Sick Sinus Syndrome is an umbrella term that comprises of a group of disorders caused by the malfunctioning of the sinus node. Also referred to as sinus node dysfunction or sinus node disease, this is a condition chiefly describing the inability of the heart's natural pacemaker (i.e., sinus node) to create a heart rate that's appropriate for the body's needs.
In a general person, the heartbeat starts in an area in the top chambers of the heart (i.e., atria). This area is what we call the heart's pacemaker. It is also called the sinoatrial node, sinus node or SA node and it consists of specialized cells. The main function of the SA node is to create a steady pace of electrical impulses that in turn keeps the heart beat steady and regular. This pace mainly changes depending on the activity, emotions, rest and other factors.
A person suffering from sick sinus syndrome has abnormally paced electrical impulses that causes the heart to beat too fast, too slow, often interrupted by long pauses — or an alternating combination of these rhythm problems. Although this condition is uncommon, it isn’t rare and the risk increases with developing age. This condition may eventually make a person use a pacemaker to keep the heart in a regular rhythm.
Sick Sinus Syndrome may occur due to a number of factors, including:
- Damage or scarring of the heart’s electrical system, caused by a disease or other health condition
- Scar tissue from a past heart surgery, especially in case of children
- Certain medications, like calcium channel blockers, beta blockers or antiarrhythmics that are used to treat high blood pressure, heart disease, and other conditions
- The breakdown of heart muscle due to age
- Tachycardias that arise in the upper chambers of the heart
In case the SA node isn’t functioning properly, it may eventually give rise to multiple disorders resulting in a heart beat or rhythm that will be different depending on the specific electrical activity at the sinus node.
The disorders that characterize different types of SSS include:
Sinus Bradycardia: In this case, the heart beats very slowly, less than 60 beats per minute.
Sinus Arrest or Sinus Pause: The sinus node in this condition temporarily stops working or pauses, causing a change in the heart’s beating.
Sinoatrial Block: Here, the sinus node impulse is blocked from reaching the atria, (i.e., the two upper chambers of the heart) on time.
Tachycardia-Bradycardia Syndrome: Also known as Tachy-Brady syndrome, the heart in this case alternates between a very slow and very fast beat.
Certain causative factors that increase the risk of Sick Sinus Syndrome include:
Age: The incidence of SSS increases with older age
Health Conditions: The risk of SSS increases if the person has a history of congenital heart disease (even with repairs, the heart is still weak), history of thyroid disease or sleep apnea disorder. Even conditions like high blood pressure, or high cholesterol makes a person prone to SSS.
Heart Problem: If the coronary artery becomes clogged, and blood flow to the heart is restricted, it may lead to SSS.
Obesity: Excessive body weight and lack of exercise may often aggravate the chances of getting diagnosed with SSS.
A mild condition of SSS may often not exhibit any characteristic symptoms. But in case the heart is compromised, signs and symptom my quickly become apparent. These include:
- Difficulty breathing
- Chest pain or angina
- Mental confusion
- Memory problems
- Fainting sensations
- Dizziness or light headedness
- Palpitations (abnormal heart beats)
- Very slow pulse (bradycardia)
- Disrupted sleep
- Exercise intolerance
- Shortness of breath
If the condition is not addressed on time due to the incapability of the heart's natural pacemaker, it can often quickly lead to:
- Heart failure
- Atrial fibrillation
- Cardiac arrest
Diagnosis And Treatment
On noticing any of the following above-mentioned symptoms, do rush to a medical facility at the earliest to get diagnosed properly. The doctor usually does a thorough physical checkup, acknowledges the patient’s past medical history and may conduct the following diagnostics:
Electrocardiogram (ECG): It records the electrical activity of the heart at that moment in time.
Holter Monitor: A pocket monitor that records the heart's activity for 24 to 72 hours.
Event Recorder: A portable ECG, that can be worn up to a month, and mainly enables the doctor to correlate symptoms and heart rhythm.
Echocardiogram: It gives an ultrasonic image of the heart.
Transesophageal echocardiogram (TEE): An ultrasound technique that gives a clear image of the heart size, the contracting strength of the heart, and any damage to the heart muscle.
Implantable loop recorder: A small ECG device implanted just under the skin of your chest and mainly used to record continuous electrical activity of the heart for a long duration.
The primary treatment of SSS chiefly aims to reduce or eliminate the symptoms so as to manage and treat any other health conditions that may be contributing to the sick sinus syndrome. This includes:
- Putting in a permanent artificial pacemaker
- AV node ablation or Cardiac ablation (in case of rapid heart beat)