Ask the Doctors

Dear Doctor: What is sick sinus syndrome? Is a pacemaker the only cure? My grandmother was just diagnosed with it but, at age 94, has refused to even consider a pacemaker.

Dear Reader: Sick sinus syndrome refers to a problem with the sinoatrial node, or SA node. This is an area of highly specialized cells that controls the heart rate. Located in the right atrium, which is the upper right chamber of the heart, the SA node produces electrical impulses that start each heartbeat. When someone has sick sinus syndrome, it means that the SA node, the heart’s intrinsic pacemaker, is not functioning properly.

Either the signals it’s sending are erratic, or the impulses are disrupted and don’t reach the rest of the heart. In someone with sick sinus syndrome, the heartbeat is often too slow, which is known as bradycardia. The condition may also cause tachycardia, which is a heartbeat that is too fast. In some individuals, the heart will cycle between rhythms that are too slow and too fast. The condition can also be marked by long pauses in which the heart remains still as beats are skipped altogether. And while the SA node directly controls only the start of each heartbeat, due to the way the heart’s electrical system is interlinked, a malfunction disrupts the optimal functioning of all four of the chambers of the heart.

Not everyone experiences symptoms as a result of the condition. When they do occur, they can include feeling lightheaded or dizzy, which can sometimes lead to fainting. There may be a fluttery sensation in the chest, or a feeling of pounding heartbeats. Because the condition prevents optimal blood flow, it can result in fatigue, memory problems and confusion. It will also often lead to problems during exercise or exertion, such as chest pain or labored breathing. Although sick sinus syndrome can occur at any age, it is most common among the elderly and is believed to be the result of age-related changes to the heart.

There is no known cure for sick sinus syndrome. For most individuals with the condition, a pacemaker is eventually needed to regulate the heartbeat. This is a medical device that is surgically implanted in the chest and, through the use of sensors and electrical pulses, monitors and then regulates the heartbeat. The sensors let the pacemaker know when the heart’s rhythm goes awry, and the device then sends an electrical pulse to prompt the heart back into a normal rhythm.

The type of pacemaker a patient needs depends on the type of heart irregularity he or she has. The technology has been advancing, with the newest pacemakers now the size of a nickel. It’s estimated that sick sinus syndrome -- which is found in 1 out of every 600 cardiac patients over the age of 65 -- is the reason behind at least half of all pacemaker implants in the United States.

Regarding your grandmother’s refusal of a pacemaker, it’s not unusual of people of advanced years to say no to medical interventions. The most you can do is make sure she fully understands the potential benefits and risks of the device.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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