed medications include blood thinners and anti-arrhythmia medicines. The most common surgical solutions include the following:
- Pacemaker implantation. Different types of heartbeat regulators (pacemakers) can be implanted to regulate heart beat. This is one of the main ways sick sinus syndrome is treated.
- AV node ablation. A catheter conducting radio frequencies is used to target tissue around the AV (atrioventricular) node. It is a form of radiofrequency ablation.
Prevention & Prophylaxis
By refraining from tobacco use, eating a healthy diet, getting rest and regular exercise, drinking alcohol only in moderation and keeping stress to a minimum, there is less likelihood the heart will sustain the type of damage that is known to lead to sick sinus syndrome.
It is also vital to get regular health checkups, especially with advanced age, as these checkups can detect early warning signs of the onset of sinus node disease. With conscious, careful living, regular health checkups, and prompt treatment of any emerging heart and other related medical issues, it is possible to reduce the risk of developing sick sinus syndrome.